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{{SI}}
{{Infra-Hisian Block}}
{{CMG}}
{{CMG}}; '''Associate Editor-In-Chief:''' {{S.M.}}


==Overview==
==Overview==
Infra-Hisian blocks are defined as impaired conduction in the [[electrical system of the heart]] that occur below the [[AV node]].
Infra-Hisian [[Blocking (statistics)|block]] is defined as an impaired [[Conduction System|conduction]] in the [[electrical system of the heart]] that occurs below the [[atrioventricular node]].
 
==Historical Perspective==
 
*In 1899, Dr. [[Wenckebach]] described the progressive delay between [[atrial]] and [[ventricular]] [[contraction]] and the [[Eventuality (Phrenology)|eventual]] [[failure]] of a [[P wave]] to [[Reachback|reach]] the [[ventricles]].
*Dr. Mobitz then [[Division (biology)|divided]] the [[second degree AV block]] into two subtypes.
*In 1905, Dr. John Hay [[Discovery Investigations|discovered]] the [[Second degree AV block|second degree of AV block]].<ref name="pmid110971382">{{cite journal| author=Upshaw CB, Silverman ME| title=John Hay: discoverer of type II atrioventricular block. | journal=Clin Cardiol | year= 2000 | volume= 23 | issue= 11 | pages= 869-71 | pmid=11097138 | doi=10.1002/clc.4960231118 | pmc=6655013 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11097138  }}</ref>
* While Dr. Hay was [[Examination|examining]] a [[patient]] who complained of a [[slow pulse]] and had [[dyspnea on exertion]] for more than 2 [[Year|years]], he noticed the [[heart rate]] [[Drop (liquid)|dropping]] from 80 [[Beats per minute|beats]] to 40 [[beats per minute]].
* Dr. Hay noted the [[A wave|a waves]] and the [[arterial]] [[pulse]] to remain [[Stability|stable]] in the beginning. However, recording the [[Pulse|pulsation]] several [[Timespan|times]] [[Result|resulted]] in "[[A wave|a" waves]] that were not followed by c [[wave]]. The [[A wave|a]]-c [[jugular]] [[wave]] [[Interval (mathematics)|interval]] was [[Usage analysis|used]] as a [[measurement]] of [[Atrioventricular|AV]] [[Conduction System|conduction]].
* Dr. Hay figured out that the pause following [[a wave]] was due to [[failure]] of [[ventricular]] [[muscles]] to [[Response element|respond]] to a [[stimulus]].


==Classification==
==Classification==
Infrahisian block describes block of the distal conduction system. Types of infrahisian block include:
 
*[[Type 2 second degree heart block]] ([[Mobitz II]])
* Infra-hisian [[Blocking (statistics)|block]] [[Description logic|describes]] the [[Blocking (statistics)|block]] of [[distal]] [[Conduction system disease|conduction system]].
*[[Left bundle branch block]]
* Types of infra-hisian [[Blocking (statistics)|block]] are shown in the following table:
 
{| class="wikitable"
|+Classification of Infra-Hisian Block
!style="background: #4479BA; width: 200px;" | {{fontcolor|#FFF|Types of Infra-Hisian Block}}
!style="background: #4479BA; width: 200px;" | {{fontcolor|#FFF|Sub-type}}
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Type 2 second degree heart block]] ([[Mobitz II]])
|_
|-
| rowspan="2" style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Left bundle branch block]]
|[[Left anterior fascicular block]]
|-
|[[Left posterior fascicular block]]
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Right bundle branch block]]
|_
|}
 
* Out of all these types of infra-hisian [[Blocking (statistics)|block]], [[Mobitz II]] [[heart block]] is considered as the most [[Importance sampling|important]] because of the [[Possibility theory|possible]] progression to a [[complete heart block]].
 
==Pathophysiology==
===Normal Cardiac Conduction===
# The [[normal]] [[cardiac]] [[Conduction System|conduction]] proceeds in a way so as to allow [[Time constant|time]] for the [[atrium]] to [[Relaxation|relax]] during [[atrial]] [[diastole]].
# The [[electrical]] [[Impulse (psychology)|impulse]] [[Generation|generated]] in the [[SA node]] travels through the [[Internodal segment|internodal]] pathways towards the [[AV node]].
# The [[Conduction System|conduction]] through the [[Atrioventricular node|AV node]] is [[Slow|slowed]] down as it travels through it. This decrease in [[velocity]] of [[Conduction System|conduction]] allows [[Time constant|time]] for the [[atrium]] to [[Contraction|contract]] ahead of the [[ventricle]] so that the [[blood]] from the [[atria]] can fill up the [[ventricles]] through the [[atrioventricular valves]].
# As the [[Impulse (psychology)|impulse]] [[Flow|flows]] through the [[Compact tissue|compact]] [[Atrioventricular node|AV node]], it rapidly [[Conductance|conducts]] through the [[ventricular]] [[myocardial]] [[Cells (biology)|cells]]. Once the [[depolarization]] is complete, the [[ventricle]] [[Relaxation|relaxes]] during [[diastole]] in [[Preparation (dental)|preparation]] for the next [[Impulse (psychology)|impulse]].
 
===Anatomy===
* The [[Conduction System|conduction system]] of [[heart]] consists of [[Specialize|specialized]] [[Cells (biology)|cells]] designed to [[Conductance|conduct]] [[electrical]] [[Impulse (psychology)|impulse]] faster than the surrounding [[myocardial]] [[Cells (biology)|cells]].
*[[Anatomical|Anatomically]], the [[Atrioventricular node|AV node]] is [[Division (biology)|divided]] into three [[Region of interest|regions]] as follows:
**'''[[Transitional cell]] zone''': This is the [[Region of interest|region]] where the [[Internodal segment|internodal]] [[atrial]] pathways merge with the [[Compact tissue|compact]] [[Atrioventricular node|AV node]].
**'''[[Compact tissue|Compact]] [[Atrioventricular node|AV node]]''': This [[Region of interest|region]] is [[Location parameter|located]] at the [[apex]] of the [[triangle of Koch]], which is formed by the [[ostium]] of [[coronary sinus]], [[tricuspid]] [[Annulus (mycology)|annulus]] and the [[tendon of Todaro]].
**'''[[Penetration|Penetrating]] portion of the [[Atrioventricular|AV]] [[Bundle branch|bundle]]''': This [[Region of interest|region]] enters the [[tendon of Todaro]] and runs within the [[fibrous]] [[body]] of the [[interventricular septum|membranous interventricular septum]] and eventually [[Division (biology)|divides]] at the crest of the [[interventricular septum|muscular interventricular septum]] into right and left branches.
* The [[Left bundle branch block|left bundle branch]] [[Penetrance|penetrates]] the [[Membrane|membranous]] portion of the [[interventricular septum]] and [[Division (biology)|divides]] into several smaller branches. Parts of the [[Left bundle branch block|left bundle branch]] include a pre-[[Division (biology)|divisional]] [[Segment (linguistics)|segment]], [[anterior]] [[fascicle]]/hemibundle and [[posterior]] [[fascicle]]/hemibundle. Rarely a [[median]] [[fascicle]] is [[Presenting symptom|present]] in some [[Heart|hearts]].
** The [[anterior]] [[fascicle]] supplies the [[anterior]] [[papillary muscle]] and the [[Purkinje System|Purkinje network]] of the [[Anterior|antero]]-[[lateral]] [[Surface anatomy|surface]] of the [[left ventricle]].
** The [[posterior]] [[fascicle]] supplies the [[posterior]] [[papillary muscle]] and the [[Purkinje System|Purkinje network]] of the [[Posterior|postero]]-inferior [[Surface anatomy|surface]] of the [[left ventricle]].
**[[Left bundle branch block|Left bundle branch]] receives its [[blood]] supply from [[left anterior descending artery]].
{|
|
[[Image:Conduction system of the heart.png|thumb|200px|none|Conduction system of the heart]]
|
[[Image:AV node.png|thumb|500px|none|Structure of the heart's conduction system]]
|
|}
 
===Pathophysiology of Mobitz type II second degree AV block===
* [[Mobitz type II]] [[second degree AV block]] is [[Characterization (mathematics)|characterized]] by a [[PR interval]] that remains unchanged with occasional [[Drop (liquid)|dropped]] [[Beats per minute|beats]] prior to a [[P wave]] that [[Failure|fails]] to [[conduct]] to the [[ventricles]] as [[Comparability|compared]] to the gradually [[Prolonged PR-interval|prolonging PR interval]] in [[Mobitz type I]].
*[[ECG]] findings include intermittently non-[[Conduct|conducted]] [[P wave]]s not preceded by [[PR prolongation]] and not followed by [[PR interval|PR]] [[shortening]].
*It almost always [[Result|results]] from a [[Conduction system disease|disease of the conduction system]] below the [[Level of measurement|level]] of [[Atrioventricular node|AV node]], occurring in the [[bundle of His]] in approximately 20% of the [[Case-based reasoning|cases]] and in the [[Bundle branch|bundle branches]] in the remainder.
*[[Dependent variable|Depending]] upon the [[Location parameter|location]] of the [[Heart block|block]], [[patients]] having [[bundle branch]] involvement also have [[axis]] shifts and [[QRS]] widening.
*At least two-thirds of the [[patients]] with [[Mobitz type II]] [[second degree AV block]] have [[Bifascicular block|bifascicular]] or even [[Trifascicular heart block|trifascicular]] [[disease]].<ref name="pmid6544636">{{cite journal| author=Puech P, Wainwright RJ| title=Clinical electrophysiology of atrioventricular block. | journal=Cardiol Clin | year= 1983 | volume= 1 | issue= 2 | pages= 209-24 | pmid=6544636 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=6544636  }}</ref><ref name="pmid8445186">{{cite journal |vauthors=Wogan JM, Lowenstein SR, Gordon GS |title=Second-degree atrioventricular block: Mobitz type II |journal=J Emerg Med |volume=11 |issue=1 |pages=47–54 |date=1993 |pmid=8445186 |doi=10.1016/0736-4679(93)90009-v |url=}}</ref>
*In the presence of 2:1 [[Atrioventricular block|AV block]], [[Mobitz type I]] and [[Mobitz type II AV block|Mobitz type II]] [[second degree AV block]] cannot be [[Differentiate|differentiated]] on the basis of [[electrocardiographic]] findings. In such cases, every other [[P wave]] is non-[[Conduct|conducted]] without a chance to [[Observation|observe]] the [[constant]] [[PR interval]] that is [[Characteristic impedance|characteristic]] of [[Mobitz type II AV block|Mobitz type II]] [[second degree AV block]].
*The [[Conduction System|conduction]] delay seen in [[Mobitz type II AV block|Mobitz type II]] [[second degree block]] is almost always at the infra-[[Nodal (protein)|nodal]] level involving the [[distal]] [[Conduction system disease|conduction system]] ([[His bundle]] (20%), [[Bundle branch|bundle branches]] or/and [[fascicles]]).
 
*Although often both the [[Term logic|terms]], [[Infranodal Wenkebach-type block|infranodal block]] or infrahisian [[Heart block|block]] are applied to [[Mobitz type II]] [[second degree AV block]], they are not [[Synonymous substitution|synonymous]] with it.
 
:*[[Infranodal Wenkebach-type block|Infranodal]] [[Heart block|block]] and [[infra-Hisian block]] are [[Term logic|terms]] which [[Reference|refer]] to the [[anatomic]] [[Location parameter|location]] of the [[Heart block|block]], whereas
:*[[Mobitz II]] [[Reference|refers]] to an [[electrocardiographic]] [[pattern]] [[Association (statistics)|associated]] with [[Heart block|block]] at these [[Leveling effect|levels]].<ref name="pmid29850368">{{cite journal |vauthors=Li X, Xue Y, Wu H |title=A Case of Atrioventricular Block Potentially Associated with Right Coronary Artery Lesion and Ticagrelor Therapy Mediated by the Increasing Adenosine Plasma Concentration |journal=Case Rep Vasc Med |volume=2018 |issue= |pages=9385017 |date=2018 |pmid=29850368 |pmc=5933017 |doi=10.1155/2018/9385017 |url=}}</ref>
 
===Pathophysiology of LBBB===
* Unlike [[right bundle branch block]] ([[RBBB]]), [[left bundle branch block]] completely modifies the way of [[depolarization]] of the [[Electrical conduction system of the heart|conduction system of the heart]].
*In [[Left bundle branch block|LBBB]] the [[Activation energy|activation]] of [[interventricular septum]] is from right to left due to uninterrupted [[Conductance|conduction]] in the [[Right bundle branch block|RBB]].
* Then the [[electrical]] [[Impulse (psychology)|impulse]] propagates [[inferiorly]] to the left [[Result|resulting]] in delayed [[depolarization]] and [[Activation energy|activation]] of the [[left ventricle]] especially the left [[lateral]] wall.<ref name="pmid17385703">{{cite journal |author=Francia P, Balla C, Paneni F, Volpe M |title=Left bundle-branch block--pathophysiology, prognosis, and clinical management |journal=Clinical Cardiology |volume=30 |issue=3 |pages=110–5 |year=2007 |month=March |pmid=17385703 |doi=10.1002/clc.20034 |url=}}</ref>
* In [[Left bundle branch block|LBBB]], the right to left [[Activation energy|activation]] of the [[septum]] [[causes]] a small negative deflection ([[Q wave]]) in [[lead]] [[V1-morph|V<sub>1</sub>]] and a [[positive]] deflection ([[R wave]]) in [[lead]] V<sub>6</sub>.
*The [[right ventricle]] [[Depolarization|depolarizes]] earlier than the [[left ventricle]] giving an [[R wave]] in [[lead]] [[V1-morph|V<sub>1</sub>]] and an [[S wave]] in [[lead]] V<sub>6</sub>.
*Subsequent delayed [[depolarization]] of the [[left ventricle]] [[Result|results]] in an [[S wave]] in [[lead]] [[V1-morph|V<sub>1</sub>]] and another [[R wave]] in [[lead]] V<sub>6</sub>.
 
===Pathophysiology of RBBB===
*[[Right bundle branch block]] occurs when the [[electrical]] [[Impulse (psychology)|impulse]] is not [[Conductance|conducted]] along the [[Right bundle branch block|right bundle branch]].
* As the [[Conduction System|conduction]] along the [[Left bundle branch block|left bundle branch]] remains unaffected, the [[electrical]] [[Impulse (psychology)|impulse]] [[Travel medicine|travels]] [[Normal|normally]] within the [[septum]] from left to right.
* However, the [[right ventricular]] [[contraction]] occurs [[Comparability|comparatively]] [[Slow|slowly]] giving the [[Characteristic impedance|characteristic]] 'M' [[pattern]] on the [[electrocardiogram]].
 
====Genetics====
*[[Familial]] [[Case-based reasoning|cases]] of [[right bundle branch block]] have been [[Observation|observed]] in 4 Lebanese [[Family|families]] and the [[Abnormality (behavior)|abnormality]] was mapped to [[chromosome 19]].
* There is a [[subset]] of [[patients]] with [[Brugada syndrome]] who have [[mutations]] in [[SCN5A]], the [[gene]] [[Encoding (memory)|encoding]] for the [[Voltage-gated sodium channel|voltage-gated cardiac sodium channel]].
 
====Associated Syndromes====
*[[Duchenne muscular dystrophy]]
*[[Myotonic dystrophy]]: Other [[EKG]] findings include:
**[[First-degree AV block]]
**[[Left anterior fascicular block]]
**[[Left anterior fascicular block]]
**[[Left posterior fascicular block]]
**[[Intraventricular conduction delay]]
*[[Right bundle branch block]]
**[[Arrhythmias]]
*[[Stokes-Adams attacks]]
*[[Kearns-Sayre Syndrome]]
*[[Brugada syndrome]]
 
====Pseudo Right Bundle Branch Block====
'''[[Brugada syndrome]]:'''
 
*[[Brugada syndrome]] is due to a [[channelopathy]] [[Mediated transport|mediated]] by the [[SCN5A]] [[gene]].
* The [[Right bundle branch block|RBBB]] [[pattern]] seen in [[patients]] of [[Brugada syndrome]] is not actually [[Right bundle branch block|RBBB]] but instead it is due to a [[repolarization]] [[Abnormality (behavior)|abnormality]]. Therefore, the [[Right bundle branch block|RBBB]] like [[pattern]] seen in [[Brugada syndrome]] is [[Reference|referred]] to as a 'pseudo [[right bundle branch block]]'.
*[[EKG]] findings include [[ST-segment elevation]] in [[Lead|leads]] [[V1-morph|V1]]-[[V3 loop|V3]].
*[[Cocaine]] [[Consumer/Survivor/Ex-Patient Movement|consumption]] and/or the [[Usage analysis|use]] of the [[antiarrhythmic]] [[propafenone]] may unmask the [[EKG]] findings seen in [[Brugada syndrome]].<ref name="pmid23613002">{{cite journal |author=Yildiz BS, Gungor H, Gul I, Bilgin M, Zoghi M, Akilli A |title=Is a drug-challenge test with propafenone adequate to exclude Brugada syndrome? |journal=Cardiovascular Journal of Africa |volume=24 |issue=2 |pages=e4–6 |year=2013 |pmid=23613002 |doi=10.5830/CVJA-2012-068 |url=}}</ref>
 
==Causes==
===Mobitz type II second degree AV block causes===
 
*[[Mobitz type II AV block|Mobitz type II]] [[second degree AV block]] is [[Rare|rarely]] seen in the [[patients]] without any [[Underlying representation|underlying]] [[heart disease]].
*The most common [[causes]] of [[Mobitz type II]] [[second degree AV block]] include:
** Reversible [[causes]] (both [[Pathological|pathologic]] and [[iatrogenic]])
**[[Idiopathic]] [[causes]] similar to other [[Degree (angle)|degrees]] of [[Atrioventricular block|AV block]] such as [[idiopathic]] progressive [[Cardiac conduction disorder|cardiac conduction disease]] with [[myocardial]] [[fibrosis]] and/or [[sclerosis]] [[Affect|affecting]] the [[Conduction system disease|conduction system]].
 
* Details of all the possible [[etiologies]] are given in the table below:
 
{| class="wikitable"
|+Major reversible causes of atrioventricular (AV) block
! colspan="2" style="background: #4479BA; width: 200px;" | {{fontcolor|#FFF|'''Physiologic and pathophysiologic'''}}
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |Increased [[vagal]] [[Tone (linguistics)|tone]]
|
* Also known as hypervagotonia
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Ischemic heart disease]]
|
*[[Acute]] or [[chronic]] [[myocardial infarction]]/[[ischemia]] involving the [[Conduction system disease|conduction system.]]
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |Progressive [[Cardiac conduction disorder|cardiac conduction system disease]]
|[[Association (statistics)|Associated]] with:
 
*[[Calcification]] in [[Lev's disease]]
*[[Fibrosis]] and/or [[sclerosis]] in [[Lenegre's Disease|Lenegre's disease]]
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Infections]]
|
*[[Viral myocarditis]]
*[[Lyme carditis]]
*[[Endocarditis]] with [[abscess]] [[Formation matrix|formation]]
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Cardiomyopathy]]
|[[Infiltration (medical)|Infiltrative]] [[Process (anatomy)|processes]] such as:
 
*[[Sarcoidosis]]
*[[Hemochromatosis]]
*[[Amyloidosis]]
*[[Malignancy]]
 
Other non-[[Ischemic cardiomyopathy|ischemic cardiomyopathies]] include:
 
*[[Idiopathic]]
*[[Infectious]]
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Congenital]] [[Atrioventricular block|AV block]]
|
* It is [[Related changes|related]] to [[Structural biology|structural]] [[congenital heart disease]]
*It occurs as a part of [[neonatal lupus syndrome]]
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |Other [[Reversible cell|reversible]] [[causes]]
|
*[[Hyperkalemia]]
* Severe [[Hypothyroidism|hypo]]- or [[hyperthyroidism]]
*[[Degenerative]] [[Neuromuscular disease|neuromuscular diseases]]
*[[Trauma]]
|-
| colspan="2" style="background: #4479BA; width: 200px;" | {{fontcolor|#FFF|'''Iatrogenic'''}}
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Drugs]] (altering [[Conduction System|conduction]] through [[Atrioventricular node|AV node]])
|
*[[Beta-blockers]]
*[[Digoxin]]
*[[Calcium channel blockers]]
*[[Adenosine]]
*[[Antiarrhythmic drugs]]
|-
|style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Cardiac surgery]]
|
* Post [[valvular]] [[surgery]]
* Post-[[Surgery|surgical]] [[Correction (newspaper)|correction]] of [[congenital heart disease]]
|-
| colspan="2" style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Catheter ablation]] of [[arrhythmias]]
|-
| colspan="2" style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |[[Alcohol septal ablation]] for [[hypertrophic cardiomyopathy]]
|-
| colspan="2" style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |Transcatheter [[Closure (psychology)|closure]] of [[ventricular septal defect]]
|-
| colspan="2" style="padding: 5px 5px; background: #DCDCDC; font-weight: bold" |Post-[[transcatheter aortic valve implantation]]
|}
 
===Life Threatening Causes===
[[Life]]-threatening [[conditions]] can [[result]] in death or permanent [[disability]] within 24 hours if left untreated.<ref name="pmid29493981">{{cite journal |vauthors=Mangi MA, Jones WM, Napier L |title= |journal= |volume= |issue= |pages= |date= |pmid=29493981 |doi= |url=}}</ref>
 
* [[Acute myocardial infarction]]<ref name="pmid30227965">{{cite journal |vauthors=Misumida N, Ogunbayo GO, Kim SM, Abdel-Latif A, Ziada KM, Elayi CS |title=Frequency and Significance of High-Degree Atrioventricular Block and Sinoatrial Node Dysfunction in Patients With Non-ST-Elevation Myocardial Infarction |journal=Am. J. Cardiol. |volume=122 |issue=10 |pages=1598–1603 |date=November 2018 |pmid=30227965 |doi=10.1016/j.amjcard.2018.08.001 |url=}}</ref><ref name="pmid23224264">{{cite journal |vauthors=Barold SS, Herweg B |title=Second-degree atrioventricular block revisited |journal=Herzschrittmacherther Elektrophysiol |volume=23 |issue=4 |pages=296–304 |date=December 2012 |pmid=23224264 |doi=10.1007/s00399-012-0240-8 |url=}}</ref>
* [[Acute rheumatic fever]]
* [[Bacterial endocarditis]]
* [[Myocarditis]]
* [[hypothermia|Severe hypothermia]]
 
===Common Causes===
* [[Acute rheumatic fever]]
* [[Bacterial endocarditis]]<ref name="pmid27585419">{{cite journal |vauthors=Kamatani T, Akizuki A, Kondo S, Shirota T |title=Second-Degree Atrioventricular Block Occurring After Tooth Extraction |journal=Anesth Prog |volume=63 |issue=3 |pages=156–9 |date=Fall 2016 |pmid=27585419 |pmc=5011958 |doi=10.2344/15-00042.1 |url=}}</ref>
* [[aortic stenosis|Calcific aortic stenosis]]
* [[Digoxin]]
* [[Dilated cardiomyopathy]]
* [[Diltiazem]]
* [[Vasovagal syncope#Cardioinhibitory Response|Enhanced vagal tone]]
* [[HCM]]
* [[Hypertension]]
* [[Iatrogenic]] after [[Surgery|surgical]] [[Correction (newspaper)|correction]] of [[VSD]], [[tetralogy of Fallot]], and [[endocardial cushion defect]]
* [[ST elevation MI|Inferior ST elevation MI]]
* [[mitral valve sclerosis|Massive calcification of the mitral annulus]]
* [[Myocarditis]]
* [[PR interval|Normal variants]]<ref name="pmid8445186">{{cite journal |vauthors=Wogan JM, Lowenstein SR, Gordon GS |title=Second-degree atrioventricular block: Mobitz type II |journal=J Emerg Med |volume=11 |issue=1 |pages=47–54 |date=1993 |pmid=8445186 |doi=10.1016/0736-4679(93)90009-v |url=}}</ref>
* [[chest trauma|Penetrating and non-penetrating trauma of the chest]]
* [[Lev's disease|Sclerodegenerative disease of the electrical conduction system]]
* [[Verapamil]]
* [[Beta blocker|β blockers]]
 
===Causes by Organ System===
{|style="width:80%; height:100px" border="1"
|style="height:100px"; style="width:25%" border="1" bgcolor="LightSteelBlue" | '''Cardiovascular'''
|style="height:100px"; style="width:75%" border="1" bgcolor="Beige" | [[Acute myocardial infarction]], [[acute rheumatic fever]], [[ASD]], [[dilated cardiomyopathy]], [[Ebstein's anomaly]], [[Carotid sinus hypersensitivity|hypersensitive carotid sinus syndrome]], [[hypertension]], [[hypertrophic cardiomyopathy]], [[Lev's disease]], [[myocardial bridging]], [[myocarditis]], [[PR interval|normal variants]], [[Aortic valve replacement|post aortic valve  replacement]], [[catheter ablation|post catheter ablation for arrhythmias]], [[ventricular septal defect surgery|post closure of a ventricular septal defect]], [[mitral valve replacement|post mitral valve replacement]], [[tetralogy of Fallot]], [[endocardial cushion defect]], [[transposition of the great vessels]], [[valvular heart disease]], [[VSD]]
|-
|-bgcolor="LightSteelBlue"
| '''Chemical / poisoning'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Dermatologic'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Drug Side Effect'''
|bgcolor="Beige"| [[Amiodarone]], [[beta-blockers]], [[digitalis]], [[calcium channel blockers]], [[cholinesterase inhibitor|cholinesterase inhibitors]], [[disopyramide]], [[dofetilide]], [[dolasetron]], [[donepezil]], [[eslicarbazepine acetate]], [[fesoterodine]], [[fingolimod]], [[flecainide]], [[ibutilide]], [[lacosamide]], [[magnesium]], [[paliperidone]], [[pramipexole]], [[procainamide]], [[propafenone]], [[propoxyphene]], [[quinidine]], [[sotalol]], [[terodiline]]
|-
|-bgcolor="LightSteelBlue"
| '''Ear Nose Throat'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Endocrine'''
|bgcolor="Beige"| [[Hyperthyroidism]], [[myxedema]], [[periodic  paralysis|thyrotoxic periodic paralysis]]
|-
|-bgcolor="LightSteelBlue"
| '''Environmental'''
|bgcolor="Beige"| [[Hypothermia]]
|-
|-bgcolor="LightSteelBlue"
| '''Gastroenterologic'''
|bgcolor="Beige"| [[Hemochromatosis]]
|-
|-bgcolor="LightSteelBlue"
| '''Genetic'''
|bgcolor="Beige"| [[Emery-Dreifuss muscular dystrophy]], [[Fabry disease]], [[glycogenosis type 2b]], [[Neuromuscular disease|hereditary neuromuscular disease]], [[Kearns-Sayre syndrome]]
|-
|-bgcolor="LightSteelBlue"
| '''Hematologic'''
|bgcolor="Beige"| [[Multiple myeloma]] [[Lymphoma]]<ref name="pmid27200273">{{cite journal |vauthors=Menicagli F, Lanza A, Sbrocca F, Baldi A, Spugnini EP |title=A case of advanced second-degree atrioventricular block in a ferret secondary to lymphoma |journal=Open Vet J |volume=6 |issue=1 |pages=68–70 |date=2016 |pmid=27200273 |pmc=4833871 |doi=10.4314/ovj.v6i1.10 |url=}}</ref>
|-
|-bgcolor="LightSteelBlue"
| '''Iatrogenic'''
|bgcolor="Beige"| [[aortic valve  replacement|Post aortic valve  replacement]], [[catheter ablation|post catheter ablation for  arrhythmias]], [[ventricular septal defect surgery|post closure of a  ventricular septal defect]], [[mitral valve  replacement|post mitral valve  replacement]]
|-
|-bgcolor="LightSteelBlue"
| '''Infectious Disease'''
|bgcolor="Beige"| [[Acute rheumatic fever]], [[Chagas disease]], [[diphtheria]], [[Lyme disease]], [[myocarditis]], [[neonatal lupus erythematosus]], [[protozoa|protozoal infection]], [[sarcoidosis]], [[SLE]], [[tuberculosis]]
|-
|-bgcolor="LightSteelBlue"
| '''Musculoskeletal / Ortho'''
|bgcolor="Beige"| [[Ankylosing spondylitis]], [[Neuromuscular disease|hereditary neuromuscular disease]], [[Kearns-Sayre syndrome]], [[mitochondrial DNA|mitochondrial genome inherited conditions]], [[muscular dystrophy]]
|-
|-bgcolor="LightSteelBlue"
| '''Neurologic'''
|bgcolor="Beige"| [[Vasovagal syncope#Cardioinhibitory Response|Enhanced vagal tone]]
|-
|-bgcolor="LightSteelBlue"
| '''Nutritional / Metabolic'''
|bgcolor="Beige"| [[Fabry disease]], [[glycogenosis type 2b]]
|-
|-bgcolor="LightSteelBlue"
| '''Obstetric/Gynecologic'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Oncologic'''
|bgcolor="Beige"| [[Multiple myeloma]]
|-
|-bgcolor="LightSteelBlue"
| '''Opthalmologic'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Overdose / Toxicity'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Psychiatric'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Pulmonary'''
|bgcolor="Beige"| [[Sarcoidosis]]
|-
|-bgcolor="LightSteelBlue"
| '''Renal / Electrolyte'''
|bgcolor="Beige"| [[Hyperkalemia]], [[hypokalemia]]
 
|-bgcolor="LightSteelBlue"
| '''Rheum / Immune / Allergy'''
|bgcolor="Beige"| [[Ankylosing spondylitis]], [[dermatomyositis]], [[rheumatoid arthritis]], [[scleroderma]], [[SLE]]
|-
|-bgcolor="LightSteelBlue"
| '''Sexual'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Trauma'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Urologic'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Dental'''
|bgcolor="Beige"| No [[Underlying representation|underlying]] [[causes]]
|-
|-bgcolor="LightSteelBlue"
| '''Miscellaneous'''
|bgcolor="Beige"|  [[Amyloidosis]], [[degenerative diseases]]
|-
|}
 
===Causes in Alphabetical Order===
{{col-begin|width=80%}}
{{col-break|width=33%}}
* [[Acute  myocardial infarction]]
* [[Acute rheumatic fever]]
* [[Amyloidosis]]
* [[Ankylosing spondylitis]]
* [[ASD]]
* [[Bacterial endocarditis]]
* [[Beta-blockers]]
* [[Calcific aortic stenosis]]
* [[Calcium channel blockers]]
* [[Cardiac glycosides]]
* [[Cardiac tumors]]
* [[Chagas disease]]
* [[Cholinesterase inhibitors]]
* [[Clonidine]]
* [[Degenerative diseases]]
* [[Dermatomyositis]]
* [[Digitalis]]
* [[Digoxin]]
* [[Dilated cardiomyopathy]]
* [[Diltiazem]]
* [[Diphtheria]]
* [[Disopyramide]]
* [[Dolasetron]]
* [[Donepezil]]
* [[Ebstein's anomaly]]
* [[Electrolyte disturbances]]
* [[Emery-Dreifuss muscular dystrophy]]
* [[Endocarditis]]
* [[vagus nerve|Enhanced vagal tone in athletes]]
{{col-break|width=33%}}
* [[Eslicarbazepine acetate]]
* [[Fabry disease]]
* [[Fesoterodine]]
* [[Fingolimod]]
* [[Glycogenosis type 2b]]
* [[HCM]]
* [[Neuromuscular disease|Hereditary neuromuscular disease]]
* [[Hodgkin lymphoma]]
* [[Hyperkalaemia]]
* [[Carotid sinus hypersensitivity|Hypersensitive carotid  sinus syndrome]]
* [[Hyperthyroidism]]
* [[Hypokalaemia]]
* [[Hypothermia]]
* [[Ibutilide]]
* [[Ischemic heart disease]]
* [[Kearns-Sayre syndrome]]
* [[Labetalol]]
* [[Lacosamide]]
* [[Lanatoside C]]
* [[Lenegre's disease]]
* [[Lev's disease]]
* [[Lyme disease]]
* [[Mitochondrial DNA|Mitochondrial genome inherited conditions]]
* [[Multiple myeloma]]
* [[Muscular dystrophy]]
* [[Myocardial bridging]]
* [[Myocarditis]]
* [[Myotonic dystrophy]]
* [[Myxedema]]
{{col-break|width=33%}}
* [[Neonatal lupus erythematosus]]
* [[prolonged PR interval|Normal variants of PR prolongation]]
* [[Paliperidone]]
* [[aortic valve  replacement|Post aortic valve replacement]]
* [[catheter ablation|Post catheter ablation for  arrhythmias]]
* [[Ventricular septal defect surgery|Post closure of a  ventricular septal defect]]
* [[mitral valve  replacement|Post mitral valve  replacement]]
* [[Procainamide]]
* [[Propoxyphene]]
* [[Propranolol]]
* [[Protozoa|Protozoal infection]]
* [[Quinidine]]
* [[Quinine]]
* [[Rheumatic fever|Rheumatic mitral valve disease]]
* [[Sarcoidosis]]
* [[SLE]]
* [[Systemic sclerosis]]
* [[Terodiline]]
* [[Tetralogy of Fallot]]
* [[periodic  paralysis|Thyrotoxic periodic paralysis]]
* [[Tolterodine]]
* [[Transposition of the great vessels]]
* [[vagus nerve|Vagal maneuvers]]
* [[Valsalva maneuvers]]
* [[Valvular heart disease]]
* [[Verapamil]]
* [[VSD]]
* [[sex linkage|X-linked inherited  conditions]]
{{col-end}}
 
*'''For causes of [[Left bundle branch block]], click [[Left bundle branch block causes|here]].'''
*'''For causes of [[Right bundle branch block]], click [[Right bundle branch block causes|here]].'''
 
==Epidemiology and Demographics==
=== Prevalence ===
 
* In [[United States]], the [[prevalence]] of [[second-degree AV block]] is believed to be 3 in 100,000 [[Individual growth|individuals]].<ref name="pmid2191578">{{cite journal| author=Zehender M, Meinertz T, Keul J, Just H| title=ECG variants and cardiac arrhythmias in athletes: clinical relevance and prognostic importance. | journal=Am Heart J | year= 1990 | volume= 119 | issue= 6 | pages= 1378-91 | pmid=2191578 | doi=10.1016/s0002-8703(05)80189-9 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2191578  }}</ref>
* Nearly 3% of the [[patients]] with [[Underlying representation|underlying]] [[structural heart disease]] [[Development|develop]] some form of [[second-degree AV block]].
*The [[male]]-to-[[female]] [[ratio]] of [[second-degree AV block]] is 1:1.
 
=== Gender ===
 
*[[Men]] and [[women]] are [[Affect|affected]] [[Equalism|equally]] by [[second degree AV block]].
 
==Risk Factors==


Of these types of infrahisian block, Mobitz II heart block is considered most important because of the possible progression to [[complete heart block]].
* Common [[risk factors]] [[Association (statistics)|associated]] with [[second degree AV block]] include the following:<ref name="pmid11988196">{{cite journal| author=Meimoun P, Zeghdi R, D'Attelis N, Berrebi A, Braunberger E, Deloche A | display-authors=etal| title=Frequency, predictors, and consequences of atrioventricular block after mitral valve repair. | journal=Am J Cardiol | year= 2002 | volume= 89 | issue= 9 | pages= 1062-6 | pmid=11988196 | doi=10.1016/s0002-9149(02)02276-2 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11988196  }}</ref><ref name="pmid119881962">{{cite journal| author=Meimoun P, Zeghdi R, D'Attelis N, Berrebi A, Braunberger E, Deloche A | display-authors=etal| title=Frequency, predictors, and consequences of atrioventricular block after mitral valve repair. | journal=Am J Cardiol | year= 2002 | volume= 89 | issue= 9 | pages= 1062-6 | pmid=11988196 | doi=10.1016/s0002-9149(02)02276-2 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11988196  }}</ref><ref name="pmid31125096">{{cite journal |vauthors=Kerola T, Eranti A, Aro AL, Haukilahti MA, Holkeri A, Junttila MJ, Kenttä TV, Rissanen H, Vittinghoff E, Knekt P, Heliövaara M, Huikuri HV, Marcus GM |title=Risk Factors Associated With Atrioventricular Block |journal=JAMA Netw Open |volume=2 |issue=5 |pages=e194176 |date=May 2019 |pmid=31125096 |pmc=6632153 |doi=10.1001/jamanetworkopen.2019.4176 |url=}}</ref><ref name="pmid8447272">{{cite journal |vauthors=Schoeller R, Andresen D, Büttner P, Oezcelik K, Vey G, Schröder R |title=First- or second-degree atrioventricular block as a risk factor in idiopathic dilated cardiomyopathy |journal=Am. J. Cardiol. |volume=71 |issue=8 |pages=720–6 |date=March 1993 |pmid=8447272 |doi=10.1016/0002-9149(93)91017-c |url=}}</ref>
**[[Intrinsic factor|Intrinsic]] [[atrioventricular node]] [[disease]]
**[[Myocarditis]]
**[[Acute myocardial infarction]]
** Prior [[cardiac surgery]]
**[[Old age|Older age]]
**[[Heart attack]] or [[coronary artery disease]]
**[[Cardiomyopathy]]
**[[Sarcoidosis]]
**[[Lyme disease]]
** High [[potassium]] levels
** Severe [[hypothyroidism]]
** Certain [[inherited]] [[Neuromuscular disease|neuromuscular diseases]]
**[[Medicine|Medicines]] that [[slow]] the [[heart rate]]
** After [[open heart surgery]]
 
==Natural History, Complications and Prognosis==
===Natural History===
*[[Mobitz II]] [[second degree AV block]] is due to the [[Blocking (statistics)|block]] [[Inferior angle|inferior]] to the [[Atrioventricular node|AV node]] (infra-Hisian [[Structure factor|structures]]) and it rapidly progresses to a [[complete heart block]] in which no escape [[rhythm]] may emerge.<ref name="pmid463945">{{cite journal |vauthors=Rodstein M, Wolloch L, Iuster Z |title=The natural history intraventricular conduction disturbances in the aged: an analysis of the developing second and third degree heart block with clinical pathological correlations |journal=Am. J. Med. Sci. |volume=277 |issue=2 |pages=179–88 |date=1979 |pmid=463945 |doi=10.1097/00000441-197903000-00006 |url=}}</ref>
 
===Complications===
* [[Complete heart block]]<ref name="pmid6373268">{{cite journal |vauthors=Bexton RS, Camm AJ |title=Second degree atrioventricular block |journal=Eur. Heart J. |volume=5 Suppl A |issue= |pages=111–4 |date=March 1984 |pmid=6373268 |doi=10.1093/eurheartj/5.suppl_a.111 |url=}}</ref>
* [[Stokes-Adams syndrome]]
* [[Syncope]]<ref name="pmid29493981">{{cite journal |vauthors=Mangi MA, Jones WM, Napier L |title= |journal= |volume= |issue= |pages= |date= |pmid=29493981 |doi= |url=}}</ref>
*[[Dizziness]]
*[[Chest pain]]
*Death
 
===Prognosis===
*[[Mobitz II]], as it involves the [[Infranodal Wenkebach-type block|infra-nodal]] [[Structure factor|structures]], [[Carrying capacity|carries]] the [[RiskMetrics|risk]] of progression to [[complete heart block]] and [[Carrying capacity|carries]] an unfavorable [[prognosis]].<ref name="pmid11988196">{{cite journal| author=Meimoun P, Zeghdi R, D'Attelis N, Berrebi A, Braunberger E, Deloche A | display-authors=etal| title=Frequency, predictors, and consequences of atrioventricular block after mitral valve repair. | journal=Am J Cardiol | year= 2002 | volume= 89 | issue= 9 | pages= 1062-6 | pmid=11988196 | doi=10.1016/s0002-9149(02)02276-2 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11988196  }}</ref>
 
==Diagnosis==
===Diagnostic Study of Choice===
* [[Electrocardiography]] ([[ECG]]) is employed to determine the type of [[Second-degree AV block|second-degree atrioventricular (AV) block]] [[Presenting symptom|present]]<ref name="pmid29493981">{{cite journal |vauthors=Mangi MA, Jones WM, Napier L |title= |journal= |volume= |issue= |pages= |date= |pmid=29493981 |doi= |url=}}</ref><ref name="pmid22813399">{{cite journal |vauthors=Thiruganasambandamoorthy V, Hess EP, Turko E, Tran ML, Wells GA, Stiell IG |title=Defining abnormal electrocardiography in adult emergency department syncope patients: the Ottawa Electrocardiographic Criteria |journal=CJEM |volume=14 |issue=4 |pages=248–58 |date=July 2012 |pmid=22813399 |doi= |url=}}</ref><ref name="pmid23224264">{{cite journal |vauthors=Barold SS, Herweg B |title=Second-degree atrioventricular block revisited |journal=Herzschrittmacherther Elektrophysiol |volume=23 |issue=4 |pages=296–304 |date=December 2012 |pmid=23224264 |doi=10.1007/s00399-012-0240-8 |url=}}</ref>.
* Follow-up [[ECG]]s and [[cardiac monitoring]] are [[Appropriate Use Criteria|appropriate]].<ref name="pmid25080840">{{cite journal |vauthors=Barold SS, Van Heuverswyn FE, Timmers L, Stroobandt RX |title=Mobitz type II second-degree atrioventricular block during dobutamine stress echocardiography. True or false? |journal=Echocardiography |volume=31 |issue=7 |pages=799–801 |date=August 2014 |pmid=25080840 |doi=10.1111/echo.12577 |url=}}</ref>
* Routine [[imaging studies]] are not required. However, if [[myocarditis]] is a concern, [[echocardiography]] may be [[Indication (medicine)|indicated]].<ref name="pmid29850368">{{cite journal |vauthors=Li X, Xue Y, Wu H |title=A Case of Atrioventricular Block Potentially Associated with Right Coronary Artery Lesion and Ticagrelor Therapy Mediated by the Increasing Adenosine Plasma Concentration |journal=Case Rep Vasc Med |volume=2018 |issue= |pages=9385017 |date=2018 |pmid=29850368 |pmc=5933017 |doi=10.1155/2018/9385017 |url=}}</ref><ref name="pmid29275956">{{cite journal |vauthors=Fu Md J, Bhatta L |title=Lyme carditis: Early occurrence and prolonged recovery |journal=J Electrocardiol |volume=51 |issue=3 |pages=516–518 |date=2018 |pmid=29275956 |doi=10.1016/j.jelectrocard.2017.12.035 |url=}}</ref>
* If [[myocardial ischemia]] is a concern, a [[chest radiograph]] may be [[Indication (medicine)|indicated]].<ref name="pmid29083636">{{cite journal |vauthors=Kashou AH, Goyal A, Nguyen T, Chhabra L |title= |journal= |volume= |issue= |pages= |date= |pmid=29083636 |doi= |url=}}</ref>
 
===History and Symptoms===
*[[History and Physical examination|History]] from [[patients]] with [[second degree AV block]] should involve [[Ask a question|asking]] about the following:<ref name="pmid7405798">{{cite journal |vauthors=Zeppilli P, Fenici R, Sassara M, Pirrami MM, Caselli G |title=Wenckebach second-degree A-V block in top-ranking athletes: an old problem revisited |journal=Am. Heart J. |volume=100 |issue=3 |pages=281–94 |date=September 1980 |pmid=7405798 |doi=10.1016/0002-8703(80)90140-4 |url=}}</ref><ref name="pmid29083636">{{cite journal| author=| title=StatPearls | journal= | year= 2020 | volume=  | issue=  | pages=  | pmid=29083636 | doi= | pmc= | url= }}</ref>
**[[Congenital heart disease]]
**[[Current]] [[heart condition]]
**[[Recent changes|Recent]] or previous [[cardiac]] [[Procedure|procedures]]
**[[History and Physical examination|History]] of [[medications]]
* Most [[People's Solidarity|people]] with [[Wenckebach]] ([[Type I Mobitz]]) do not show [[symptoms]].<ref name="pmid11988196">{{cite journal| author=Meimoun P, Zeghdi R, D'Attelis N, Berrebi A, Braunberger E, Deloche A | display-authors=etal| title=Frequency, predictors, and consequences of atrioventricular block after mitral valve repair. | journal=Am J Cardiol | year= 2002 | volume= 89 | issue= 9 | pages= 1062-6 | pmid=11988196 | doi=10.1016/s0002-9149(02)02276-2 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11988196  }} </ref><ref name="pmid29493981">{{cite journal |vauthors=Mangi MA, Jones WM, Napier L |title= |journal= |volume= |issue= |pages= |date= |pmid=29493981 |doi= |url=}}</ref>
* If the [[sinus]] [[rate]] is [[slow]] and only [[Fewmets|few]] [[Beats per minute|beats]] are [[Conductance|conducted]] (higher [[Grading (tumors)|grade]] [[Blocking (statistics)|blocks]]) there may be a [[Significant figure|significantly]] [[reduced cardiac output]].
*Usual [[symptoms]] in such [[patients]] include:<ref name="pmid6373268">{{cite journal |vauthors=Bexton RS, Camm AJ |title=Second degree atrioventricular block |journal=Eur. Heart J. |volume=5 Suppl A |issue= |pages=111–4 |date=March 1984 |pmid=6373268 |doi=10.1093/eurheartj/5.suppl_a.111 |url=}}</ref><ref name="pmid8445186">{{cite journal |vauthors=Wogan JM, Lowenstein SR, Gordon GS |title=Second-degree atrioventricular block: Mobitz type II |journal=J Emerg Med |volume=11 |issue=1 |pages=47–54 |date=1993 |pmid=8445186 |doi=10.1016/0736-4679(93)90009-v |url=}}</ref>
**[[Light-headedness]]
**[[Dizziness]]
**[[Fainting]]
**[[Fatigue]]
**[[Heart failure]] [[symptoms]]
**[[Pre-syncope]]
**[[Syncope]]
 
===Physical Examination===
*[[Patients]] with [[Mobitz II]] can [[Appearance|appear]] [[asymptomatic]] as well. However, in more [[Case-based reasoning|cases]] they may be in [[distress]] or progress to the more severe [[third degree AV block]].
*[[Patients]] may [[Appearance|appear]] [[Pale skin color|pale]] in [[Case-based reasoning|cases]] of [[bradycardia]] with decreased [[cardiac output]].<ref name="pmid4701376">{{cite journal| author=Rosen KM, Dhingra RC, Loeb HS, Rahimtoola SH| title=Chronic heart block in adults. Clinical and electrophysiological observations. | journal=Arch Intern Med | year= 1973 | volume= 131 | issue= 5 | pages= 663-72 | pmid=4701376 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=4701376  }}</ref>
*[[Bradycardia]] with an [[irregular pulse]]<ref name="pmid699934">{{cite journal |vauthors=Schneider MD, Roller DH, Morganroth J, Josephson ME |title=The syndromes of familial atrioventricular block with sinus bradycardia: prognostic indices, electrophysiologic and histopathologic correlates |journal=Eur J Cardiol |volume=7 |issue=5-6 |pages=337–51 |date=July 1978 |pmid=699934 |doi= |url=}}</ref>
*[[Lightheadedness]]
*[[Hypotension]]<ref name="pmid27642736">{{cite journal |vauthors=Trappe HJ |title=[Consciousness disorders from cardiological view] |language=German |journal=Dtsch. Med. Wochenschr. |volume=141 |issue=19 |pages=1361–9 |date=September 2016 |pmid=27642736 |doi=10.1055/s-0042-103177 |url=}}</ref>
*[[Syncope]] or [[presyncope]]
*[[Jugular venous distension]]
*Bibasilar [[crackles]] in [[patients]] with exacerbated [[heart failure]]
*[[Peripheral edema]]
 
===Laboratory Findings===
[[Patients]] with [[second degree AV block]] should be [[Check|checked]] for the following [[laboratory]] [[Test|tests]]:<ref name="pmid1008977">{{cite journal| author=Gupta PK, Lichstein E, Chadda KD| title=Chronic His bundle block. Clinical, electrocardiographic, electrophysiological, and follow-up studies on 16 patients. | journal=Br Heart J | year= 1976 | volume= 38 | issue= 12 | pages= 1343-9 | pmid=1008977 | doi=10.1136/hrt.38.12.1343 | pmc=483178 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1008977  }}</ref>
*[[Serum electrolyte|Serum electrolytes]]
* [[Calcium]]
* [[Magnesium]]
* [[Myocardial]] [[enzymes]] in [[patients]] with [[myocardial infarction]]
* [[Myocarditis]] [[Related phenomena|related]] [[laboratory]] [[Test|tests]] as the following:<ref name="pmid18532885">{{cite journal| author=Steere AC, McHugh G, Damle N, Sikand VK| title=Prospective study of serologic tests for lyme disease. | journal=Clin Infect Dis | year= 2008 | volume= 47 | issue= 2 | pages= 188-95 | pmid=18532885 | doi=10.1086/589242 | pmc=5538270 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18532885  }}</ref>
**[[Lyme]] [[Titre|titres]]
**[[HIV test|HIV tests]]
**[[PCR]] for [[enteroviruses]]
**[[Chagas]] [[Titre|titres]]
 
===Electrocardiogram===
* There are intermittent [[Blocking (statistics)|blocked]] [[P wave]]s.
* In the [[Conductance|conducted]] [[Beats per minute|beats]], the [[PR interval]]s remain [[constant]].
* The [[PR]] is fairly [[constant]] except that slight [[shortening]] may occur in the first [[Beats per minute|beat]] after the [[Blocking (statistics)|blocked]] [[Cycle (gene)|cycle]]. This is the [[result]] of improved [[Conduction System|conduction]] following the [[Blocking (statistics)|block]].
* Most [[patients]] with type II [[second-degree AV block]] have [[Association (statistics)|associated]] [[bundle branch block]].
* In these instances, the [[Blocking (statistics)|block]] is usually [[Location parameter|located]] [[distal]] to the [[His bundle]]. However, in approximately 27% to 35% of the [[patients]], the [[lesion]] is [[Location parameter|located]] in the [[His bundle]] itself, and a narrow [[Complex (chemistry)|complex]] may be inscribed. <br>
* 2:1 [[Atrioventricular block|AV Block]]:
 
:*Impossible to determine whether the [[second-degree AV block]] is type I or type II.
:*A long [[rhythm]] strip is helpful to [[Document classification|document]] any [[Change detection|change]] in the [[behavior]] of the [[Conduction System|conduction]] [[ratio]].
:*When the [[atrial]] [[rate]] is increased by [[exercise]] or by [[atropine]], the [[Atrioventricular block|AV block]] in type I tends to decrease and that in type II tends to increase.
 
----
Shown below is an [[electrocardiogram]] of a 12 [[lead]] [[EKG]] with a 2:1 [[Atrioventricular block|AV block]].
[[File:2to1AVBlock1.jpg|center|500px]]
Copyleft image obtained, courtesy of ECGpedia, http://en.ecgpedia.org/wiki/Main_Page
----
 
Shown below is an [[electrocardiogram]] of a type II [[second degree AV block]] ([[Mobitz type II AV block|Mobitz type II]]).
[[File:Rhythm Mobitz.png|center|500px]]
Copyleft image obtained, courtesy of ECGpedia, http://en.ecgpedia.org/wiki/Main_Page
----
==Treatment==
===Medical therapy for Mobitz II===
*[[Correction (newspaper)|Correction]] of [[Reversible cell|reversible]] [[causes]] of the [[Blocking (statistics)|block]] such as [[ischemia]], [[medications]], and [[Vagotonic agents|vagotonic]] [[conditions]] should be considered.<ref name="pmid29850368">{{cite journal |vauthors=Li X, Xue Y, Wu H |title=A Case of Atrioventricular Block Potentially Associated with Right Coronary Artery Lesion and Ticagrelor Therapy Mediated by the Increasing Adenosine Plasma Concentration |journal=Case Rep Vasc Med |volume=2018 |issue= |pages=9385017 |date=2018 |pmid=29850368 |pmc=5933017 |doi=10.1155/2018/9385017 |url=}}</ref>
*[[Treatments|Treatment]] may also include [[Medicine|medicines]] to [[control]] [[blood pressure]] and [[atrial fibrillation]], as well as [[lifestyle]] and [[dietary]] [[Change detection|changes]] to [[Reduced|reduce]] the [[risk factors]] [[Association (statistics)|associated]] with [[myocardial infarction|heart attack]] and [[stroke]].<ref name="pmid26745972">{{cite journal |vauthors=Schernthaner C, Kraus J, Danmayr F, Hammerer M, Schneider J, Hoppe UC, Strohmer B |title=Short-term pacemaker dependency after transcatheter aortic valve implantation |journal=Wien. Klin. Wochenschr. |volume=128 |issue=5-6 |pages=198–203 |date=March 2016 |pmid=26745972 |doi=10.1007/s00508-015-0906-4 |url=}}</ref>
*[[Treatments|Treatment]] in [[emergency]] situations are [[atropine]] and an [[external pacer]].<ref name="pmid23224264">{{cite journal |vauthors=Barold SS, Herweg B |title=Second-degree atrioventricular block revisited |journal=Herzschrittmacherther Elektrophysiol |volume=23 |issue=4 |pages=296–304 |date=December 2012 |pmid=23224264 |doi=10.1007/s00399-012-0240-8 |url=}}</ref><ref name="pmid8445186">{{cite journal |vauthors=Wogan JM, Lowenstein SR, Gordon GS |title=Second-degree atrioventricular block: Mobitz type II |journal=J Emerg Med |volume=11 |issue=1 |pages=47–54 |date=1993 |pmid=8445186 |doi=10.1016/0736-4679(93)90009-v |url=}}</ref>
 
====Contraindicated medications====
{{MedCondContrAbs
 
|MedCond = Second degree AV block(except in patients with a functioning artificial pacemaker)<ref name="pmid26115830">{{cite journal |vauthors=Brignole M, Deharo JC, Guieu R |title=Syncope and Idiopathic (Paroxysmal) AV Block |journal=Cardiol Clin |volume=33 |issue=3 |pages=441–7 |date=August 2015 |pmid=26115830 |doi=10.1016/j.ccl.2015.04.012 |url=}}</ref><ref name="pmid11229299">{{cite journal |vauthors=Kelkar PN |title=Atenolol induced high grade AV block |journal=J Assoc Physicians India |volume=46 |issue=8 |pages=748, 751 |date=August 1998 |pmid=11229299 |doi= |url=}}</ref>|Adenosine|Atenolol|Betaxolol|Bisoprolol|Brimonidine tartrate and Timolol maleate|Carteolol|Diltiazem|Disopyramide|Dronedarone|Fingolimod|Flecainide|Metoprolol|Mexiletine|Nadolol|Nebivolol|Penbutolol|Pindolol|Propranolol|Sotalol|Timolol|Labetalol}}<ref name="pmid15234417">{{cite journal |vauthors=Zeltser D, Justo D, Halkin A, Rosso R, Ish-Shalom M, Hochenberg M, Viskin S |title=Drug-induced atrioventricular block: prognosis after discontinuation of the culprit drug |journal=J. Am. Coll. Cardiol. |volume=44 |issue=1 |pages=105–8 |date=July 2004 |pmid=15234417 |doi=10.1016/j.jacc.2004.03.057 |url=}}</ref>
===Surgery for Mobitz II===
====Definitive treatment-Pacemaker insertion====
*[[Mobitz type II AV block|Type II Mobitz]] ([[symptomatic]] or [[asymptomatic]]) is by itself an [[Indication (medicine)|indication]] for [[insertion]] of a [[pacemaker]] (definitive [[Treatments|treatment]]). Other [[Indication (medicine)|indications]] include:<ref name="pmid29275956">{{cite journal |vauthors=Fu Md J, Bhatta L |title=Lyme carditis: Early occurrence and prolonged recovery |journal=J Electrocardiol |volume=51 |issue=3 |pages=516–518 |date=2018 |pmid=29275956 |doi=10.1016/j.jelectrocard.2017.12.035 |url=}}</ref><ref name="pmid28823599">{{cite journal |vauthors=Tuohy S, Saliba W, Pai M, Tchou P |title=Catheter ablation as a treatment of atrioventricular block |journal=Heart Rhythm |volume=15 |issue=1 |pages=90–96 |date=January 2018 |pmid=28823599 |doi=10.1016/j.hrthm.2017.08.015 |url=}}</ref><ref name="pmid30412709">{{cite journal |vauthors=Kusumoto FM, Schoenfeld MH, Barrett C, Edgerton JR, Ellenbogen KA, Gold MR, Goldschlager NF, Hamilton RM, Joglar JA, Kim RJ, Lee R, Marine JE, McLeod CJ, Oken KR, Patton KK, Pellegrini CN, Selzman KA, Thompson A, Varosy PD |title=2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society |journal=J. Am. Coll. Cardiol. |volume=74 |issue=7 |pages=e51–e156 |date=August 2019 |pmid=30412709 |doi=10.1016/j.jacc.2018.10.044 |url=}}</ref><ref name="pmid7471363">{{cite journal |vauthors=Strasberg B, Amat-Y-Leon F, Dhingra RC, Palileo E, Swiryn S, Bauernfeind R, Wyndham C, Rosen KM |title=Natural history of chronic second-degree atrioventricular nodal block |journal=Circulation |volume=63 |issue=5 |pages=1043–9 |date=May 1981 |pmid=7471363 |doi=10.1161/01.cir.63.5.1043 |url=}}</ref>:
**[[Myotonic dystrophy]]
** [[Kearns-Sayre syndrome]]
** [[Erb's dystrophy]]
** [[Peroneal muscular atrophy]]. These [[Neuromuscular disorder|neuromuscular disorders]] have a high [[potential]] for unpredictable rapid progression to [[complete heart block]].
*[[Implantation]] of [[Permanent pacemaker|permanent pacemakers]] in both [[asymptomatic]] and [[symptomatic]] [[patients]] is usually [[done]]. [[Asymptomatic]] [[Mobitz II]] are [[prone]] to be converted to [[symptomatic]] or [[third degree heart block]]. Thus, they should be considered for a [[pacemaker]] even if [[asymptomatic]].
* A dual chamber [[DDD]] [[pacemaker]] is [[Preferences|preferred]] over a single chambered VVI [[Pacemaker|pacemakers]] as it maintains [[physiologic]] [[Atrioventricular|AV]] [[Synchronicity|synchrony]].
* A dual-chamber [[artificial pacemaker]] is a type of device that typically listens for a [[pulse]] from the [[SA node]] and sends a [[pulse]] to the [[AV node]] at an appropriate [[Interval (mathematics)|interval]], essentially completing the connection between the two [[Node (physics)|nodes]]. [[Pacemaker|Pacemakers]] in this role are usually programmed to enforce a [[minimum]] [[heart rate]] and to record instances of [[atrial flutter]] and [[atrial fibrillation]].
 
==Prevention==
===Primary Prevention===
*[[Effect size|Effective]] [[Treatments|treatment]] of [[hypertension]] and [[Maintenance dose|maintenance]] of [[normal]] [[blood glucose]] [[Level of measurement|levels]] may be [[Usage analysis|useful]] [[Strategies for Improving Care|strategies]] in [[Prevention (medical)|preventing]] the [[Atrioventricular block|AV block]].
 
==Differentiating Infra-Hisian Block from other Diseases==
<br />
{| class="wikitable"
|+
! colspan="2" align="center" style="background:#4479BA; color: #FFFFFF;" + |Arrhythmia
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Rhythm
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Rate
! align="center" style="background:#4479BA; color: #FFFFFF;" + |P wave
! align="center" style="background:#4479BA; color: #FFFFFF;" + |PR Interval
! align="center" style="background:#4479BA; color: #FFFFFF;" + |QRS Complex
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Response to Maneuvers
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Epidemiology
! align="center" style="background:#4479BA; color: #FFFFFF;" + |Co-existing Conditions
|-
! rowspan="3" |[[Atrioventricular block]]<ref name="pmid311250962">{{cite journal| author=Kerola T, Eranti A, Aro AL, Haukilahti MA, Holkeri A, Junttila MJ et al.| title=Risk Factors Associated With Atrioventricular Block. | journal=JAMA Netw Open | year= 2019 | volume= 2 | issue= 5 | pages= e194176 | pmid=31125096 | doi=10.1001/jamanetworkopen.2019.4176 | pmc=6632153 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=31125096  }}</ref>
![[First degree AV block|First degree]] <ref name="pmid8734740">{{cite journal| author=Barold SS| title=Indications for permanent cardiac pacing in first-degree AV block: class I, II, or III? | journal=Pacing Clin Electrophysiol | year= 1996 | volume= 19 | issue= 5 | pages= 747-51 | pmid=8734740 | doi=10.1111/j.1540-8159.1996.tb03355.x | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8734740  }}</ref><ref name="pmid15233485">{{cite journal| author=Upshaw CB| title=Comparison of the prevalence of first-degree atrioventricular block in African-American and in Caucasian patients: an electrocardiographic study III. | journal=J Natl Med Assoc | year= 2004 | volume= 96 | issue= 6 | pages= 756-60 | pmid=15233485 | doi= | pmc=2568382 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15233485  }}</ref>
|
* Regular
|
|
*[[Normal]]
|
*[[Prolonged PR interval]] (>200 [[Millisecond|msec]])
|
* Less than 0.12 [[Second|seconds]], consistent, and [[normal]] in [[Morphology (biology)|morphology]].
|
* No [[Treatments|treatment]] required
 
<br />
|
*[[Prevalence]]: 650 to 1600 per 100,000 [[Individual growth|individuals]] in the [[United States]].
| rowspan="3" |<br />
 
*[[Heart failure]]
*[[Coronary heart disease]]
*[[Cardiomyopathy]]
*[[Sarcoidosis]]
*[[Lyme disease]]
*[[Degenerative disease|Degenerative]] [[muscle]] [[disorders]] as [[Lev's disease]] and [[Lenegre's disease]].
* Overly active [[vagus nerve]].
|-
![[Second degree AV block|Second degree]]<ref name="pmid2191578">{{cite journal| author=Zehender M, Meinertz T, Keul J, Just H| title=ECG variants and cardiac arrhythmias in athletes: clinical relevance and prognostic importance. | journal=Am Heart J | year= 1990 | volume= 119 | issue= 6 | pages= 1378-91 | pmid=2191578 | doi=10.1016/s0002-8703(05)80189-9 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2191578  }}</ref><ref name="pmid1176840">{{cite journal| author=Friedman HS, Gomes JA, Haft JI| title=An analysis of Wenckebach periodicity. | journal=J Electrocardiol | year= 1975 | volume= 8 | issue= 4 | pages= 307-15 | pmid=1176840 | doi=10.1016/s0022-0736(75)80003-3 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1176840  }}</ref>
|
* Regular [[Irregular heart rhythms|irregular]]
|
|
*[[Normal]]
|
*[[Mobitz I|Mobtiz I]]: Progressive [[PR prolongation]]
*[[Mobitz II]]: [[Normal]] [[PR interval]]
|[[QRS complex|QRS]] is [[normal]] but [[Drop (liquid)|dropped]] as the following:
 
*[[Mobitz I]]: [[QRS complex]] is [[Drop (liquid)|dropped]] after a progressive [[Length|lengthening]] of [[PR interval|PR]]
*[[Mobitz II]]: [[QRS complex]] is [[Drop (liquid)|dropped]] after a [[normal]] [[PR interval|PR]]
|
* Can be reversed by [[Usage analysis|using]] a [[pacemaker]].
|
*[[Prevalence]]: 3 per 100,000 [[Individual growth|individuals]] in the [[United States]].
|-
![[Third degree AV block|Third degree]]<ref name="pmid14297523">{{cite journal |vauthors=OSTRANDER LD, BRANDT RL, KJELSBERG MO, EPSTEIN FH |title=ELECTROCARDIOGRAPHIC FINDINGS AMONG THE ADULT POPULATION OF A TOTAL NATURAL COMMUNITY, TECUMSEH, MICHIGAN |journal=Circulation |volume=31 |issue= |pages=888–98 |date=June 1965 |pmid=14297523 |doi=10.1161/01.cir.31.6.888 |url=}}</ref><ref name="pmid16236932">{{cite journal |vauthors=Movahed MR, Hashemzadeh M, Jamal MM |title=Increased prevalence of third-degree atrioventricular block in patients with type II diabetes mellitus |journal=Chest |volume=128 |issue=4 |pages=2611–4 |date=October 2005 |pmid=16236932 |doi=10.1378/chest.128.4.2611 |url=}}</ref>
|
* Regular
|
|
*[[Normal]] but no relationship between [[P wave]] and the [[QRS complex|QRS]].
* More [[P waves]] than the [[QRS complexes]].
|
*[[Variable|Varies]]
|
*[[Normal]] [[QRS complex|QRS]]
|
* Can be reversed by [[Usage analysis|using]] a [[pacemaker]].
|
* The [[prevalence]]: 20 per 100,000 [[Individual growth|individuals]] worldwide.
|-
! colspan="2" |'''[[Atrial fibrillation|Atrial Fibrillation (AFib)]]<ref name="pmid24837984">{{cite journal |vauthors=Lankveld TA, Zeemering S, Crijns HJ, Schotten U |title=The ECG as a tool to determine atrial fibrillation complexity |journal=Heart |volume=100 |issue=14 |pages=1077–84 |date=July 2014 |pmid=24837984 |doi=10.1136/heartjnl-2013-305149 |url=}}</ref><ref name="pmid22518390">{{cite journal |vauthors=Harris K, Edwards D, Mant J |title=How can we best detect atrial fibrillation? |journal=J R Coll Physicians Edinb |volume=42 Suppl 18 |issue= |pages=5–22 |date=2012 |pmid=22518390 |doi=10.4997/JRCPE.2012.S02 |url=}}</ref>'''
|
*[[Irregularly irregular pulse|Irregularly irregular]]
|
* On a 10-[[second]] [[12-lead ECG|12-lead EKG]] [[Stripping|strip]], multiply [[number]] of [[QRS complexes]] by 6
|
* Absent
*[[Fibrillation|Fibrillatory]] [[waves]]
|
* Absent
|
* Less than 0.12 [[Second|seconds]], consistent, and [[normal]] in [[Morphology (biology)|morphology]] in the absence of aberrant [[Conduction System|conduction]]
|
* Does not break with [[adenosine]] or [[vagal maneuvers]]
|
* 2.7–6.1 million [[People's Solidarity|people]] in the [[United States]] have [[Atrial fibrillation|AFib]]
* 2% of [[People's Solidarity|people]] [[Young adult|younger]] than [[age]] 65 have [[Atrial fibrillation|AFib]], while about 9% of [[People's Solidarity|people]] aged 65 [[Year|years]] or [[Old age|older]] have [[Atrial fibrillation|AFib]]
|
*[[Elderly]]
* Following [[Coronary artery bypass surgery|bypass surgery]]
*[[Mitral valve disease]]
*[[Hyperthyroidism]]
*[[Diabetes mellitus|Diabetes]]
*[[Heart failure]]
*[[Ischemic heart disease]]
*[[Chronic kidney disease]]
* Heavy [[alcohol]] use
* Left chamber enlargement
|-
! colspan="2" |'''[[Atrial Flutter]]'''<ref name="pmid28835836">{{cite journal |vauthors=Cosío FG |title=Atrial Flutter, Typical and Atypical: A Review |journal=Arrhythm Electrophysiol Rev |volume=6 |issue=2 |pages=55–62 |date=June 2017 |pmid=28835836 |pmc=5522718 |doi=10.15420/aer.2017.5.2 |url=}}</ref>
|
* Regular or [[Irregular heart rhythms|Irregular]]
|
* 75 (4:1 [[Blocking (statistics)|block]]), 100 (3:1 [[Blocking (statistics)|block]]) and 150 (2:1 [[Blocking (statistics)|block]]) [[beats per minute]] ([[Beats per minute|bpm]]), but 150 is more common
|
* Sawtooth [[pattern]] of [[P waves]] at 250 to 350 [[Beats per minute|bpm]]
*[[Biphasic]] deflection in [[V1-morph|V1]]
|
*[[Variable|Varies]] [[Dependent variable|depending]] upon the [[Magnitude (mathematics)|magnitude]] of the [[Blocking (statistics)|block]], but is short
|
* Less than 0.12 [[Second|seconds]], consistent, and [[normal]] in [[morphology]]
|
*[[Conduction System|Conduction]] may [[Variable|vary]] in [[Response element|response]] to [[drugs]] and maneuvers [[Drop (liquid)|dropping]] the [[rate]] from 150 to 100 or to 75 [[Beats per minute|bpm]]
|
*[[Incidence]]: 88 per 100,000 [[Individual growth|individuals]]
|
*[[Elderly]]
*[[Alcohol]]
|-
! colspan="2" |'''[[Atrioventricular nodal reentry tachycardia]] ([[AV nodal reentrant tachycardia|AVNRT]])<ref name="pmid27617092">{{cite journal |vauthors=Katritsis DG, Josephson ME |title=Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia |journal=Arrhythm Electrophysiol Rev |volume=5 |issue=2 |pages=130–5 |date=August 2016 |pmid=27617092 |pmc=5013176 |doi=10.15420/AER.2016.18.2 |url=}}</ref><ref name="pmid20458824">{{cite journal |vauthors=Letsas KP, Weber R, Siklody CH, Mihas CC, Stockinger J, Blum T, Kalusche D, Arentz T |title=Electrocardiographic differentiation of common type atrioventricular nodal reentrant tachycardia from atrioventricular reciprocating tachycardia via a concealed accessory pathway |journal=Acta Cardiol |volume=65 |issue=2 |pages=171–6 |date=April 2010 |pmid=20458824 |doi=10.2143/AC.65.2.2047050 |url=}}</ref>'''<ref name="urlAtrioventricular Nodal Reentry Tachycardia (AVNRT) - StatPearls - NCBI Bookshelf">{{cite web |url=https://www.ncbi.nlm.nih.gov/books/NBK499936/ |title=Atrioventricular Nodal Reentry Tachycardia (AVNRT) - StatPearls - NCBI Bookshelf |format= |work= |accessdate=}}</ref><ref name="pmid25196716">{{cite journal |vauthors=Schernthaner C, Danmayr F, Strohmer B |title=Coexistence of atrioventricular nodal reentrant tachycardia with other forms of arrhythmias |journal=Med Princ Pract |volume=23 |issue=6 |pages=543–50 |date=2014 |pmid=25196716 |pmc=5586929 |doi=10.1159/000365418 |url=}}</ref>
|
* Regular
|
* 140-280 [[Beats per minute|bpm]]
|
*[[Slow]]-[[Fast and wide|Fast]] [[AV nodal reentrant tachycardia|AVNRT]]:
**Pseudo-[[S wave]] in [[Lead|leads]] II, III, and AVF
**Pseudo-[[R wave|R]]' in [[lead]] V1.
*[[Fast and wide|Fast]]-[[Slow]] [[AV nodal reentrant tachycardia|AVNRT]]
**[[P waves]] between the [[QRS complex|QRS]] and [[T waves]] ([[QRS complex|QRS]]-[[P wave|P]]-[[T wave|T]] [[Complex (chemistry)|complexes]])
*[[Slow]]-[[Slow]] [[AV nodal reentrant tachycardia|AVNRT]]
**Late [[P waves]] after a [[QRS complex|QRS]]
**Often [[Appearance|appears]] as [[atrial tachycardia]].
*[[Inverted P wave|Inverted]], [[Superimposition|superimposed]] on or buried within the [[QRS complex]] (pseudo [[R wave|R]] [[Prime ECG|prime]] in [[V1-morph|V1]]/pseudo [[S wave]] in [[Inferior angle|inferior]] [[Lead|leads]])
|
* Absent ([[P wave]] can [[Appearance|appear]] after the [[QRS complex]] and before the [[T wave]], and in [[Atypical AV nodal reentrant tachycardia|atypical AVNRT]], the [[P wave]] can [[Appearance|appear]] just before the [[QRS complex]])
|
* Less than 0.12 [[Second|seconds]], consistent, and [[normal]] in [[Morphology (biology)|morphology]] in the absence of aberrant [[Conduction System|conduction]]
*[[QRS complex alternans|QRS alternans]] may be [[Presenting symptom|present]]
|
* May break with [[adenosine]] or [[vagal maneuvers]]
|
* 60%-70% of all [[supraventricular tachycardias]]
|
*[[Structural heart disease]]
*[[Atrial tachyarrhythmias]]
|-
! colspan="2" |'''[[Multifocal atrial tachycardia|Multifocal Atrial Tachycardia]]<ref name="pmid2570520">{{cite journal |vauthors=Scher DL, Arsura EL |title=Multifocal atrial tachycardia: mechanisms, clinical correlates, and treatment |journal=Am. Heart J. |volume=118 |issue=3 |pages=574–80 |date=September 1989 |pmid=2570520 |doi=10.1016/0002-8703(89)90275-5 |url=}}</ref><ref name="pmid11884328">{{cite journal |vauthors=Goodacre S, Irons R |title=ABC of clinical electrocardiography: Atrial arrhythmias |journal=BMJ |volume=324 |issue=7337 |pages=594–7 |date=March 2002 |pmid=11884328 |pmc=1122515 |doi=10.1136/bmj.324.7337.594 |url=}}</ref>'''
|
*[[Irregular heart rhythms|Irregular]]
|
*[[Atrial]] [[rate]] is > 100 [[beats per minute]]
|
* Varying [[morphology]] from at least three [[Difference (philosophy)|different]] [[Focus (optics)|foci]]
* Absence of one [[dominant]] [[Atrial|atria]]<nowiki/>l [[pacemaker]], can be mistaken for [[atrial fibrillation]] if the [[P waves]] are of low [[amplitude]]
|
*[[Variable]] [[PR interval|PR intervals]], [[RR interval|RR intervals]], and [[PP interval|PP intervals]]
|
* Less than 0.12 [[Second|seconds]], consistent, and [[normal]] in [[Morphology (biology)|morphology]]
|
* Does not [[Termination signal|terminate]] with [[adenosine]] or [[vagal maneuvers]]
|
* 0.05% to 0.32% of [[electrocardiograms]] in general [[hospital]] [[Admission note|admissions]]
|
*[[Elderly]]
*[[Chronic obstructive pulmonary disease]] ([[Chronic obstructive pulmonary disease|COPD]])
|-
! colspan="2" |'''Paroxysmal [[Supraventricular tachycardia|Supraventricular Tachycardia]]'''
|
* Regular
|
* 150 and 240 [[Beats per minute|bpm]]
|
* Absent
* Hidden in [[QRS complex|QRS]]
|
* Absent
|
*[[Narrow complex tachycardia|Narrow complexes]] (< 0.12 [[Second|s]])
|
* Breaks with [[vagal maneuvers]], [[adenosine]], [[diving reflex]], [[oculocardiac reflex]]
|
*[[Prevalence]]: 0.023 per 100,000
|
*[[Alcohol]]
*[[Caffeine]]
*[[Nicotine]]
*[[Psychological stress]]
*[[Wolff-Parkinson-White syndrome]]
|-
! colspan="2" |'''[[Premature atrial contraction|Premature Atrial Contractrions]] ([[Premature atrial contraction|PAC]])'''<ref name="pmid26316525">{{cite journal |vauthors=Lin CY, Lin YJ, Chen YY, Chang SL, Lo LW, Chao TF, Chung FP, Hu YF, Chong E, Cheng HM, Tuan TC, Liao JN, Chiou CW, Huang JL, Chen SA |title=Prognostic Significance of Premature Atrial Complexes Burden in Prediction of Long-Term Outcome |journal=J Am Heart Assoc |volume=4 |issue=9 |pages=e002192 |date=August 2015 |pmid=26316525 |pmc=4599506 |doi=10.1161/JAHA.115.002192 |url=}}</ref><ref name="pmid18063110">{{cite journal |vauthors=Strasburger JF, Cheulkar B, Wichman HJ |title=Perinatal arrhythmias: diagnosis and management |journal=Clin Perinatol |volume=34 |issue=4 |pages=627–52, vii–viii |date=December 2007 |pmid=18063110 |pmc=3310372 |doi=10.1016/j.clp.2007.10.002 |url=}}</ref>
|
* Regular except when disturbed by [[premature]] [[Beats per minute|beat(s)]]
|
* 80-120 [[Beats per minute|bpm]]
|
* Upright
|
* > 0.12 [[second]]
* May be shorter than that in [[normal sinus rhythm]] ([[Normal sinus rhythm|NSR]]) if the [[origin]] of [[PAC]] is [[Location parameter|located]] closer to the [[Atrioventricular node|AV node]]
*[[Ashman phenomenon|Ashman’s phenomenon]]:
**[[Premature atrial contraction|PAC]] displaying a [[right bundle branch block]] [[pattern]]
|
* Usually narrow (< 0.12 [[Second|s]])
|
* Breaks with [[vagal maneuvers]], [[adenosine]], [[diving reflex]], [[oculocardiac reflex]]
|
|
*[[Infant|Infants]]
*[[Cardiomyopathy]]
*[[Myocarditis]]
*[[Elderly]]
*[[Coronary artery disease]]
*[[Stroke]]
*Increased [[atrial natriuretic peptide]] ([[Atrial natriuretic peptide|ANP]])
*[[Hypercholesterolemia]]
|-
! colspan="2" |'''[[Wolff-Parkinson-White syndrome|Wolff-Parkinson-White Syndrome]]<ref name="pmid24982705">{{cite journal |vauthors=Rao AL, Salerno JC, Asif IM, Drezner JA |title=Evaluation and management of wolff-Parkinson-white in athletes |journal=Sports Health |volume=6 |issue=4 |pages=326–32 |date=July 2014 |pmid=24982705 |pmc=4065555 |doi=10.1177/1941738113509059 |url=}}</ref><ref name="pmid10597097">{{cite journal |vauthors=Rosner MH, Brady WJ, Kefer MP, Martin ML |title=Electrocardiography in the patient with the Wolff-Parkinson-White syndrome: diagnostic and initial therapeutic issues |journal=Am J Emerg Med |volume=17 |issue=7 |pages=705–14 |date=November 1999 |pmid=10597097 |doi=10.1016/s0735-6757(99)90167-5 |url=}}</ref>'''
|
* Regular
|
*[[Atrial]] [[rate]] is nearly 300 [[Beats per minute|bpm]] and [[ventricular]] [[rate]] is at 150 [[Beats per minute|bpm]]
|
* With [[orthodromic]] [[Conduction System|conduction]] due to a [[bypass tract]], the [[P wave]] [[Generalization|generally]] follows the [[QRS complex]], whereas in [[AVNRT]], the [[P wave]] is generally buried in the [[QRS complex]].
|
* Less than 0.12 [[Second|seconds]]
|
* A [[delta wave]] and [[evidence]] of [[ventricular]] [[pre-excitation]] if there is [[Conduction System|conduction]] to the [[ventricle]] via ante-grade [[Conduction System|conduction]] down an [[accessory pathway]]
* A [[delta wave]] and [[pre-excitation]] may not be [[Presenting symptom|present]] because [[Bypass tract|bypass tracts]] do not [[conduct]] ante-grade.
|
* May break in [[Response element|response]] to [[procainamide]], [[adenosine]], [[vagal maneuvers]]
|
* Worldwide [[prevalence]] of [[Wolff-Parkinson-White syndrome|WPW syndrome]] is 100 - 300 per 100,000
|
*[[Ebstein's anomaly]]
*[[Mitral valve prolapse]]: This [[cardiac]] [[Disorder (medicine)|disorder]], if [[Presenting symptom|present]], is [[Association (statistics)|associated]] with left-sided [[accessory pathways]].
*[[Hypertrophic cardiomyopathy]]: This [[Disorder (medicine)|disorder]] is [[Association (statistics)|associated]] with [[familial]]/[[inherited]] form of [[Wolff-Parkinson-White syndrome|WPW syndrome]].
*[[Hypokalemic periodic paralysis]]
*[[Pompe disease]]
*[[Tuberous sclerosis]]
|-
! colspan="2" |'''[[Ventricular fibrillation|Ventricular Fibrillation]] ([[Ventricular fibrillation|VF]])'''<ref name="pmid27899944">{{cite journal |vauthors=Glinge C, Sattler S, Jabbari R, Tfelt-Hansen J |title=Epidemiology and genetics of ventricular fibrillation during acute myocardial infarction |journal=J Geriatr Cardiol |volume=13 |issue=9 |pages=789–797 |date=September 2016 |pmid=27899944 |pmc=5122505 |doi=10.11909/j.issn.1671-5411.2016.09.006 |url=}}</ref><ref name="pmid11334828">{{cite journal |vauthors=Samie FH, Jalife J |title=Mechanisms underlying ventricular tachycardia and its transition to ventricular fibrillation in the structurally normal heart |journal=Cardiovasc. Res. |volume=50 |issue=2 |pages=242–50 |date=May 2001 |pmid=11334828 |doi=10.1016/s0008-6363(00)00289-3 |url=}}</ref><ref name="pmid20142817">{{cite journal |vauthors=Adabag AS, Luepker RV, Roger VL, Gersh BJ |title=Sudden cardiac death: epidemiology and risk factors |journal=Nat Rev Cardiol |volume=7 |issue=4 |pages=216–25 |date=April 2010 |pmid=20142817 |pmc=5014372 |doi=10.1038/nrcardio.2010.3 |url=}}</ref>
|
*[[Irregular heart rhythms|Irregular]]
|
* 150 to 500 [[Beats per minute|bpm]]
|
* Absent
|
* Absent
|
* Absent ([[R wave|R]] on [[T wave|T]] [[Phenomenology|phenomenon]] in the [[Set|setting]] of [[ischemia]])
|
* Does not break in response to [[procainamide]], [[adenosine]], [[vagal maneuvers]]
|
* 3-12% [[Case-based reasoning|cases]] of [[acute myocardial infarction]] ([[Acute myocardial infarction|AMI]])
* Out of 356,500 out of [[hospital]] [[Cardiac arrest|cardiac arrests]], 23% have [[Ventricular fibrillation|VF]] as initial [[rhythm]]
|
*[[Myocardial ischemia]] / [[Myocardial infarction|infarction]]
*[[Cardiomyopathy]]
*[[Channelopathies]] [[Example 1|e.g]]. [[Long QT syndrome|Long QT]] ([[acquired]] / [[congenital]])
*[[Electrolyte abnormalities]] ([[hypokalemia]]/[[hyperkalemia]], [[hypomagnesemia]])
*[[Aortic stenosis]]
*[[Aortic dissection]]
*[[Myocarditis]]
*[[Cardiac tamponade]]
*[[Blunt trauma]] ([[Commotio cordis|Commotio Cordis]])
*[[Sepsis]]
*[[Hypothermia]]
*[[Pneumothorax]]
*[[Seizures]]
*[[Stroke]]
|-
! colspan="2" |'''[[Ventricular tachycardia|Ventricular Tachycardia]]'''<ref name="pmid19252119">{{cite journal |vauthors=Koplan BA, Stevenson WG |title=Ventricular tachycardia and sudden cardiac death |journal=Mayo Clin. Proc. |volume=84 |issue=3 |pages=289–97 |date=March 2009 |pmid=19252119 |pmc=2664600 |doi=10.1016/S0025-6196(11)61149-X |url=}}</ref><ref name="pmid21505622">{{cite journal |vauthors=Levis JT |title=ECG Diagnosis: Monomorphic Ventricular Tachycardia |journal=Perm J |volume=15 |issue=1 |pages=65 |date=2011 |pmid=21505622 |pmc=3048638 |doi=10.7812/tpp/10-130 |url=}}</ref>
|
* Regular
|
* > 100 [[Beats per minute|bpm]] (150-200 [[Beats per minute|bpm]] common)
|
* Absent
|<br />
 
*Absent
*Initial [[R wave]] in [[V1-morph|V1]], initial r > 40 [[Millisecond|ms]] in [[V1-morph|V1]]/V2, [[Notch|notched]] [[S wave|S]] in [[V1-morph|V1]], initial [[R wave|R]] in [[aVR]], [[lead]] II [[R wave]] [[Peakadilly|peak]] [[Time constant|time]] ≥50 [[Millisecond|ms]], no RS in [[V1-morph|V1]]-V6, and [[atrioventricular dissociation]]
|
*[[Wide complex tachycardias|Wide complex]], [[QRS complex|QRS]] duration > 120 [[Millisecond|milliseconds]]
|
* Does not break in response to [[procainamide]], [[adenosine]], [[vagal maneuvers]]
|
* 5-10% of [[patients]] [[Presenting symptom|presenting]] with [[Acute myocardial infarction|AMI]]
|
*[[Coronary artery disease]]
*[[Aortic stenosis]]
*[[Cardiomyopathy]]
*[[Electrolyte imbalance|Electrolyte imbalances]] (e.g., [[hypokalemia]], [[hypomagnesemia]])
*[[Inherited]] [[channelopathies]] (e.g., [[long-QT syndrome]])
*[[Catecholaminergic polymorphic ventricular tachycardia]]
*[[Arrhythmogenic right ventricular dysplasia]]
*[[Myocardial infarction]]
*[[Torsades de pointes]] is a form of [[polymorphic VT]] that is often [[Association (statistics)|associated]] with a [[prolonged QT interval]]
|}


==References==
==References==
{{Reflist|2}}
{{Reflist|2}}


[[Category:Disease]]
[[Category:Cardiology]]
[[Category:Types of Heart Blocks]]
[[Category:Types of Heart Blocks|Infra-Hisian Block]]
[[Category:Cardiology]]
[[Category:Cardiology]]
[[Category:Electrophysiology]]
[[Category:Disease]]


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Latest revision as of 20:59, 19 August 2020

Infra-Hisian Block Microchapters

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Epidemiology and Demographics

Risk Factors

Natural History, Complications and Prognosis

Diagnosis

Treatment

Prevention

Differentiating Infra-Hisian Block from other Diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor-In-Chief: Sara Mohsin, M.D.[2]

Overview

Infra-Hisian block is defined as an impaired conduction in the electrical system of the heart that occurs below the atrioventricular node.

Historical Perspective

Classification

Classification of Infra-Hisian Block
Types of Infra-Hisian Block Sub-type
Type 2 second degree heart block (Mobitz II) _
Left bundle branch block Left anterior fascicular block
Left posterior fascicular block
Right bundle branch block _

Pathophysiology

Normal Cardiac Conduction

  1. The normal cardiac conduction proceeds in a way so as to allow time for the atrium to relax during atrial diastole.
  2. The electrical impulse generated in the SA node travels through the internodal pathways towards the AV node.
  3. The conduction through the AV node is slowed down as it travels through it. This decrease in velocity of conduction allows time for the atrium to contract ahead of the ventricle so that the blood from the atria can fill up the ventricles through the atrioventricular valves.
  4. As the impulse flows through the compact AV node, it rapidly conducts through the ventricular myocardial cells. Once the depolarization is complete, the ventricle relaxes during diastole in preparation for the next impulse.

Anatomy

Conduction system of the heart
Structure of the heart's conduction system

Pathophysiology of Mobitz type II second degree AV block

Pathophysiology of LBBB

Pathophysiology of RBBB

Genetics

Associated Syndromes

Pseudo Right Bundle Branch Block

Brugada syndrome:

Causes

Mobitz type II second degree AV block causes

  • Details of all the possible etiologies are given in the table below:
Major reversible causes of atrioventricular (AV) block
Physiologic and pathophysiologic
Increased vagal tone
  • Also known as hypervagotonia
Ischemic heart disease
Progressive cardiac conduction system disease Associated with:
Infections
Cardiomyopathy Infiltrative processes such as:

Other non-ischemic cardiomyopathies include:

Congenital AV block
Other reversible causes
Iatrogenic
Drugs (altering conduction through AV node)
Cardiac surgery
Catheter ablation of arrhythmias
Alcohol septal ablation for hypertrophic cardiomyopathy
Transcatheter closure of ventricular septal defect
Post-transcatheter aortic valve implantation

Life Threatening Causes

Life-threatening conditions can result in death or permanent disability within 24 hours if left untreated.[7]

Common Causes

Causes by Organ System

Cardiovascular Acute myocardial infarction, acute rheumatic fever, ASD, dilated cardiomyopathy, Ebstein's anomaly, hypersensitive carotid sinus syndrome, hypertension, hypertrophic cardiomyopathy, Lev's disease, myocardial bridging, myocarditis, normal variants, post aortic valve replacement, post catheter ablation for arrhythmias, post closure of a ventricular septal defect, post mitral valve replacement, tetralogy of Fallot, endocardial cushion defect, transposition of the great vessels, valvular heart disease, VSD
Chemical / poisoning No underlying causes
Dermatologic No underlying causes
Drug Side Effect Amiodarone, beta-blockers, digitalis, calcium channel blockers, cholinesterase inhibitors, disopyramide, dofetilide, dolasetron, donepezil, eslicarbazepine acetate, fesoterodine, fingolimod, flecainide, ibutilide, lacosamide, magnesium, paliperidone, pramipexole, procainamide, propafenone, propoxyphene, quinidine, sotalol, terodiline
Ear Nose Throat No underlying causes
Endocrine Hyperthyroidism, myxedema, thyrotoxic periodic paralysis
Environmental Hypothermia
Gastroenterologic Hemochromatosis
Genetic Emery-Dreifuss muscular dystrophy, Fabry disease, glycogenosis type 2b, hereditary neuromuscular disease, Kearns-Sayre syndrome
Hematologic Multiple myeloma Lymphoma[11]
Iatrogenic Post aortic valve replacement, post catheter ablation for arrhythmias, post closure of a ventricular septal defect, post mitral valve replacement
Infectious Disease Acute rheumatic fever, Chagas disease, diphtheria, Lyme disease, myocarditis, neonatal lupus erythematosus, protozoal infection, sarcoidosis, SLE, tuberculosis
Musculoskeletal / Ortho Ankylosing spondylitis, hereditary neuromuscular disease, Kearns-Sayre syndrome, mitochondrial genome inherited conditions, muscular dystrophy
Neurologic Enhanced vagal tone
Nutritional / Metabolic Fabry disease, glycogenosis type 2b
Obstetric/Gynecologic No underlying causes
Oncologic Multiple myeloma
Opthalmologic No underlying causes
Overdose / Toxicity No underlying causes
Psychiatric No underlying causes
Pulmonary Sarcoidosis
Renal / Electrolyte Hyperkalemia, hypokalemia
Rheum / Immune / Allergy Ankylosing spondylitis, dermatomyositis, rheumatoid arthritis, scleroderma, SLE
Sexual No underlying causes
Trauma No underlying causes
Urologic No underlying causes
Dental No underlying causes
Miscellaneous Amyloidosis, degenerative diseases

Causes in Alphabetical Order

Epidemiology and Demographics

Prevalence

Gender

Risk Factors

Natural History, Complications and Prognosis

Natural History

Complications

Prognosis

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Physical Examination

Laboratory Findings

Patients with second degree AV block should be checked for the following laboratory tests:[27]

Electrocardiogram

Shown below is an electrocardiogram of a 12 lead EKG with a 2:1 AV block.

Copyleft image obtained, courtesy of ECGpedia, http://en.ecgpedia.org/wiki/Main_Page

Shown below is an electrocardiogram of a type II second degree AV block (Mobitz type II).

Copyleft image obtained, courtesy of ECGpedia, http://en.ecgpedia.org/wiki/Main_Page

Treatment

Medical therapy for Mobitz II

Contraindicated medications

Second degree AV block(except in patients with a functioning artificial pacemaker)[30][31] is considered an absolute contraindication to the use of the following medications:

Surgery for Mobitz II

Definitive treatment-Pacemaker insertion

Prevention

Primary Prevention

Differentiating Infra-Hisian Block from other Diseases


Arrhythmia Rhythm Rate P wave PR Interval QRS Complex Response to Maneuvers Epidemiology Co-existing Conditions
Atrioventricular block[36] First degree [37][38]
  • Regular



Second degree[12][39] QRS is normal but dropped as the following:
Third degree[40][41]
  • Regular
Atrial Fibrillation (AFib)[42][43]
  • Absent
Atrial Flutter[44]
Atrioventricular nodal reentry tachycardia (AVNRT)[45][46][47][48]
  • Regular
Multifocal Atrial Tachycardia[49][50]
Paroxysmal Supraventricular Tachycardia
  • Regular
  • 150 and 240 bpm
  • Absent
  • Hidden in QRS
  • Absent
Premature Atrial Contractrions (PAC)[51][52]
  • Upright
  • Usually narrow (< 0.12 s)
Wolff-Parkinson-White Syndrome[53][54]
  • Regular
Ventricular Fibrillation (VF)[55][56][57]
  • Absent
  • Absent
Ventricular Tachycardia[58][59]
  • Regular
  • > 100 bpm (150-200 bpm common)
  • Absent

References

  1. ↑ Upshaw CB, Silverman ME (2000). "John Hay: discoverer of type II atrioventricular block". Clin Cardiol. 23 (11): 869–71. doi:10.1002/clc.4960231118. PMC 6655013 Check |pmc= value (help). PMID 11097138.
  2. ↑ Puech P, Wainwright RJ (1983). "Clinical electrophysiology of atrioventricular block". Cardiol Clin. 1 (2): 209–24. PMID 6544636.
  3. ↑ 3.0 3.1 3.2 3.3 Wogan JM, Lowenstein SR, Gordon GS (1993). "Second-degree atrioventricular block: Mobitz type II". J Emerg Med. 11 (1): 47–54. doi:10.1016/0736-4679(93)90009-v. PMID 8445186.
  4. ↑ 4.0 4.1 4.2 Li X, Xue Y, Wu H (2018). "A Case of Atrioventricular Block Potentially Associated with Right Coronary Artery Lesion and Ticagrelor Therapy Mediated by the Increasing Adenosine Plasma Concentration". Case Rep Vasc Med. 2018: 9385017. doi:10.1155/2018/9385017. PMC 5933017. PMID 29850368.
  5. ↑ Francia P, Balla C, Paneni F, Volpe M (2007). "Left bundle-branch block--pathophysiology, prognosis, and clinical management". Clinical Cardiology. 30 (3): 110–5. doi:10.1002/clc.20034. PMID 17385703. Unknown parameter |month= ignored (help)
  6. ↑ Yildiz BS, Gungor H, Gul I, Bilgin M, Zoghi M, Akilli A (2013). "Is a drug-challenge test with propafenone adequate to exclude Brugada syndrome?". Cardiovascular Journal of Africa. 24 (2): e4–6. doi:10.5830/CVJA-2012-068. PMID 23613002.
  7. ↑ 7.0 7.1 7.2 7.3 Mangi MA, Jones WM, Napier L. PMID 29493981. Missing or empty |title= (help)
  8. ↑ Misumida N, Ogunbayo GO, Kim SM, Abdel-Latif A, Ziada KM, Elayi CS (November 2018). "Frequency and Significance of High-Degree Atrioventricular Block and Sinoatrial Node Dysfunction in Patients With Non-ST-Elevation Myocardial Infarction". Am. J. Cardiol. 122 (10): 1598–1603. doi:10.1016/j.amjcard.2018.08.001. PMID 30227965.
  9. ↑ 9.0 9.1 9.2 Barold SS, Herweg B (December 2012). "Second-degree atrioventricular block revisited". Herzschrittmacherther Elektrophysiol. 23 (4): 296–304. doi:10.1007/s00399-012-0240-8. PMID 23224264.
  10. ↑ Kamatani T, Akizuki A, Kondo S, Shirota T (Fall 2016). "Second-Degree Atrioventricular Block Occurring After Tooth Extraction". Anesth Prog. 63 (3): 156–9. doi:10.2344/15-00042.1. PMC 5011958. PMID 27585419.
  11. ↑ Menicagli F, Lanza A, Sbrocca F, Baldi A, Spugnini EP (2016). "A case of advanced second-degree atrioventricular block in a ferret secondary to lymphoma". Open Vet J. 6 (1): 68–70. doi:10.4314/ovj.v6i1.10. PMC 4833871. PMID 27200273.
  12. ↑ 12.0 12.1 Zehender M, Meinertz T, Keul J, Just H (1990). "ECG variants and cardiac arrhythmias in athletes: clinical relevance and prognostic importance". Am Heart J. 119 (6): 1378–91. doi:10.1016/s0002-8703(05)80189-9. PMID 2191578.
  13. ↑ 13.0 13.1 13.2 Meimoun P, Zeghdi R, D'Attelis N, Berrebi A, Braunberger E, Deloche A; et al. (2002). "Frequency, predictors, and consequences of atrioventricular block after mitral valve repair". Am J Cardiol. 89 (9): 1062–6. doi:10.1016/s0002-9149(02)02276-2. PMID 11988196.
  14. ↑ Meimoun P, Zeghdi R, D'Attelis N, Berrebi A, Braunberger E, Deloche A; et al. (2002). "Frequency, predictors, and consequences of atrioventricular block after mitral valve repair". Am J Cardiol. 89 (9): 1062–6. doi:10.1016/s0002-9149(02)02276-2. PMID 11988196.
  15. ↑ Kerola T, Eranti A, Aro AL, Haukilahti MA, Holkeri A, Junttila MJ, Kenttä TV, Rissanen H, Vittinghoff E, Knekt P, Heliövaara M, Huikuri HV, Marcus GM (May 2019). "Risk Factors Associated With Atrioventricular Block". JAMA Netw Open. 2 (5): e194176. doi:10.1001/jamanetworkopen.2019.4176. PMC 6632153 Check |pmc= value (help). PMID 31125096.
  16. ↑ Schoeller R, Andresen D, Büttner P, Oezcelik K, Vey G, Schröder R (March 1993). "First- or second-degree atrioventricular block as a risk factor in idiopathic dilated cardiomyopathy". Am. J. Cardiol. 71 (8): 720–6. doi:10.1016/0002-9149(93)91017-c. PMID 8447272.
  17. ↑ Rodstein M, Wolloch L, Iuster Z (1979). "The natural history intraventricular conduction disturbances in the aged: an analysis of the developing second and third degree heart block with clinical pathological correlations". Am. J. Med. Sci. 277 (2): 179–88. doi:10.1097/00000441-197903000-00006. PMID 463945.
  18. ↑ 18.0 18.1 Bexton RS, Camm AJ (March 1984). "Second degree atrioventricular block". Eur. Heart J. 5 Suppl A: 111–4. doi:10.1093/eurheartj/5.suppl_a.111. PMID 6373268.
  19. ↑ Thiruganasambandamoorthy V, Hess EP, Turko E, Tran ML, Wells GA, Stiell IG (July 2012). "Defining abnormal electrocardiography in adult emergency department syncope patients: the Ottawa Electrocardiographic Criteria". CJEM. 14 (4): 248–58. PMID 22813399.
  20. ↑ Barold SS, Van Heuverswyn FE, Timmers L, Stroobandt RX (August 2014). "Mobitz type II second-degree atrioventricular block during dobutamine stress echocardiography. True or false?". Echocardiography. 31 (7): 799–801. doi:10.1111/echo.12577. PMID 25080840.
  21. ↑ 21.0 21.1 Fu Md J, Bhatta L (2018). "Lyme carditis: Early occurrence and prolonged recovery". J Electrocardiol. 51 (3): 516–518. doi:10.1016/j.jelectrocard.2017.12.035. PMID 29275956.
  22. ↑ 22.0 22.1 Kashou AH, Goyal A, Nguyen T, Chhabra L. PMID 29083636. Missing or empty |title= (help)
  23. ↑ Zeppilli P, Fenici R, Sassara M, Pirrami MM, Caselli G (September 1980). "Wenckebach second-degree A-V block in top-ranking athletes: an old problem revisited". Am. Heart J. 100 (3): 281–94. doi:10.1016/0002-8703(80)90140-4. PMID 7405798.
  24. ↑ Rosen KM, Dhingra RC, Loeb HS, Rahimtoola SH (1973). "Chronic heart block in adults. Clinical and electrophysiological observations". Arch Intern Med. 131 (5): 663–72. PMID 4701376.
  25. ↑ Schneider MD, Roller DH, Morganroth J, Josephson ME (July 1978). "The syndromes of familial atrioventricular block with sinus bradycardia: prognostic indices, electrophysiologic and histopathologic correlates". Eur J Cardiol. 7 (5–6): 337–51. PMID 699934.
  26. ↑ Trappe HJ (September 2016). "[Consciousness disorders from cardiological view]". Dtsch. Med. Wochenschr. (in German). 141 (19): 1361–9. doi:10.1055/s-0042-103177. PMID 27642736.
  27. ↑ Gupta PK, Lichstein E, Chadda KD (1976). "Chronic His bundle block. Clinical, electrocardiographic, electrophysiological, and follow-up studies on 16 patients". Br Heart J. 38 (12): 1343–9. doi:10.1136/hrt.38.12.1343. PMC 483178. PMID 1008977.
  28. ↑ Steere AC, McHugh G, Damle N, Sikand VK (2008). "Prospective study of serologic tests for lyme disease". Clin Infect Dis. 47 (2): 188–95. doi:10.1086/589242. PMC 5538270. PMID 18532885.
  29. ↑ Schernthaner C, Kraus J, Danmayr F, Hammerer M, Schneider J, Hoppe UC, Strohmer B (March 2016). "Short-term pacemaker dependency after transcatheter aortic valve implantation". Wien. Klin. Wochenschr. 128 (5–6): 198–203. doi:10.1007/s00508-015-0906-4. PMID 26745972.
  30. ↑ Brignole M, Deharo JC, Guieu R (August 2015). "Syncope and Idiopathic (Paroxysmal) AV Block". Cardiol Clin. 33 (3): 441–7. doi:10.1016/j.ccl.2015.04.012. PMID 26115830.
  31. ↑ Kelkar PN (August 1998). "Atenolol induced high grade AV block". J Assoc Physicians India. 46 (8): 748, 751. PMID 11229299.
  32. ↑ Zeltser D, Justo D, Halkin A, Rosso R, Ish-Shalom M, Hochenberg M, Viskin S (July 2004). "Drug-induced atrioventricular block: prognosis after discontinuation of the culprit drug". J. Am. Coll. Cardiol. 44 (1): 105–8. doi:10.1016/j.jacc.2004.03.057. PMID 15234417.
  33. ↑ Tuohy S, Saliba W, Pai M, Tchou P (January 2018). "Catheter ablation as a treatment of atrioventricular block". Heart Rhythm. 15 (1): 90–96. doi:10.1016/j.hrthm.2017.08.015. PMID 28823599.
  34. ↑ Kusumoto FM, Schoenfeld MH, Barrett C, Edgerton JR, Ellenbogen KA, Gold MR, Goldschlager NF, Hamilton RM, Joglar JA, Kim RJ, Lee R, Marine JE, McLeod CJ, Oken KR, Patton KK, Pellegrini CN, Selzman KA, Thompson A, Varosy PD (August 2019). "2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society". J. Am. Coll. Cardiol. 74 (7): e51–e156. doi:10.1016/j.jacc.2018.10.044. PMID 30412709.
  35. ↑ Strasberg B, Amat-Y-Leon F, Dhingra RC, Palileo E, Swiryn S, Bauernfeind R, Wyndham C, Rosen KM (May 1981). "Natural history of chronic second-degree atrioventricular nodal block". Circulation. 63 (5): 1043–9. doi:10.1161/01.cir.63.5.1043. PMID 7471363.
  36. ↑ Kerola T, Eranti A, Aro AL, Haukilahti MA, Holkeri A, Junttila MJ; et al. (2019). "Risk Factors Associated With Atrioventricular Block". JAMA Netw Open. 2 (5): e194176. doi:10.1001/jamanetworkopen.2019.4176. PMC 6632153 Check |pmc= value (help). PMID 31125096.
  37. ↑ Barold SS (1996). "Indications for permanent cardiac pacing in first-degree AV block: class I, II, or III?". Pacing Clin Electrophysiol. 19 (5): 747–51. doi:10.1111/j.1540-8159.1996.tb03355.x. PMID 8734740.
  38. ↑ Upshaw CB (2004). "Comparison of the prevalence of first-degree atrioventricular block in African-American and in Caucasian patients: an electrocardiographic study III". J Natl Med Assoc. 96 (6): 756–60. PMC 2568382. PMID 15233485.
  39. ↑ Friedman HS, Gomes JA, Haft JI (1975). "An analysis of Wenckebach periodicity". J Electrocardiol. 8 (4): 307–15. doi:10.1016/s0022-0736(75)80003-3. PMID 1176840.
  40. ↑ OSTRANDER LD, BRANDT RL, KJELSBERG MO, EPSTEIN FH (June 1965). "ELECTROCARDIOGRAPHIC FINDINGS AMONG THE ADULT POPULATION OF A TOTAL NATURAL COMMUNITY, TECUMSEH, MICHIGAN". Circulation. 31: 888–98. doi:10.1161/01.cir.31.6.888. PMID 14297523.
  41. ↑ Movahed MR, Hashemzadeh M, Jamal MM (October 2005). "Increased prevalence of third-degree atrioventricular block in patients with type II diabetes mellitus". Chest. 128 (4): 2611–4. doi:10.1378/chest.128.4.2611. PMID 16236932.
  42. ↑ Lankveld TA, Zeemering S, Crijns HJ, Schotten U (July 2014). "The ECG as a tool to determine atrial fibrillation complexity". Heart. 100 (14): 1077–84. doi:10.1136/heartjnl-2013-305149. PMID 24837984.
  43. ↑ Harris K, Edwards D, Mant J (2012). "How can we best detect atrial fibrillation?". J R Coll Physicians Edinb. 42 Suppl 18: 5–22. doi:10.4997/JRCPE.2012.S02. PMID 22518390.
  44. ↑ Cosío FG (June 2017). "Atrial Flutter, Typical and Atypical: A Review". Arrhythm Electrophysiol Rev. 6 (2): 55–62. doi:10.15420/aer.2017.5.2. PMC 5522718. PMID 28835836.
  45. ↑ Katritsis DG, Josephson ME (August 2016). "Classification, Electrophysiological Features and Therapy of Atrioventricular Nodal Reentrant Tachycardia". Arrhythm Electrophysiol Rev. 5 (2): 130–5. doi:10.15420/AER.2016.18.2. PMC 5013176. PMID 27617092.
  46. ↑ Letsas KP, Weber R, Siklody CH, Mihas CC, Stockinger J, Blum T, Kalusche D, Arentz T (April 2010). "Electrocardiographic differentiation of common type atrioventricular nodal reentrant tachycardia from atrioventricular reciprocating tachycardia via a concealed accessory pathway". Acta Cardiol. 65 (2): 171–6. doi:10.2143/AC.65.2.2047050. PMID 20458824.
  47. ↑ "Atrioventricular Nodal Reentry Tachycardia (AVNRT) - StatPearls - NCBI Bookshelf".
  48. ↑ Schernthaner C, Danmayr F, Strohmer B (2014). "Coexistence of atrioventricular nodal reentrant tachycardia with other forms of arrhythmias". Med Princ Pract. 23 (6): 543–50. doi:10.1159/000365418. PMC 5586929. PMID 25196716.
  49. ↑ Scher DL, Arsura EL (September 1989). "Multifocal atrial tachycardia: mechanisms, clinical correlates, and treatment". Am. Heart J. 118 (3): 574–80. doi:10.1016/0002-8703(89)90275-5. PMID 2570520.
  50. ↑ Goodacre S, Irons R (March 2002). "ABC of clinical electrocardiography: Atrial arrhythmias". BMJ. 324 (7337): 594–7. doi:10.1136/bmj.324.7337.594. PMC 1122515. PMID 11884328.
  51. ↑ Lin CY, Lin YJ, Chen YY, Chang SL, Lo LW, Chao TF, Chung FP, Hu YF, Chong E, Cheng HM, Tuan TC, Liao JN, Chiou CW, Huang JL, Chen SA (August 2015). "Prognostic Significance of Premature Atrial Complexes Burden in Prediction of Long-Term Outcome". J Am Heart Assoc. 4 (9): e002192. doi:10.1161/JAHA.115.002192. PMC 4599506. PMID 26316525.
  52. ↑ Strasburger JF, Cheulkar B, Wichman HJ (December 2007). "Perinatal arrhythmias: diagnosis and management". Clin Perinatol. 34 (4): 627–52, vii–viii. doi:10.1016/j.clp.2007.10.002. PMC 3310372. PMID 18063110.
  53. ↑ Rao AL, Salerno JC, Asif IM, Drezner JA (July 2014). "Evaluation and management of wolff-Parkinson-white in athletes". Sports Health. 6 (4): 326–32. doi:10.1177/1941738113509059. PMC 4065555. PMID 24982705.
  54. ↑ Rosner MH, Brady WJ, Kefer MP, Martin ML (November 1999). "Electrocardiography in the patient with the Wolff-Parkinson-White syndrome: diagnostic and initial therapeutic issues". Am J Emerg Med. 17 (7): 705–14. doi:10.1016/s0735-6757(99)90167-5. PMID 10597097.
  55. ↑ Glinge C, Sattler S, Jabbari R, Tfelt-Hansen J (September 2016). "Epidemiology and genetics of ventricular fibrillation during acute myocardial infarction". J Geriatr Cardiol. 13 (9): 789–797. doi:10.11909/j.issn.1671-5411.2016.09.006. PMC 5122505. PMID 27899944.
  56. ↑ Samie FH, Jalife J (May 2001). "Mechanisms underlying ventricular tachycardia and its transition to ventricular fibrillation in the structurally normal heart". Cardiovasc. Res. 50 (2): 242–50. doi:10.1016/s0008-6363(00)00289-3. PMID 11334828.
  57. ↑ Adabag AS, Luepker RV, Roger VL, Gersh BJ (April 2010). "Sudden cardiac death: epidemiology and risk factors". Nat Rev Cardiol. 7 (4): 216–25. doi:10.1038/nrcardio.2010.3. PMC 5014372. PMID 20142817.
  58. ↑ Koplan BA, Stevenson WG (March 2009). "Ventricular tachycardia and sudden cardiac death". Mayo Clin. Proc. 84 (3): 289–97. doi:10.1016/S0025-6196(11)61149-X. PMC 2664600. PMID 19252119.
  59. ↑ Levis JT (2011). "ECG Diagnosis: Monomorphic Ventricular Tachycardia". Perm J. 15 (1): 65. doi:10.7812/tpp/10-130. PMC 3048638. PMID 21505622.


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