Paroxysmal AV block: Difference between revisions

Jump to navigation Jump to search
Line 19: Line 19:


[[Paroxysmal AV Block Intrinsic AV Block|Intrinsic AV Block]] | [[Paroxysmal AV Block Extrinsic Vagal AV Block|Extrinsic Vagal AV Block]] | [[Paroxysmal AV Block Extrinsic Idiopathic AV Block|Extrinsic Idiopathic AV Block]]
[[Paroxysmal AV Block Intrinsic AV Block|Intrinsic AV Block]] | [[Paroxysmal AV Block Extrinsic Vagal AV Block|Extrinsic Vagal AV Block]] | [[Paroxysmal AV Block Extrinsic Idiopathic AV Block|Extrinsic Idiopathic AV Block]]
==Extrinsic Idiopathic AV Block==
*The pathogenesis of extrinsic idiopathic paroxysmal AV block (EI-AVB) can be correlated to ''' adenosine plasma levels (APL) and increased affinity of adenosine A1 receptors'''.
*There is a recurrent history of unexplained syncope, absence of ECG and cardiac abnormalities and a good prognosis.
*Due to innately low APL values seen in these patients, there is '''an upregulation of A1 receptors''', such that even during a mild transient surge in endogenous adenosine levels, AV block occurs.
*A1 receptors, which are present more in the AV node than the SA node, impose an '''antiadrenergic action''' by antagonizing β1 receptors, the sympathetic nervous system, hyperpolarizing the SA and AV nodes through potassium channels and lowering intracellular cAMP levels. <ref name="pmid26115830">{{cite journal| author=Brignole M, Deharo JC, Guieu R| title=Syncope and Idiopathic (Paroxysmal) AV Block. | journal=Cardiol Clin | year= 2015 | volume= 33 | issue= 3 | pages= 441-7 | pmid=26115830 | doi=10.1016/j.ccl.2015.04.012 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=26115830  }} </ref>
*Therefore, in such patients an injection of adenosine or adenosine triphosphate (ATP) may reproduce the attack and adenosine antagonists such as theophylline may be an efficacious treatment option.
*On an ECG, there is an absence of signs of vagal stimulation, atrial/ventricular premature beats and there may be a presence of narrow QRS complexes prior to the period of complete AV Block/ asystole
*Certain studies have also noticed '''genetic polymorphisms in A2A receptors''' in a population of people experiencing recurrent unexplained syncope.<ref name="pmid19386617">{{cite journal| author=Saadjian AY, Gerolami V, Giorgi R, Mercier L, Berge-Lefranc JL, Paganelli F | display-authors=etal| title=Head-up tilt induced syncope and adenosine A2A receptor gene polymorphism. | journal=Eur Heart J | year= 2009 | volume= 30 | issue= 12 | pages= 1510-5 | pmid=19386617 | doi=10.1093/eurheartj/ehp126 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=19386617  }} </ref>


==[[Paroxysmal AV block causes|Causes]]==
==[[Paroxysmal AV block causes|Causes]]==

Revision as of 07:14, 15 June 2020

Paroxysmal AV block Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Paroxysmal AV block from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

X-ray

Echocardiography and Ultrasound

CT scan

MRI

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Interventions

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Paroxysmal AV block On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Paroxysmal AV block

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Paroxysmal AV block

CDC on Paroxysmal AV block

Paroxysmal AV block in the news

Blogs on Paroxysmal AV block

Directions to Hospitals Treating Psoriasis

Risk calculators and risk factors for Paroxysmal AV block

For patient information, click here

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Akash Daswaney, M.B.B.S[2]

Synonyms and keywords:

Overview

Historical Perspective

Historical Perspective | Famous cases

Classification

Classification Based on Cause

Pathophysiology

Intrinsic AV Block | Extrinsic Vagal AV Block | Extrinsic Idiopathic AV Block

Causes

Differentiating Paroxysmal AV block from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Diagnosis

Initial Approach | History and Symptoms | Electrocardiogram, Holter Monitoring, External Loop Recorder | Implantable Loop Recorder | Electrophysiologic studies | Vagal Maneuvers,Carotid Sinus Massage and Tilt Table testing | Laboratory Findings and Stimulation tests | Diagnostic Summary Table |


Treatment

Cardiac Pacing |Treatment for Reflex Syncope|Theopylline |

Case Studies

Case #1


Template:WH Template:WS