Premature atrial contraction: Difference between revisions

Jump to navigation Jump to search
No edit summary
No edit summary
Line 65: Line 65:
|-bgcolor="LightSteelBlue"
|-bgcolor="LightSteelBlue"
| '''Endocrine'''
| '''Endocrine'''
|bgcolor="Beige"| [[Diabetic ketoacidosis]], [[metabolic syndrome]], [[hyperthyroidism|subclinical hyperthyroidism]], [[thyrotoxicosis]]
|bgcolor="Beige"| [[Cushing's syndrome]], [[Diabetic ketoacidosis]], [[metabolic syndrome]], [[hyperthyroidism|subclinical hyperthyroidism]], [[thyrotoxicosis]]
|-
|-
|-bgcolor="LightSteelBlue"
|-bgcolor="LightSteelBlue"

Revision as of 03:46, 11 August 2013

Premature atrial contraction
12 lead EKG shows Premature Atrial Contractions and bifascicular block (RBBB + LAFB)
ICD-10 I49.1
ICD-9 427.61
MeSH D018880

WikiDoc Resources for Premature atrial contraction

Articles

Most recent articles on Premature atrial contraction

Most cited articles on Premature atrial contraction

Review articles on Premature atrial contraction

Articles on Premature atrial contraction in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Premature atrial contraction

Images of Premature atrial contraction

Photos of Premature atrial contraction

Podcasts & MP3s on Premature atrial contraction

Videos on Premature atrial contraction

Evidence Based Medicine

Cochrane Collaboration on Premature atrial contraction

Bandolier on Premature atrial contraction

TRIP on Premature atrial contraction

Clinical Trials

Ongoing Trials on Premature atrial contraction at Clinical Trials.gov

Trial results on Premature atrial contraction

Clinical Trials on Premature atrial contraction at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Premature atrial contraction

NICE Guidance on Premature atrial contraction

NHS PRODIGY Guidance

FDA on Premature atrial contraction

CDC on Premature atrial contraction

Books

Books on Premature atrial contraction

News

Premature atrial contraction in the news

Be alerted to news on Premature atrial contraction

News trends on Premature atrial contraction

Commentary

Blogs on Premature atrial contraction

Definitions

Definitions of Premature atrial contraction

Patient Resources / Community

Patient resources on Premature atrial contraction

Discussion groups on Premature atrial contraction

Patient Handouts on Premature atrial contraction

Directions to Hospitals Treating Premature atrial contraction

Risk calculators and risk factors for Premature atrial contraction

Healthcare Provider Resources

Symptoms of Premature atrial contraction

Causes & Risk Factors for Premature atrial contraction

Diagnostic studies for Premature atrial contraction

Treatment of Premature atrial contraction

Continuing Medical Education (CME)

CME Programs on Premature atrial contraction

International

Premature atrial contraction en Espanol

Premature atrial contraction en Francais

Business

Premature atrial contraction in the Marketplace

Patents on Premature atrial contraction

Experimental / Informatics

List of terms related to Premature atrial contraction

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Mugilan Poongkunran M.B.B.S [3]

Synonyms and keywords: PAC; PACs; premature atrial contractions; premature atrial complex; premature atrial complexes; APC; APCs; atrial premature contraction; atrial premature contractions; atrial premature complex; atrial premature complexes; APB; atrial premature beat; atrial premature beats; extrasystole, atrial; premature atrial beat; premature atrial beats; premature supraventricular beat; premature supraventricular beats

Overview

Premature atrial contractions is a benign type of premature heart beat which originates in one of the upper two chambers of the heart (the atria). PACs usually reflect one of the conditions listed in the differential diagnosis of underlying causes below, and the treatment involves removing or treating the underlying cause. PACs are to be distinguished from premature ventricular contractions (PVCs) that originate in one of the lower pumping chambers (the ventricles).

Causes

Life Threatening Causes

Common Causes

Causes by Organ System

Cardiovascular Congenital heart disease, congestive heart failure, coronary heart disease, dilated cardiomyopathy, holiday heart syndrome, hypertensive heart disease, hypertrophic cardiomyopathy, mitral regurgitation, mitral stenosis, mitral valve prolapse, myocardial infarction, myocarditis, STEMI, valvular heart disease, ischemic heart disease
Chemical / poisoning No underlying causes
Dermatologic No underlying causes
Drug Side Effect Alpha interferon, aminophylline, amiodarone, amlodipine, amphetamines, cocaine, digoxin, diltiazem, dobutamine, ephedrine, 5-fluorouracil, isoproterenol, phenylephrine, salbutamol, sympathomimetic agents, tacrolimus, theophylline, thiazides, verapamil
Ear Nose Throat No underlying causes
Endocrine Cushing's syndrome, Diabetic ketoacidosis, metabolic syndrome, subclinical hyperthyroidism, thyrotoxicosis
Environmental No underlying causes
Gastroenterologic No underlying causes
Genetic No underlying causes
Hematologic No underlying causes
Iatrogenic Acute cardiac allograft rejection, cardiac stress test, cardiac transplantation, cardioversion, pacemaker malfunction, transjugular intrahepatic portosystemic shunts
Infectious Disease Myocarditis
Musculoskeletal / Ortho No underlying causes
Neurologic Subarachnoid hemorrhage
Nutritional / Metabolic Dehydration, electrolyte disturbance, hypokalemia, hypomagnesemia
Obstetric/Gynecologic New born
Oncologic No underlying causes
Opthalmologic No underlying causes
Overdose / Toxicity Amphetamines, cocaine, digoxin, cannabis
Psychiatric Anxiety disorders, bulimia nervosa, Takotsubo cardiomyopathy
Pulmonary Chronic lung disease, COPD, hypoxia, pulmonary embolism, hypercapnia, respiratory acidosis, pneumonia, pulmonary hypertension, obstructive sleep apnea
Renal / Electrolyte Chronic renal failure
Rheum / Immune / Allergy Acute cardiac allograft rejection
Sexual No underlying causes
Trauma No underlying causes
Urologic No underlying causes
Dental No underlying causes
Miscellaneous Alcoholism, caffeine, chocolate, heavy exercise, fatigue, fever, idiopathic, stress

Causes in Alphabetical Order

Prognosis

In general the prognosis of PACs is good, and their occurrence and prognosis is determined by the underlying condition that triggered the PACs. In rare cases, a PAC can, like a PVC, trigger a more serious arrhythmia such as atrial flutter or atrial fibrillation. Unlike PVC's, PAC's generally do not cause hemodynamic compromise because the conduction throughout the AV node and ventricles is normal, and the filling and contraction of the heart is therefore normal.

Diagnosis

Symptoms

There may be a sense of "a skipped beat" or "a thump in the chest" or neck. In many cases, the person feels nothing.

Physical Examination

Pulse

The pulse may feel irregular in a patient who actively has frequent PACs.

Laboratory Findings

Electrocardiogram

The presence of PACs is diagnosed based upon either an EKG, Holter, or Cardiac Event Monitor.

  1. By definition the P waves are premature
  2. Morphology of the P' wave is different than the P wave in normal sinus rhythm. If its origin is close to that of the sinus node, then the P' morphology is hard to distinguish from the native sinus P wave.
  3. A PAC differs from a Premature Junctional Contraction (PJC) in that the PR interval is > 0.12 second in a PAC.
  4. The PR interval may be shorter than that in Normal Sinus Rhythm (NSR) if it is located closer to the AV node.
  5. The PR interval tends to lengthen when the coupling time to the PAC is short.
  6. A PAC may not be conducted to the ventricles and this is called a blocked PAC.
    • The differential diagnosis in this scenario includes second degree AV block. In second degree AV block, the PP intervals remain constant.
  7. Usually the QRS is of normal duration, but occasionally there is aberrant conduction, most frequently of Right Bundle Branch Block (RBBB) morphology.
    • Aberrancy is more likely to occur when the coupling time is shorter.
  8. Usually there is no compensatory pause. The PAC resets the sinus node.
  9. Most of these patients do not have organic heart disease.
    • 64% of healthy subjects will have PACs on 24 hour Holter monitoring.
    • Frequency higher in the elderly
  10. The QRS complex is normal
  11. There is normal T wave repolarization (not inverted to the other T waves)

{{#ev:youtube|KPN1Jgf7hfM}}

EKG Examples


Shown below is an example of an EKG showing sinus rhythm with atrial premature beats in trigemini.

Copyleft image obtained courtesy of ECGpedia, http://en.ecgpedia.org/wiki/File:Rhythm_premature.png


Shown below is an example of an EKG showing premature atrial contractions with evident negative p-wave.

Copyleft image obtained courtesy of ECGpedia, http://en.ecgpedia.org/wiki/File:Bes.png


Shown below is an example of a 12 lead EKG showing premature atrial contractions in a patient with RBBB + LAFB

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


Shown below is an EKG showing sinus rhythm with atrial premature beats in trigemini.

Copyleft image obtained courtesy of ECGpedia, http://en.ecgpedia.org/wiki/File:E287.jpg


Shown below is an EKG showing sinus rhythm with premature atrial complexes. The P' wave can be seen deforming the T wave in the lead II rhythm strip. Note also that the atrial premature complexes reset the sinus node and hence there is no compensatory pause before the next sinus P wave. The QRS is deformed with a rsR' in V1 and a broad S in I with a duration of > 120 ms. diagnostic of aberrance with a right bundle branch morphology. The S1 Q3 and the right ward axis of the aberrant complexes suggest an additional left posterior fasicular block.

Copyleft image obtained courtesy of ECGpedia, http://en.ecgpedia.org/wiki/File:E000746.jpg


Shown below is an EKG showing an atrial premature beat (3rd beat). In fact note the QT interval of the second beat is short and in fact this was an artifact from a paper jam in the EKG recorder. The EKG also shows a first degree A/V block and abnormal Q waves in the inferior and anterior leads consistent with inferior and anterior myocardial infarctions which are probably old.

Copyleft image obtained courtesy of ECGpedia, http://en.ecgpedia.org/wiki/File:E281.jpg


Treatment

Removal or treatment of the underlying cause of PACs listed in the differential diagnosis is generally sufficient. Beta-blockers may be helpful if the patient remains symptomatic.

References


Template:WikiDoc Sources