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accelerated idioventricular rhythm (AIVR)
Etiology:
1) acute myocardial infarction (MI)
- percutaneous coronary intervention after MI
2) drug toxicity - digitalis
Pathology:
- accelerated idioventricular rhythm (AIVR) generally occurs secondary to increased automaticity from within the terminal Purkinje system of ventricular myocardium
- occurs with reperfusion of infarct-associated coronary artery
Clinical manifestations:
1) transient & intermittent
2) usually asymptomatic
3) hemodynamic deterioration may occur in patients who do not tolerate AV asynchrony
Special laboratory:
- electrocardiogram:
a) ventricular rate of 60-110/min
- almost always < 120/min, generally < 100/min [2]
b) ventricular rate usually exceeds spontaneous atrial rate
c) QRS complex usually wide & bizarre
d) intact AV retrograde conduction
- inverted p-waves after each wide QRS complex
e) retrograde AV block
- normal QRS complexes preceded by p-waves among wide bizarre QRS complexes (atrial capture)
f) AVIR is suppressed when the atrial rate exceeds the ventricular rate
Management:
1) AVIR is generally self-limited not requiring therapy within 1st 24 hours after MI [2]
2) in symptomatic patients, therapy is directed towards increasing the sinus rate with:
a) atropine
b) isoproterenol
c) overdrive atrial pacing
General
ventricular arrhythmia
wide complex tachycardia
References
- Manual of Medical Therapeutics, 28th ed, Ewald &
McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 147
- Medical Knowledge Self Assessment Program (MKSAP) 17,
American College of Physicians, Philadelphia 2015