Electrophysiological disturbances in heart failure.

Cardiac arrhythmias are a frequent and important complication of cardiac failure regardless of aetiology. It might be expected that those afflicted would be aware of their occurrence, but surprisingly, even salvoes of ventricular tachycardia often are not perceived by patients. It has required 24 hour ambulatory electrocardiographic recordings to disclose the true prevalence of arrhythmias. The typical arrhythmias complicating heart failure comprise atrial and ventricular extrasystoles, atrial fibrillation (which is arguably the most important arrhythmia), and short paroxysms of polymorphic ventricular tachycardia. Sustained regular narrow QRS tachycardias and monomorphic ventricular tachycardia are unusual. This speczrum of arrhythmias suggests that either triggered automaticity or complex functional re-entry are the more usual basic electrophysiological arrhythmogenic mechanisms in heart failure than is single circuit re-entry.