pause-dependent arrhythmia
Arrhythmia that is triggered or facilitated by bradycardia or pauses in cardiac rhythm, often related to early afterdepolarizations.
Full Definition
Pause-dependent arrhythmias are abnormal cardiac rhythms that are triggered or facilitated by periods of bradycardia, long pauses, or slow heart rates. These arrhythmias typically occur after a pause in the underlying rhythm and are often associated with early afterdepolarizations (EADs) that develop during prolonged repolarization phases. The classic example is torsades de pointes, which characteristically follows a short-long-short sequence where a premature beat is followed by a pause, then another beat that triggers the polymorphic ventricular tachycardia. The pause allows for prolonged repolarization and increased dispersion of refractoriness, creating conditions favorable for triggered activity. Treatment typically involves increasing the heart rate through temporary pacing or isoproterenol infusion to prevent the pauses that precipitate these arrhythmias. Understanding this mechanism is crucial for appropriate acute management.
Usage
Usage note: Always specify the type of arrhythmia that is pause-dependent for clarity.
In Context
- "The patient's pause-dependent torsades de pointes was successfully prevented with temporary ventricular pacing at 90 bpm." — ICU progress note
- "Pause-dependent arrhythmias secondary to quinidine were eliminated after drug discontinuation." — Cardiology discharge summary