Clinical characteristics of rapid atrial fibrillation preceding ventricular tachycardia

Spontaneous degeneration of rapid atrial fibrillation (AF) to ventricular f ibrillation has been documented in patients with hypertrophic cardiomyopath y (HCM) and Wolff-Parkinson-White (WPW) syndrome. However, the importance o f rapid AF as a triggering factor leading to sustained ventricular tachycar dia (VT) in patients with other structural heart diseases is unknown. The p urpose of this study was to characterize patients who developed VT followin g paroxysmal or chronic AF with a rapid ventricular response. The mode of V T initiation and clinical characteristics were reviewed in 8 patients (7 me n, 1 woman age 64 +/-9 years) with monomorphic VT preceded by rapid AF (6 p aroxysmal, 2 chronic). All patients developed monomorphic VT (mean cycle le ngth 285 +/- 31 ms) with syncope only after rapid, but hemodynamically stab le, AF (mean heart rate 153 +/- 30 beats/min) without acute ischemia or exa cerbation of heart failure. There was no significant variation in R-R inter vals of the AF preceding VT. All patients had structural heart disease othe r than HCM with a mean left ventricular ejection fraction of 41 +/- 12%. Du ring the 807 +/- 201 days of follow-up, VTs did not recur in 7 patients. Si nus rhythm was maintained in all patients who received amiodarone. Rapid AF may be an important triggering factor of monomorphic VT in some patients w ith moderately impaired cardiac function.