The Prognostic Significance of Inducing Nonsustained Ventricular Tachycardia in Patients Presenting with Sustained Ventricular Tachycardia or Cardiac Arrest

The significance of inducing nonsustained ventricular tachycardia during baseline electrophysiological testing in patients presenting with sustained ventricular arrhythmias is unclear. In this study, 145 consecutive patients presenting with cardiac arrest or sustained ventricular tachycardia underwent electrophysiological study. Twenty five (17%) had no inducible ventricular tachycardia (group I), 33 (23%) had inducible nonsustained ventricular tachycardia (group II), and 87 (60%) had inducible sustained ventricular tachycardia (group 111). Group I was not treated with antiarrhythmic therapy. Groups II and III underwent serial drug trials guided by electrophysiological testing. Mean follow-up for all three groups was 31 ± 18 months. The actuarial rate of arrhythmia recurrence for group 1 at 12, 24, and 36 months of follow-up was 0%, 6%, and 17%, respectively. This actuarial arrhythmia recurrence rate for group I was significantly lower (P < 0.05) than that of group II (16%, 27%, and 32%) and group III (32%, 39%, and 44%). There was no significant difference between the arrhythmia recurrence rates in groups 11 and III. When groups II and III were broken down into drug responders and nonresponders, drug responders in both groups had significantly fewer arrhythmia recurrences than nonresponders (P < 0.05). The overall incidence of sudden death was low (11 of 145, 8%) and not significantly different between groups I, II, and III. In summary, among patients who present with sustained ventricular arrhythmias, those who have nonsustained ventricular tachycardia induced during baseline electrophysiological testing respond to serial drug testing and have long-term outcomes similar to those with inducible sustained ventricular tachycardia.