Long-term outcome of survivors of cardiac arrest whose therapy is guided by electrophysiologic testing

Abstract

The long-term outcome of 217 consecutive survivors of cardiac arrest whose therapy was guided by electrophysiologic testing was analyzed. After electrophysiologic testing, 81 patients (37%) were classified as having no inducible arrhythmia and were treated without antiarrhythmic drugs; 23 received an implantable defibrillator. Of the 136 patients with inducible arrhythmia, the 51 (38%) who responded to serial drug testing were treated with the successful drug and the 85 (62%) with unsuccessful drug testing were treated with an implantable defibrillator (47 patients), amiodarone (36 patients) or drugs that were unsuccessful during testing (2 patients). The mean follow-up interval for all patients was 35 ± 23 months.The actuarial incidence of sudden death and overall death was similar for patients whose arrhythmias were not inducible, drug responders and nonresponders. The actuarial incidence rate of recurrent arrhythmic events in nonresponders was 35 ± 5% and 53 ± 7% at 2 and 5 years, respectively. These values were significantly lower (and statistically similar to each other) in the other two patient groups: patients with noninducible arrhythmia (19 ± 5% and 31 ± 7%, respectively, p < 0.05) and drug responders (13 ± 5% and 23 ± 8%, respectively, p < 0.01). Patients with an implantable defibrillator who had recurrent arrhythmic events were significantly less likely to die suddenly than were patients without a defibrillator who had recurrent events (p < 0.001).The electrophysiologic study was useful in subgrouping survivors of cardiac arrest into relatively high risk (nonresponders) and low risk (patients with no inducible arrhythmias and drug responders) groups, but even the low risk groups had a substantial cumulative risk of recurrent arrhythmic events. With an implantable defibrillator, mortality in the high risk group was similar to that in the low risk groups despite a significantly higher incidence of recurrent arrhythmic events. The use of the implantable defibrillator should be studied prospectively in survivors of cardiac arrest who respond to drug testing or have no inducible arrhythmia.