961-82 Abnormal Signal Averaged Electrocardiogram Predicts Mortality in Patients with Non-Ischemic Cardiomyopathy and Severe Congestive Heart Failure

Abstract

Patients with severe congestive heart failure have a high mortality; many deaths are thought to be arrhythmic. The presence of late potentials on signal averaged electrocardiograms (SAECG) identifies a substrate for reentrant ventricular arrhythmias. We evaluated the prevalence and prognostic significance of an abnormal SAECG in a prospectively followed population of patients undergoing evaluation for cardiac transplantation. Ninety patients were followed for a mean of 447 days. Twenty-six patients died and 17 patients were censored on the day of transplantation. Kaplan-Meier survival curves were constructed and the effect of SAECG variables was tested with a log-rank test. Fifty-four percent of the patients had a non-ischemic cardiomyopathy and the remainder had an ischemic cardiomyopathy. Fifteen patients had BBB and were excluded from this analysis. The average QRS duration on 12 lead ECG was similar in ischemic cardiomyopathy and nonischemic cardiomyopathy groups (116 ± 23 vs 115 ± 19 ms, p = ns) and the average FQRS duration was similar in ischemic cardiomyopathy and nonischemic cardiomyopathy groups (131 ± 26 vs 132 ± 21 ms. p = ns). Fortyfour percent of the non-ischemic cardiomyopathy group and 50% of the ischemic cardiomyopathy group had an abnormal SAECG (defined as having 2 of the following: fQRS > 114 msec, RMS < 20 μ V, LAS > 38 msec). An abnormal SAECG was associated with mortality in the non-ischemic cardiomyopathy group (p < 0.05) but not in the ischemic cardiomyopathy group (p = ns). Twenty-eight patients had QRS duration 2:: 120 ms on 12 lead ECG. When these patients were excluded, 20% of the non-ischemic cardiomyopathy group and 41% of the ischemic cardiomyopathy group had an abnormal SAECG and an abnormal SAECG still predicted mortality in non-ischemic cardiomyopathy group (p < 0.001) but not in ischemic cardiomyopathy group (p = ns). In conclusion, an abnormal SAECG is associated with increased mortality in non-ischemic cardiomyopathy but not in ischemic cardiomyopathy.