T‐Wave Variability as a Risk Stratifier in Patients with Dilated Cardiomyopathy

BACKGROUND: T-wave alternans is an important identifier of patients at risk of sudden cardiac death (SCD), but the procedure usually requires stress testing. In this study, the variability of T-wave amplitude (TVAR) was evaluated at rest, as a risk stratifier for SCD. METHODS: This study included 57 patients in sinus rhythm and with a left ventricular ejection fraction < or =40%, of whom 34 (60%) received an implantable cardioverter-defibrillator (ICD) after surviving SCD, and 23 (40%) presented with ischemic or nonischemic cardiomyopathy and no history of SCD. A 20-minute high-resolution electrocardiographic recording for TVAR assessment was performed during supine rest. The vector magnitude was used as a primary lead for TVAR analysis. RESULTS: The mean, median, and maximum (max) values of TVAR were measured. The patients with ICD had a lower max TVAR than the patients without ICD (67 vs 95 muV; P = 0.045), though the mean and median TVAR values were similar. By multivariate logistic analysis, max TVAR remained a predictor of SCD, after adjustments for potentially confounding factors (P = 0.044). CONCLUSION: Max TVAR was a predictor of arrhythmic events in patients with dilated cardiomyopathy at rest.