Long-term prognostic value of time domain analysis of signal-averaged electrocardiography in idiopathic dilated cardiomyopathy

The aim of this study was to evaluate the long-term prognostic value of sig nal-averaged electrocardiography (SAECG) in idiopathic dilated cardiomyopat hy (IDC). Time domain analysis of SAECG was assessed in 131 patients with a ngiographically confirmed IDC (age 52 +/- 12 years; 108 men; left ventricul ar ejection fraction 33 +/- 12%) using specific criteria in 44 patients wit h bundle branch black. Late potentials (LP) on SAECG were present in 27% of the patients. patients with LP had a similar left ventricular ejection fra ction and a similar left ventricular end-diastolic diameter than patients w ith a normal SAECG. With a follow-vp of 54 +/- 41 months, 24 patients suffe red cardiac death and 19 had major arrhythmic events (sudden death, resusci tated ventricular fibrillation, or sustained ventricular tachycardia). Pati ents with LP had an increased risk of all-cause cardiac death (RR 3.3, 95% confidence interval 1.5 to 7.5, p = 0.004) and of arrhythmic events (RR 7.2 , 95% confidence interval 2.6 to 19.4, p = 0.0001). Using multivariate anal ysis, only LP on SAECG (p = 0.001), reduced SD of all normal-to-normal inte rvals (SDNN) (p = 0.002), increased pulmonary capillary wedge pressure (p = 0.005), and history of sustained ventricular tachyarrhythmia (p = 0.02) pr edicted cardiac death. A history of previous sustained ventricular tachyarr hythmia tp = 0.0001), reduced SDNN (p = 0.003), and LP on SAECG (p = 0.006) were the only independent predictors of major arrhythmic events. Results w ere not altered when considering separately patients with or without bundle branch block, or after exclusion of patients with a history of sustained v entricular tachyarrhythmia. This study is one of the first to suggest that tp on SAECG is an independent predictor of ail-cause cardiac death and is o f high interest for arrhythmia risk stratification in IDC. (C) 2000 by Exce rpta Medica, Inc.