SPECTRAL TURBULENCE ANALYSIS VERSUS TIME-DOMAIN ANALYSIS OF THE SIGNAL-AVERAGED ECG IN SURVIVORS OF ACUTE MYOCARDIAL-INFARCTION

This study compared the time-domain and spectral turbulence analyses o f signal-averaged electrocardiogram (ECG) for the prediction of risk a fter acute myocardial infarction. Signal-averaged ECGs were recorded i n 553 survivors of acute myocardial infarction before hospital dischar ge. The study excluded cases with bundle branch block and other conduc tion abnormalities, and pa patients were followed for at least 1 year. During the first year of the follow-up period, 30 patients died and 2 0 presented with ventricular tachycardia/fibrillation. The signal-aver aged ECG recordings were analyzed using conventional time domain at 40 -250 Hz and spectral turbulence analyses. The indices provided by both types of analysis were compared in patients with and without endpoint s. The optimum positive predictive characteristics were calculated for the prediction of all cause mortality and of ventricular tachycardia based on the time domain and on the spectral turbulence indices. Spect ral turbulence analysis provided significantly lower positive predicti ve accuracy (14.5% at 40% sensitivity) than the time-domain analysis ( 26.7% at 40% sensitivity) for prediction of ventricular tachycardia/fi brillation during 1 year after infarction (P < .01). However, spectral turbulence analysis provided significantly higher positive predictive accuracy (27.2% at 30% sensitivity) than the time-domain analysis (16 .9% at 30% sensitivity) for the prediction of 1-year all-cause mortali ty (P < .01). Thus, spectral turbulence analysis was inferior to the t ime-domain analysis in predicting ventricular tachycardia/fibrillation during the first year after myocardial infarction, but it was more po werful in predicting 1-year mortality.