Sudden cardiac death after coronary artery bypass grafting is not predicted by signal-averaged ECG

Abstract

Background. Sudden cardiac death (SCD) is a major cause of death despite successful revascularization in patients with coronary artery disease. The signal-averaged ECG (SAECG) is a sensitive predictor of SCD and could be used in the screening strategy to select patients for prophylactic cardioverter implantation. Methods. The SAECG was recorded in 561 patients (mean age: 60 ± 8.8 years) within 10 days of coronary artery bypass grafting. Signal-averaged ECG was performed with a bandpass filtering of 40 to 250 Hz for more than 250 beats until a noise level of 0.6 μV was achieved. All patients were followed for 5.5 ± 1.2 years after the procedure. Results. Preoperative angiographic ejection fraction was at least 60% in 393 patients (72%), 40% to 60% in 126 patients (23%), and 40% or less in 28 patients (5%). There were 34 deaths, 10 of which were SCD. Late potentials were found in a total of 150 patients (27%) and were equally frequent preoperatively and postoperatively and among patients with (30%) and without (27%) SCD. The only predictors for overall mortality were age and a reduced ejection fraction. Conclusions. Signal-averaged ECG did not predict prognosis in low-risk patients undergoing coronary artery bypass grafting.