Influence of left ventricular function on signal averaged late potentials in patients with coronary artery disease with and without ventricular tachycardia.

Left ventricular dysfunction has been suggested as a cause of late potentials on the signal averaged ECG of patients with coronary artery disease. We compared the averaged surface ECG with angiographic findings in 57 patients with coronary artery disease and left ventricular dysfunction. Sixteen patients had sustained ventricular tachycardia and 41 had no documented arrhythmia. These two patient groups were comparable with respect to age, mean ejection fraction, and wall motion score. Late potentials, defined as voltage less than 25 microV in the last 40 msec of the filtered QRS complex, were found in 10 of 16 patients with ventricular tachycardia and in 6 of 41 patients without arrhythmia (p less than 0.005). However, late potentials were independent of ejection fraction, wall motion score, or presence of dyskinesis in both groups. There was no correlation between the total filtered QRS duration and ejection fraction or wall motion score in either patient group. In patients with coronary artery disease, late potentials are associated with ventricular tachycardia but are independent of global or regional left ventricular function. This finding has important implications for studies of the prognostic value of late potentials following myocardial infarction.