PREDICTION OF ARRHYTHMIC EVENTS AFTER ACUTE MYOCARDIAL-INFARCTION USING 2 METHODS FOR LATE POTENTIALS RECORDING

One hundred consecutive patients recovering from an acute myocardial i nfarction underwent, prior to home discharge, signal-averaged electroc ardiography (ECG), left ventriculography, and 24-hour Holter ECG recor ding. The signal-averaged ECG was recorded and analyzed using two proc edures: the orthogonal bipolar XYZ lead configuration with a bidirecti onal filter, and a precordial unipolar lead configuration with a nonre cursive digital filter. An abnormal signal-averaged ECG was seen in 40 % of patients with the XYZ system and in 30% of patients in the precor dial method, abnormal ejection fraction (< 40%) in 24% of patients and high grade ectopy activity in 22%. During the 24-month follow-up peri od, 12 patients (12%) had an arrhythmic event defined as either sudden death (11 patients) or sustained ventricular tachycardia (i patient). Neither the signal-averaged ECG with the XYZ configuration, the abnor mal ejection fraction, nor the high grade ectopy were able to statisti cally predict a higher arrhythmic event rate. The signal-averaged ECG with the precordial configuration was able to statistically predict a higher arrhythmic event rate, P < 0.03; odds ratio = 3.96. The combina tion of the orthogonal XYZ configuration signal-averaged ECG with the ejection fraction (P < 0.01, odds ratio = 7.33), or with ejection frac tion and Holter monitoring (P < 0.06, odds ratio = 6.17) was able to p redict a higher arrhythmic event rate. The combination of the precordi al configuration signal-averaged ECG with the ejection fraction (P < 0 .002, odds ratio = 14.4), or with ejection fraction and Holter monitor ing (P < 0.06, odds ratio = 10) was able to better predict a higher ar rhythmic event rate. The combination of a normal or abnormal signal-av eraged ECG and ejection fraction gave a sensitivity, specificity, posi tive, or negative value prediction of arrhythmic events of 60%, 90.6%, 37.5%, and 96%, respectively. It must be emphasized that the number o f arrhythmic events during the 2-year follow-up was small and further study is required to determine the true predictive value of each metho d for arrhythmic events.