REDUCTION IN THE FREQUENCY OF VENTRICULAR LATE POTENTIALS AFTER ACUTE MYOCARDIAL-INFARCTION BY EARLY THROMBOLYTIC THERAPY

Ventricular late potentials are strong predictors of arrhythmic events after acute myocardial infarction (AMI). To assess the effect of intravenous thrombolysis on the incidence of ventricular late potentials, 223 consecutive patients surviving a first AMI were included in the present study: 59 patients (53 men, 6 women, mean age +/- standard deviation 55 +/- 10 years) received intravenous recombinant tissue-type plasminogen activator (100 mg over 3 hours, group A) and 164 patients (123 men, 41 women, mean age 61 +/- 11 years) received conventional medical treatment (group B). A time-domain signal-averaged electrocardiogram and a high-resolution beat-to-beat recording (gain 10(6), filters 100 to 300 Hz) were performed at 10 +/- 3 days after AMI. There was no difference between group A and B patients in terms of AMI location (anterior in 28 of 59 vs 80 of 164, difference not significant [NS]), mean left ventricular ejection fraction (55 +/- 10 vs 55 +/- 13%, NS), or presence of heart failure (New York Heart Association class III or IV in 12 of 59 vs 40 of 164, NS). The incidence of ventricular late potentials was 10% (6 of 59) in group A and 24% (39 of 164) in group B (p < 0.05). Among the 146 patients who underwent coronary arteriography, the incidence of ventricular late potentials was 13% (10 of 80) in patients with a patent infarct-related artery and 26% (17 of 66) in patients with an occluded infarct-related artery (p < 0.05). No relation was found between the presence of ventricular late potentials and the presence of nonsustained ventricular tachycardia as detected by 24-hour Holter monitoring. In conclusion, intravenous thrombolysis with recombinant tissue-type plasminogen activator reduces the incidence of ventricular late potentials in survivors of a first AMI; this reduced frequency is not related to global left ventricular function and appears to be related to the patency of the infarct-related artery (induced by a thrombolytic agent or occurring spontaneously). Further prospective studies are needed to assess the prognostic significance of this finding.