Most ventricular depolarization and repolarization abnormalities are not predictors of arrhythmic events in postinfarction patients with normal intraventricular conduction.

BACKGROUND

Survivors of acute myocardial infarction (AMI) are at increased risk for arrhythmic events (AE), which include sudden death (SD) or sustained ventricular tachycardia (sVT). In the prethrombolytic era, abnormal parameters of depolarization and repolarization were considered to be markers of susceptibility to these events. The purpose of the present study was to assess whether these variables should still be considered predictors of AE in postinfarction patients with normal intraventricular conduction.

MATERIAL/METHODS: The study population consisted of 236 survivors of AMI, in whom the parameters of depolarization on SAECG (QRSd, LAS, RMS, LPs) and repolarization on ECG (QTc-max, QTd) were assessed before hospital discharge. The patients were followed for 18 months, and all episodes of SD and sVT were recorded.

RESULTS

During long-term observation, 3 patients died from SD, and sVT occurred in 1 patient. Univariate Cox regression analysis showed that among the SA-ECG and ECG variables, only QRSd was significantly related to the incidence of AE (p<0.04). A comparison of event-free survival curves by the Kaplan-Meier method at the dichotomy limit of 119ms showed significantly worse prognosis in patients with QRSd> or =119ms (p<0.01).

CONCLUSIONS

In postinfarction patients with normal intraventricular conduction treated in the acute and chronic phase of MI according to recent management strategies, QRSd> or =119ms on SAECG is associated with arrhythmic events. Other parameters of depolarization, such as LAS, RMS, and positive LPs, and also repolarization, such as prolonged QTc-max and QTd, seem to be of little use in predicting these events.