[Late potentials in the diagnosis of post-infarction patients: arrhythmogenic risk and clinical symptomatology].

A prospective study was performed of the correlation of ventricular late potentials (LP) and clinical parameters in patients after acute myocardial infarction. To evaluate the prognostic significance of the signal-averaged-electrocardiogram (SAECG) in risk stratification of sudden cardiac death and arrhythmogenic events, the clinical characteristics of these post-infarction patients were performed in a follow-up-period. 243 consecutive patients underwent SAECG for detection of late potentials in the second week after acute myocardial infarction. After a mean follow-up of 9 months the patients were asked a standardized questionnaire. Late potentials are independent of age, sex, left ventricular ejection fraction, peak activity of MB fraction of creatine kinase, and the cardiovascular risk factors in postinfarction patients. In patients, who received thrombolytic therapy, the incidence of late potentials is lower (p < 0.05) and in patients with posterior wall infarction it is significantly higher (p < 0.04). In the follow-up period patients with abnormal SAECG show a significantly higher rate of angina pectoris, palpitations, dizziness, and syncope. By way of contrast, postinfarction patients with normal SAECG feel mainly comfortable in the follow-up (p < 0.01). The mortality was even in both groups. Sudden cardiac death in the late postinfarction period shows a significant correlation with the finding of late potentials in SAECG in the early myocardial infarction period (p < 0.01). The SAECG for detection of late potentials as a non-invasive investigation in the early postinfarction period characterizes patients with an arrhythmogenic risk, especially sudden cardiac death, independent of other conventional methods. Furthermore, the impaired patient with clinical symptoms in the late postinfarction period is hereby identified.