[Simplified method for the early detection of post potentials in patients with acute myocardial infarct]

The risk of suddenly presenting ventricular tachyarrhythmias or death was analyzed in a prospective way in 71 patients with acute myocardial infarction and in 21 patients without any apparent cardiopathy. The average surface signal was measured when the patient was admitted in the hospital and on the following days of the acute phase of the infarction. Holter 24 hours monitoring and determination of the ejection fraction with radionuclide angiocardiography were also performed. Patients were divided into 4 groups, depending on the existence of arrhythmias and if late electric activity was recorded or not. Fifty-five patients (group I), presented an abnormal signal analysis (voltage in the 40 msec of the QRS period higher than 20 microvolts), and ventricular arrhythmias. Group II was formed by 8 patients who presented arrhythmogenic activity but did not present late electric activity. Group III was formed by 6 patients who did not present arrhythmias but presented late electric activity. Twenty-three patients who did not present late electric activity or ventricular arrhythmias formed group IV. Late electric activity that was registered at 41 +/- 1 msec with a QRS complex lasting 115 +/- 4 msec and with a voltage lower than 20 microvolts in group I showed meaningful differences with the other groups: Group II: (24 +/- 5 msec, QRS 111 +/- 4 msec, P less than 0.001); Group III: (41 +/- 2 msec, QRS 109 +/- 5 msec, P less than 0.01); Group IV: (26 +/- 5 msec, QRS 80 +/- 7 msec, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)