In patients following an acute myocardial infarction (AMI), ventricular late potentials (LPs) from signal averaged electrocardiograms (SA-ECG) identify an area of abnormal tissue considered as an arrhythmogenic substrate with a propensity towards the development of ventricular tachycardia. Many studies have shown a reduced prevalence of LPs in patients with a patent infarct related artery (IRA). The influence of gender onSA-ECG parameters has been reported in healthy subjects but not in post-infarction patients, particularly in relation towards IRA patency. The aim of this study was to assess (survivors of a first AMI) the influence of gender and IRA patency on the prevalence of an arrhythmogenic substrate detected by means of SA-ECG and the occurrence of late arrhythmic events during a 1-year follow-up period. The study population comprised 92 survivors following a first AMI, 61 men and 31 women, aged between 27-75 years (mean age 56±11), in whom coronary angiography and SA-ECG had been performed during hospitalization. We assessed the prevalence of an arrhythmogenic substrate considered as the presence of late potentials (LPs) or a filtered QRS duration greater than 120 ms (QRSd ³ 120ms) in patients divided by gender and subdivided according to IRA patency. There was no significant difference in LPs incidence in men compared with women independently of IRA patency. The prevalence of QRSd ³ 120 ms was also similar in different gender groups. When this arrhythmogenic substrate marker had been analysed in relation to IRA patency, we noted a significantly more frequent incidence of QRSd ³ 120ms in men with an occluded coronary artery (21% vs 0%, p<0.05). This relation was not observed in women (7% vs 0%, NS). During the 12 months follow-up period 4 patients (4% - 3 men and 1 women) died. Two patients (one woman and one man) died suddenly and two patients due to reinfarction.
Conclusions: 1. Out of the first acute myocardial infarction survivors we observed gender difference between IRA patency and arrhythmogenic substrate prevalence on the SAECG: a) in men the incidence of QRSd ³ 120ms is more frequent when IRA is occluded; b) in women the prevalence of QRSd ³ 120ms is low and independent of IRA patency. 2. Arrhythmic patient events following an acute myocardial infarction treated by means of contemporary therapeutical guidelines are very rare during the 1 year follow-up period.

Keywords: acute myocardial infarction, Diagnosis, arrhythmic risk factor