DIFFERENCES IN HEART-RATE-VARIABILITY IN THE ACUTE-PHASE OF FIRST AND2ND ATTACKS OF MYOCARDIAL-INFARCTION

The purpose of the study was to examine the differences between first and second myocardial infarctions with respect to improvement in measu res of heart rate variability (HRV). The study population comprised 48 non-diabetic patients with acute myocardial infarction (AMI), and wit h angiographically documented coronary artery occlusion and successful reperfusion. The subjects were grouped as 35 cases with a first AMI a ttack and 13 with their second AMI. Two weeks after the onset of infar ction, indices of HRV were higher in first infarction cases than in se cond infarction cases. In the latter, there were no significant increa ses in HRV indices from day of onset to 2 weeks later, nor were there any significant changes in left ventricular ejection fraction (LVEF) f rom onset to 3 weeks later. All patients studied had a patent infarct- related artery 3 weeks later. We found sustained low values of HRV aft er a second AMI. Different risk stratification may be needed between u ncomplicated first AMI and second AMI cases.