Effect of Preinfarction Angina on Heart Rate Variability in the Early Phase of the First Anterior Wall Acute Myocardial Infarction.

The aim of this study was to clarify the effect of preinfarction angina on heart rate variability (HRV) in anterior wall acute myocardial infarction (AMI). A total of 36 patients experiencing their first anterior wall AMI were prospectively examined. The patients were divided into 2 groups according to the presence (group A, n=24) or absence (group B, n = 12) of preinfarction angina. HRV was assessed on 24-h Holter electrocardiograms recorded on day 3. Peak creatine kinase activity was significantly lower in group A than in group B (2,747+/-1,939 vs 4,891+/-2,639 IU/L, p<0.05). The SD of all RR intervals and ultra-low frequency, very low frequency, and low frequency powers was significantly less reduced in group A than in group B (86+/-24 vs 64+/-22 ms, p<0.05; 2,098+/-1,462 vs 867+/-502 ms2, p<0.01; 1,430+/-1,042 vs 546+/-344ms2, p<0.01; and 354+/-272 vs 186+/-136ms2, p<0.05; respectively). High frequency power, low frequency/high frequency, and pNN50 did not differ significantly between the 2 groups. In conclusion, preinfarction angina has a favorable influence on HRV in the early phase of anterior wall AMI.