features of heart rate variability and early postinfarction remodeling process in patients with recurrent myocardial infarction

Abstract

The purpose of this study was to evaluate the heart rate variability (HRV) level and the features of early post-infarction left ventricular remodeling (PIR) in patients with recurrent myocardial infarction (MI), which developed within six months post the initial Q-wave MI (Q-MI). Material and Methods: The study surveyed 105 male patients between 29 and 69 years of age (mean age 52.08±8.5), who underwent a Q-MI and who, for various reasons, have not undergone coronary angiography. All patients underwent echocardiography and the LVM, EDV, ESV and their indexed values, as well as the ejection fraction were determined, including Holter ECG monitoring. In the interim, analysis included the indicators recommended by the standards of measurement, physiological interpretation and clinical use of heart rate variability, such as SDNN, SDANN and RMSSD. The reduction of the total reduction of HRV was taken as SDNN≤100ms, and the marked reduction in HRV - SDNN≤50ms. Results: All the patients were divided into two groups: Group I consisted of patients who, within six months after the initial Q-wave MI, developed fatal or nonfatal reinfarction; Group II included those patients with a favorable course of the disease. The patients in both groups belonged to a somewhat similar age category. By localization of MI, occurrence of AH, as well as the incidence of LV aneurysm, both groups were comparable. However, the Group I patients in acute Q-MI showed significantly more preserved signs of residual myocardial ischemia, which was manifested as early post-infarction angina. The average values of SDNN in patients in Group I were noted to be significantly lower than that in the Group II patients. The same ratio was observed in both groups and also the indicator of SDANN, whereas the mean RMSSD values of the patients of both groups were not significantly different. The percentage of patients with reduced HRV in Group I was 1.8 times higher than that in Group II, including those patients with a marked reduction in HRV, which were 25% and 5.1% in Groups I and II, respectively. The patients in Group I compared with Group II patients had significantly higher values for LVM, EDV, ESV, as well as their indexed values for LVMI, iEDV, and iESV. The average values of EF in Group I were significantly lower than those in Group II. Conclusion: In patients with recurrent MI, which had developed within six months from the time of the initial Q-infarction in the acute phase of the disease, significantly more preserved signs of residual ischemia were revealed. The average EF, SDNN and SDANN values in these patients were significantly lower than in patients having a favorable course of the disease. Patients with recurrent MI differed significantly by showing higher values of the left ventricular mass, left ventricular volume indices, as well as the indexed values determined during the 10-14 day period of the primary IM.