NONLINEAR DYNAMICS METHODS FOR ASSESSING HEART RATE VARIABILITY IN PATIENTS WITH RECENT MYOCARDIAL INFARCTION

Heart rate variability (HRV) is defined by the fluctuating time between normal sinus beats (RR intervals) and indicates modulation of the heart rate by the autonomic nervous system. Decreased variability parameters have been studied as markers of increased pathology and a predictor of morbidity and mortality in multiple medical disciplines. The aim of the study was to assess HRV by nonlinear dynamics parameters (Poincare plot and entropy constants) in patients with recent myocardial infarction (MI). We analyzed two groups of patients: a test group of 12 patients with recent myocardial infarction and a control group of 12 healthy subjects. For each patient, a 7 minutes ECG signal was recorded and the nonlinear dynamics parameters were calculated. Strong visual differences were found between Poincare plots of healthy subjects and MI patients. Also, most calculated nonlinear dynamics parameters were significantly lower in MI patients. In conclusion, MI affects nonlinear dynamics parameters, revealing a statistically significant decrease in HRV. Also, visual modifications of the Poincare plot were found.