Mathematical analysis of the stability of heart-rate dynamics in postinfarction patients

The stability of different modes of heart-rate dynamics was studied in patients who had experienced a myocardial infarction. The stability of the time series of RR intervals was estimated according to the critical point of the transition of heart-rate dynamics from the linear to the chaotic mode. The point of transition to the chaotic mode was identified by occurrence of atrial extrasystoles. It was shown that the transition of heart-rate dynamics from the linear to the nonlinear mode in postinfarction patients occurs in a jump, in agreement with the theoretical results obtained previously by mathematical modeling.