Effects of exercise-based cardiac rehabilitation on heart rate variability and turbulence in patients with ST elevation myocardial infarction

Abstract

Objectives: The objective of this study was to evaluate the effect of the exercise-based cardiac rehabilitation(CR) on the heart rate variability (HRV) and turbulence (HRT) in patients with ST elevation myocardialinfarction (STEMI) treated with the primary percutaneous coronary intervention (PCI).Methods: One hundred one patients with STEMI, who underwent primary PCI were included in our study.Sixty-eight of these patients were randomized to the CR group and the remaining 33 patients to the controlgroup. One month after the primary PCI, cardiac rehabilitation was performed in CR group with a cycleergometer for 8 weeks (30 sessions). One month after STEMI, rhythm Holter monitorization was carried outin both groups for 48 hours. The rhythm Holter monitorization was repeated in cardiac rehabilitation group(CR group) after the cardiac rehabilitation again for 48 hours. HRV was evaluated according to time andfrequency domains; HRT was evaluated with the turbulence onset and turbulence slope parameters obtainedfrom the Holter recordings.Results: Baseline characteristics and baseline HRV and HRT parameters were comparable between CR groupand control group. In CR group, there was no statistically significant difference between the HRV and HRTparameters, which were obtained before and after the cardiac rehabilitation. The subgroup analyses (leftventricular ejection fraction lower or higher than 40%) showed that turbulence onset improved with the cardiacrehabilitation in the group with an ejection fraction lower than 40%.Conclusions: Our results showed that exercise-based cardiac rehabilitation did not affect HRV and HRT inpatients whose left ventricular ejection fraction was mildly affected (> 40%) after the treatment with primaryPCI. However, the cardiac rehabilitation provided an improvement of turbulence onset in patients with the lowleft ventricular ejection fraction.