Short-term supervised inpatient physiotherapy exercise protocol improves cardiac autonomic function after coronary artery bypass graft surgery – a randomised controlled trial

Abstract

Objective. Coronary artery bypass grafting (CABG) is accompanied by severe impairment of cardiac autonomous regulation (CAR). This study aimed to determine whether a short-term physiotherapy exercise protocol post-CABG, during inpatient cardiac rehabilitation (CR), might improve CAR.

Design. Seventy-four patients eligible for CABG were recruited and randomised into physiotherapy exercise group (EG) or physiotherapy usual care group (UCG). EG patients underwent a short-term supervised inpatient physiotherapy exercise protocol consisting of an early mobilisation with progressive exercises plus usual care (respiratory exercises). UCG only received respiratory exercises. Forty-seven patients (24 EG and 23 UGC) completed the study. Outcome measures of CAR included linear and non-linear measures of heart rate variability (HRV) assessed before discharge.

Results. By hospital discharge, EG presented significantly higher parasympathetic HRV values [rMSSD, high frequency (HF), SD1)], global power (STD RR, SD2), non-linear HRV indexes [detrended fluctuation analysis (DFA)α1, DFAα2, approximate entropy (ApEn)] and mean RR compared to UCG (p < 0.05). Conversely, higher values of mean HR, low frequency (LF) (sympathetic activity) and the LF/HF (global sympatho-vagal balance) were found in the UCG.

Conclusions. A short-term supervised physiotherapy exercise protocol during inpatient CR improves CAR at the time of discharge. Thus, exercise-based inpatient CR might be an effective non-pharmacological tool to improve autonomic cardiac tone in patient's post-CABG.

Keywords:

• Coronary care
• cardiac surgery
• physiotherapy
• exercise

Acknowledgements

The authors thank the staff of the Irmandade Santa Casa de Misericordia Hospital of Araraquara for their enthusiastic participation in this project. They also thank the following cardiovascular surgeons, who referred patients to the study: Sergio Luzzi MD, Othon Amaral Neto MD and Luiz Ricardo de Oliveira MD and Joselene Levada for competent secretarial assistance. More importantly, however, they are indebted to the patients for their effort and enthusiastic cooperation throughout the study.