Changes in heart rate variability at exercise after cardiac rehabilitation in elderly cardiac patients. EU-CaRE substudy

Abstract

Improvement in autonomic responses is part of the benefits from the cardiac rehabilitation (CR). Acute effects during exercise on cardiac autonomy nervous activity in cardiac patients and their evolution after an exercise training program are not known. The aim of our study was to assess the evolution and the relation between parameters of cardiopulmonary exercise test (CPET) and markers of heart rate variability (HRV). Prospective cohort study (French cohort from EU-CaRE study) of elderly patients with ischemic or valvular disease enrolled in CR. Only patients in sinus rhythm are included. The analysis of HRV include heart rate, SDNN and HF/LF ratio using a first 24-hours Holter-ECG performed at inclusion on the CR program including the CPET time and a second short Holter ECG (during CPET) at the end of CR. One hundred and eighteen patients (72.7 years, 79% male) who complete the CR program and had full data available were included. We define two groups: 74 patients after cardiac surgery (CABG, valve replacement), 44 patients in post-acute coronary syndrome (ACS). We found no correlation between the baseline 24-hours HRV parameters and the gain of peak VO2 for the whole population, but an r = 0.45 ( P < 00.5) was found in post ACS patients. Exercise capacity and HRV parameters during exercise are improved after 11–15 sessions of training in both groups ( Table 1 ). Correlations between SDNN and HRR were found statistically significant ( P < 0.05) before and after CR program ( r = 0.33 and r = 0.45 respectively). Exercise training improves HRV in elderly cardiac patients. Cardiac autonomic function recovery seems more pronounced after cardiac surgery than after an acute coronary syndrome.