Abstract 18497: Hospital-based Exercise Training Program Post Coronary Artery Bypass Graft Surgery: Impact of Once and Twice Daily Exercise Program on Cardiac Autonomic Modulation

Abstract

Introduction: Coronary artery bypass surgery (CABG) patients with postoperative decreased cardiac autonomic modulation (CAM) have a higher mortality rate and although cardiovascular rehabilitation and exercises have substantial benefits in CAM, there is a paucity of information about its effects considering a possible "dose-dependent” autonomic adaptation in a hospital-based exercise program. The aim was to evaluate the impact of once daily versus twice daily dosing regimens of hospital-based exercise training on CAM in post CABG patients. Hypothesis: We hypothesized that there is a dose-dependent exercise adaptation on CAM and greater benefit to twice daily exercise group. Methods: Thirty-seven patients post-CABG were divided into: GEX1 (n = 12) and GEX2 (n = 11), composed of patients who underwent exercises one and two daily sessions, respectively; and of a control group (CG, n = 14) who received usual care (respiratory therapy). GEX patients initiated the exercises on post-operative day 1 (PO1), following a whole progressive program until discharge. CAM was assessed by indices of heart rate variability (HRV) analyzed from heart rate and R-R intervals signals recording at rest during 10 minutes on PO1 (baseline) and discharge time. Results: At the time of discharge after the hospital rehabilitation conclusion, GEX2 presented higher values of rMSSD index, representative of parasympathetic modulation, and also higher values of RRtri, TINN and STDRR indices, representative of overall variability of RRi compared to GC, respectively (rMSSD: 7.5±1.9 vs 5.2±1.8 ms; RRtri: 3.2±1.4 vs 2.0±0.7ms; TINN: 46.0±30.5 vs 25.7±11.0 ms and STDRR: 10.0±6.3 vs 5.4±3.3 ms), while GEX1 presented only higher values of rMSSD compared to CG (rMSSD: 7.8±2.5 vs 5.2±1.8 ms). However, no differences were observed between groups on HRV baseline and at discharge time between groups GEX1 and GEX2. Conclusion: Our results suggested that twice daily hospital-based exercise program stimulated more favorably the cardiac autonomic nervous system adaptations in patients post-CABG. Although a daily exercise session promotes beneficial adaptations, two sessions should be encouraged to additional benefits in the cardiac autonomic modulation FAPESP 2015/2015 / 16730-3.