Changes in diastolic function after exercise training in patients with and without diabetes mellitus after coronary artery bypass surgery. A randomized controlled trial

Background. Left ventricular diastolic dysfunction and diabetes were associated with prognosis after coronary artery bypass surgery (CABG). Aim. This study investigated whether short-term exercise improves diastolic function in patients with and without diabetes mellitus (DM) after CABG and examined the relationship of these changes to exercise capacity. Design. RCT Setting. Outpatient. Population. Patients with left ventricular ejection fraction. >= 50% after CABG were included in this study. Methods. Participants were randomly assigned to a control (N.=33) or exercise (N.=28) group. The exercise group participated in three-month treadmill exercise training. We evaluated all participants on diastolic function, peak oxygen uptake (VO2peak), and concomitant stroke volume. Results. Exercise significantly enhanced VO2(peak) to a similar extent in all patients (P<0.05). Patients with DM improved in arteriovenous oxygen difference ([av] O-2 diff) after training (P=0.016), whereas those without DM improved in deceleration time of early filling (P=0.031) with exercise training. The magnitude of improvement in VO2peak correlated with the change in (a-v) O-2 cliff in patients regardless of DM (r=0.442 similar to 0.542) and with baseline (a-v) O-2 diff only in patients with DM (r=-0.480). Conclusion. After CABG, all patients showed similar improvements in VO2peak with exercise training, mainly through increased (a-v) O-2 diff, but those without DM showed greater improvements in deceleration time. Clinical Rehabilitation Impact. Exercise training is beneficial for improving exercise capacity associated with restorations of peripheral oxygen utilization in both patients with and without DM.