Effect of a cardiac rehabilitation program on left ventricular diastolic function and its relationship to exercise capacity in patients with coronary heart disease: Experience from a randomixed, controlled study

Background A cardiac rehabilitation and prevention program (CRPP) is a recognized nonpharmacological modality in the management of coronary heart disease (CHD). However, the effect of a CRPP on systolic function of the heart is controversial, and no data exists on diastolic function in CHD. A randomized, controlled study was conducted to address these issues. Methods Patients (n=269) with recent acute myocardial infarction (n=193) or after percutaneous coronary intervention (PCI) (n=76) were randomized to either CRPP (2-hour twice-weekly exercise program for 8 weeks) or conventional therapy (control group). Serial treadmill exercise testing and at-rest echocardiography were performed during phases 1 (baseline), 2 (post-exercise training), and 3 (8-month follow up). Results The prevalence of left ventricular (LV) abnormal relaxation pattern (ARP) of diastolic dysfunction was increased in the control group only in phase 3 (65% vs 88%, chi(2)=7.6, P<.01). Significant improvement of individual LV diastolic parameters towards less severe delayed relaxation was also observed in the CRPP group, especially in those with recent acute myocardial infarction or ARP. The gain in exercise capacity was faster and more substantial in the CRPP than the control group (P<.001 for phase 2, P<.05 for phase 3), and was significantly correlated with LV diastolic indices in those with ARP. Exercise training had neutral effects on LV systolic function and rate-pressure product. Conclusions In patients with CHD, CRPP prevented the progression of resting LV diastolic dysfunction, without affecting systolic function. In those with ARP, the improvement of diastolic function predicted the gain in exercise capacity.