Exercise Capacity and Kinetics of Recovery Oxygen Consumption after Exercise in Patients with Mitral Stenosis: Effects of Percutaneous Balloon Mitral Valvuloplasty and Exercise Training

ABSTRACT

BACKGROUND: The kinetics of recovery oxygen consumption plays an important role in determining exercise capacity. This study was performed to evaluate the kinetics of recovery oxygen consumption and the effects of percutaneous balloon mitral valvuloplasty (PMV) and exercise training on the recovery kinetics in mitral stenosis (MS). METHOD: Thirty patients with MS (valve area 1.0 cm2) and thirty age-and size-matched healthy volunteers were included for this study. All subjects performed symptom-limited, upright, graded bicycle exercise. Patients were randomized to either the exercise training group or the non-training group after successful PMV (valve area 1.5 cm2 and mitral regurgitation grade 2). The exercise group performed daily exercise training for 3 months. RESULTS: Half-recovery time of peak oxygen consumption (T1/2VO2) was significantly delayed in MS patients than in the volunteers (12,042 sec vs 595, p<0.01). Peak oxygen consumption (pVO2, ml/min/kg) was significantly increased in both the training (16.84.9 to 25.36.9) and the non-training group (16.35.1 to 19.66.0) 3 months after PMV. T1/2VO2 was significantly shortened in the training group (12,439 to 7,613, p<0.01), but not in the non-training group (11,446 to 10,944 sec, p-0.12) at 3 months follow-up. The degrees of symptomatic improvement after PMV were more closely correlated with the changes of T1/2VO2 than those of pVO2. CONCLUSION: Kinetics of recovery oxygen consumption was markedly delayed in MS patients, but the kinetics improved after exercise training but not after PMV alone. These results suggest that adjunctive exercise training may be useful for improvement of recovery kinetics and subjective symptoms after PMV.