Exercise Capacity and Maximum Oxygen Consumption before and after Percutaneous Mitral Balloon Valvuloplasty

ABSTRACT

To evaluate exercise capacity, treadmill test and exercise pulmonary function test with cycle ergometer were preformed in 52 patients(pts) (M/F 18/34, mean age 43+/-11 yrs) with mitral stenosis before and 5~10 days after percutaneous mitral balloon valvuloplasty(PMV). Twenty four pts had atrial fibrillation. The results are as follow 1) The mitral valve area increased from 0.9+/-0.2 to 1.8+/-0.3cm2(P<0.001). 2) The duration of exercise time on treadmill test(modified Bruce protocol) increased from 7.7+/-3.3min to 11.1+/-2.6min(P<0.001), but peak heart rate(HR) and maximum double product(MDP) did not change significantly. After exclusion of the patients with atrial fibrillation, peak HR and MDP increased from 157+/-24beats/min and 22350+/-8220mmHg beat to 165+/-19beats/min and 26290+/-5770mmHg beat respectively(P<0.05). 3) Diffusion capacity and diffusing capacity/alveolar volume at rest decreased from 95+/-25% and 112+/-24% to 87+/-22% and 100+/-18% respectively(p<0.001). 4) FVC, FEV1, FEV1/FVC, FEF25~75% and maximum voluntary ventilation increased from 77+/-12%, 79+/-16%, 104+/-10%, 69+/-25%, and 68+/-14%, to 80+/-11%, 84+/-14%. 106+/-9%, 78+/-25%, and 74+/-12%, respectively(P<0.05). But total lung capacity, residual volume and functional residual capacity did not change significantly. 5) Maximum oxygen consumption, anaerobic threshold, oxygen pulse and maximum work load during exercise increased form 53+/-14%, 34+/-8%, 6.2+/-2.1ml/min and 48+/-18 watts to 61+/-13%, 39+/-7%, 7.3+/-2.0ml/min and 58+/-20 watts respectively(P<0.0005). We conclude that oxygen transport and exercise capacity improve within 10days after PMV and the improvement results from not only hemodynamic improvement but also improvement of static pulmonary function.