Influence of mitral regurgitation on the response to captopril therapy for congestive heart failure caused by idiopathic dilated cardiomyopathy

To assess the influence of mitral regurgitation (MR) on the response to captopril therapy for congestive heart failure (CHF), 30 patients with idiopathic dilated cardiomyopathy in New York Heart Association functional class III were studied. Left ventricular end-diastolic diameter and stroke volume were measured by Doppler echocardiography, and exercise tolerance by exercise testing before and at 1, 3 and 12 months after treatment. Patients were classified into 2 groups: those with (n = 14) and those without (n = 16) MR. No significant differences were observed between the 2 groups in pretreatment studies. Exercise tolerance increased significantly in the group with MR (p < 0.001) during the year of follow-up, from 514 ± 193 seconds at baseline study to 671 ± 178 seconds (p < 0.0005) at 1 month, 688 ± 127 seconds (p < 0.0005) at 3 months and 690 ± 108 seconds (p < 0.01) at 12 months. The group without MR had no significant changes. Stroke volume increased significantly only in the MR group during follow-up (p < 0.01), changing from 43 ± 9 ml at baseline study to 52 ± 11 ml (p < 0.01) at 1 and 49 ± 11 ml (p < 0.01) at 3 months. At 12 months the increase was not statistically significant. Left ventricular end-diastolic diameter decreased more in the group with than without MR, although the differences were not significant. Thus, the presence of dynamic MR appears to be an important factor in the therapeutic response to captopril therapy for CHF.