Exercise-induced changes in degenerative mitral regurgitation.

Objectives: We sought to quantify exercise-induced changes in patients with degenerative mitral regurgitation (MR), to examine the relationship between exercise-induced changes in MR and in systolic pulmonary artery pressure (PAP), and to identify their potential impact on symptom-free survival.

Background: MR severity can change during exercise in patients with functional MR. Quantified changes in MR severity during exercise remain undetermined in patients with degenerative MR.

Methods: Resting and bicycle exercise Doppler-echocardiography were performed in 61 asymptomatic patients (age 62+/-14 years) with moderate to severe degenerative MR (i.e., mitral valve prolapse or flail). Mitral regurgitation was quantified at rest and exercise with effective regurgitant orifice (ERO) area and regurgitant volume calculated with the proximal isovelocity surface area (EROP) and the quantitative Doppler (EROD) methods.

Results: At rest, EROP and EROD were well-correlated (r=0.87, p<0.0001), but EROD was larger than EROP (54+/-21 mm2 vs. 42+/-24 mm2, p<0.0001). During exercise, mean ERO and regurgitant volume markedly increased in 32% of patients by >or=10 mm2 and >or=15 ml, respectively. There was good correlation between exercise EROP and EROD (r=0.84, p<0.0001). Changes in systolic PAP were correlated with changes in ERO and regurgitant volume (r=0.59, p=0.02 and r=0.60, p=0.02). Patients with a marked increase in regurgitant volume during exercise had lower symptom-free survival than those in whom MR decreased or remained unchanged (p=0.0015).

Conclusions: Degenerative MR might be dynamic and increases during exercise in one-third of patients. Marked changes in MR severity are associated with exercise-induced changes in systolic PAP and reduced symptom-free survival.