BACKGROUND: The role of exercise-induced pulmonary hypertension in decision making regarding surgical timing for asymptomatic chronic mitral regurgitation is controversial. We reasoned that the exercise-induced pulmonary hypertension response could not be interpreted without knowledge of right ventricular (RV) function. The aim of this study was to assess the role of RV measures at rest and during exercise as predictors of prognosis in asymptomatic mitral regurgitation. METHODS AND RESULTS: Comprehensive resting and exercise echocardiography was performed in 196 consecutive patients (56±13 years; 64% male) with isolated moderate to severe mitral regurgitation (effective regurgitant orifice area, 38±18 mm(2)) and preserved left ventricular function in whom initial management was expectant. Left ventricular and RV longitudinal strain were analyzed at rest using velocity vector imaging. Tricuspid annular plane systolic excursion and systolic pulmonary arterial pressure were measured at rest and during exercise. Valve surgery was performed in 88 patients (45%) over 27±15 months. After adjustment for age and sex in a Cox proportional-hazards model, exercise tricuspid annular plane systolic excursion (hazard ratio, 0.26; P<0.001), was associated with valve surgery-free survival, independent of resting left ventricular strain (hazard ratio, 1.09; P=0.027), exercise systolic pulmonary arterial pressure (hazard ratio, 1.03; P<0.001), and resting RV strain (hazard ratio, 1.10; P=0.004). In sequential Cox models, a model based on clinical data and left ventricular strain (χ(2), 15.9) was improved by RV strain and RV chamber size (χ(2), 28.8; P=0.003) and exercise systolic pulmonary arterial pressure (χ(2), 40.1; P=0.002) and further increased by exercise tricuspid annular plane systolic excursion (χ(2), 52.2; P=0.002). CONCLUSIONS: Exercise-induced RV dysfunction provides important incremental prognostic value in the management of asymptomatic mitral regurgitation.