A young woman with bileaflet mitral valve prolapse and anomalous left coronary artery arising from the pulmonary artery, accompanied by significant mitral regurgitation (MR), underwent dobutamine stress echocardiography to assess the effect of anomalous left coronary artery arising from the pulmonary artery on MR severity. On the basis of the dobutamine stress echocardiography-induced ischemia, which exacerbated the degree of MR, a revascularization operation sparing the mitral valve was performed, resulting in significant improvement of the MR. We suggest that dobutamine stress echocardiography could be used to assess the relative contribution of each syndrome to the pathophysiology of MR, directing the surgical procedure.