Because aldosterone antagonism is thought to work in part by inhibiting fibrosis, its role in MR, where little fibrosis occurs, is unclear. 2. Because vasodilator therapy appears to be effec- tive in acute severe symptomatic MR, it seems rea- sonable to attempt afterload reduction in chronic asymptomatic MR with normal LV function in an effort to forestall the need for surgery. However, the results from the limited number of trials addressing this therapy have been disappointing, demonstrating little or no clinically important ben- Conversely, because vasodilators decrease LV size and mitral closing force, they may increase CLINICAL STATEMENTS AND GUIDELINES mitral valve prolapse, worsening rather than decreasing severity of MR.6 The foregoing does not apply to patients with concomitant hypertension. Hypertension must be treated because of the well- known morbidity and mortality associated with that condition and because increased LV systolic pressure by itself increases the systolic transmitral gradient and worsens severity of MR. Recommendations for Intervention for Chronic Primary MR Referenced studies that support the recommendations are summarized in Online Data Supplement 30. 