COR LOE Recommendations In patients with known or suspected primary MR, TTE is indicated for baseline evaluation of LV size and function, RV function, LA size, pulmonary artery pressure, and the mechanism and severity of primary MR (Stages A to D).1 5 In patients with primary MR, when TTE provides insufficient or discordant information, TEE is indicated for evaluation of the severity of MR, mechanism of MR, and status of LV function (Stages B to D). In patients with primary MR, CMR is indicated to assess LV and RV volumes and function and may help with assessing MR severity when there is a discrepancy between the findings on clinical assessment and echocardiography.6 9 In patients with severe primary MR undergoing mitral intervention, intraoperative TEE is indicated to establish the anatomic basis for primary MR (Stages C and D) and to guide Synopsis TTE is the initial imaging modality for patients with primary MR to look at valve morphology, severity of the MR, and the status of the LV, with TEE, CMR, or cardiac catheterization performed when insufficient or discordant information is obtained from the TTE. A TEE should be used to guide mitral valve interventions. Recommendation-Specific Supportive Text 1. TTE images provide the diagnostic data needed for clinical decision-making in chronic primary The outcome of the patient with chronic primary MR is determined by lesion severity,5 the presence of LV dys- function, and whether valve pathology is cor- rectable by valve repair, which is superior to valve replacement when repair is possible. Usually only severe (not mild or moderate) MR leads to nega- Favorable loading conditions in MR increase LVEF but do not affect the extent of shortening. Thus, a normal LVEF in MR is approximately 70%. 