The attenuation of LV/LA remodeling, defined as the reduction in LV end-systolic volume and LA volume, is an important goal of MR reduction after Mitra-clip placement. Post Mitra-Clip TTE is limited by acoustic windows in at least one-third of patients, rendering 3-D TTE measurements of LV/LA volumes unfeasible. Contrast Echo can mitigate the drawbacks of TTE, but 2-D volumes are under-estimated compared to CMR. Hence, the impact of MR reduction by Mitra-clip on LV/LA remodeling is best determined by CMR. Furthermore, CMR will provide an independent reference standard to validate RV/RF measured by RT-VCFD TEE pre- and post-Mitra-clip placement.