NPPB and hydrops fetalis: Symptomatic secondary MR (≥3+) with•Adequately treated per applicable standards, including for coronary artery disease, LV dysfunction, MR, and HF•Subject had at least 1 hospitalization for HF in the 12 months prior to subject registration and/or a corrected BNP ≥300 pg/ml or a corrected NT-proBNP ≥1,500 pg/ml