MYBPC3 and hydrops fetalis: In a comparison of patients with mutations in MYH7 and MYBPC3, MYH7 mutation carriers had a ≈1.7- to nearly 3-fold higher risk of the overall composite outcome, AF, and advanced HF (New York Heart Association functional class III/IV and/or need for cardiac transplantation or LV assist device; Figure IV in the online-only Data Supplement).