PDE4B and hydrops fetalis: While PDE4B is reduced in human HF and myocardial PDE4B overexpression attenuates isoprenaline-induced heart hypertrophy/dysfunction [91], suggesting the interest of PDE4B agonists in HF, PDE4B has been proposed as a potential therapeutic target for cardioprotection in patients with acute myocardial infarction subjected to reperfusion therapy [92].