APLN and pulmonary arterial hypertension: Apelin is reported to be the most potent inotropic agent measured in human isolated heart in vitro3 with significant effects on cardiac contractility in in vivo animal models,36,37 including ischemic cardiomyopathy38 and myocardial injury.39 The hemodynamic goals in patients with ventricular failure secondary to pulmonary hypertension are decreased pulmonary vascular resistance and augmented cardiac output, which may potentially be achieved with an apelin agonist.