H19 and pulmonary arterial hypertension: The critical role of EZH2 in the prevention of cardiac remodeling and dysfunction is further illustrated by a recent observation showing that (i) EZH2 presents a biphasic expression pattern during the natural course of RV remodeling in the setting of PAH, being upregulated in the human and rat compensated RV, and then downregulated in decompensated PAH RV; and (ii) the cardioprotective effects elicited by knockdown of the long non-coding RNA H19 in two animal models of RV failure is accompanied by an up-regulation of EZH2 [100].