As an example, during PAH, whereas chronic hypoxia induces activation of Hypoxia-inducible factor 1-alpha (HIF-1α) and leads to increased angiogenesis in the RV, pressure overload of the LV induces capillary rarefaction with decreased capillary networks surrounding the CMs [57,60]. The gene discussed is HIF1A; the disease is pulmonary arterial hypertension.