To test this general premise, we examined whether hCT1 administration could limit and/or improve cardiac performance in a model of RHF due to severe pulmonary arterial hypertension (PAH)-induced inhibition of VEGFR2 with SU5416 (SU) followed by a 3-week exposure to hypoxia (Hx). This evidence concerns the gene KDR and pulmonary arterial hypertension.