Characteristics of the right atrial and right ventricular contractility in a model of monocrotaline-induced pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) leads to changes in the pump function of the heart and causes right-sided myocardial hypertrophy and heart failure. This study was the first to compare the contractile characteristics of the multicellular myocardial preparations of the right atrium (RA) and right ventricle (RV) of male rats from the control group (CON) and the group with monocrotaline (MCT)-induced hypertrophy at the molecular and multicellular levels. In both RA and RV in MCT-treated rats, the fraction of motile filaments and the maximum sliding velocity of actin and reconstituted thin filaments over myosin decreased, and the ratio of α-/β-myosin heavy chains (MHC) shifted towards β-MHC.