The mechanisms of right ventricular myocardial stiffness in pulmonary arterial hypertension evolve with disease severity, shifting from purely myofibril-driven in mild dysfunction to a combination of myofibril and fibrosis-driven in severe dysfunction.
RV myocardial stiffness is increased in rats with mild and severe RV dysfunction. In mild RV dysfunction, stiffness is mainly determined by increased myofibril stiffness. In severe RV dysfunction, both myofibril- and fibrosis-mediated stiffness contribute to increased RV myocardial stiffness.
Rain et al. (Fri,) studied this question.
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