Right Ventricle Remodelling in Left-Sided Heart Failure in Rats: The Role of Calcium Signalling

Right ventricular dysfunction (RVD) can follow primary pulmonary diseases, but the most common cause of its development is left-sided heart failure (HF). RVD is associated with HF progression, increased risk of death and hospitalisation. The mechanism of right ventricle (RV) remodelling leading to RVD due to left-sided HF is not fully elucidated. Rats underwent LAD ligation to induce extensive left ventricle (LV) myocardial infarction (MI) and subsequent left-sided HF. Sham-operated animals served as controls. After 8 weeks of follow-up, the animals underwent LV and RV catheterisation, and systolic function and intracellular Ca²⁺ signalling were assessed in cardiomyocytes isolated from both ventricles. We demonstrated that rats with LV failure induced by extensive LV myocardial infarction also develop RV failure, leading to symptomatic biventricular HF, despite only mildly increased RV afterload. The contractility of RV cardiomyocytes was significantly increased, which could be related to increased amplitude of Ca²⁺ transient, preserved SERCA2a activity and reduced Ca²⁺ efflux via NCX1 and PMCA. Our study indicates that RV failure associated with post-MI LV failure in a rat model cannot be explained by a decline in cardiomyocyte function. This indicates that other factors may play a role here, pointing to the need for further research to better understand the biology of RV failure in order to ultimately develop therapies targeting the RV.