Differential microRNA-21 and microRNA-221 Upregulation in the Biventricular Failing Heart Reveals Distinct Stress Responses of Right Versus Left Ventricular Fibroblasts.

Background: The failing right ventricle (RV) does not respond like the left ventricle (LV) to guideline-directed medical therapy of heart failure, perhaps due to interventricular differences in their molecular pathophysiology.

Methods: Using the canine tachypacing-induced biventricular heart failure (HF) model, we tested the hypothesis that interventricular differences in microRNAs (miRs) expression distinguish failing RV from failing LV.

Results: Severe RV dysfunction was indicated by elevated end-diastolic pressure (11.