Reductions in myocardial interstitial fibrosis are dissociated from LV chamber stiffness in swine with repetitive pressure overload

Swine with increased left ventricular (LV) chamber stiffness and fibrosis from 2 wk of repetitive pressure overload demonstrated discordant effects following two disparate antifibrotic interventions. A single infusion of intracoronary allogeneic cardiosphere-derived cells and 4 wk of oral finerenone each effectively reduced myocardial interstitial fibrosis. Despite reversal of fibrosis, LV chamber stiffness did not improve with either intervention, suggesting that myocyte-dependent mechanisms may play an important role in diastolic dysfunction from intermittent hemodynamic overload.