Cardiomyocyte myofilament function in common animal models of heart failure with preserved ejection fraction

Human cardiomyocytes from very obese patients with heart failure and preserved ejection fraction (HFpEF) have markedly depressed calcium-activated tension and increased resting stiffness. To test if either are recapitulated by obese-HFpEF animal models, tension‑calcium and tension-sarcomere length relations were measured in myocytes from mice on a high fat diet (HFD) with L-NAME, ZSF1 rats, and Göttingen minipigs on HFD + DOCA (MP). Only MP myocytes displayed reduced Ca²⁺-activated tension, and none exhibited increased resting stiffness versus respective controls. Consistent with prior myofibrillar data, crossbridge attachment and detachment rates at matched tension were slower in rodent models, and detachment slower in MP.