Pathophysiology
Clinical meaning
Heart Failure with Preserved Ejection Fraction (HFpEF, EF >=50%) represents ~50% of HF cases driven by diastolic dysfunction from myocardial stiffness and impaired relaxation. Microvascular endothelial inflammation reduces nitric oxide bioavailability, decreasing cGMP and PKG activity. This leads to unphosphorylated titin increasing passive myocardial stiffness. Concurrent cardiomyocyte hypertrophy and interstitial fibrosis further impair diastolic filling. The H2FPEF score helps diagnose HFpEF.