Prognostic value of potential energy derived from noninvasive pressure-volume loop analysis in heart failure with...

Heart failure with preserved ejection fraction (HFpEF) is characterized by impaired relaxation and increased stiffness, leading to elevated filling pressures and inefficient cardiac performance despite preserved ejection fraction (LVEF ≥ 50%). These changes alter pressure-volume (PV) loop profiles. Noninvasive PV loop analysis using cardiovascular magnetic resonance (CMR) and brachial cuff pressure offers a novel approach to evaluating ventricular energetics. This study aimed to assess the prognostic value of CMR-derived PV loop parameters in HFpEF. Patients with HFpEF confirmed by invasive cardiopulmonary exercise testing who underwent CMR were included. PV loop parameters-including potential energy (PE), stroke work (SW), ventricular efficiency (VE), external power, and energy per ejected volume-were derived from CMR cine imaging and brachial cuff pressure measurement. The primary outcome was a composite of cardiovascular death and heart failure hospitalization. Associations were assessed using multivariable Cox proportional hazards models. Between February 2017 and August 2021, 161 patients (median age 55.1 years; 42.9% female) were enrolled. Nineteen (11.8%) experienced the primary endpoint over a median follow-up of 1.63 years. In unadjusted analysis, PE and VE were significantly associated with events (P < 0.05). In multivariable models adjusting for age, sex, hypertension, diabetes, hematocrit, and SW, PE remained an independent predictor (HR 3.59, 95% CI 1.24-10.42, P = 0.02). Noninvasive PV loop analysis using CMR and brachial cuff pressure identifies PE as a novel predictor of cardiovascular events in HFpEF, emphasizing impaired ventricular energetics as a key mechanism.