Understanding HFpEF Through Imaging: Strengths, Limitations, and Current State of the Art.

Heart failure with preserved ejection fraction (HFpEF) is a clinical syndrome characterized by dyspnea caused by hemodynamic congestion, which develops at rest or with exercise. Noninvasive diagnosis remains challenging, because resting diastolic pressures may be normal, and even when abnormal, currently applied noninvasive indices lack sensitivity. The pathophysiology of HFpEF extends far beyond diastolic dysfunction, and such complexity can be better understood through imaging. This State-of-the-Art Review emphasizes echocardiography and other noninvasive imaging approaches as the first-line tools for HFpEF evaluation, while linking multimodality imaging to invasive hemodynamics as a physiologic reference standard. The authors emphasize evidence-based, multiparametric assessment, where combined cardiopulmonary exercise testing with exercise stress echocardiography can quantify the diverse reserve limitations that characterize HFpEF, including cardiac and extracardiac contributors, atrial and right heart dysfunction, pulmonary vascular and ventilatory limitation, dynamic atrioventricular regurgitation, extrinsic restraint, pulmonary congestion, and peripheral impairments, acknowledging that such phenotyping must be anchored to actionable findings and evidence-based interventions. The authors describe the potential role of exercise cardiac magnetic resonance and artificial intelligence-enabled imaging analysis for phenotyping and risk stratification. Finally, the authors propose an echo-first Bayesian pathway that updates pretest to posttest probability and supports identification of patients in whom invasive hemodynamic exercise testing may be required to confirm the diagnosis and validate imaging markers against invasively measured congestion.