The aim of the present study was to diagnose heart failure with preserved ejection fraction (HFPEF) in outpatients with unexplained chronic dyspnea and to elucidate its underlying mechanisms in this population using invasive pressure-volume loop analysis. The diagnosis of HFPEF in stable outpatients with unexplained dyspnea is difficult.
A significant proportion of stable outpatients with unexplained chronic dyspnea may have HFPEF. In the patients whom we studied, increased LV stiffness, dyssynchrony, and dynamic mitral regurgitation were the major mechanisms underlying development of HFPEF.