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.
Thirty patients (age 67 +/- 8.6 years, 27% males) with preserved left ventricular
(LV) ejection fraction (>50%) and unexplained chronic New York Heart Association functional
class II to III dyspnea underwent heart catheterization. Patients with significant
coronary artery stenosis (>50%) were excluded. Pressure-volume loops were assessed
using a conductance catheter at rest, hand-grip exercise, leg lifting, and nitroprusside
and dobutamine infusion.
Twenty (66%) patients showed LV end-diastolic pressure >16 mm Hg (HFPEF), whereas
the remaining 10 patients served as controls. Patients with HFPEF had significantly
higher end-diastolic stiffness (0.205 +/- 0.074 vs. 0.102 +/- 0.017, p < 0.001) at
rest, and their end-diastolic pressure-volume relationship showed a consistent upward
and leftward shift during all hemodynamic interventions compared with controls. Regarding
the underlying mechanism of HFPEF, 14 (70%) patients had markedly increased end-diastolic
stiffness, which was considered a sufficient single pathology to induce increased
LV end-diastolic pressure. Four (20%) patients showed a concomitant presence of moderately
increased stiffness and severe LV dyssynchrony, and the remaining 2 (10%) patients,
with normal stiffness, showed significant exercise-induced mitral regurgitation at
hand-grip exercise. If the invasive pressure measurements were absent, only 5 (25%)
of the outpatients with HFPEF fulfilled the European Society of Cardiology definition
of HFPEF.
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.
Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier
Inc. All rights reserved.