Left ventricular concentric remodeling and impaired cardiorespiratory fitness in patients with heart failure and preserved ejection fraction

BACKGROUND: Left ventricular (LV) concentric remodeling refers to a process by which increased LV relative wall thickness alters myocardial geometry, resulting in reduced LV end-diastolic volume (LVEDV) and stroke volume (SV). While the degree of concentric remodeling is a negative prognostic factor in heart failure with preserved ejection fraction (HFpEF), it is not known how it contributes to cardiorespiratory fitness (CRF). METHODS: We performed a retrospective analysis of patients with HFpEF who underwent treadmill single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) and cardiopulmonary exercise testing (CPX). From exercise SPECT-MPI, we recorded postexercise LVEDVi, LVESVi, SVi, LVEF, the presence and extent of perfusion defects, and perfusion reversibility. Peak oxygen consumption (VO<inf>2</inf>), the oxygen uptake efficiency slope (OUES), oxygen (O<inf>2</inf>) pulse, ventilatory efficiency (V<inf>E</inf>/VCO<inf>2</inf> slope), ventilatory anaerobic threshold, respiratory exchange ratio, exercise time, and maximum heart rate were obtained from CPX. Data are expressed as mean (±standard deviation). Univariate and multivariate linear regression was performed. RESULTS: ). Greater LVEDVi and LVESVi correlated positively with peak VO<inf>2</inf> (R=+0.648, P=0.001; R=+0.601, P=0.002), O<inf>2</inf> pulse (R=+0.686, P<0.001; R=+0.625, P=0.001) and OUES (R=+0.882, P<0.001; R=+0.779, P<0.001). The LVEF correlated inversely with peak VO<inf>2</inf> and OUES (R=-0.450, P=0.031; R=-0.485, P=0.035). Perfusion defect area, grade of severity, and presence of reversibility were not associated with CRF variables. CONCLUSIONS: Postexercise reduced LV volumes correlate with measures of impaired CRF in patients with HFpEF, thus supporting a pathophysiologic role of concentric remodeling in impaired CRF in HFpEF.