Hemodynamic determinants of the abnormal cardiopulmonary exercise response in heart failure with preserved left ventricular ejection fraction

Background: The cardiopulmonary exercise testing (CPET) response in heart failure with preserved left ventricular ejection fraction (HFPEF) is incompletely understood. We aimed to describe the CPET response in HFPEF and to assess its invasive hemodynamic determinants. Methods and Results: Ten patients with HFPEF and 8 asymptomatic controls underwent resting and exercise right heart catheterization and maximal symptom-limited CPET. The slope of the minute ventilation/carbon dioxide production relationship (VE/VCO₂ slope; 34.3 ± 5.4 vs. 28.4 ± 3.4; P = .02) was steeper, peak oxygen consumption (peak VO₂; 15.1 ± 4.9 vs. 26.6 ± 12.5 mLkg^-1min^-1; P = .02) was lower, and heart rate recovery 1 minute after exercise termination (HRR-1; 10 ± 5 vs. 27 ± 10 beats/min; P < .001) was slower in HFPEF compared to controls. A steeper VE/VCO₂ slope (r = 0.67, P = .002), lower peak VO₂ (r = -0.48, P = .04), and slower HRR-1 (r = -0.58, P = .02) were significantly related to a higher ratio of the change in pulmonary capillary wedge pressure per change in work rate as a measure of the left ventricular pressure volume relationship. Conclusions: In HFPEF patients, fundamental alterations in the CPET profile occur and these may, in part, result from the rapid rise in left ventricular filling pressures which accompanies exercise in these patients.