The study aimed to investigate the differences in oxygen uptake (o2) and heart rate (HR) (at rest, submaximal exercise, peak exercise, and recovery) in patients with heart failure with preserved ejection fraction (HFpEF) with β-blockers (BB) or without BB treatment (NBB) and to analyze the relationship between HR reserve (HRresv) and peak o2 (o2peak) in BB and NBB.
A total of 174 HFpEF patients (>65 yr; BB, n = 59; NBB, n = 115) were assessed with a cardiopulmonary exercise test to peak exertion using an incremental protocol. After 5 min of supine rest, HR and o2 (HRrest, o2rest) at submaximal exercise (HRsubmax, o2submax), at peak exercise (HRpeak, o2peak), at 1 min of passive recovery (HRrec1), HRresv (HRpeak− HRrest), and HR recovery (HRrecov = HRpeak− HRrec1) were evaluated.
Analysis showed that HRrest (66.0 ± 12.2 vs 69.7 ± 10.6 bpm), HRsubmax (91.7 ± 16.2 vs 98.6 ± 15.2 bpm), and HRrec1 (102.9 ± 18.9 vs 109.4 ± 16.9 bpm) were significantly lower (P ≤ .05) in BB than in NBB, respectively. However, there were no significant differences (P > .05) between the BB and the NBB for HRpeak, HRresv, HRrecov, o2rest, o2submax, and o2peak. A significant relationship was found between HRresv and o2peak values in both groups (BB, r = 0.52; NBB, r = 0.49, P < .001).
The nonsignificant differences in HRpeak, HRresv, HRrecov, or o2 values between BB and NBB HFpEF patients, along with significant correlation between HRresv and o2peak, suggest that these measures may have equal utility in prognostic and functional assessment as well as clinical applications, including the prescription of exercise, in elderly HFpEF patients.