Effect of increased inspired oxygen on exercise performance in patients with heart failure and normal ejection fraction.
Int J Cardiol 2018;
268:166-169. [PMID:
29803343 DOI:
10.1016/j.ijcard.2018.05.029]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 05/02/2018] [Accepted: 05/09/2018] [Indexed: 02/02/2023]
Abstract
INTRODUCTION
We investigated whether increased concentrations of inspired oxygen (Fio2) affects exercise tolerance in patients with heart failure and normal ejection fraction (HeFNEF).
METHODS
46 patients (mean age 75 years (63% male) and median NTproBNP 1432 (interquartile range: 543-2378 ng/l)) with HeFNEF (defined as signs or symptoms of heart failure requiring treatment with diuretics, with a left ventricular ejection fraction of >45% by echocardiography and amino terminal pro brain natriuretic peptide (NTproBNP) >220 ng/l) completed three maximal incremental exercise tests with different Fio2 (21%, 28% and 40%) in random order. Fio2 was controlled by investigator but blinded to patients. The primary outcome was exercise time (ET).
RESULTS
Increasing Fio2 significantly increased exercise time (522 ± 180 seconds for 21% to 543 ± 176 seconds, and 542 ± 177 seconds, for 28% and 40%, respectively, P = 0.04) with no difference in peak workload (57 ± 25 W, 58 ± 25 W and 57 ± 25 W, for 21%, 28% and 40%, respectively, P = 0.50). There was an increase in oxygen saturation but no change in peak heart rate with increasing Fio2. Compared to patients with LVEF ≥50%, patients with LVEF between 45 and 49% had a significantly greater exercise time and peak workload. There was a correlation between the difference in exercise time between Fio2 21% and 40% and age; but not with BMI, haemoglobin, creatinine or NTproBNP.
CONCLUSION
Increasing Fio2 during exertion leads to a small increase in exercise time in patients with HeFNEF.
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