Effects of age on aerobic capacity in heart failure patients under beta-blocker therapy: Possible impact in clinical decision-making?

Abstract

Background: Heart failure (HF) is associated with impaired maximal aerobic capacity asindicated by decreases in peak oxygen uptake (peak VO₂). Considering that aging by itself has a negative effect on this variable, the evaluation of maximum capacity is often questioned because current predicted peak VO₂ is based on subjects without heart disease or b-blocker therapy. In contrast, if decline in predicted and attained peak VO₂ were age-related, proportionally, loss ofaerobic function (predicted peak VO₂, %) would remain stable over time in these patients. The purpose of this investigation is to assess the effects of age on peak VO₂ in HF patients taking b-blockers.\

Methods: We retrospectively evaluated 483 (132 female) patients (aged 20–88 years, LVEF31 ± 11%) with non-ischemic (n = 362), ischemic (n = 74) and Chagas-related HF (n = 47) who had been submitted to an incremental cardiopulmonary exercise testing on a motorized treadmill. Linear regression was used to develop the equation to predict peak VO₂, based on age.

Results: Peak VO₂ decreased 0.9 mL/min/kg per age-decade, maximum HR also decreased with aging and VE/VCO₂ slope was similar among all decades. The predicted new b-blocker equation to peak VO₂ bb was 20.934 – 0.092 × age.

Conclusions: Clinical interpretation of aerobic capacity impairment is infl uenced by agingin HF patients. This evidence must be considered when using peak VO₂ for prognostic stratification and clinical decision-making in patients with HF under b-blocker therapy.