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 as indicated 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 β-blocker therapy. In contrast, if decline in predicted and attained peak VO2 were age-related, proportionally, loss of aerobic 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 β-blockers. Methods: We retrospectively evaluated 483 (132 female) patients (aged 20-88 years, LVEF 31 ± 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 β-blocker equation to peak VO2bb was 20.934 - 0.092 × age. Conclusions: Clinical interpretation of aerobic capacity impairment is influenced by aging in HF patients. This evidence must be considered when using peak VO2 for prognostic stratification and clinical decision-making in patients with HF under β-blocker therapy. © 2013 Via Medica.