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

BACKGROUND

Heart failure (HF) is associated with impaired maximal aerobic capacity as indicated by decreases in peak oxygen uptake (peak VO(2)). Considering that aging by itself has a negative effect on this variable, the evaluation of maximum capacity is often questioned because current predicted peak VO(2) is based on subjects without heart disease or b-blocker therapy. In contrast, if decline in predicted and attained peak VO(2) were age-related, proportionally, loss of aerobic function (predicted peak VO(2), %) would remain stable over time in these patients. The purpose of this investigation is to assess the effects of age on peak VO(2) in HF patients taking b-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 VO(2), based on age.

RESULTS

Peak VO(2) decreased 0.9 mL/min/kg per age-decade, maximum HR also decreased with aging and VE/VCO(2) slope was similar among all decades. The predicted new b-blocker equation to peak VO(2 bb) 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 VO(2) for prognostic stratification and clinical decision-making in patients with HF under b-blocker therapy.