VO2 improvements after cardiac rehabilitation tied to better outcomes in high-risk HF

Higher-risk heart failure (HF) patients who show improvements in peak oxygen consumption (VO₂) following cardiac rehabilitation (CR) have lower risks of new-onset atrial arrhythmias, mortality, and hospitalization due to HF exacerbation, a recent study has found.

A total of 220 HF patients (median age 67 years, 23 percent women) participated in the study and underwent symptom-limited cardiopulmonary exercise testing. VO₂, minute ventilation, carbon dioxide production, and expiratory gas were all assessed. Exercise testing and assessments were performed 2 and 5 months after CR.

At 2 months, 50 percent (n=110) of participants had low peak VO₂ and were categorized as higher-risk patients. At 5 months, 78 percent (n=86) of this subgroup saw VO₂ improvements.

After a median follow-up of 6 years, higher-risk patients who saw VO₂ improvements had a mortality rate of 4 percent, significantly lower than that in comparators with no such improvements (29 percent; log-rank p<0.001). Likewise, hospitalization due to HF exacerbation occurred significantly less frequently in higher-risk patients with VO₂ improvements (6 percent vs 17 percent; log-rank p=0.044).

Cox regression analysis confirmed that the risks of death (hazard ratio [HR], 0.132, 95 percent confidence interval [CI], 0.034–0.511; p=0.003) and HF hospitalization (HR, 0.156, 95 percent CI, 0.018–0.1373; p=0.094) were lower in higher-risk patients with VO₂ improvements.

A similar trend was reported for new-onset atrial arrhythmias (9 percent vs 27 percent; log-rank p=0.013; HR, 0.263, 95 percent CI, 0.085–0.830; p=0.021).

“Further studies are warranted to determine whether early detection and management at the early stage of new-onset atrial arrhythmias could improve clinical outcomes in higher-risk patients without improvement in exercise capacity after CR,” the researchers said.