Prognostic Value of Post-exercise Oxygen Uptake Kinetics in Heart Failure with Reduced Ejection Fraction

Objectives Recent data indicate high predictive value of oxygen uptake (VO 2 ) kinetics following exercise test in patients with heart failure (HF). The aim of this study was to confirm prognostic significance of VO 2 recovery delay (VO 2 RD) in HF with reduced ejection fraction (HFrEF). Methods We retrospectively analyzed the subgroup of 70 patients with HFrEF, NYHA classes II-III (55 male, mean age 58.8±12,6 years, mean EF=29,7±8,4%) previously included in the prospective observational study. All patients were on optimal medical treatment. At baseline the patients underwent comprehensive investigation including standard clinical examination, echocardiography and cardiopulmonary exercise testing. VO 2 RD defined as time from the end of loaded exercise until permanent fall of VO 2 below VO 2 peak values, was used for estimation of VO 2 recovery kinetics. Average follow-up amounted 38 months. Composite end-point of cardiovascular death and hospitalization for HF decompensation was considered a primary analysis variable. Results Composite end-point was observed in 57.7% of patients (n=41). ROC-analysis demonstrated significant independent predictive value of VO 2 RD (AUC=0,775; 95%CI=0,646 to 0,874; p 2 RD of 25 seconds used in the previous study as a cut-off point. Kaplan-Meier analysis confirmed prognostic relevance of VO 2 RD for composite end-point (Log rank P=0.03). Conclusions Prolonged post-exercise VO 2 recovery delay indicates unfavorable prognosis and may be used as an independent non-invasive marker for risk stratification in HF patients with reduced ejection fraction.