A moderate 1-km treadmill walk predicts mortality in men with mid-range left ventricular dysfunction

Background We have previously demonstrated that peak oxygen uptake (VO2peak) estimated by a moderate one-km treadmill-walking test (1k-TWT) predicts mortality in men with cardiovascular disease and preserved left ventricular ejection fraction (LVEF). Methods and Results We now studied 209 chronic heart failure outpatients aged 35-83 years classified as NYHA class I (LVEF 40±5%), who were referred to an exercise-based secondary prevention programme. VO2peak was determined in all subjects by a previously described 1k-WT. Based on the VO2peak values obtained, participants were subdivided into tertiles. LVEF was not different among the three groups. During a median 9.4 year follow-up, 51 all-causes deaths occurred: 23 in the lowest VO2peak tertile, 11 in the intermediate, and 3 in the highest tertile. Mortality risk increased across decreasing tertiles of VO2peak (P<0.0001). Compared to the lowest tertile, the full-adjusted mortality risk decreased for the second, and third tertile, with Hazard ratios of 0.64 (95% CI: 0.33-1.20, P=0.18), and 0.26 (95% CI: 0.08-0.80, P=0.02), respectively (P for trend <0.0001). Each 1 mL/kg/min increase in VO2peak was associated with a 7% lower risk of death (P=0.04). Conclusions VO2peak estimated by a moderate and self-paced one-km treadmill walk predicts mortality in NYHA class I CHF patients with mid-range left ventricular dysfunction.