Excessive Ventilation During Early Phase of Exercise: A New Predictor of Poor Long-Term Outcome in Patients with Chronic Heart Failure

BACKGROUND: Studies demonstrating prognostic value of excessive exercise ventilation in chronic heart failure (CHF) have focused on data derived from the whole cardiopulmonary exercise test (CPET). Whether ventilatory response to early phase of exercise is useful for risk stratification in CHF is unknown. METHODS AND RESULTS: We evaluated 216 patients with systolic CHF who underwent CPET (age: 60+/-11 years, NYHA class [I/II/III/IV]: 18/104/77/17). Ventilatory response to exercise (slope of regression line relating ventilation to carbon dioxide production) was calculated from the whole exercise test (VE-VCO(2)-all) and from the first 3 min of exercise (early phase - VE-VCO(2)-3 min). During follow-up (mean: 40+/-20 months, >3 years in survivors), 89 (41%) CHF patients died. High VE-VCO(2)-all and VE-VCO(2)-3 min predicted poor outcome in single predictor analyses, and in multivariable models when adjusted for prognosticators (age, NYHA class, ejection fraction, peak VO(2)) (P<0.0001). In receiver operating characteristic curve analysis, areas under curve for 3-year follow-up were similar for VE-VCO(2)-all and VE-VCO(2)-3 min. VE-VCO(2)-3 min maintained its prognostic value in patients taking beta-blockers (P<0.0001) and those unable to perform maximal CPET (P=0.0009). CONCLUSIONS: In CHF patients, excessive ventilation assessed over the first 3 min predicts poor outcome. Assessment of ventilatory response to exercise for prognostic stratification may be extended to patients unable to perform maximal CPET.