Abstract 583: Clinical and Doppler Echocardiographic Correlates of VE/VCO2 Slope in Systolic Heart Failure: The HF-ACTION Trial
Background: VE/VCO2 slope, an index of ventilatory efficiency obtained during cardiopulmonary exercise testing (CPX), is a powerful independent predictor of mortality in patients with systolic heart failure (SHF). Left ventricular (LV) performance is also an important determinant of outcomes as well as a correlate of exercise performance in SHF. Therefore, the purpose of this analysis was to examine the relationship between VE/VCO2 slope and both clinical and echo-Doppler (echo) LV performance in a large SHF sample..
Methods: HF-ACTION was a large multicenter NIH-funded trial of aerobic exercise training in patients with SHF (LV ejection fraction [LVEF] < 35%) and included detailed clinical evaluation, echo and symptom limited CPX testing at baseline.
Results: In 693 patients (age 58 +/−13 yr, 69% men, body mass index (BMI) 32+/−7, 65% NYHA class II, peak VO2= 15.2 +/− 4.6 ml/kg/min), each of the following variables correlated significantly with VE/VCO2 slope on bivariate analysis: left atrial dimension (r=0.16), LVEF (r= −0.16), transmitral peak E/A velocity ratio (r=0.28), and transmitral E/E’ velocity ratio (r=0.19), each p<0.0001, and mitral valve deceleration time (r= −0.09, p<0.01). From a list of 31 demographic and clinical variables plus the 5 above echo variables, a multivariate linear regression model for VE/VCO2 slope was derived (Table⇓). Of note, the strongest predictor variable for VE/VCO2 slope was E/A ratio.
Conclusion: Among a wide range of commonly available clinical and echo variables, Doppler LV peak E/A diastolic filling ratio was the strongest correlate of VE/VCO2 slope, a powerful independent predictor of prognosis in SHF. This suggests that increased LV filling pressures may play a role in the decreased exercise ventilatory efficiency and poor prognosis observed in SHF.