Cardiopulmonary exercise test predicts sustained ventricular arrhythmias in chronic heart failure.

BACKGROUND

The cardiopulmonary exercise test (CPX) is an affordable tool for risk prediction in patients with chronic heart failure (CHF). We aimed to determine the role of CPX parameters in predicting the risk of incidence of sustained ventricular arrhythmias (SVA) in CHF.

METHODS

Sixty-one consecutive patients with CHF enrolled in the Daunia Heart Failure Registry underwent CPX and were followed for 327 ± 247 days. Clinical follow-up was performed every month and anticipated in case of re-hospitalisation for cardiac disease. Incidence of SVA was evaluated by direct clinical examination (ECG, ambulatory ECG).

RESULTS

Patients with episodes of SVA (N 14) showed lower values of pVO2 and PetCO2, and higher values of VE/VCO2, VE/VCO2 slope, and VE%. After correction for age, gender, diabetes, ischaemic heart disease and left ventricular ejection fraction, peak VO2 (hazard ratio (HR) 0.68, 95 % confidence interval (CI) 0.51-0.91, p < 0.05), VE% (HR 1.38, 95 % CI 1.04-1.84, p < 0.05), VE/VCO2 (HR 1.38, 95 % CI 1.04-1.82, p < 0.05), VE/VCO2 slope (HR 1.77, 95 % CI 1.31-2.39, p < 0.01), PetCO2 (HR 0.66, 95 % CI 0.50-0.88, p < 0.01) were found as predictors of SVA. At Kaplan-Meier analysis, lower event-free rates were found in subjects with peak VO2 values below median (log rank p < 0.05), values of VE/VCO2 above mean (p < 0.05), higher VE/VCO2 slope tertiles (p <0.05), and values of PetCO2 below median (p < 0.05).

CONCLUSIONS

CPX provides prognostic independent information for risk of SVA in subjects with CHF.