Relationship between cardiopulmonary exercise testing parameters and heart failure risk (H2ARDD score) in atrial fibrillation

BackgroundA novel risk scoring system (H2ARDD) for estimating the incidence of heart failure (HF) events in atrial fibrillation (AF) has been developed, which represents points assigned for organic heart disease (2 points), anemia (1 point), renal dysfunction (1 point), diabetes (1 point), and diuretic use (1 point). We aimed to clarify whether H2ARDD score is related to cardiopulmonary exercise testing (CPX) parameters in patients with AF.MethodsThe study population included 344 consecutive patients with AF who underwent CPX as initial screening between June 2004 and March 2012. The association between 4 CPX parameters and the incidence of HF events was analyzed by using multiple linear regression models.ResultsThe peak O2 uptake (peak V̇O2), anaerobic (gas exchange) threshold (AT), and ratio of the increase in V̇O2 to the increase in work rate (ΔV̇O2/ΔWR) were lower and the slope of the increase in ventilation to the increase in CO2 output (V̇E–V̇CO2 slope) was higher in patients with than in those without each H2ARDD score component. Accordingly, the parameters significantly increased or decreased according to H2ARDD score. With the multiple linear regression models, H2ARDD score was independently associated with each CPX parameter even after adjustment for various cofactors.ConclusionsH2ARDD score was independently associated with the well-established CPX parameters in patients with AF, suggesting a potential pathophysiological basis for a risk stratification system for predicting HF events in patients with AF.