The association between congestive heart failure (CHF) of the CHA2DS2-VASc scores and thromboembolic (TE) events in patients with atrial fibrillation (AF) is a topic of debate due to conflicting results. As the importance of diastolic impairment in the occurrence of TE events is increasingly recognized, it is crucial to evaluate the predictive power of CHA2DS2-VASc scores with C criterion integrating diastolic parameters. We analyzed 4200 Korean nonvalvular AF patients (71 years of age, 59% men) to compare multiple echocardiographic definitions of CHF. Various guideline-suggested echocardiographic parameters for systolic or diastolic impairment, including left ventricular ejection fraction (LVEF) ≤ 40%, the ratio of early diastolic mitral inflow velocity to early diastolic velocity of the mitral annulus (E/E’) ≥ 11, left atrial volume index > 34 mL/m2, and many others were tested for C criteria. Multivariate-adjusted Cox regression analysis showed that CHA2DS2-VASc score was an independent predictor for composite thromboembolic events only when CHF was defined as E/E’ ≥ 11 (hazard ratio, 1.26; p = 0.044) but not with other criteria including the original definition (hazard ratio, 1.10; p = 0.359). Our findings suggest that C criterion defined as diastolic impairment, such as E/E’ ≥ 11, may improve the predictive value of CHA2DS2-VASc scores.