Table 6. Results of Empirical Study.

caliper	Standardized difference for covariates									Matching ratio
	sex	rhythm	LVEDD	age	NYHA	QRS	LVEF	Heart rate	Medicine therapy
unmatched	0.214	0.387	4.288	0.276	0.317	0.407	0.203	0.156	0.292	—
20%	0.100	0.053	0.027	0.088	0.050	0.098	0.043	0.094	0.142	73.6%