Table 3.

Correlation and root mean squared error (RMSE) statistics of the digitised results from selected 308 12 by 1 ECG images and the ground truth digital ECGs before image thresholding (validation 2).

Lead name	Correlation				Root mean squared error
	Average	SD	p-value	95% confidence interval	Average	SD	p-value	95% confidence interval
I	0.894	0.209	$<0.001$	0.871–0.918	0.073	0.078	$<0.001$	0.064–0.082
II	0.933	0.197	$<0.001$	0.911–0.955	0.063	0.085	$<0.001$	0.054–0.073
V1	0.880	0.261	$<0.001$	0.850–0.909	0.086	0.184	$<0.001$	0.065–0.106
V2	0.772	0.315	$<0.001$	0.737–0.807	0.139	0.184	$<0.001$	0.119–0.160
V3	0.660	0.296	$<0.001$	0.627–0.693	0.174	0.157	$<0.001$	0.156–0.187
V4	0.638	0.287	$<0.001$	0.606–0.670	0.168	0.125	$<0.001$	0.154–0.182
V5	0.724	0.295	$<0.001$	0.690–0.757	0.139	0.116	$<0.001$	0.126–0.152
V6	0.822	0.302	$<0.001$	0.788–0.856	0.100	0.109	$<0.001$	0.088–0.112