Table 3.

ECG P-wave characteristics (duration, amplitude, and morphology) and correlation coefficients comparison between Smartwatch and standard 12-leads ECG.

Variables	Lead	SW-ECG	12-Leads ECG	Correlation coefficient with S-ECG	p-value
Presence of P-wave	DI	Absence = 45	Absence = 44	91.4 %	<0.01
		Presence = 91	Presence = 95
	V1	Absence = 76	Absence = 44	64.81 %	<0.01
		Presence = 60	Presence = 95
	V3	Absence = 55	Absence = 44	79.6 %	<0.01
		Presence = 80	Presence = 95
	V6	Absence = 42	Absence = 44	88.0 %	<0.01
		Presence = 93	Presence = 95
Duration (milliseconds)	DI	72.61 ± 24.49	80.71 ± 20.81	94.3 %	<0.05
	V1	51.53 ± 14.94	81.04 ± 22.58	73.3 %	<0.05
	V3	60.26 ± 19.19	81.54 ± 21.82	83.9 %	<0.05
	V6	70.65 ± 26.46	82.12 ± 23.83	90.9 %	<0.05
Amplitude (millivolts)	DI	1.21 ± 0.43	1.4 ± 0.82	90.3 %	<0.05
	V1	1.07 ± 0.192	1.6 ± 0.63	75.6 %	<0.05
	V3	1.04 ± 0.169	1.7 ± 0.31	82.8 %	<0.05
	V6	1.16 ± 0.38	1.5 ± 0.55	88.7 %	<0.05
Morphology (Normal/LAH/RAH)	DI (n = 91)	Normal = 84	Normal = 76	84.1 %	<0.01
		LAH = 6	LAH = 12
		RAH = 1	RAH = 7
	V1 (n = 60)	Normal = 60	Normal = 76	44.9 %	<0.01
		LAH = 0	LAH = 12
		RAH = 0	RAH = 7
	V3 (n = 80)	Normal = 76	Normal = 76	67.6 %	<0.01
		LAH = 4	LAH = 12
		RAH = 0	RAH = 7
	V6 (n = 93)	Normal = 83	Normal = 76	80 %	<0.01
		LAH = 8	LAH = 12
		RAH = 2	RAH = 7
	LAH: left atrial hypertropia RAH: right atrial hypertropia