Table 2.

ECG Characteristics

	Patients With SMI	Controls Without Mental Illness	P Value
n	10 028	336 524	NA
Heart rate, bpm	75 [66–86]	69 [61–78]	<0.001
Missing	686	30 361
P‐wave duration, ms	108 [100–116]	108 [100–116]	<0.001
Missing	686	30 361
PR interval, ms	156 [142–172]	156 [144–174]	0.604
Missing	686	30 361
QRS duration, ms	90 [84–98]	92 [84–100]	<0.001
Missing	686	30 361
QT interval, ms	388 [366–410]	396 [376–416]	<0.001
Missing	686	30 361
QTcF interval, ms	417 [404–431]	414 [402–427]	<0.001
Missing	686	30 361
No ECG abnormality	7295 (72.7)	237 397 (70.5)	<0.001
Minor ECG abnormality	660 (6.6)	18 541 (5.5)	<0.001
First‐degree atrioventricular block	384 (3.8)	13 477 (4.0)	0.391
Incomplete bundle branch block	210 (2.1)	8504 (2.5)	0.007
Incomplete right bundle branch block	192 (1.9)	7680 (2.3)	0.016
Incomplete left bundle branch block	18 (0.2)	824 (0.2)	0.227
Left fascicular block	177 (1.8)	4504 (1.3)	<0.001
Left anterior fascicular block	102 (1.0)	2743 (0.8)	0.031
Left posterior fascicular block	75 (0.7)	1761 (0.5)	0.003
QTcF prolongation	324 (3.2)	5831 (1.7)	<0.001
Major ECG abnormality	2073 (20.7)	80 586 (23.9)	<0.001
Left ventricular hypertrophy	850 (8.5)	35 832 (10.6)	<0.001
Atrial fibrillation/flutter	234 (2.3)	12 561 (3.7)	<0.001
Bundle branch block	302 (3.0)	11 550 (3.4)	0.024
Right bundle branch block	217 (2.2)	7803 (2.3)	0.326
Left bundle branch block	85 (0.8)	3747 (1.1)	0.014
Intraventricular conduction disturbance	76 (0.8)	2786 (0.8)	0.479
Q waves	541 (5.4)	17 064 (5.1)	0.152
ST‐T deviations	381 (3.8)	15 283 (4.5)	<0.001

Data are reported as median (25th–75th percentiles) or n (%). P values based on Mann‐Whitney U and χ² tests, as appropriate. bpm indicates beats per minute; QTcF, Fridericia‐corrected QT; and SMI, severe mental illness.