Table 2 ECG parameters and arrhythmias during hospitalization in patients with and without QTP

ECG at diagnosis

Heart rate, bpm

90.9 ± 21.3

97.9 ± 24.4

 < 0.001

QRS duration, ms

89.8 ± 13.0

98.7 ± 23.3

 < 0.001

PR interval, ms

151.9 ± 27.3

151.4 ± 28.0

0.829

QT interval, ms

346.0 ± 42.3

387.5 ± 43.5

 < 0.001

Corrected QT interval^b, ms

415.3 ± 22.0

479.6 ± 25.1

 < 0.001

Axis, degree

38 [13, 63]

39 [9, 68]

0.672

RV5 + SV1, MV

2.12 ± 1.13

2.03 ± 1.11

0.296

TWD^c/QT

–

59.1 ± 11.5

–

T_peak-T_end^d/QT

–

27.1 ± 7.0

–

U wave, %

0 (0)

9 (3.83)

 < 0.001

Atrioventricular block, %

25 (3.17)

11 (4.68)

0.269

Left bundle branch block, %

1 (0.13)

3 (1.28)

0.013

Right bundle branch block, %

36 (4.56)

27 (11.49)

 < 0.001

Left ventricular hypertrophy, %

38 (4.82)

16 (6.81)

0.230

Sinus tachycardia, %

234 (29.66)

84 (35.74)

0.077

Sinus bradycardia, %

22 (2.79)

2 (0.85)

0.085

ST-segment depression, %

36 (4.56)

9 (3.83)

0.630

Arrhythmic events during hospitalization

Paroxysmal AF or AT^e, %

36 (4.56)

31 (13.19)

 < 0.001

Frequent PVCs^f, %

29 (3.58)

19 (8.09)

0.005

VT or VF^g, %

5 (0.63)

13 (5.53)

< 0.001