Table 2.

ECG characteristics of the study patients during hydroxychloroquine treatment

	All patients (n = 819)	QTc ≤470 ms (n = 752)	QTc 471–500 ms (n = 55)	QTc >500 ms (n = 12)	P value∗
Ventricular rate (bpm)	74.8 ± 17.3	74.1 ± 17.0	80.9 ± 16.5	85.4 ± 25.7	.001
QRS duration (ms)	100.9 ± 22.8	101.0 ± 23.2	98.3 ± 16.3	104.0 ± 24.2	.47
QT interval (ms)	392.8 ± 44.5	389.6 ± 42.6	421.3 ± 40.0	462.6 ± 73.6	<.0001
QTc-Bazett (ms)	430.9 ± 31.8	425.5 ± 26.2	481.6 ± 7.9	535.3 ± 39.0	<.0001
QTc-Framingham (ms)	417.8 ± 30.3	413.3 ± 27.3	457.3 ± 15.9	491.5 ± 45.7	<.0001
QTc-Fridericia (ms)	418.1 ± 30.5	413.4 ± 27.2	460.2 ± 13.3	494.2 ± 49.4	<.0001

Continuous variables are given as mean ± SD.

ECG = electrocardiogram.

^∗Comparison of QTc ≤470 ms vs QTc >470 ms.