. Author manuscript; available in PMC: 2019 Oct 7.

Published in final edited form as: Pediatr Res. 2018 Dec 17;85(3):398–404. doi: 10.1038/s41390-018-0256-9

Table 1.

Electrocardiographic Outcomes of 28 Rhesus Macaque Monkeys after Receiving Methylphenidate for Five Years, by Dosage Group.

	Methylphenidate Dosage (mg/kg, bid)
Outcome^*	Control group (0) n=9	Low-dose group (2.5) n=9	High-dose group (12.5) n=10	P^*
Heart rate, mean (SD), beats/min	136 (11.2)	126 (5.4)	132 (9.4)	0.62
QT interval, mean (SD), msec	271 (30.6)	290^** (16.0)	281^† (28.5)	0.36
QTc interval, mean (SD), msec	400 (56.1)	418^** (27.2)	409^‡ (20.8)	0.69
QRS axis, mean (SD), degrees	64.3 (33.7)	29.0 (94.1)	84.3 (25.4)	0.12
QRS duration, mean (SD), msec	46.7^§ (11.0)	51.7 (16.3)	47.2 (9.0)	0.68

Type I error rate (α) =0.01.

^**

Atrioventricular block, Q wave width <0.035, ST depression, non-specific ST and T wave changes, and ST elevation were negative for all animals. Probability values for statistical differences in means between dosage groups were calculated with exact permutation tests.

^†

n=8

^‡

n=9

^§

n=6