Table 2.

Characteristics of Caucasian and Japanese LQT1 Patients

	Caucasian (n = 62)	Japanese (n = 38)	P‐Value
A. Characteristics
Female, n (%)	38 (61)	21 (55)	0.55
QTc, ms	487 ± 53	497 ± 35	0.30
Female, ms	498 ± 59	496 ± 39	0.92
Male, ms	468 ± 38	499 ± 32	0.02
Beta‐blocker use, n (%)	28 (45)	14 (36)	0.41
ICD, n	10	0
Pacemaker, n (%)	5 (8)	1 (3)	0.27
Sympathectomy, n	0	0
Mutation characteristics
Missense mutation, n (%)	38 (61)	28 (74)	0.20
Dominant negative, n (%)	17 (28)	24 (63)	<0.001
B. Cardiac Events
Any cardiac event, n (%)*	25 (40)	22 (58)	0.09
Syncope, n (%)	21 (34)	17 (45)	0.28
Aborted cardiac arrest, n (%)	4 (7)	6 (16)	0.13
Sudden cardiac death, n	5 (8)	2 (5)	0.59
Other Death, n (%)	3 (5)	0 (0)	0.17
Age at first cardiac event, y	11	5	0.12
Syncope as a first cardiac event	21 (34)	16 (42)	0.41
Aborted cardiac arrest as a first cardiac event	1 (2)	5 (13)	0.02
Sudden cardiac death as first a cardiac event	3 (5)	1 (3)	0.59

Plus‐minus values are means ± SD.

*Denotes the number of patients who experienced at least one cardiac event during follow‐up. Mean QTc values include 87 cases; 13 cases were missing: 6 males and 7 females.

ICD = implantable cardioverter defibrillator.