Table 3:

Cardiac manifestations in subjects with CGL4.

Family ID	ID	Age of onset	Type of arrhythmia and other cardiac findings/ comments	Sudden death history in the siblings/family	Pacemaker implantation/sympathectomy
1	P1	At age 15†	Non-sustained episodes of VT and polymorphic VES beats; catecholaminergic polymorphic VT; episodes of rapid atrial fibrillation	No	ICD at age 16
2	P2	At age 13	Non-sustained VT and supraventricular tachycardia episodes consistent with atrial tachycardia; VT with syncope	No	No
3	P3	At age 4	Polymorphic VT (age 6); HCM (age 4)	No	No
4	P4	At age 13	Polymorphic VT (age 15); HCM (age 13)	No	No
5	P5	At age 9	VT	No	No
6	P6	No cardiac work up	No cardiac work up	Yes	No
7	P7	No	Screened by Holter ECG	No	No
8	P8	At 18 months	Wolff-Parkinson-White syndrome (18 months); non-sustained VT and supraventricular tachycardia episodes (age 5); preexited atrial tachycardia	No	No
	P9	No	Screened by ECG	No	No
9	P10	At age 2	Short runs of VT (age 2); VES and PAC (age 7)	No	No
	P11	No	Screened by ECG	No	No
10	P12	No	Screened by ECG	No	No
	P13	No	Screened by ECG	No	No
11	P14	At age 36	Extra systoles; sinus tachycardia	Yes	No
12	P15	At age 14	Non-sustained VT	Unknown	ICD at age 14
13	P16	At age 17	Polymorphic premature VES. ventricular couplets; non-sustained VT	No	No
14	P17	No	Screened by ECG	No	No
	P18	At infancy	Non-sustained VT and supraventricular tachycardia episodes consistent with atrial tachycardia	No	No
15	P19	No	Screened by ECG	No	No
16	P20	At 12 years	Biphasic catecholaminergic polymorphic VT; supraventricular tachycardia	Self	ICD at age 16; cervical sympathectomy at age 17
	P21	At 4 years	Nonsustained ventricular ectopy	Self. brother at age 22	No
17	P22	At 14 years	Catecholaminergic polymorphic VT	Brother at age 15	No
	P23	At 8 years	Catecholaminergic polymorphic VT	Self	No
18	P24	No	No cardiac work up	No	No
19	P25	At age 11	VT with syncope; intermittent atrial fibrillation (age 13)	Sister at age 14	ICD at age 13
20	P26	At age 9	Non-sustained supraventricular tachycardia with occasional ventricular extrasystoles	No	No
	P27	No cardiac work up	No cardiac work up	No	No
21	P28	No	No exercise test	Yes	No
	P29	At 7 y	Sinus dysrhythmia	No	No
	P30	At 40 y	Atrial fibrillation	No	No
	P31	No cardiac work up	No cardiac work up	No	No
	P32	No cardiac work up	No cardiac work up	No	No
	P33	No cardiac work up	No cardiac work up	No	No
	P34	No cardiac work up	No cardiac work up	No	No
22	P35	No	No exercise test	No	No
	P36	No	No exercise test	No	No
	P37	No cardiac work up	No cardiac work up	No	No
23	P38	No cardiac work up	No cardiac work up	NA	No
	P39	No	No exercise test	No	No
24	P40	No	Sudden death at age of 14	Self	No
25	P41	At 3 y	PAC	No	No
	P42	No cardiac work up	No cardiac work up	No	No
	P43	No cardiac work up	No cardiac work up	No	No
26	P44	No	No exercise test	No	No
27	P45	No	Normal ECG and ECHO	NA	No
	P46	No	Normal ECG and ECHO	NA	No

ECG: electrocardiogram, HCM: hypertrophic cardiomyopathy, PAC: premature atrial contractions, VES: ventricular extra systoles, VT: ventricular tachycardia

^†patient described palpitations first at age 12 but formally diagnosed with arrhythmia later at the age of 15.