Critical analysis of ineffective post implantation implantable cardioverter-defibrillator-testing

Table 1 Baseline characteristics

	All	Effective SMT	Ineffective SMT	P-value
Number, n (%)	618	596 (96.3)	22 (3.7)
Sex
Male, n	470	452	18
Female, n	148	144	4
Age (years)
Mean (± SD)	66.4 (± 11)	66.7 (± 10.6)	54.6 (± 16.5)	P = 0.0003
Median (IQR)	69 (60-74)	69 (62-74)	54 (41-69)
LVEF (%)
Mean (± SD)	31 (± 12.4)	31 (± 12.5)	26.9 (± 9.0)	P = n.s.
Median (IQR)	30 (22-35)	30 (23-35)	30 (20-35)
LVEF > 30%, n (%)	248 (40.1)	240 (36.9)	8 (3.2)
LVEF < 30%, n (%)	370 (59.9)	356 (56.1)	14 (3.8)	P = n.s. (> 30% vs < 30%)
LVEF > 20%, n (%)	334 (54.0)	320 (49.8)	14 (4.2)
LVEF < 20%, n (%)	284 (46)	276 (43.2)	8 (2.8)	P = n.s. (> 20% vs < 20%)
BMI (kg/m2)
Mean (± SD)	28.4 (± 4.7)	28 (± 4.7)	29 (± 4.0)	P = n.s.
Median (IQR)	28 (17-28)	28 (25-31)	29 (25.5-33)
Indikation
Primary prevention, n (%)	468 (76)	452 (72.6)	16 (3.4)
Secundary prevention, n (%)	150 (24)	144 (20)	6 (4.0)	P = n.s. (pp vs sp)
Type of arrhythmia for secondary prevention, n (%)
Sustained VT	108 (72)	106 (70.1)	2 (1.9)
VF	42 (28)	38 (18.1)	4 (9.5)	P = 0.05 (VT vs VF)
SMT-Energy (J)
Mean (± SD)	21 (± 2.3)	20.8 (± 2.3)	30.9 (± 2.0)
Median (IQR)	20 (20-22)	20 (20-20)	30 (30-30)
Diagnosis
Non CAD, n (%)	270	254 (94.1)	16 (5.9)
DCM (myocarditis), n (%)	232 (85)	218 (79)	14 (6.0)
Other CM (non myocarditis), n (%)	38 (15)	36 (9.8)	2 (5.2)
CAD, n (%)	348	342 (98.3)	6 (1.7)	P = 0.007 (nonCAD vs CAD)
Complete revascularized, n (%)	196 (56)	192 (54)	4 (2.0)
Not complete revascularized, n (%)	152 (44)	150 (42.7)	2 (1.3)	P = n.s. (complete vs in-complete revascularized)
One vessel disease	124 (81.6)	122 (80.0)	2 (1.6)
> One vessel disease	28 (18.4)	28 (18.4)	0 (0)	P = n.s. (one vesel vs > one)
Stenosed	100 (65.8)	100 (65.8)	0 (0)
Occluded	52 (34.2)	50 (30.4)	2 (3.8)	P = n.s. (stenosed vs occluded)
Medication
Amiodaron medication, n (%)	124 (20)	118 (15.2)	6 (4.8)
No amiodaron, n (%)	494 (80)	478 (76.8)	16 (3.2)	P = n.s. (amio vs no amio)

SMT: Safety margin test; n: Number; SD: Standard deviation; IQR: Interquartile range; LVEF: Left ventricular ejection fraction; BMI: Body mass index; pp: Primary prevention; sp: Secondary prevention; VT: Ventricular tachycardia; VF: Ventricular fibrillation; CAD: Coronary artery disease; DCM: Dilated cardiomyopathy; CM: Cardiomyopathy; amio: Amiodarone; n.s.: Not significant; n/a: Not applicable.

Table 2 Characteristics of patients with failed intra-operative safety margin test

n	Age at time of implantation (years)	Sex (m/f)	Indication for ICD implantation	LVEF (%)	Primary vs secondary ICD indication	Further management after failed initial SMT
1	46	m	LAD stenosed	30	pp	Subcutaneous array
2	45	w	oCM	15	pp	PDT OK
3	74	w	oCM	36	pp	Subcutaneous array
4	41	m	cmpl revasc	39	pp	Subcutaneous array
5	54	w	DCM	10	pp	Subcutaneous array
6	25	m	oCM	20	sp	Subcutaneous array
7	68	m	DCM	35	sp	Subcutaneous array
8	69	m	RCA occluded	31	sp	PDT OK
9	73	m	oCM	30	pp	PDT OK
10	37	m	TGV surgery	30	pp	Subcutaneous array
11	69	m	DCM	20	pp	none
12	46	m	LAD stenosed	30	pp	Subcutaneous array
13	45	w	DCM	15	pp	PDT OK
14	74	w	DCM	36	pp	Subcutaneous array
15	41	m	cmpl revasc	39	pp	Subcutaneous array
16	54	w	DCM	10	pp	Subcutaneous array
17	25	m	DCM	20	sp	Subcutaneous array
18	68	m	DCM	35	sp	Subcutaneous array
19	69	m	RCA occluded	31	sp	PDT OK
20	73	m	DCM	30	pp	PDT OK
21	37	m	vs D surgery	30	pp	Subcutaneous array
22	69	m	DCM	20	pp	None

m: Male; w: Women; ICD: Internal cardioverter defibrillator; LAD: Left anterior descendent coronary artery; oCM: Other cardiomyopathy; cplm revasc: Complete revascularized; RCA: Right coronary artery; TGV: Transposition of the great vessels; VSD: Ventricular septum defect.

Table 3 Follow up

		All	Effective SMT	Ineffective SMT	P-value
FU, n (%)		552 (89.3)	530 (96)	22 (100)
FU duration (mo)	Mean (± SD)	21.1 (± 21)	21.5 (± 21)	15.8 (± 21)	P = n.s.
Antiarrhythmica, n (%)
	Amiodarone		122 (23.0)	6 (27)	P = n.s.
	Sotalex		2 (0.4)	0 (0)	P = n.s.
	β-blocker		485 (91.5)	20 (91)	P = n.s.
Events during FU, n (%)			124 (23.4)	2 (9.1)	P = 0.02
	Inadequate therapy		4 (0.8)	2 (9.1)	P = n.s.
	ATP		58 (10.9)	0 (0)
	Shock delivery		36 (6.8)	0 (0)
	ATP and shock delivery		20 (3.8)	0 (0)
	VT ablation		6 (1.1)	0 (0)

FU: Follow up; ATP: Anti tachycardia pacing; n.s.: Not significant.