Subcutaneous implantable defibrillator: State-of-the art 2013

Table 1 Subcutaneous implantable cardioverter-defibrillator programming

Device options	Nominal settings
Shock therapy (“ON/OFF”)	On
Post shock pacing (“ON/OFF”)	On
Conditional discrimination zone (“ON/OFF”; rate cutoff: 170 to 250 bpm)	On (200 to 220 bpm)

Table 2 Clinical subcutaneous implantable cardioverter-defibrillator case series n (%)

	Bardy et al[8] (2010)	Jarman et al[15] (2012)	Aydin et al[11] (2012)	Olde Nordkamp et al[14] (2012)	Köbe et al[12] (2013)	Jarman et al[16] (2013)	Burke et al[9] (ongoing, initial results)
Number of patients	55	16	40	118	69	111	304
Male	80%	56%	70%	75%	73%	N/A	74%
Age [median (range)/ mean ± SD]	56 ± 13	23 (10-48)	42 ± 15	50 ± 15	46 ± 16	33 (10-87)	52 ± 16
Primary prevention	78%	N/A	44%	60%	59%	50%	79%
Secondary prevention	22%	N/A	56%	40%	41%	50%	21%
Underlying pathology
Ischemic cardiomyopathy or idiopathic dilated cardiomyopathy	85%	0%	45%	57%	52%	19%	52%
Hypertrophic cardiomyopathy	N/A	0%	13%	N/A	15%	20%	9%
Congenital heart disease	4%	25%	3%	1%	4%	12%	N/A
Electrical heart disease1	N/A	75%	33%	26%	20%	43%	12%
Others	11%	0%	6%	16%	10%	7%	27%
Follow-up
Mean/median follow-up (mo)	10	9	8	18	7	13	N/A
Patients with re-interventions	6 (11)	3 (19)	5 (13)	16 (14)	3 (4)	19 (17)	92% procedure-related complication-free rate at 180 d
Patients with inappropriate shocks	5 (9)	4 (25)	2 (5)	15 (13)	3 (4)	17 (15)	38 (13)
Patients with appropriate shocks	3 (5)	4 (25)	4 (10)	8 (7)	3 (4)	13 (12)	16 (5)
Spontaneous VT/VF episode successfully converted by S-ICD or spontaneously converted	100%	100% [2 VF episodes with prolonged time (24 and 27 s) to therapy]	96% (1 episode of electrical storm was terminated by external shocks)	100%	100%	96% (1 death, see text for details)	100%

¹Brugada syndrome; long QT syndrome; catecholamine polymorphic ventricular tachycardia; idiopathic ventricular fibrillation. N/A: Data not available; S-ICD: Subcutaneous implantable cardioverter-defibrillator; VT: Ventricular tachycardia; VF: Ventricular fibrillation.

Table 3 Subcutaneous implantable cardioverter-defibrillator patient suitability

Suitable	Unsuitable
Young and active	Present (or high risk of) AV conduction loss requiring pacing
No venous access	Recurrent monomorphic VT
Permanent indwelling catheters	CRT indication
High infection risk
Electrical heart disease
Congenital structural heart disease

AV: Atrioventricular; CRT: Cardiac resynchronization therapy; VT: Ventricular tachycardia.