Remote monitoring of implantable defibrillators is associated with fewer inappropriate shocks and reduced time to medical assessment in a remote and rural area

Table 1 Baseline characteristics

	Clinic, n (%)	RM, n (%)
n	45	111
Age at implant (year)	63.6 ± 13.0	64.2 ± 11.5
Male	30 (85.7)	85 (82.5)
NYHA functional class
I	12 (34.3)	40 (38.8)
II	18 (51.4)	52 (50.5)
III	5(14.3)	11 (10.7)
Cardiac disease category
Coronary artery disease	21 (60.0)	54 (52.4)
Non ischaemic dilated cardiomyopathy	4 (11.4)	15 (14.6)
Primary electrical disease	3 (8.6)	5 (4.9)
Hypertrophic cardiomyopathy	1 (2.9)	6 (5.8)
Valvular heart disease	1 (2.9)	2 (1.9)
Hypertensive	1 (2.9)	3 (2.9)
Other cardiomyopathy	1 (2.9)	5 (4.9)
Undetermined	2 (5.7)	10 (9.7)
None	1 (2.9)	1 (1.0)
ECG history of
Sustained ventricular tachycardia	7 (20.0)	24 (23.3)
Ventricular fibrillation	6 (17.1)	19 (18.4)
Torsade de pointes	1 (2.9)	3 (2.9)
Indication for ICD
Primary	20 (57.1)	57 (55.3)
Secondary	15 (42.9)	46 (44.7)
Implanted device
Single chamber ICD	13 (37.1)	27 (26.2)
Dual chamber ICD	19 (54.3)	74 (71.8)
CRT-D	5 (14.3)	23 (22.3)
Type of implant
Original	30 (85.7)	83 (80.6)
Replacement	5 (14.3)	20 (19.4)
Drug therapy
Beta-blocker	25 (71.4)	69 (70.0)
Digoxin	2 (5.7)	12 (11.7)
Amiodarone	4 (11.4)	8 (7.8)
Manufacturer
Biotronik	11 (31.4)	44 (42.7)
Boston scientific/guidant	8 (28.8)	0 (0)1
Medtronic	5 (14.3)	41 (39.8)
St Jude Medical	11 (31.4)	18 (17.5)

¹Boston remote monitoring (latitude) was not available at the time of implant.

RM: Remote monitoring; NYHA: New York Heart Association; ECG: Electrocardiograph; ICD: Implantable cardioverter defibrillator; CRT-D: Cardiac resynchronisation therapy with defibrillators.

Table 2 Incidence of appropriate and inappropriate shocks and time to medical assessment

	Clinic, n (%)	RM, n (%)
n	45	111
Reason lost to follow up
Out of area	3 (6.7)	4 (3.6)
Death	7(15.6)	4 (3.6)
Number of patients receiving shocks (appropriate)	3 (8.6)	14 (13.6)
1 shock	3 (8.6)	9 (8.7)
2-9 shocks	0	6 (5.8)
≥ 10	0	0
Number of patients receiving shocks (inappropriate)	4 (11.4)	4 (3.9)
1 shock	0	2 (1.9)
2-9 shocks	2 (5.7)	2 (1.9)
≥ 10	2 (5.7)	0
Causes inappropriate shocks (number of shocks)
AF/flutter	18 (42.9)	2 (20.0)
SVT	14 (33.3)	1 (10.0)
T wave over sense	0	1 (10.0)
V lead displacement	0	6 (60.0)
Noise	10 (23.8)	0
TMA
Appropriate shocks	11.7 ± 9.2	1.8 ± 0.6
Inappropriate shocks	15.1 ± 6.8	1.0 ± 0.0

TMA: Time to medical assessment; RM: Remote monitoring; AF: Atrial fibrillation; SVT: Supraventricular tachycardia.