. 2018 Aug 12;2018(3):31. doi: 10.21542/gcsp.2018.31

Table 3. Clinical, echocardiographic, and demographic features in 224 children and adolescents with HCM who underwent ICD implantation for primary or secondary prevention.

		Primary Prevention		Secondary Prevention
Characteristic	All Study Patients	Overall	≥1 Appropriate Intervention	Overall	≥1 Appropriate Intervention
Number of patients	224	188	26	36^§	17
Age at implantation (yrs)	14.5 ± 3.6	14.7 ± 3.5^*	14.0 ± 2.7^†	12.9 ± 4.4	12.9 ± 4.5
Age at first ICD intervention (yrs)	16.4 ± 4.8	–	17.0 ± 3.4	–	15.6 ± 6.4
Male	151 (67%)	124 (66%)	16 (62%)^†	27 (75%)	12 (71%)
Follow-Up duration (yrs)	4.3 ± 3.3	4.5 ± 3.3^*	3.0 ± 2.7	3.5 ± 3.4	2.7 ± 2.7
NYHA class at implantation
I	159 (71%)	126 (67%)	20 (77%)^†	33 (92%)	16 (94%)
II	49 (22%)	46 (24%)^*	3 (12%)^†	3 (8%)	1 (6%)
III/IV	16 (7%)	16 (9%)^*	3 (12%)^†	0	0
NYHA class at last evaluation
I	159 (71%)	133 (71%)	18 (69%)	26 (72%)	9 (53%)
II	47 (21%)	39 (21%)	6 (23%)	8 (19%)	6 (35%)
III/IV	18 (8%)	16 (9%)	2 (8%)	2 (6%)	2 (12%)
Maximal LV wall thickness (mm)	25.5 ± 9.8	26.0 ± 9.3	29.8 ± 11.4^‡	22.7 ± 11.8	21.5 ± 9.4
LV end-diastolic dimension (mm)	40.2 ± 8.8	40.5 ± 8.6	41.8 ± 15.2^†	38.7 ± 9.7	39.5 ± 10.5
Left atrial dimension (mm)	37.8 ± 9.2	37.9 ± 9.1	37.5±9.8^†	37.6 ± 9.8	34.5 ± 9.8
LV outflow gradient at rest
>30 mm Hg	54 (24%)	48 (26%)	10 (38%)^†	6 (17%)	3 (18%)
<30 mm Hg	170 (76%)	140 (74%)	16 (62%)	30 (83%)	14 (82%)
Cardioactive medications at implantation	158 (71%)	135 (72%)	21 (81%)	23 (64%)	11 (65%)
Cardioactive medications at first appropriate intervention	36 (84%)	–	21 (81%)	–	15 (88%)
Ejection fraction <50%	9 (4%)	5 (3%)	1 (4%)	4 (11%)	3 (8%)

Notes.

Values are mean ± SD or n (%).

Significant difference versus secondary prevention (p < 0.01).

^†

Variables unassociated with the likelihood of a primary prevention ICD appropriate intervention (p = 0.054 to 0.83).

^‡

Significant difference versus secondary prevention appropriate interventions (p = 0.017).

^§

Includes 10 patients with extreme LV hypertrophy with wall thickness ≥30 mm, of whom 4 had appropriate ICD shocks.