(A)
| Variables | Early-Onset n = 36 | Late-Onset n = 35 | p |
|---|---|---|---|
| Age at diagnosis (years) | 18.6 ± 8.5 | 70.4 ± 4.8 | 0.0001 |
| Male | 27 (77.1) | 9 (25.7) | 0.0001 |
| LV obstruction | 14 (40) | 24 (68.6) | 0.03 |
| Family history of HCM | 21 (60) | 4 (11.4) | 0.0001 |
| NYHA functional class | |||
| I | 24 (68.6) | 4 (11.4) | 0.0001 |
| II | 9 (25.7) | 25 (71.4) | |
| III | 2 (5.7) | 6 (17.1) | |
| Unexplained syncope | 5 (14.3) | 6 (17.1) | 1 |
| Non sustained ventricular tachycardia | 6 (24) | 5 (22.7) | 1 |
| Left atrial dimension (mm) | 39.3 ± 6.2 | 45 ± 4.5 | 0.0001 |
| Maximal LV wall thickness (mm) | 21.4 ± 6.2 | 18.7 ± 2.6 | 0.02 |
| Late gadolinium enhancement | 24/29 (82.8) | 9/19 (47.4) | 0.01 |
| Atrial fibrillation | 11 (31.4) | 10 (28.6) | 1 |
| End stage disease | 4 (11.4) | 0 (0) | 0.11 |
| Myectomy | 2 (5.7) | 0 (0) | 0.49 |
| ICD implantation | 12 (34.3) | 2 (5.7) | 0.006 |
| Death | 0 (0) | 1 (2.9) | 1 |