Baseline characteristics of relatives to index cases, that is, at the time of pacemaker implantation in the relative
| Offspring of index mother, n (%) | Offspring of index father, n (%) | Sibling to index sibling, n (%) | |
| Total | 19 213 (100) | 35 148 (100) | 5349 (100) |
| Male sex | 10 220 (53.2) | 18 458 (52.5) | 2848 (53.2) |
| Median age | 46.9 (IQR 38.2–53.5) | 43.8 (IQR 35.6–50.4) | 48.8 (IQR 34.8–57.6) |
| Age at baseline, years | |||
| <30 | 2366 | 5278 | 1062 |
| 30–40 | 3203 | 7741 | 643 |
| 40–50 | 6254 | 12 870 | 1146 |
| 50–60 | 6048 | 8299 | 1497 |
| 60–70 | 1294 | 945 | 640 |
| 70–80 | 48 | 15 | 244 |
| 80–90 | 0 | 0 | 104 |
| >90 | 0 | 0 | 13 |
| Cardiovascular comorbidity | |||
| Congestive heart failure | 100 (1.1) | 115 (0.3) | 69 (1.3) |
| Diabetes mellitus | 177 (0.9) | 224 (0.6) | 88 (1.6) |
| Prior MI | 205 (1.1) | 211 (0.6) | 128 (2.4) |
| AF/AFL | 170 (0.9) | 218 (0.6) | 113 (2.1) |
| VT | 33 (0.2) | 36 (0.1) | 9 (0.2) |
AF, atrial fibrillation; AFL, atrial flutter; MI, myocardial infarction; VT, ventricular tachycardia.