Intraoperative characteristics by age group
| Group 1 (⩽50 years) | Group 2 (51–64 years) | Group 3 (⩾65 years) | |
|---|---|---|---|
| No of patients | 81 | 254 | 115 |
| Mean (SD) defibrillation threshold (J) | |||
| VT | 12 (10) | 13 (9) | 11 (8) |
| Range | 2–30 | 1–30 | 1–30 |
| VF | 17 (10) | 17 (11) | 15 (8) |
| Range | 5–30 | 3–30 | 2–30 |
| ICD implant | |||
| Epicardial | 36 (44%) | 121 (48%) | 52 (45%) |
| Transvenous | 45 (56%) | 133 (52%) | 63 (55%) |
| Lead-alone | 40 (89%) | 121 (91%) | 58 (92%) |
| + subcutaneous patch | 5 (11%) | 12 (9%) | 5 (8%) |
| Pulse generators | |||
| Monophasic | 37 (46%) | 138 (54%) | 52 (45%) |
| Biphasic | 44 (54%) | 116 (46%) | 63 (55%) |
| Third generation ICD | 27 (33%) | 105 (41%) | 67 (58%) |
ICD, implantable cardioverter-defibrillator; VF, ventricular fibrillation; VT, ventricular tachycardia.