Table 3. Baseline Characteristics and Outcomes in the Patients of a High- and Low-Rate ICD Therapy Zone in Each Group.
| Group 1 | Group 2 | Group 3 | ||||
|---|---|---|---|---|---|---|
| High-rate (n=56)* | Low-rate (n=60)* | High-rate (n=45)* | Low-rate (n=47)* | High-rate (n=129)* | Low-rate (n=64)* | |
| Age (yr) | 66.2±13.0 | 64.8±11.7 | 61.8±13.4 | 67.1±13.2 | 49.3±16.2 | 50.1±17.9 |
| Male, n (%) | 40 (71.4) | 37 (61.7) | 33 (73.3) | 37 (78.7) | 105 (81.4) | 57 (89.1) |
| Hypertension, n (%) | 31 (55.4)† | 20 (33.3)† | 21 (46.7) | 25 (53.2) | 25 (19.4) | 16 (25.0) |
| Diabetes, n (%) | 27 (48.2) | 19 (31.7) | 14 (31.1) | 13 (27.7) | 7 (5.4) | 8 (12.5) |
| Ischemic HF, n (%) | 24 (42.9) | 16 (26.7) | 21 (46.7) | 26 (55.3) | 0 (0) | 0 (0) |
| NYHA functional class | 2.5±0.6 | 2.6±0.5 | 1.9±0.9 | 2.1±0.9 | − | − |
| Ejection fraction (%) | 23.8±8.3 | 23.4±4.5 | 33.5±12.1 | 33.0±12.7 | 63.5±10.4† | 58.3±12.2† |
| Defibrillator type, n (%) | ||||||
| Single-chamber | 21 (37.5) | 14 (23.3) | 32 (71.1) | 28 (59.6) | 101 (78.3)† | 39 (60.9)† |
| Dual-chamber | 34 (60.7) | 45 (75.0) | 11 (24.4) | 18 (38.3) | 28 (21.7)† | 25 (39.1)† |
| CRT-D | 1 (1.8) | 1 (1.7) | 2 (4.4) | 1 (2.1) | 0 (0) | 0 (0) |
| Follow-up period (month) | 34.3±30.7 | 24.6±23.7 | 68.5±46.4 | 55.4±38.8 | 83.9±53.3† | 51.9±48.1† |
| Patients who experienced ICD therapy (%) | ||||||
| Appropriate, annual | 3.7† | 10.6† | 9.3 | 11.5 | 5.3 | 8.3 |
| Inappropriate, annual | 1.9 | 5.7 | 4.3 | 4.1 | 2.7† | 5.4† |
| Annual mortality | 5.0 | 4.0 | 1.9 | 6.0 | 0.4 | 0.4 |
CRT-D, cardiac resynchronization therapy-defibrillator; HF, heart failure; ICD, implantable cardioverter-defibrillator; NYHA, New York Heart Association.
*ICD therapy zone has been changed in 2, 1, and 1 patient in group 1, 2, and 3, respectively, †p<0.05.