Table 1.
Clinical Characteristics of the LQTS Study Population
| Parameters | Total Population n=641 | No Coronary Disease n=554 | Coronary Disease n=87 |
|---|---|---|---|
| Female | 451 (70) | 397 (72) | 54 (62) |
| Age range (yrs) | 41–92 | 41–92 | 41–83 |
| Mean age at baseline ECG | |||
| Baseline QTc findings | |||
| QTc (ms) | 489 ± 43 | 488 ± 43 | 491 ± 41 |
| 450–499 ms | 452 (71) | 396 (71) | 56 (64) |
| ≥500 ms | 189 (29) | 158 (29) | 31 (36) |
| Syncope before age 40 | 213 (33) | 185 (33) | 28 (32) |
| Genotype positive | 282 | 244 | 38 |
| LQT1 | 135 (48) | 120 (50) | 15 (39) |
| LQT2 | 128 (46) | 107 (44) | 21 (55) |
| LQT3 | 19 (7) | 17 (7) | 2 (5) |
| Co-morbidity | |||
| Diabetes mellitus | 44 (7) | 27 (5) | 17 (20) |
| Hypertension | 192 (30) | 143 (26) | 49 (56) |
| Cardiac therapy, any time | |||
| Beta-blockers | 413 (64) | 340 (61) | 73 (84) |
| Implantable defibrillator | 107 (17) | 81 (15) | 26 (30) |
| Pacemaker | 59 (9) | 47 (8) | 12 (14) |
| Left sympathetic ganglionectomy | 14 (2) | 11 (2) | 3 (3) |
| 1st diagnosis of coronary disease | 87 (14) | - | 87 (100) |
| Angina pectoris | 41 (6) | - | 41 (47) |
| Coronary angioplasty | 20 (3) | - | 20 (23) |
| Coronary artery bypass surgery | 10 (2) | - | 10 (11) |
| Myocardial infarction | 16 (2) | - | 16 (18) |
| 1st LQTS-related cardiac event | 98 (15) | 83 (15) | 15 (17) |
| Syncope | 88 (14) | 76 (14) | 12 (14) |
| Aborted cardiac arrest | 9 (1) | 6 (1) | 3 (3) |
| Sudden cardiac death | 1 (0.1) | 1 (0.2) | 0 (0) |
Values in parentheses are percentages.