Heart rate and QT interval dynamics in control subjects, and patients with long QT syndrome types 1 (LQT1) and 2 (LQT2) at rest, and during mental stress and exercise
| Heart rate (beats/min) | QT interval (ms) | ΔQT interval (ms) |
Change from resting values (%) | ΔQT/ΔHR (ms/s) | QTcf(ms) | ΔQTcf (ms) | |
| Control | |||||||
| Rest | 59 (4) | 387 (16) | – | – | – | 384 (12) | – |
| Mental stress | 90 (15) | 358 (22)1-168 | –29 (25)1-160 | 7.4 (6.4)1-168 | –0.96 (1.02)1-150 | 409 (25)1-165 | 24 (26)1-165 |
| Exercise stress | 93 (13) | 341 (25)1-168 | –47 (31)1-160 | 11.7 (7.7)1-168 | –1.33 (0.69)1-150 | 393 (21)1-165 | 9 (27)1-165 |
| LQT1 | |||||||
| Rest | 64 (10) | 420 (35) | – | – | – | 426 (28) | – |
| Mental stress | 98 (16) | 386 (33) | –34 (34) | 9.1 (8.6) | –1.21 (1.19) | 453 (35) | 27 (36) |
| Exercise stress | 100 (14) | 382 (41) | –38 (33) | 10.2 (8.74) | –1.33 (1.27) | 451 (48) | 25 (42) |
| LQT2 | |||||||
| Rest | 59 (10) | 422 (40) | – | – | – | 419 (40) | – |
| Mental stress | 91 (13) | 392 (40) | –30 (51) | 6.4 (12.4) | –0.71 (1.68) | 449 (37) | 30 (47) |
| Exercise stress | 95 (13) | 383 (33) | –38 (46) | 8.5 (10.9) | –0.85 (1.37) | 445 (27) | 26 (42) |