Comparison of the short term reproducibility (relative errors %) of QT dispersion and conventional ECG measurements
| Study A | Study B | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Supine | Standing | Supine | Standing | ||||||||
| RE-2 | RE-5 | RE-2 | RE-5 | RE-2 | RE-5 | RE-2 | RE-5 | ||||
| Global QT dispersion | 16.4 (18.0) | 13.0 (14.7) | 26.6 (27.4) | 19.9 (19.8) | 17.1 (21.7) | 13.6 (13.3) | 28.8 (29.1) | 16.3 (16.1)5-150 | |||
| Precordial QT dispersion | 23.3 (26.0) | 17.4 (14.6) | 35.8 (41.4) | 30.7 (32.0) | 19.1 (24.0) | 19.0 (14.0) | 34.9 (46.0) | 28.2 (32.4) | |||
| Global QT-SD | 13.7 (13.1) | 10.7 (11.1) | 23.9 (26.5) | 18.4 (18.2)5-150 | 15.5 (17.9) | 12.0 (10.9) | 27.9 (30.0) | 15.0 (15.6)5-150 | |||
| Precordial QT-SD | 21.8 (22.1) | 14.4 (12.2)5-150 | 37.4 (47.4) | 27.7 (30.0) | 19.1 (20.4) | 17.3 (11.5) | 38.0 (49.1) | 29.4 (44.1)5-150 | |||
| Heart rate | 3.5 (3.0) | 2.7 (2.1) | 4.8 (4.4) | 4.3 (3.3) | 3.3 (2.5) | 2.7 (2.0) | 5.2 (4.0) | 3.5 (2.8)5-150 | |||
| PR interval | 2.3 (2.4) | 1.5 (1.6)5-150 | 3.6 (7.3) | 2.0 (4.2)5-150 | 2.3 (2.2) | 1.9 (2.0)5-150 | 2.6 (3.3) | 1.8 (1.7)5-150 | |||
| QRS duration | 2.6 (2.5) | 1.6 (1.5)5-150 | 3.3 (3.1) | 1.9 (1.9)5-150 | 2.4 (2.4) | 1.7 (1.9)5-150 | 3.0 (2.9) | 1.5 (1.5)5-150 | |||
| QT interval | 1.4 (1.2) | 1.1 (1.3) | 2.3 (1.7) | 1.9 (1.4)5-150 | 1.4 (1.3) | 1.2 (1.0) | 3.2 (2.8) | 1.9 (1.5) | |||
| QTc interval | 1.3 (0.9) | 0.9 (1.0)5-150 | 2.3 (2.1) | 1.1 (0.9)5-150 | 1.4 (1.2) | 0.8 (0.7)5-150 | 2.8 (2.7) | 1.5 (1.3)5-150 | |||
Values are mean (SD).
↵5-150 p < 0.05 v RE-2.
RE-2, relative error alculated using repeated measures, which were derived from the first two and second two recordings of the 10 consecutive recordings in each position; RE-5, relative error calculated using repeated measures, which were derived from the first five and second five recordings of the 10 consecutive recordings in each position; QT-SD, QT standard deviation.