Table 2. Description of baseline electrocardiograms in 1991–1992 according the Buenos Aires method (n = 94).
| Buenos Aires method | All children (n = 94) |
|---|---|
| Electrocardiographic measurements | Median / 25th and 75th percentiles / minimum and maximum |
| Heart rate, beats per minute | 86 / 77, 96 / 63, 123 |
| PR interval, seconds/100 | 0.12 / 0.12, 0.14 / 0.10, 0.20 |
| QRS duration, seconds/100 | 0.07 / 0.06, 0.08 / 0.05, 0.08 |
| QRS axis, degrees | 60 / 45, 60 / -45, 150 |
| Ventricular extrasystoles, n | 0 / 0, 0 / 0, 0 |
| Electrocardiographic items* | n (%) |
| Overall assessment | |
| Normal | 86 (91) |
| Abnormal | 8 (9) |
| Rhythm | |
| Sinus | 94 (100) |
| Supraventricular arrhythmias | |
| None | 92 (98) |
| Supraventricular extrasystoles | 2 (2) |
| Ventricular arrhythmias | |
| None | 94 (100) |
| Atrioventricular conduction disturbances | |
| None | 94 (100) |
| Ventricular conduction defects | |
| None | 86 (92) |
| rR’ or R in V1 (i.e., right bundle branch block) | 4 (4) |
| Left anterior fascicular block | 3 (3) |
| Noncodifiable | 1 (1) |
| Abnormal initial QRS complex | |
| None | 92 (98) |
| Noncodifiable | 2 (2) |
| Primary ST-T wave changes | |
| None | 93 (99) |
| Noncodifiable | 1 (1) |
| Miscellaneous | |
| None | 93 (99) |
| Right ventricular hypertrophy | 1 (1) |
* Only electrocardiographic items with non-zero values are displayed for simplicity.