Table 2.
Characteristics of electrocardiogram data distribution.
| Total (N = 7907) | Non-ObCAD (N = 4204) | ObCAD (N = 3703) | p-value | |
|---|---|---|---|---|
| Measurement of electrocardiographic features | ||||
| QRS duration, ms | 92 (86–102) | 92 (86–102) | 94 (86–104) | < 0.01 |
| QT, ms | 400 (376–426) | 400 (376–424) | 402 (378–428) | < 0.01 |
| QTc, ms | 435 (415–460) | 434 (414–458) | 437 (416–462) | < 0.01 |
| PR interval, ms | 164 (150–182) | 164 (148–180) | 166 (150–182) | < 0.01 |
| Ventricular rate, bpm | 71 (62–82) | 71 (63–82) | 41 (62–82) | 0.50 |
| P axis, ˚ | 52 (35–63) | 52 (35–64) | 52 (36–63) | 0.55 |
| R axis, ˚ | 31 (4–58) | 35 (8–60) | 27 (-1–55) | < 0.01 |
| T axis, ˚ | 47 (25–69) | 44 (24–63) | 51 (26–78) | < 0.01 |
| Machine-provided interpretation | ||||
| Normal | 26.3% | 31.1% | 20.7% | < 0.01 |
| Left bundle branch block | 1.7% | 1.9% | 1.4% | 0.08 |
| Incomplete left bundle branch block | 0.3% | 0.33% | 0.24% | 0.46 |
| Right bundle branch block | 4.6% | 4.1% | 5.2% | 0.02 |
| Incomplete right bundle branch block | 1.6% | 1.2% | 2.0% | 0.01 |
| Complete heart block | 0.1% | 0.17% | 0.08% | 0.35 |
| Atrial fibrillation | 6.1% | 6.9% | 5.2% | < 0.01 |
| Atrial flutter | 0.4% | 0.5% | 0.4% | 0.48 |
| Acute myocardial infarction | 3.2% | 2.3% | 4.2% | < 0.01 |
| Left ventricular hypertrophy | 10.2% | 9.0% | 11.5% | < 0.01 |
| Premature ventricular contractions | 3.7% | 3.7% | 3.8% | 0.69 |
| Premature atrial contractions | 2.4% | 2.3% | 2.4% | 0.77 |
| First-degree atrioventricular block | 5.3% | 4.6% | 6.2% | < 0.01 |
| Second-degree atrioventricular block | 0.1% | 0.12% | 0.08% | 0.73 |
| Fascicular block | 1.6% | 1.6% | 1.6% | 0.86 |
| Sinus bradycardia | 16.3% | 15.4% | 17.3% | 0.02 |
| Other bradycardia | 0.2% | 0.17% | 0.22% | 0.61 |
| Sinus tachycardia | 5.1% | 4.9% | 5.3% | 0.49 |
| Ventricular tachycardia | 0.04% | 0.00% | 0.08% | 0.10 |
| Supraventricular tachycardia | 0.05% | 0.02% | 0.08% | 0.35 |
| Prolonged QT | 7.4% | 7.6% | 7.2% | 0.42 |
| Pacemaker | 0.1% | 0.10% | 0.08% | 0.99 |
| Ischemia | 12.9% | 11.1% | 14.9% | < 0.01 |
| Low QRS voltage | 1.8% | 1.5% | 2.1% | 0.06 |
| Intraventricular block | 0.7% | 0.6% | 0.8% | 0.20 |
| Prior infarct | 14.4% | 8.8% | 20.7% | < 0.01 |
| Nonspecific T-wave abnormality | 8.1% | 8.3% | 7.8% | 0.40 |
| Nonspecific ST abnormality | 4.3% | 3.6% | 5.0% | < 0.01 |
| Left axis deviation | 6.0% | 5.3% | 6.9% | < 0.01 |
| Right axis deviation | 0.3% | 0.3% | 0.2% | 0.13 |
| Early repolarization | 1.5% | 2.0% | 1.0% | < 0.01 |
Values are presented as median (interquartile range) for continuous variables and proportion (%) for categorical variables.