Table 4.
ECG characteristics at admission.
| Variable | Overall N = 238 |
Discharged alive and not treated at ICU within 30 days N = 139 |
Dead in-hospital or treated at ICU within 30 days N = 99 |
p-value |
|---|---|---|---|---|
| Heart rate (bpm) | 92 (80–107) | 91 (81–106) | 92 (80–109) | 0.562 |
| Heart rate < 50 bpm % (n/N) | 0.4% (1/238) | 0% (0/139) | 1.0% (1/99) | 0.416 |
| Sinus rhythm | 89% (212/238) | 89% (124/139) | 89% (88/99) | >0.99 |
| Atrial fibrillation | 9.7% (23/238) | 8.6% (12/139) | 11% (11/99) | 0.657 |
| Atrial flutter | 0.4% (1/238) | 0.7% (1/139) | 0% (0/99) | >0.99 |
| Other rhythm | 0.4% (1/238) | 0.7% (1/139) | 0% (0/99) | >0.99 |
| QRS axis (degrees) | 21 (−7.0–56) | 26 (−4.3–59) | 16 (−16–53) | 0.346 |
| Abnormal QRS axisa % (n/N) | 20% (48/238) | 17% (24/139) | 24% (24/99) | 0.194 |
| QRS duration (ms) | 92 (85–102) | 90 (84–102) | 94 (86–102) | 0.174 |
| QRS duration >120 ms | 9.7% (23/238) | 10% (14/139) | 9.1% (9/99) | >0.99 |
| QTc interval (ms) | 433 (417–450) | 431 (415–445) | 437 (421–451) | 0.091 |
| Long QTc % (n/N) | 29% (70/238) | 25% (35/139) | 35% (35/99) | 0.112 |
| QTc > 500 ms | 0.8% (2/238) | 0.7% (1/139) | 1.0% (1/99) | >0.99 |
| Normal AV conduction | 87% (206//238) | 87% (121/139) | 86% (85/99) | 0.848 |
| First-degree AV block | 2.5% (6/238) | 2.2% (3/139) | 3.0% (3/99) | 0.695 |
| Second-degree AV block Mobitz I | 0% (0/238) | 0% (0/139) | 0% (0/99) | NA |
| Second-degree AV block Mobitz II | 0% (0/238) | 0% (0/139) | 0% (0/99) | NA |
| Third-degree AV block | 0% (0/238) | 0% (0/139) | 0% (0/99) | NA |
| Q wave pathologyb | 6.7% (16/238) | 5.8% (8/139) | 8.1% (8/99) | 0.601 |
| Abnormal QRS morphologyc | 11% (26/238) | 11% (15/139) | 11% (11/99) | >0.99 |
| QRS morphology RBBB | 5.9% (14/238) | 5.8% (8/139) | 6.1% (6/99) | >0.99 |
| QRS morphology LBBB | 2.5% (6/238) | 2.9% (4/139) | 2.0% (2/99) | >0.99 |
| QRS morphology LAH or LPH | 2.5% (6/238) | 2.2% (3/139) | 3.0% (3/99) | 0.695 |
| Low voltage QRSd | 7.1% (17/238) | 6.5% (9/139) | 8.1% (8/99) | 0.799 |
| ST elevatione | 5.0% (12/238) | 4.3% (6/139) | 6.1% (6/99) | 0.562 |
| ST depressionf | 4.2% (10/238) | 5.0% (7/139) | 3.0% (3/99) | 0.528 |
| T wave inversiong | 24% (58/238) | 21% (29/139) | 29% (29/99) | 0.168 |
| Abnormal ECGh | 57% (135/238) | 50% (69/139) | 67% (66/99) | 0.012 |
ECG = electrocardiogram; ICU = intensive care unit; bpm = beats per minute; ms = milliseconds; QTc = corrected QT interval; AV = atrioventricular; NA = not applicable: RBBB = right bundle branch block; LBBB = left bundle branch block; LAH = left anterior hemiblock; LPH = left posterior hemiblock.
QRS axis < minus 30 degrees or >90 degrees.
Negative deflection preceding R-wave with duration >40 ms or > 2 mm deep or >25% of QRS amplitude in two anatomically consecutive leads.
Right/left bundle branch block or left anterior/posterior hemiblock.
QRS complex with amplitude ≤5 mm in all limb leads or ≤10 mm in all precordial leads.
≥1 mm ST elevation in any two anatomically consecutive leads.
≥1 mm ST depression in any two anatomically consecutive leads.
Negative T-wave with depth >1 mm in any lead except for minus aVR or V1.
Any of heart rate ≤50 beats per minute, QRS duration ≥120 milliseconds, QTc interval ≥500 milliseconds, abnormal QRS axis, abnormal QRS morphology, low voltage QRS, Q wave pathology, ST elevation ≥1 mm in any two continuous leads, or ST depression ≥1 mm in any two continuous leads, abnormal T wave inversion, non-sinus rhythm or AV block ≥2.