Baseline characteristics, management and outcomes of patients according to time-of-day infarction
| Total | Period 1: Midnight–6:00 h | Period 2: 6:00–noon | Period 3: Noon–18:00 h | Period 4: 18:00–midnight | p Value | |
| Number of patients (% of total) | 811 (100%) | 141 (17%) | 269 (33%) | 240 (29%) | 161 (20%) | <0.001 |
| Demographics | ||||||
| Mean±SEM age (years) | 62±0.5 | 61±1 | 62±1 | 62±1 | 60±1 | 0.416 |
| Male (%) | 78.4 | 84.4 | 78.4 | 74.2 | 79.5 | 0.130 |
| Hypertension (%) | 45.4 | 38.3 | 53.9 | 43.8 | 39.8 | 0.005 |
| Dyslipidaemia (%) | 41.1 | 40.4 | 42.0 | 42.1 | 38.5 | 0.883 |
| Current smoking (%) | 52.3 | 52.5 | 50.2 | 50.0 | 59.0 | 0.273 |
| Diabetes mellitus (%) | 19.9 | 18.4 | 25.3 | 16.7 | 16.8 | 0.054 |
| Prior Rx β blockers (%) | 5.4 | 4.1 | 6.9 | 5.3 | 4.2 | 0.591 |
| Prior Rx statins (%) | 13.9 | 12.5 | 16.5 | 16.1 | 7.9 | 0.419 |
| Prior Rx ACE inhibitors (%) | 19 | 11.4 | 27.1 | 18.9 | 12.7 | <0.001 |
| Weekday (%) | 74.1 | 75.9 | 76.6 | 71.3 | 72.7 | 0.516 |
| Weekend (%) | 25.9 | 24.1 | 23.4 | 28.8 | 27.3 | |
| Spring (%) | 27 | 24.1 | 26.4 | 29.6 | 26.7 | 0.482 |
| Summer (%) | 18.5 | 24.8 | 17.8 | 15.4 | 18.6 | |
| Autumn (%) | 27.5 | 25.5 | 27.5 | 25.8 | 31.7 | |
| Winter (%) | 27 | 25.5 | 28.3 | 29.2 | 23 | |
| Clinical presentation | ||||||
| Killip class ≥2 (%) | 29.4 | 28.8 | 34.6 | 24.3 | 29.1 | 0.089 |
| Mean±SEM LVEF (%) | 51.0±0.4 | 49.9±0.9 | 49.9±0.6 | 52.3±0.6 | 51.9±0.9 | 0.025 |
| Anterior wall location (%) | 44.1 | 49.6 | 48.7 | 40.0 | 37.9 | 0.042 |
| Multivessel disease (%) | 12.9 | 14.9 | 12.3 | 10.8 | 15.5 | 0.478 |
| Management | ||||||
| Mean±SEM time from symptom onset to reperfusion (min) | 229±6 | 311±20 | 226±10 | 198±8 | 215±12 | <0.001 |
| Primary PCI (%) | 79.2 | 88.7 | 77.3 | 77.5 | 76.4 | 0.024 |
| GP IIb/IIIa inhibitors | 46.1 | 50.4 | 43.5 | 44.2 | 49.7 | 0.398 |
| In-hospital outcomes | ||||||
| Death (%) | 3.8 | 5.0 | 4.1 | 2.1 | 5.0 | 0.376 |
| Reinfarction (%) | 1.6 | 2.1 | 1.9 | 1.7 | 0.6 | 0.718 |
| VF/VT (%) | 8.3 | 7.1 | 10.4 | 6.7 | 8.1 | 0.444 |
ACE inhibitors, angiotensin converter enzyme inhibitors; CCU, coronary care unit; CK, creatine kinase; GM, geometric mean; GP, glycoprotein; LVEF, left ventricular ejection fraction; MI, myocardial infarction; PCI, percutaneous coronary intervention; Rx, treatment; TnI, troponin-I; VF, ventricular fibrillation; VT, ventricular tachycardia.