Baseline characteristics, management and outcomes of patients according to time-of-day of infarction
| Demographics | 6:00–noon | Noon–6:00 h | p Value |
| Mean±SEM age (years) | 62±0.8 | 61±0.6 | 0.542 |
| Male (%) | 78.4 | 78.4 | 0.993 |
| Hypertension (%) | 53.9 | 41.1 | 0.001 |
| Dyslipidaemia (%) | 42.0 | 40.6 | 0.699 |
| Current smoking (%) | 50.2 | 53.3 | 0.400 |
| Diabetes mellitus (%) | 25.3 | 17.2 | 0.006 |
| Prior Rx β blockers (%) | 6.9 | 4.7 | 0.21 |
| Prior Rx statins (%) | 16.5 | 12.6 | 0.371 |
| Prior Rx ACE inhibitors (%) | 27.1 | 15.1 | <0.001 |
| Weekday (%) | 76.6 | 72.9 | 0.269 |
| Weekend (%) | 23.4 | 27.1 | |
| Spring (%) | 26.4 | 27.3 | 0.944 |
| Summer (%) | 17.8 | 18.8 | |
| Autumn (%) | 27.5 | 27.5 | |
| Winter (%) | 28.3 | 26.4 | |
| Clinical presentation | |||
| Killip class ≥2 (%) | 34.6 | 26.9 | 0.024 |
| Mean±SEM LVEF (%) | 49.9±0.6 | 51.6±0.5 | 0.037 |
| Anterior wall location (%) | 48.7 | 41.9 | 0.066 |
| Multivessel disease (%) | 12.3 | 13.3 | 0.685 |
| Management | |||
| Mean±SEM time from symptom onset to reperfusion (min) | 226±20 | 230±15 | 0.725 |
| Primary PCI (%) | 77.3 | 80.1 | 0.364 |
| GP IIb/IIIa inhibitors | 43.5 | 47.4 | 0.291 |
| In-hospital outcomes | |||
| Death (%) | 4.1 | 3.7 | 0.780 |
| Reinfarction (%) | 1.9 | 1.5 | 0.683 |
| VF/VT (%) | 10.4 | 7.2 | 0.118 |
Patients were divided into two groups, those with myocardial infarction onset in the dark-to-light transition (6:00–noon) and those with infarct onset at any other time of the day.
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.