Abstract 12497: Timing of ST Elevation MI is Related to Patient Baseline Characteristics
Background: The presence of a morning peak in the onset of ST-Elevation Myocardial infarction (STEMI) has been observed. We investigated the relationships between patient baseline characteristics and the timing of STEMI in two large fibrinolytic megatrials and the ACTION Registry-GTWG.
Methods: We performed an analysis in unselected patients with STEMI (managed with primary PCI, fibrinolysis, or neither) in the ACTION Registry-GTWG (N=45,218, 10.4% missing times) and patients enrolled in two different randomized trials investigating novel fibrinolytic regimens, InTIME II-TIMI 17(N=15,031) and ExTRACT-TIMI 25(N=20,461). Patients were categorized by time of symptom onset: early-day(6AM–2PM), late-day(2PM–10PM), and overnight(10PM–6AM) and evaluated for variations in their baseline characteristics.
Results: The incidence of STEMI in the early-day cohort was highest (41.4%–48.5%) in each of the three datasets and lowest overnight (21.1%–26.3%). Five features had consistent patterns in all datasets (Table). Patients in the early-day groups were more likely older, non-smokers. The overnight group had higher rates of beta blocker use, obesity, and diabetes mellitus. Findings not present in the clinical trials but revealed in the registry study include higher rates of female gender (28.7%, 29.0%, 31.2%, p<0.001) and non-white race(13.3%, 14.2%, 14.8%, p<0.001) with overnight STEMI.
Conclusions: The morning excess of STEMI continues to represent a potential target for preventive therapies with events nearly twice as likely to begin in the early-day compared to overnight in three large contemporary studies. Consistent patterns in the variation of age, smoking, obesity, diabetes, and beta blocker use suggest a physiologic relationship between these factors and timing of STEMI.
- © 2010 by American Heart Association, Inc.