| 안성규¹, 차광수¹, 윤은영², 최진희¹, 최정천¹, 김보원¹, 이혜원¹, 양미진¹, 오준혁¹, 최정현¹, 이한철¹, 홍택종¹ |
Background: Previous studies showed seasonal variation in the incidence of acute myocardial infarction (MI), in which MI occurred more frequent in winter. But, there is rare study that analyzed seasonal variation on clinical outcomes in acute MI. The aim of this study is to evaluate seasonal pattern on incidence and clinical outcomes in ST segment elevation myocardial infarction (STEMI) and non ST segment elevation myocardial infarction (NSTEMI). Methods: We evaluatge 3,582 STEMI patients who admitted within 12 hours of symptom and with door-to-balloon time ≤6 hours and 2,734 NSTEMI patients who admitted within 1 week of symptom onset and with PCI done within 2 weeks after presentation. Patients were divided to four groups according to four seasons. We evaluated death, MI, revascularization, and composite of major cardiac adverse events (MACE) at in-hospital, 1, 6, and 12 month. Results: The season of highest incidence was winter (STEMI: 30.2%, NSTEMI: 31.5%) and summer was the lowest (STEMI: 22.0%, NSTEMI: 21.1%). There are no differences of baseline characteristics, symptom-to-door time, door-to-balloon time, angiographic findings in each group except summer in which door-to-balloon time was significantly lower than the other seasons in NSTEMI. In STEMI, incidence of MACE were no significant difference among four seasons in hospital (spring: 5.6% summer: 3.8%,fall: 5.8%, winter: 5.5%, p=0.258). Incidence of MACE was not statistically different at 1 month MACE and 6 month follow up. At 12 month follow up, total MACE were also no significant difference (spring: 14.7%, summer: 12.3%, fall: 15.0%, winter: 13.3%, p=0.354). In patient with non-STEMI, incidence of MACE were no significant difference among four seasons at hospital (spring:6.0%, summer:6.3%, fall:4.9%, winter:4.6%, p=0.466). Incidence of MACE was not statistically different at 1 month MACE and 6 month follow up. At 12 month follow up, total MACE were also no significant difference (spring:14.6% , summer:16.0%, fall:14.0%, winter:13.1%, p=0.496). Conclusions: Incidence of MI is higher during winter season, but seasonal variation did not influence clinical outcome in patient with acute MI.
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