BACKGROUND: Sleep apnea (SA) is associated with intermittent hypoxemia that may lead to ischemic preconditioning in the myocardium. This potential cardioprotective effect of SA may play a role in the development of non-ST-elevation myocardial infarction (NSTEMI) versus ST-elevation myocardial infarction (STEMI) during acute ischemia. However, there is limited evidence about the relative prevalence of NSTEMI versus STEMI in SA patients. We therefore prospectively investigated the prevalence of these two types of MI in patients with SA. METHODS: We prospectively studied 782 consecutive patients admitted with the diagnosis of acute MI (both NSTEMI and STEMI). All subjects underwent sleep evaluations using a portable diagnostic device after at least 48h post-admission, provided they were in stable condition. Six hundred and seven out of 782 patients had technically adequate sleep studies, and therefore were included in the final analysis. RESULTS: SA was present in 65.7% (n=399) and NSTEMI in 30% (n=182) of patients. Increasing severity of SA was associated with increasing likelihood of NSTEMI, and with decreasing likelihood of STEMI (p<0.001). Relative frequency of NSTEMI in the moderate to severe SA group (AHI≥15events/h) was 40.6% versus 29.9% for STEMI (p=0.01). CONCLUSION: The prevalence of NSTEMI increases with increasing severity of SA. This finding may suggest a cardioprotective role of SA, which may attenuate the development of STEMI, perhaps through ischemic preconditioning.

Department of Cardiovascular Diseases and International Clinical Research Center St Anne's University Hospital Brno Czech Republic; Department of Cardiovascular Diseases Mayo Clinic and Mayo Foundation Rochester MN United States

Department of Cardiovascular Diseases and International Clinical Research Center St Anne's University Hospital Brno Czech Republic; Department of Cardiovascular Diseases Mayo Clinic and Mayo Foundation Rochester MN United States; Department of Cardiovascular Diseases Heart Hospital of Hamad Medical Corporation Doha Qatar; Center for Cardiovascular and Transplant Surgery Brno Brno Czech Republic

Department of Cardiovascular Diseases and International Clinical Research Center St Anne's University Hospital Brno Czech Republic; Faculty of Medicine Masaryk University Brno Czech Republic

Department of Cardiovascular Diseases Mayo Clinic and Mayo Foundation Rochester MN United States

Department of Internal Medicine and Cardiology University Hospital Brno Czech Republic; Department of Cardiovascular Diseases and International Clinical Research Center St Anne's University Hospital Brno Czech Republic; Faculty of Medicine Masaryk University Brno Czech Republic

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