Obstructive Sleep Apnea and Myocardial Infarction: Evidence of a Clinical Association

Background. Obstructive sleep apnea (OSA) is frequently associated with hypertension, chronic heart failure and atrial fibrillation; a correlation with ischemic heart disease is less defined. Aim of this study was to assess the prevalence of OSA and its clinical predictors after a recent myocardial infarction (MI). Methods. We studied all consecutive patients (pts) with MI, evaluated by our out-patient Clinic at 1-month follow up (exclusion criteria: atrial fibrillation and permanent pacemaker). For detection of OSA we used a validated tool (Lifescreen, Spacelabs/ESAOTE) which determines the mean Apnea-Hypopnea Index (AHI) by processing the electrocardiographic data of the sleep period. According to AHI, pts were classified as normal (5), borderline (5.1–15) or diseased (>15). Results. Between March 2007 and February 2008, we studied 107 pts (age: 62±13 years; men: 83.2%; weight: 78±12 Kg). Left ventricular ejection fraction was 49±12%. The prevalence of STEMI and anterior MI was 68.4 and 37.7%, respectively; primary PCI was performed in 76.5% of pts. Mean sleep period was 8:04±1.20 hours; AHI was 14.3±12.0; 80/107 pts (74.1%) scored >5, with 43 pts (39.8%) >15. In univariate analysis, women had lower AHI values than men (7.0±6.6 vs 15.7±12.4, p<0.001). AHI correlated directly with body weight (p=0.013), creatinine and uric acid concentrations (p=0.046 and p=0.030, respectively), and with the presence of aortic insufficiency (24.3±8.4 vs 13.8±12.1, p=0.020). AHI increased with CK MB and troponin I concentrations (p<0.001 and p=0.033) and was higher in pts treated with primary PCI of the left coronary artery (p=0.044) and in pts with complex ventricular arrhythmias (16.8±12.2 vs 12.2±10.3, p=0.049). At multivariate analysis, complex ventricular arrhythmias, body weight, creatinine concentration, and the presence of aortic insufficiency significantly correlated with AHI values, with complex ventricular arrhythmias being the best predictor of the presence of OSA (p=0.009). Conclusions. OSA is a common clinical condition in pts with a recent MI and correlates with the presence of complex ventricular arrhythmias. OSA evaluation might be particularly important in pts with MI to plan interventions such as CPAP therapy or ICD implantation.