Aims: Sleep-disordered breathing (SDB) may be a risk factor for expansion of infarct size early after acute myocardial infarction (MI) by exposing the heart to repetitive oxygen desaturations and increased cardiac afterload. The objective of this study was to assess the impact of SDB on myocardial salvage and infarct size within 3 months after acute MI.
Methods and results: Patients with acute MI and percutaneous coronary intervention were enrolled in this prospective observational study. All patients underwent cardiovascular magnetic resonance (CMR) to define salvaged myocardium and infarct size within three to five days and at 3 months after acute MI. Patients were stratified according to apnoea-hypopnoea index (AHI) assessed by polysomnography at baseline into those with (AHI ≥ 15/h) and without (AHI < 15/h) SDB. Of the 56 patients included, 29 (52%) had SDB. The area at risk between both groups was similar (40 ± 12% vs. 40 ± 14%, P = 0.925). Patients with SDB had significantly less salvaged myocardium (myocardial salvage index 52% vs. 77%, P < 0.001), smaller reduction in infarct size (0.3% vs. 6.5%, P < 0.001) within 3 months after acute MI, a larger final infarct size (23% vs. 12%, P < 0.001), and a lower final left ventricular ejection fraction (48% vs. 54%, P = 0.023). In a multivariate analysis, including established risk factors for large MI, AHI was independently associated with less myocardial salvage and a larger infarct size 3 months after acute MI.
Conclusions: Sleep-disordered breathing was associated with less myocardial salvage and a smaller reduction in infarct size. These findings suggest a contribution of SDB to impaired healing of MI.
Keywords: Heart failure; Magnetic resonance imaging; Myocardial infarction; Sleep apnoea.