Obstructive Sleep Apnea in Myocardial Infarction: Paradoxical Cardioprotection, Chronic Detriment, and Unresolved Therapeutic Dilemmas.

Obstructive sleep apnea (OSA), characterized by recurrent apneic/hypopneic events and intermittent hypoxia, exhibits a high yet underrecognized prevalence (40%-65%) among patients with acute myocardial infarction (MI), compounded by suboptimal performance of conventional screening modalities. A defining epidemiological feature is the pronounced nocturnal predominance of MI onset in OSA cohorts, diverging from the diurnal pattern observed in non-OSA populations.Pathophysiologically, OSA manifests a paradoxical duality in the context of MI: acute cardioprotective effects, including reduced in-hospital mortality, attenuated infarct size (evidenced by lower peak troponin levels), and enhanced coronary collateralization, are attributed to ischemic preconditioning induced by chronic intermittent hypoxia. Conversely, OSA independently exacerbates long-term post-MI risk, with severe nocturnal hypoxemia driving elevated rates of major adverse cardiovascular events (MACE), alongside maladaptive ventricular remodeling, electrical instability, and endothelial dysfunction-mechanisms underpinned by synergistic activation of inflammatory pathways and cell death signaling.Therapeutically, the role of OSA-directed interventions in post-MI management remains contentious. Observational data suggest potential benefits of continuous positive airway pressure (CPAP), but large randomized controlled trials fail to demonstrate incremental cardioprotection in broader cardiovascular cohorts. Emerging proof-of-concept evidence suggests that early adaptive servo-ventilation (ASV) may influence myocardial salvage after acute MI in carefully selected patients with sleep-disordered breathing, particularly those without reduced ejection fraction. However, these findings should be interpreted cautiously given the small trial size and prior safety concerns regarding ASV in patients with heart failure and reduced ejection fraction. Resolving these uncertainties necessitates targeted research incorporating optimized adherence strategies and enhanced screening protocols to reconcile OSA's acute phenotypic associations with its long-term prognostic implications.