Obstructive sleep apnoea and cardiac arrhythmias understanding and detailing a complex relationship

Sleep disordered breathing has been increasingly correlated with metabolic disorders and cardiovascular disease. A large base of evidence has demonstrated that obstructive sleep apnoea is a major risk factor for hypertension, type 2 diabetes mellitus, coronary artery disease, stroke and arrhythmias. With sleep apnoea affecting up to 30 % of Western adults with huge co-morbidity overlap, the total cost to healthcare is large. Understanding the complex relationship of this breathing disorder, its treatment and the relationship with cardiovascular risk may help us optimise screening, treatment pathways and reduce overall costs. Of particular interest are the mixed findings for risk of cardiovascular disease and arrhythmia despite the gold standard treatment, continuous positive airways pressure. Our main study investigated arrhythmia incidence using implantable loop recorders in a real-world clinical setting through a nested-cohort study and explores the potential mechanisms linking obstructive sleep apnoea and arrhythmia. Included are a retrospective study of local obstructive sleep apnoea patients and a systematic review of arrhythmias detected by implantable cardiac monitors in obstructive sleep apnoea. We found atrial fibrillation with prevalence of 5.4 % and incidence of 3.1 % in the retrospective study. The systematic review revealed very few papers and heterogenous data but a possible increase in newly diagnosed atrial fibrillation in an obstructive sleep apnoea. The main study revealed a 20 % incidence of newly diagnosed atrial fibrillation compared to 0 % in a non-monitored cohort. There was an indication that the heart rate variability parameter low frequency/high frequency power ratio and the matrix metalloproteinase-9 biomarker may be predictive of atrial fibrillation. Further well-designed studies including these biomarkers alongside continuous positive airways pressure and arrhythmia monitoring may yield a strong correlation and predictors for arrhythmia allowing for appropriate screening to reduce cardiovascular risk.