Arrhythmogenic mechanisms of obstructive sleep apnoea in heart failure patients.
Sleep. 2018 Jul 16;:
Authors: Chadda KR, Fazmin IT, Ahmad S, Valli H, Edling CE, Huang CL, Jeevaratnam K
Heart failure (HF) affects 23 million people worldwide and results in 300,000 annual deaths. It is associated with many comorbidities, such as obstructive sleep apnoea (OSA), and risk factors for both conditions overlap. 11% of HF patients have OSA and 7.7% of OSA patients have left ventricular ejection fraction <50% with arrhythmias being a significant comorbidity in HF and OSA patients. 40% of HF patients develop atrial fibrillation (AF) and 30-50% of deaths from cardiac causes in HF patients are from sudden cardiac death. OSA is prevalent in 32-49% of patients with AF and there is a dose-dependent relationship between OSA severity and resistance to anti-arrhythmic therapies. HF and OSA lead to various downstream arrhythmogenic mechanisms, including metabolic derangement, remodelling, inflammation, and autonomic imbalance. a) Metabolic derangement and production of reactive oxidative species increase late Na+ currents, decrease outward K+ currents and downregulate connexin-43 and cell-cell coupling. b) Remodelling also features downregulated K+ currents in addition to decreased Na+/K+ ATPase currents, altered Ca2+ homeostasis, and increased density of If current. c) Chronic inflammation leads to downregulation of both Nav1.5 channels and K+ channels, altered Ca2+ homeostasis and reduced cellular coupling from alterations of connexin expression. d) Autonomic imbalance causes arrhythmias by evoking triggered activity through increased Ca2+ transients and reduction of excitation wavefront wavelength. Thus, consideration of these multiple pathophysiological pathways (a-d) will enable the development of novel therapeutic strategies that can be targeted against arrhythmias in the context of complex disease, such as the comorbidities of HF and OSA.
PMID: 30016501 [PubMed – as supplied by publisher]