Clinical significance of sleep-related breathing disorders in patients with implantable cardioverter defibrillators

The prevalence and clinical significance of sleep-related breathing disorde rs (SRBDs) in patients with cardiac disease and a history of life-threateni ng ventricular tachyarrhythmias is unclear. Forty consecutive recipients of implantable cardioverter defibrillators (ICDs) with cardiac disease and a documented history of spontaneous, life-threatening, ventricular tachyarrhy thmias underwent full night polysomnography. SRBDs were diagnosed if the ap nea/hypopnea index was > 10. SRBD were diagnosed in 16 of 40 patients (40%) : central sleep apnea (CSA) was present in 9 of these 16 patients (56%), 8 of whom had associated Cheyne-Stoke respiration. Seven of the 16 patients w ith SRBD (44%) had obstructive sleep apnea (OSA). Patients with and without SRBDs were comparable with respect to left ventricular ejection fraction, NYHA classification, underlying heart disease, ICD indications, and concomi tant antiarrhythmic drug and beta-blocker therapy. Patients were followed p rospectively for 2 years. ICD-treated ventricular tachyarrhythmias occurred in 10 of 24 patients (42%) without SRBD, in 4 of 9 patients (44%) with CSA , and in 3 of 7 patients (44%) with OSA (NS). The numbers and circadian dis tributions of episodes recorded during follow-up in patients without SRBD v ersus with CSA or OSA were not significantly different (14 +/- 25, median = 4 vs 4 +/- 5, median = 2.5 vs 15 +/- 15, median = 7 respectively). The 2-y ear mortality, which was entirely attributable to nonsudden cardiac events, was high est in patients with CSA (4/9 [44%], vs 0/7 [0%] with OSA, vs 3/2 4 patients (12.5%) without SRBD; P < 0.05).