1322 Resolution of Central Sleep Apnea and Cheyne-Stokes Breathing Following Pacemaker Implantation for Atrioventricular Block

Abstract Introduction Central sleep apnea with Cheyne Stokes breathing may appear in patients with cardiac conduction disease when severe bradyarrhythmia prolongs circulatory time and destabilizes ventilatory control. In such cases, positive airway pressure therapy may not resolve central events because the underlying mechanism is impaired cardiac rhythm rather. This report describes a patient with long-standing obstructive sleep apnea who developed new central sleep apnea due to progressive atrioventricular block, with marked improvement after pacemaker implantation. Report of case(s) A 77 year old man with obstructive sleep apnea had been highly adherent to continuous positive airway pressure since before 2015. He previously demonstrated excellent control, with a residual apnea hypopnea index of 6.4 per hour on 8 cm H2O, and an August 2022 titration showed complete elimination of events at 10 cm H2O with no central apneas. His Epworth Sleepiness Scale was 3. In 2023, he developed weight gain, lower extremity edema, and progressive bradycardia. Continuous positive airway pressure downloads revealed rising central events, Cheyne Stokes breathing exceeding three hours nightly, and a residual apnea hypopnea index of 25.1 per hour. Obstructive events remained minimal, supporting combined obstructive and central sleep apnea rather than treatment emergent central sleep apnea. He declined retitration or advanced positive airway pressure therapy. Echocardiograms from 2022 to 2024 consistently showed preserved systolic function with ejection fraction. Holter monitoring demonstrated progressive conduction disease including Wenckebach pattern, 2:1 atrioventricular block, bifascicular block, and episodes concerning for complete heart block. A dual chamber rate responsive pacemaker with left bundle branch pacing lead (DDDR 60 to 120 bpm) was implanted on October 30, 2024. Within one month, continuous positive airway pressure data showed improvement. The apnea hypopnea index decreased to 10.7 per hour, Cheyne Stokes breathing reduced to one hour and thirty minutes, and his Epworth Sleepiness Scale improved to 0. He reported restored sleep quality without changes in continuous positive airway pressure settings. Conclusion This case shows that central sleep apnea and Cheyne Stokes breathing caused by bradyarrhythmia may improve after correction of atrioventricular block with dual chamber pacing. Continuous positive airway pressure data were crucial in revealing the cardiac etiology. Support (if any)