1052 Hypertrophic Cardiomyopathy and Sleep Apnea- The Central Plot

Abstract

Introduction: Limited data exists on sleep-disordered breathing (SDB) in hypertrophic cardiomyopathy (HCM) with an estimated frequency of 40-80%, predominantly of obstructive sleep apnea (OSA). We present a case of Central Sleep Apnea (CSA) and Cheyne-Stoke Respiration (CSR) in a patient with HCM and normal sinus rhythm (NSR). To the best of our knowledge this may be the first case that provides physiological insight to the pathogenesis of CSR in HCM patient in NSR. Report of Case: A 62 y/o woman with a history of HCM underwent polysomnography (PSG) for excessive daytime sleepiness. The PSG demonstrated severe CSA with CSR with an apnea-hypopnea index of 65, and a central apnea index of 54. None of the tested continuous positive airway pressure settings effectively controlled the CSA. A repeat titration study with adaptive servo-ventilation demonstrated optimal control of the CSA. Her echocardiogram showed asymmetric septal hypertrophy, ejection fraction (EF) of 80% and diastolic dysfunction. Brain MRI did not show any lesions which would account for CSA or CSR. Conclusion: Very limited data exists on CSR in patients with HCM. CSA with CSR is common among patients with congestive heart failure with low EF, unlike our patient with preserved EF. We hypothesize that like systolic dysfunction, diastolic dysfunction with preserved EF may also contribute to CSR by elevating left sided pressure resulting in pulmonary congestion. This can stimulate pulmonary vagal afferent C fibers, which in turn stimulate respiration and drive the CO2 down resulting in CSA during sleep. CSR may also occur as a direct result of the prolonged circulation time that can occur in these patients. This case highlights that CSR could be a presentation of patients with HCM in NSR and preserved EF. They may represent a particularly important subgroup as CSA with CSR is independently associated with an elevated risk for appropriate cardioverter-defibrillator therapies and ventricular arrhythmias. Appropriate identification and treatment of these patients could have a mortality benefit, although further research is needed to answer these specific questions.