Dilated cardiomyopathy is associated with increased prevalence of sleep apnea

Background Sleep apnea（SA） is a common disorder in general population, especially cardiovascular disease （CVD） patients. However, its role in cardiomyopathy etiology is still unclear. Methods In this single-center observational study, we enrolled 2740 CVD patients consecutively from 2013 to 2016. Among study subjects, 65 were diagnosed as idiopathic dilated cardiomyopathy（DCM） and 34 were hypertrophic cardiomyopathy（HCM）. Patients underwent sleep study with portable monitoring devices and diagnosed as non-SA （AHI〈5）, mild （5-≤ AHI≤15）, moderate （15〈AHI≤30） or severe SA （AHI〉30） using the apnea-hypopnea index （AHI）. Central sleep apnea（CSA） and obstructive sleep apnea（OSA） were defined by central event percentage, with 50% as cut-value. Results The prevalence of SA was higher in DCM patients. While the prevalence of moderate to severe SA was similar in HCM and other CVD patients （32.4% vs. 34.3%, P 〉0.1）, it was significantly higher in DCM patients （49.2%, P =0.017 vs. other CVD patients）. The prevalence of CSA in DCM patients was also higher than other CVD patients （9.2% vs. 3.2%, P〈0.01）, but the difference of OSA was not statistically significant （40.0% vs. 30.3%, P =0.229）. In comparison to other heart failure with reduced ejection fraction （HFrEF） patients, the result was nearly at the same level. Conclusions SA is more common in idiopathic dilated cardiomyopathy patients. Prevalence of moderate to severe SA and CSA is higher in idiopathic HCM patients than other CVD and HFrEF patients.