Incidence of sleep-disordered breathing in patients with hypertrophic cardiomyopathy.

The authors investigated the prevalence of sleep-disordered breathing (SDB) together with its clinical correlations in patients with hypertrophic cardiomyopathy (HCM). A total of 113 consecutive patients including 63 patients with HCM (40 men; mean age, 59.5±13.0 years; New York Heart Association class, 2.0±0.9) underwent cardiorespiratory polygraphy in addition to their clinical work-up including echocardiography. Patients with an apnea-hypopnea-index (AHI) ≥5/h were considered to have SDB. If thoracic and abdominal inspiration efforts were documented, SDB was considered to be obstructive sleep apnea (OSA), otherwise SDB was considered to be central sleep apnea (CSA). The age- and sex-matched control group of 50 patients had exclusion of coronary artery disease by angiography, and normal left ventricular (ejection fraction ≥55%) and valvular function. SDB was diagnosed in 52 patients (82.5% vs 72% in the control group; P =not significant) with a mean AHI of 23.0±17.8/h. Severity of SDB was higher in patients with HCM than in the control group (AHI 12.2±7.6/h; P =.003). OSA was documented in 39 patients (AHI 21.2±16.5/h) and CSA in 13 (AHI 28.4±20.9/h). The severity of SDB correlated with New York Heart Association functional class (η=0.9, η(2) =0.811) and with left ventricular end-diastolic (r=0.6, P <.01) and left atrial (r=0.4, P <.01) diameter. No correlations were found between SDB and other clinical or echocardiographic parameters. SDB is common in patients with hypertrophic cardiomyopathy, with a predominance of OSA and correlations with markers of left ventricular function.