RATIONALE

Cardiomyopathy is a rare condition in children that is associated with high mortality. Although sleep-disordered breathing is prevalent, its frequency and patterns in children with cardiomyopathy are unknown.

OBJECTIVES

To evaluate the frequency and patterns of sleep-disordered breathing and their relationship to cardiac function in children with primary cardiomyopathy.

METHODS

This study comprised a prospective, uncontrolled case series. Children with cardiomyopathy completed a sleep questionnaire, overnight polysomnography, blood pressure monitoring, otolaryngological assessment, and transthoracic echocardiography at the Hospital for Sick Children in Toronto, Canada.

MEASUREMENTS AND MAIN RESULTS

Twenty-one patients (17 males) were recruited. The median age of the patients was 10.7 years, and the median body mass index z score was 0.8. Sleep-disordered breathing was observed in 10 (48%) of 21 patients. Significant central sleep apnea was the main finding in 5 (24%) of 21 of the cohort and in 50% of the sleep-disordered breathing population. The left ventricular end diastolic volume index was greater in children with central sleep apnea than in children without sleep-disordered breathing (P = 0.03). There were significant correlations between the central apnea-hypopnea index and both left ventricular end diastolic and end systolic volume indexes (Spearman's r = 0.55, P = 0.01; Spearman's r = 0.47, P = 0.03, respectively). Snoring, sleep architecture, blood pressure, and otolaryngological findings were not significantly different between children with sleep-disordered breathing versus those without sleep-disordered breathing.

CONCLUSIONS

Sleep-disordered breathing is common in children with cardiomyopathy. In our present study, 24% of participants exhibited primarily central sleep apnea. The severity of cardiac dysfunction, as measured by left ventricular end diastolic volume index and left ventricular end systolic volume index, is associated with central sleep apnea. Longitudinal research is necessary to better characterize sleep disorders and their impact on cardiac function in a large pediatric cardiomyopathy population.