Abstract

Background: Childhood obstructive sleep apnoea (OSA) is suggested to be associated with cardiac structural abnormalities and dysfunction but existing evidence are limited and the treatment effect on echocardiographic outcome remains controversial.

Objective: To examine for the presence of subclinical cardiac abnormalities in childhood OSA and the effects of treatment on cardiac changes.

Methods: Polysomnography (PSG) and echocardiographic examinations were performed on 101 children aged between 6 and 13 years were invited from a community based questionnaire survey. They were classified into reference group (Apnoea-hypopnoea index (AHI)<1, n=35), mild OSA group (AHI 1-5, n=39) and moderate-to-severe group (AHI>5, n=27) based on PSG result. Treatments including adenotonsillectomy or nasal steroid were offered to the mild and moderate-to-severe OSA group.

Results: Moderate-to-severe OSA group had greater right ventricular (RV) systolic volume index (RVSVI), lower RV ejection fraction (RVEF) and higher RV myocardial performance index (RVMPI) than the reference group. They also had more significant left ventricular (LV) diastolic dysfunction and remodeling with larger interventricular septal thickness index (IVSI) and relative wall thickness than those with lower AHI values. Moderate-to-severe OSA group had an increased risk of abnormal LV geometry compared to reference group [OR(95%CI) = 4.21(1.35-13.12)]. Log-transformed AHI was associated with RVSVI (p=0.0002), RVEF (p=0.0001) and RVMPI (p<0.0001) independent of the effect of obesity. Improvement in RVMPI, IVSI, and E/e' were observed in those with significant reduction in AHI (>50%) comparing 6 months to baseline.

Conclusions: OSA is an independent risk factor for subclinical RV and LV dysfunction, and improvement in AHI is associated with reversibility of these abnormalities.