Assessment of left atrial volume and function by real-time three-dimensional echocardiography in obstructive sleep apnea

Aims: To evaluate the volumetric and functional abnormalities of the left atrium (LA) using real-time three-dimensional echocardiography (RT3DE) in patients with obstructive sleep apnea (OSA) compared with a control group. Methods: Patients with OSA and age-and sex-matched control subjects were recruited to the study in Bach Mai hospital. All patients underwent polysomnography recording. Comprehensive 2-dimensional echocardiographic (2DE) was performed to all subjects according to American Society of Echocardiography guidelines, followed by RT3DE. Maximum LA volume, maximum LA volume indexed for body surface area (BSA), minimum LA volume, and LA volume before contraction were obtained. Results: From June 2021 to June 2022, there were 46 OSA patients and 30 controls were included in the study. Mean age of OSA patients 51.3 ± 11.7. Men accounted for 63% (29/46). The apnea-hypopnea index, percentage of total sleep time with an oxygen saturation level < 90%, arousal index were higher in OSA patients compared with controls. There was a significantly higher 2D LA volume index and E/E’ ratio in the OSA patients compared with the controls (p<0.05). RT3D echocardiography results showed a larger maximum LA volume indexed for BSA, LA volume before atrial contraction, total LA systolic volume, and active LA systolic volume and a higher active LA ejection fraction in the OSA patients compared with controls (p<0.05 for all). There was an increase in the following LA parameters on RT3DE according to the levels of OSA severity: 3D maximum LA volume, 3D maximum LA volume index, 3D LA volume before LA contraction; 3D LA total systolic volume, 3D LA active systolic volume, 3D LA active systolic ejection fraction (p<0.05). On the other hand, 2D maximum LA volume and 2D maximum LA volume index did not differ according to the severity of OSA (p>0.05) Conclusion: There was a significant increase in LA volume and augmentation of LA active systolic function in patients with OSA. The severity of OSA was directly linked with the enlargement of 3D LA volume while this was not seen with 2D LA volume.