Impact of continuous positive airway pressure therapy on atrial electromechanical delay and P-wave dispersion in patients with obstructive sleep apnea.

BACKGROUND: Obstructive sleep apnea (OSA) has been shown to be associated with atrial fibrillation (AF). Prolongation of inter- and intraatrial conduction times during sinus rhythm has also been shown to be related to AF generation. Nasal continuous positive airway pressure (CPAP) is an effective treatment modality of OSA.

METHODS: Twenty-four OSA patients diagnosed through polysomnography and 18 controls were included in the study. The basal inter- and intraatrial electromechanic delays prior to onset of the therapy were measured using tissue Doppler imaging. P-wave dispersion (Pd) was calculated on the basis of 12-lead electrocardiography. Same measurements were performed in OSA patients 6 months after the initiation of the therapy.

RESULTS: Interatrial (39.2 ± 8 vs. 21.1 ± 2.8 ms, P < 0.001), left intraatrial (20.5 ± 7.2 vs. 11.1 ± 2 ms, P = 0.003), and right intraatrial electromechanical delays (20.7 ± 11 vs. 10 ± 2.6 ms, P < 0.001) prior to CPAP therapy were found to be significantly greater in OSA group as compared with the controls. Pd was also greater in the OSA group as compared with the controls (44 ± 7 vs. 28.5 ± 4 ms, P < 0.001). However, significant improvement has been noted after 6 months of CPAP therapy in interatrial (P < 0.0001), left intraatrial (P = 0.002), and right intraatrial electromechanical delays (P < 0.0001) as well as in Pd (P < 0.0001) as compared to baseline values in patients with OSA.

CONCLUSION: Our findings suggested that CPAP therapy provides more homogenous conduction through atria in patients with OSA. This effect may translate into decreased risk for AF associated with OSA.