Obstructive sleep apnea (OSA) is associated with several cardio-vascular abnormalities as atrial fibrillation (AF). AF occurrence in OSA increases the risk of stroke which worsens the prognosis of these patients. P wave dispersion (Pd) and maximal P wave duration (P max) are simple electrocardiographic parameters which reflect atrial conduction abnormalities and have been reported to be predictors of atrial fibrillation

the aim of this study is to determine the correlation between apnea-hypopnea index (AHI) and P wave dispersion and maximal P wave duration.

Forty patients (18 men and 22 women) who were diagnosed with OSA by overnight polysomnography were included in this prospective study. The mean age was 56±10 years old. They were all in sinus rhythm. Before initiating continuous positive airway pressure therapy, we evaluated on a 12 lead ECG P wave duration and P wave dispersion (P max - P min).

Twenty four patients had severe OSA (AHI >30), 4 had moderate OSA (AHI between 15 and 30) and 12 had a mild OSA (AHI between 5 and 15). Mean P max duration was 119±21 ms. P wave dispersion was 93±6 ms. There was a significant positive correlation between P max and AHI (r= 0.45, p=0.001) and between P wave dispersion and AHI (r=0.42, p=0.001)

The severity of OSA seems to be correlated with the importance of atrial conduction abnormalities. These results suggest the higher is the AHI the higher is the risk of AF occurrence in OSA. Further studies are needed to validate these results.