Abstract: Objective: The purpose of this study was to investigate the relationship between nocturnal hypoxemia and risk of ventricular arrhythmia (VA) during sleep in patients with chronic obstructive pulmonary disease (COPD). Method: 36 patients with COPD and 36 healthy subjects were selected . All the patients accepted Polysomnography, 24-h Holter electrocardiographic recording, Arterial blood gas analysis and pulmonary function tests. Results : Nocturnal hypoxemia episodes were found in nineteen patients with COPD during sleep but none of the control subjects . The prevalence of VA in patients with COPD was also significantly higher than that observed in healthy subjects( 58.3% vs 5.6% ,P<0.01). No associations were found between VA and nocturnal hypoxemia in patients with COPD (rho=-0.077,P=0.646). No differences were found between during REM and non-REM sleep for the frequency of VA[（5.51±0.53）times/h vs（5.58±0.32）times/h] . Conclusion：Patients with COPD have a higher frequency of VA and nocturnal hypoxemia episodes than health subjects. However, no associations were found between VA and nocturnal hypoxemia in patients with COPD.

Key words: COPD, nocturnal hypoxemia, ventricular arrhythmia, sleep stages