( @ ) Incidence of Sinus bradycardia , sinus tachycardia , sinus arrest , atrial premature beats , ventricular premature beats , paroxysmal atrial tachycardia , paroxysmal ventricular tachycardia , atrial fibrillation , II-III degree atrioventricular block , ST-T segment changes were reduced from @ % , @ % , @ % , @ % , @ % , @ % , @ % , @ % , @ % , @ % to @ % , @ % ,@ % , @ % , @ % , @ % , @ % , @ % , @ % , @ % ( all P < @ ) and the total number of arrhythmias happened at night were significantly lower ( all P < @ ) while the heart rate variability ( HRV ) were significantly higher ( P < @ ) in NPPV group than in control group ; AHI was positively while LSaO@ was negatively correlated with the total night arrhythmia number ( P < @ ) .