Objectives: to assess the effects of intravenous magnesium on converting acute onset atrial fibrillation to sinus rhythm, reducing ventricular response and risk of bradycardia.

Results showed that long _ cycle leading to atrial fibrillation and flutter were mostly compensating period due to atrial premature beat or obviously sinus bradycardia.

The ECG abnormalities were commonly sinus bradycardia, ST-T changes, and myocardial ischemia while others mainly included premature beat, arrhythmia, conduction block, abnormal Q waves, and so on.