A portable ECG monitor is introduced in the paper, which has a temporary intravenous and transesophageal fixable rate pacing function. During the PSVT attack, the tachyarrythmia can be stopped by the transesophageal cardiac pacing while the ECG signals are monitored. The instrument has some advantages such as small size, low price and good practicality. It is worth while introducing and popularizing it to all hospitals.