We often see in the film and television drama that when the patient is rescued, when the electrocardiogram becomes a straight line, the doctor picks up the electrode of the defibrillator and puts it on the chest of the patient, and the electric shock hits twice, and the heartbeat returns to normal.

In fact, the ECG line represents the cardiac arrest. At this time, the heart does not have any electrical activity. The electric shock is completely meaningless. The shock defibrillation is used to eliminate the rapid arrhythmia such as ventricular fibrillation. At this time, the ECG is not a straight line. Is a jagged waveform
In the rescue, if the ECG is in a straight line, chest compression should be performed immediately, instead of electric shock defibrillation.