Automatic defibrillator and method of defibrillate

PURPOSE: An automatic defibrillator and a method of defibrillate are provided to make an automatic electrical shock against a heart of a patient in accordance with the cardiac state of the patent. CONSTITUTION: In a first step, an electrocardiogram is detected from a patient. In a second step, noise is removed from the detected electrocardiogram. In a third step, a wave having highest voltage level is selected from R, S, T, Q, P waves of the electrocardiogram having noise removed. In a fourth step, the voltage level of the selected wave is measured and heart rate is calculated from the selected wave at the same time. In a fifth step, the measured heart rate and voltage level are stored if the patient is normal. In a sixth step, respective critical values corresponding to the measured heart rate and voltage level are stored. In a seventh step, the voltage level of wave selected from the patient and the heart rate are detected while repeating the first to fourth steps. In an eighth step, the difference between the voltage level and the heart rate stored in the seventh step is calculated. In a ninth step, the value calculated in the eighth step and the critical value are compared. In a tenth step, an alarm sound is sounded if the value calculated in the ninth step is greater than the critical value. In an eleventh step, a pulse is applied to the patient if the value calculated in the ninth step is greater than the critical value.