The discovery by Kouwenhoven, Knickerbacker, and Jude of the value of external cardiac massage in the treatment of cardiac arrest is an important one. Although some slight pulmonary ventilation is usually caused by properly performed external massage, it is not sufficient; and the procedure should be supplemented by positive-pressure ventilation, such as mouth-to-mouth or other available means. Furthermore, if ventricular fibrillation is present, equipment should be available for performing external defibrillation. Fortunately, defibrillation may be accomplished many minutes after its onset, provided that external massage and positive-pressure ventilation have been used during the interval. It has been found that upon application of the defibrillating shock the heart will usually resume normal rhythm.
The underlying principle of external cardiac massage is that the heart is more or less anchored between the sternum and the vertebral column, and its lateral motion is limited by the pericardium. Therefore, the heart may be effectively