The sites for intracardiac injections include a vertical puncture of 4-5 centimeters at 1-2 centimeters from the left edge of the sternum or a direct puncture into the left ventricle slightly medial to the turbinate border of the heart at the fourth or fifth intercostal space, as well as a puncture about 1 centimeter below the left costal arch just below the xiphoid process, which is penetrated subcutaneously and then passed through the lower edge of the ribs, at a 15-35° angle to the skin of the abdominal wall, with the tip of the needle directed toward the base of the heart into the ventricle. Intracardiac injection is a treatment for cardiac arrest in which a medication, such as epinephrine, is injected directly into the heart to be able to cause the heart to contract. An intracardiac injection is usually used in cardiac arrests that require electrical defibrillation in conjunction with an intracardiac injection. It can also be used without defibrillation equipment. Intracardiac injections are contraindicated in patients with bleeding disorders and in patients who have not stopped their heartbeat; the injection must be withdrawn first, and only if there is blood can it be injected. The puncture site must be positioned accurately to avoid pneumothorax or other injuries. Be aware of complications after puncture, such as pericardial hemorrhage and myocardial tears. Intracardiac injections must be performed by a specialist.