Cardiac arrest is a sudden loss of blood flow resulting from the failure of the heart to pump effectively. Signs include loss of consciousness and abnormal or absent breathing. Some individuals may experience chest pain, shortness of breath, or nausea before cardiac arrest. Sudden, unexpected loss of heart function, breathing and consciousness.In cardiac arrest, the heart abruptly stops beating. Without prompt intervention, it can result in the person's death.The main symptom is loss of consciousness and unresponsiveness.This medical emergency needs immediate CPR or use of a defibrillator. Hospital care includes drugs, an implantable device or other procedures.