Cardiac arrest
Cardiac arrest is a critical medical condition characterized by the complete cessation of both mechanical and electrical activity of the heart. This often results from a heart attack, where blood flow to the heart muscle is blocked, leading to a lack of oxygen. Other causes can include drug overdoses, drowning, poisoning, and electrocution. Key symptoms include a lack of pulse, loss of consciousness, and cessation of breathing. Without prompt intervention—typically within minutes—permanent brain damage or death may occur. Immediate treatment involves cardiopulmonary resuscitation (CPR) to restore blood flow and may also include defibrillation to normalize the heart's rhythm and medications to support heart function. The success of CPR and the use of automated external defibrillators (AEDs) by trained bystanders can significantly improve survival rates. Understanding cardiac arrest and the importance of rapid response can empower individuals to act in emergency situations, potentially saving lives.
Cardiac arrest
ANATOMY OR SYSTEM AFFECTED: Circulatory system, heart
DEFINITION: A complete cessation of the mechanical and/or electrical activity of the heart.
CAUSES: Usually a heart attack; also, drug overdose, drowning, poisoning, electrocution
SYMPTOMS: Lack of pulse, loss of consciousness, and cessation of breathing; if blood flow is not resumed quickly, permanent brain damage and sometimes death
DURATION: Acute
TREATMENTS: Cardiopulmonary resuscitation (CPR), defibrillation, medications (atropine, epinephrine, lidocaine), sometimes surgery
Causes and Symptoms
Many conditions, such as drug overdoses, drowning, poisoning, and electrocution, can result in cardiac arrest, but the major cause is insufficient oxygen supply to the heart as a result of a heart attack. When a major coronary artery becomes blocked, blood cannot flow to the heart muscle cells to deliver oxygen. Without sufficient oxygen, the heart is unable to pump blood to the rest of the body. Within seconds, the blood flow to the brain is inadequate and the individual loses consciousness and stops breathing. If blood flow is not resumed within several minutes, permanent brain damage will occur, frequently followed by death.
The major symptoms of cardiac arrest are lack of a pulse and lack of normal breathing. Medical personnel can also use an electrocardiogram (ECG or EKG) to identify specific problems with the heart, including too rapid of a heart rate to pump blood, quivering of the heart muscle, the complete absence of electrical activity, or the absence of contractions with normal electrical activity. Any of these cases is a medical emergency and treatment is required.
Treatment and Therapy
Cardiopulmonary resuscitation (CPR) is the initial treatment for cardiac arrest. The sooner the blood flow to the brain is restored, the better is the prognosis. Breathing into the victim’s mouth and externally compressing the chest over the heart can circulate oxygenated blood throughout the body. However, emergency medical treatment is generally required to get the heart beating on its own. Cardioversion, the use of an external defibrillator to shock the heart, is administered to restore the heart’s normal cardiac rhythm. Additionally, medical personnel will administer specific medications such as atropine, epinephrine, and lidocaine. In some extreme cases, emergency surgery is required.
Perspective and Prospects
One of the best strategies to save the lives of those who suffer cardiac arrest is to decrease the time that it takes to restore blood flow and get the heart beating on its own again.
CPR was first promoted to the general public as a tool to save lives in the 1970s. By teaching many individuals how to respond to this emergency situation, the likelihood of receiving CPR quickly increases. Unfortunately CPR cannot save everyone. In recent years, automatic external defibrillators (AEDs) have been placed in public areas and worksites to improve survival. AEDs can be administered by nonmedical personnel who have been trained how to use them, thus greatly decreasing the time that it takes to restart a normal cardiac rhythm.
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