Cardiac arrest occurs when the heart suddenly stops effectively pumping blood to the body, leading to a loss of pulse and often death. In the United States, cardiac arrest is a major cause of mortality, with hundreds of thousands of deaths annually. It is commonly linked to underlying medical conditions such as heart disease, electrolyte imbalances, or pulmonary embolism. Other triggers include drowning, physical trauma, and drug overdose.

Types of Cardiac Arrest

There are several forms of cardiac arrest, including:

  • Cardiac arrest: The heart abruptly stops functioning, halting blood circulation.

  • Sudden cardiac arrest: An unexpected occurrence of cardiac arrest.

  • Sudden cardiac death: Death resulting from cardiac arrest.

  • Aborted sudden cardiac death: A case where CPR and emergency care successfully prevent death during cardiac arrest.

Signs and Symptoms

If someone collapses suddenly, is gasping, or cannot breathe, cardiac arrest should be suspected, and CPR should be started immediately. Immediate CPR can significantly improve the chances of survival.

Warning signs include:

  • Sudden collapse

  • Loss of consciousness

  • Unresponsiveness

  • Gasping or absence of breathing

  • Lack of pulse

Causes

Cardiac arrest happens when the heart fails to supply blood to the body. All organs, particularly the brain, need a steady flow of oxygenated blood to function. A lack of blood to the brain (cerebral ischemia) results in quick loss of consciousness.

Medical conditions associated with cardiac arrest include:

  • Heart-related issues: Heart attack, cardiac tamponade, cardiomyopathy, congenital heart disease, myocarditis

  • Pulmonary embolism: Blood clot in the lungs

  • Electrolyte imbalances: Such as high or low potassium or magnesium levels

Other causes:

  • Trauma (including commotio cordis)

  • Drug overdose

  • Drowning

  • Severe bleeding

  • Airway obstruction or asphyxiation

Diagnosis

Identifying the cause of cardiac arrest is critical for proper treatment. During or shortly after resuscitation, several diagnostic tests may be used:

  • Electrocardiogram (ECG): Assesses heart rhythm and potential heart attacks

  • Laboratory tests: Check electrolytes, pH, and oxygen levels

  • Chest imaging (X-ray, CTA): Detects issues like pulmonary embolism

  • Echocardiogram: Evaluates heart structure and fluid accumulation

  • Cardiac catheterization: Identifies blocked coronary arteries

  • Electrophysiology studies: Examines heart rhythm problems

Treatment

In cardiac arrest, the absence of a heartbeat cuts off blood supply to vital organs. Every moment is critical—prompt recognition and CPR are essential.

Steps for Hands-Only CPR:

  1. Call for help: Dial 911 and ask for an AED if in a public space.

  2. Prepare: Lay the person flat, kneel beside them, and position your hands in the center of the chest.

  3. Start compressions: Push hard and fast (100–120 times per minute), pressing down about 2 inches.

  4. Continue CPR: Maintain chest compressions until help arrives.

Emergency responders use advanced techniques upon arrival, transporting the person to an emergency department for further care. Treatment options depend on the cause. For example, if the arrest stems from a heart attack, cardiac catheterization may be performed to restore blood flow by placing a stent.

How to Prevent Cardiac Arrest

While many cardiac arrests occur suddenly and without warning, some risk can be reduced through heart-healthy habits. These include:

  • Eating a diet rich in fruits, vegetables, whole grains, legumes, and nuts

  • Limiting salt, processed foods, and trans fats

  • Engaging in regular moderate physical activity

  • Avoiding tobacco products

  • Monitoring blood pressure, cholesterol, and blood sugar with a healthcare provider

If you have a family history of cardiac arrest or heart disease, it’s important to talk to your provider about personalized prevention strategies.

Complications

Without immediate treatment, cardiac arrest is usually fatal. Survival rates are higher for those who experience cardiac arrest in hospitals. Early recognition and CPR are vital.

Even among survivors, serious complications can result from prolonged lack of oxygen, such as:

  • Brain damage and neurological issues

  • Kidney damage

  • Heart failure

  • Anxiety and depression