Cardiac Arrest: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Cardiac Arrest?
Cardiac arrest is treated first by emergency teams, then by a cardiologist, a doctor who treats heart problems, for testing and prevention after survival. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is cardiac arrest?
Cardiac arrest occurs when the heart suddenly stops beating. Blood flow to the brain and the rest of the body stops too. It is a medical emergency. Without quick treatment it most often causes death. But fast CPR and a defibrillator may be lifesaving. A defibrillator is a device that sends an electric shock to the heart. Cardiac arrest is not the same as a heart attack, which happens when blood flow to the heart is blocked. A heart attack can sometimes trigger a cardiac arrest.
Symptoms
Most people do not have any symptoms until cardiac arrest happens. The main signs are sudden loss of consciousness (a person falls to the floor or slumps down if sitting), no pulse, and no breathing.
In some cases, warning signs appear about an hour before. These may include a racing heart, dizziness, shortness of breath, nausea, and chest pain.
Causes and who gets it
Ventricular fibrillation causes most cases. It is an arrhythmia where the heart's lower chambers quiver instead of beating. The heart cannot pump blood to the body. Problems that can lead to cardiac arrest include:
- Coronary artery disease, which clogs the arteries of the heart. Most people with cardiac arrest have it.
- A prior heart attack, which can leave scar tissue that leads to abnormal rhythms.
- Heart problems such as congenital heart disease, heart valve problems, heart rhythm problems, and an enlarged heart.
- Abnormal blood levels of potassium, calcium, or magnesium. These minerals affect the heart's electrical system.
- Severe physical stress, such as trauma, electrical shock, or major blood loss.
- Using certain recreational drugs, such as cocaine or amphetamines.
- Certain inherited disorders can cause these rhythm problems, too.
Risk is higher in older people, in men, and in people who have had a heart attack or heart failure.
How doctors diagnose it
Cardiac arrest happens so fast that there is no time for tests during the event. Doctors recognize it when a person suddenly collapses and is not breathing normally. If a person survives, tests done afterwards look for the cause. Doctors may use blood tests, an ECG to check the heart's electrical activity, and an echocardiogram to show if the heart has been damaged. Cardiac catheterization can show if the arteries of the heart are narrowed or blocked.
Treatment
Cardiac arrest needs emergency treatment right away to get the heart started again. Treatments include:
- Call 911 right away if someone has signs of cardiac arrest. The sooner you call, the sooner treatment starts.
- CPR is often the first treatment. The letters CPR stand for cardiopulmonary resuscitation, keeping blood moving by hand. It keeps oxygen flowing until help arrives. If you are not trained, give hands-only CPR: push hard and fast on the center of the chest.
- Defibrillation is the most important treatment for cardiac arrest caused by ventricular fibrillation. A defibrillator gives an electric shock that can restore a normal rhythm. It works best within a few minutes. AEDs in public places give voice instructions and shock only if a dangerous rhythm is found.
People who survive are admitted to a hospital for ongoing care. They may need medicines, procedures, or surgery. Some get angioplasty or bypass surgery to restore blood flow. Many get an ICD, which shocks the heart if a dangerous rhythm occurs and can lower the chance of another arrest.
When to see a doctor
Cardiac arrest is always a 911 emergency. If someone collapses and is not breathing normally, call 911, start CPR, and send someone for the nearest AED. Call 911 or your local emergency number right away if you have chest pain or shortness of breath. If you have a heart condition, ask your provider how to lower your risk.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. Such a doctor can review the problems and medicines that raise your risk and refer you to a cardiologist if you are at high risk. They can also help manage your recovery if you have survived a cardiac arrest.
Common questions
Is cardiac arrest the same as a heart attack?
No. A heart attack happens when a blocked artery stops blood flow to the heart. During a heart attack the heart usually does not suddenly stop beating. In cardiac arrest the heart stops. A heart attack can sometimes trigger a cardiac arrest.
What should I do if I see someone collapse?
Call 911 right away, start CPR, and use an AED if one is nearby. AEDs give step-by-step voice instructions and are programmed to shock only if they detect a dangerous arrhythmia.
Can cardiac arrest be prevented?
You may be able to lower your risk by following a heart-healthy lifestyle and treating heart disease. Avoiding recreational drugs such as cocaine also helps. People who survived an arrest can lower the chance of another one with an ICD.
Do people survive cardiac arrest?
Most people do not survive cardiac arrest, which is why fast CPR and defibrillation matter so much. Survivors are at high risk of another one and need close follow-up care.
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Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
