Defibrillation: What It Is and What to Expect
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor provides Defibrillation?
Defibrillation is usually performed by an emergency medicine doctor or a cardiologist. A cardiologist is a doctor who treats heart problems. Paramedics and other trained emergency responders can also do it with a defibrillator machine. The goal is to restore a normal heartbeat during a cardiac arrest, which is when the heart suddenly stops pumping blood the way it should.
What it is
Defibrillation is a treatment that uses a quick, strong electric shock to reset the heart's rhythm. The shock comes from a defibrillator and travels through pads placed on the chest. The shock briefly stops all heart activity so the heart's natural pacemaker can restart a normal rhythm.
Why a doctor might recommend it
The most common reason is cardiac arrest. A person in cardiac arrest collapses, stops breathing normally, and has no pulse. The heart often quivers in a rhythm called ventricular fibrillation, and defibrillation is the main treatment for it. Without it, death can occur within minutes.
How to prepare
Defibrillation is an emergency treatment, so there is usually no time to prepare. If someone collapses and is not responding, call 911 right away. Start CPR if you have been trained, and use an AED if one is nearby.
What happens during it
The care team places sticky pads on the person's chest, connected to the defibrillator. The device reads the heart's rhythm to see whether a shock is needed. Everyone steps back, and the machine delivers the shock.
Recovery
Recovery depends on what caused the cardiac arrest and how long the brain went without blood. Some people wake up soon after, while others need days of intensive care. Many survivors need further testing or an implanted device to prevent future rhythm problems.
Risks and side effects
The shock can cause a mild skin burn where the pads were placed, and the chest muscles may be sore afterward. In some cases, the heart does not return to a normal rhythm, or changes to another dangerous one.
Who performs it
Paramedics, emergency medical technicians, nurses, and doctors can all perform defibrillation when trained. Bystanders can safely use an AED, since the device only shocks when it detects a shockable rhythm.
Common questions
Is defibrillation the same as cardioversion?
They are similar but not the same. Cardioversion uses a lower energy shock. It is often planned ahead of time for people with less urgent rhythm problems. Defibrillation uses more energy and is used in emergencies when the heart is quivering or beating dangerously fast and not pumping blood.
Does defibrillation hurt?
A person in cardiac arrest is usually unconscious, so they do not feel the shock. People who receive a planned cardioversion are given medicine to keep them comfortable. Some muscle soreness afterward is common.
Can an AED hurt someone whose heart is beating normally?
No. An AED only allows a shock when it detects a dangerous rhythm. If the heart rhythm is normal, the device will not deliver a shock.
How does a direct primary care or concierge doctor fit in?
A direct primary care doctor charges a flat monthly fee instead of billing insurance. A concierge doctor usually costs more and often works alongside insurance. Either one can help with follow-up care after a cardiac event. They can manage medicines, order heart tests, and check blood pressure and other risk factors over time. They do not perform emergency defibrillation. They would refer you to a cardiologist for rhythm problems, implanted devices, or advanced testing.
Sources
- MedlinePlus - Sudden Cardiac Arrest
- Centers for Disease Control and Prevention - About Cardiac Arrest | Heart Disease
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.
