Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Cardioversion-Defibrillation

By

L. Brent Mitchell

, MD, Libin Cardiovascular Institute of Alberta, University of Calgary

Full review/revision Jan 2023
VIEW PROFESSIONAL VERSION
Topic Resources

There are many causes of abnormal heart rhythms Causes Abnormal heart rhythms (arrhythmias) are sequences of heartbeats that are irregular, too fast, too slow, or conducted via an abnormal electrical pathway through the heart. Heart disorders are... read more Causes (arrhythmias). Some arrhythmias are harmless and do not need treatment. Sometimes arrhythmias stop on their own or with changes in lifestyle, such as avoiding alcohol, caffeine (in beverages and foods), and smoking. Other arrhythmias are dangerous or bothersome enough to need treatment. Cardioversion-defibrillation is one type of treatment. Other treatments for arrhythmias include insertion of a pacemaker Artificial Pacemakers There are many causes of abnormal heart rhythms (arrhythmias). Some arrhythmias are harmless and do not need treatment. Sometimes arrhythmias stop on their own or with changes in lifestyle,... read more Artificial Pacemakers or an implantable cardioverter-defibrillator (ICD) Implantable Cardioverter-Defibrillator (ICD) There are many causes of abnormal heart rhythms (arrhythmias). Some arrhythmias are harmless and do not need treatment. Sometimes arrhythmias stop on their own or with changes in lifestyle,... read more , use of antiarrhythmic drugs Drugs to Treat Abnormal Heart Rhythms There are many causes of abnormal heart rhythms (arrhythmias). Some arrhythmias are harmless and do not need treatment. Sometimes arrhythmias stop on their own or with changes in lifestyle,... read more , or destruction of a small area of heart tissue that is responsible for the arrhythmia (ablation Destroying Abnormal Heart Tissue (Ablation) There are many causes of abnormal heart rhythms (arrhythmias). Some arrhythmias are harmless and do not need treatment. Sometimes arrhythmias stop on their own or with changes in lifestyle,... read more ).

Cardioversion-defibrillation involves giving an electrical shock to the heart. Sometimes this shock can stop a fast arrhythmia and restore normal rhythm. The shock briefly stops the heart from beating and, after a second or two, it starts beating again on its own. Often, it starts back in a normal rhythm but sometimes the arrhythmia starts again. However, electrical shocks cannot restart a heart that has no electrical activity at all (asystole).

Giving the heart such an electrical shock is called cardioversion, or defibrillation, depending on the type of abnormal rhythm for which it is used.

Defibrillation is giving an electrical shock during ventricular fibrillation Ventricular Fibrillation Ventricular fibrillation is a potentially fatal, uncoordinated series of very rapid, ineffective contractions of the ventricles (lower chambers of the heart) caused by many chaotic electrical... read more Ventricular Fibrillation . During ventricular fibrillation, there is no organized electrical activity in the heart to which the shock can be timed.

The machine that delivers the shock is called a defibrillator, even though it is used for both defibrillation and cardioversion. Defibrillators can be used by a team of doctors and nurses, by paramedics, or by firefighters.

An automated external defibrillator (AED) Automated External Defibrillator: Jump-Starting the Heart Automated External Defibrillator: Jump-Starting the Heart can automatically detect the presence of an arrhythmia, determine if a shock is advisable, and deliver the proper strength shock. Thus, using an AED requires only minimal training, such as that provided in a first-aid course. . AEDs are present in many public places, such as airports, sports arenas, hotels, and shopping malls.

NOTE: This is the Consumer Version. DOCTORS: VIEW PROFESSIONAL VERSION
VIEW PROFESSIONAL VERSION
quiz link

Test your knowledge

Take a Quiz!
iOS ANDROID
iOS ANDROID
iOS ANDROID
TOP