What does defibrillate mean?
To defibrillate is to deliver a controlled electric shock to the heart, usually through pads placed on the chest, in order to halt a dangerous abnormal rhythm — most often ventricular fibrillation, in which the heart's muscle fibers quiver chaotically instead of contracting in unison. The shock momentarily stops all electrical activity in the heart, allowing its natural pacemaker to resume a coordinated, effective beat. The word derives from Latin fibrilla, meaning 'small fiber', combined with the prefix de-, reflecting the aim of stopping the disorganized twitching of those muscle fibers. Defibrillate is a transitive verb used almost exclusively in medical and emergency contexts: paramedics, nurses, and physicians defibrillate patients, while automated external defibrillators (AEDs) have made the procedure accessible to trained laypeople in public places. Because sudden cardiac arrest is time-critical, the ability to defibrillate quickly can mean the difference between life and death.
verbTo administer an electric shock to the heart using a defibrillator, in order to restore a normal heartbeat when it has stopped or become irregular, especially during cardiac arrest.
- To deliver an electric shock to the chest or heart with a defibrillator in order to terminate an abnormal cardiac rhythm, especially ventricular fibrillation, and restore normal heart function.
"Paramedics defibrillated the patient within minutes of his collapse, and his heart resumed a steady rhythm."
"The nurse prepared to defibrillate the patient after monitors showed ventricular fibrillation."
"Modern automated external defibrillators are designed so that even bystanders can safely defibrillate someone in cardiac arrest."
The word literally means to stop your heart's fibers from quivering — because in ventricular fibrillation, the heart muscle isn't beating at all; it's trembling uselessly until an electric shock snaps it back into rhythm.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of defibrillate
Defibrillate was formed in English from the Latin diminutive fibrilla, 'small fiber', itself derived from fibra, 'fiber', together with the prefix de- and the verbal suffix -ate. The term arose in early twentieth-century medical writing to describe the reversal of fibrillation — the chaotic, ineffective quivering of the heart's muscle fibers. Its cognates include fibril, fibrous, fibrin, and fibrillation, all tracing back to that same Latin root for thread-like structures.
Related word forms
How defibrillate is actually used
A technical medical term used primarily by healthcare professionals, emergency responders, and in first-aid training; it appears in general journalism but is rare in casual conversation. It is typically used transitively ('defibrillate a patient'), though passive constructions are common ('the patient was defibrillated'). The verb is neutral in tone, not euphemistic or slangy.
Easily confused with defibrillate
'Defibrate' means to break down into fibers (used in industrial contexts such as pulp processing), whereas 'defibrillate' refers specifically to delivering an electric shock to stop abnormal heart rhythm.