defibrillaation

Defibrillation is a medical procedure that delivers a controlled electric shock to the heart with the aim of restoring a normal heart rhythm in life-threatening arrhythmias such as ventricular fibrillation or pulseless ventricular tachycardia. The term is commonly misspelled as defibrillaation, but the accepted spelling is defibrillation.

There are external and internal forms of defibrillation. External defibrillation uses defibrillators, including automated external defibrillators (AEDs) accessible to the public and manual external defibrillators used by healthcare providers. Internal defibrillation employs implanted devices, such as implantable cardioverter-defibrillators (ICDs), or is performed during surgery with epicardial leads. The basic mechanism is to depolarize a large portion of the heart, briefly interrupting chaotic electrical activity so the heart’s natural pacemaker can reestablish a normal rhythm.

Defibrillation is used primarily for cardiac arrest caused by shockable rhythms, namely ventricular fibrillation and pulseless ventricular tachycardia. It is not effective for non-shockable rhythms such as asystole or pulseless electrical activity, where other resuscitation measures are required.

In practice, defibrillation is most effective when delivered early, often in combination with high-quality CPR. External devices deliver energy in joules; modern biphasic shocks typically range around 120–200 J, while older monophasic devices used higher settings. AEDs analyze heart rhythm and guide users to deliver a shock when indicated, and safety steps include ensuring no one is touching the patient during shock.

Public health use includes widespread availability of AEDs in public spaces and training programs that emphasize rapid defibrillation and CPR. ICDs provide ongoing monitoring and automatic shocks to prevent recurrence of dangerous arrhythmias, improving long-term outcomes in at-risk individuals. Limitations exist, and defibrillation is not a universal remedy for all cardiac emergencies.