When does defibrillation have the greatest chance of success?

Defibrillation has the greatest chance of success when it is administered within the first few minutes of a cardiac arrest, particularly if the patient is experiencing ventricular fibrillation or pulseless ventricular tachycardia. The likelihood of successful defibrillation decreases significantly as time passes without intervention, especially after 10 minutes. Early recognition of cardiac arrest, prompt cardiopulmonary resuscitation (CPR), and rapid access to an automated external defibrillator (AED) are critical factors that enhance the chances of a successful outcome.