Which intervention is the primary treatment for ventricular fibrillation?

Defibrillation with an AED (Automated External Defibrillator) is the primary treatment for ventricular fibrillation because it directly addresses the underlying heart rhythm disturbance. In cases of ventricular fibrillation, the heart's electrical activity becomes chaotic, preventing it from pumping blood effectively. The application of a defibrillator delivers a controlled electrical shock to the heart, which can momentarily reset the heart's electrical state, allowing it to regain a normal rhythm.

While medications, chest compressions, and oxygen are important components of the overall management of a cardiac arrest, they do not restore the heart's normal rhythm as effectively as defibrillation. Emergency medications can support the treatment but serve primarily as adjuncts. Chest compressions are crucial for maintaining circulation during a cardiac arrest, and providing high-flow oxygen helps address hypoxia, but neither can resolve the electrical problem seen in ventricular fibrillation. Thus, defibrillation is the critical and immediate intervention required to save a life in this scenario.