Final answer:
Ventricular fibrillation is the most common heart rhythm during cardiac arrest. It is a serious condition that requires immediate medical attention. Defibrillation is the most common treatment for ventricular fibrillation.
Step-by-step explanation:
Ventricular fibrillation is the most common heart rhythm during cardiac arrest. In ventricular fibrillation, the electrical activity of the heart becomes severely disrupted, causing the heart to beat in a wild, uncontrolled manner, which prevents it from effectively pumping blood. If left untreated, ventricular fibrillation can lead to brain death. The most common treatment for ventricular fibrillation is defibrillation, which uses an external electrical source to deliver a charge to the heart in an attempt to establish a normal sinus rhythm.