What is the most common arrhythmia observed in patients experiencing cardiac arrest?

Ventricular fibrillation is recognized as the most common arrhythmia in patients experiencing cardiac arrest due to its critical role in the pathophysiology of out-of-hospital cardiac arrest events. During cardiac arrest, the heart's normal electrical rhythm is disrupted, often leading to chaotic electrical activity in the ventricles. This disorganized firing of electrical signals prevents the heart from effectively pumping blood, resulting in immediate loss of effective circulation and subsequently, loss of consciousness and, if not treated quickly, death.

The abrupt onset of ventricular fibrillation is typically witnessed in primary cardiac events, such as myocardial infarction. This arrhythmia is particularly lethal as it can rapidly lead to a cessation of effective cardiac output, emphasizing the urgency of rapid defibrillation to restore a viable rhythm. The treatment for ventricular fibrillation is immediate cardiopulmonary resuscitation (CPR), along with defibrillation, which can significantly improve survival rates if administered promptly.

In contrast, the other arrhythmias listed are less common in the setting of cardiac arrest. Atrial fibrillation, while it may be present in various cardiac conditions, does not typically lead to cardiac arrest in the same manner as ventricular fibrillation. Bradycardia involves a slower heart rate, which