Which rhythm is a common cause of sudden cardiac arrest?

• A. Atrial fibrillation
• B. Ventricular tachycardia
• C. Ventricular fibrillation
• D. Asystole

Answer: (B)

Ventricular fibrillation is the rhythm most often seen in sudden cardiac arrest. In VF, the ventricles quiver in a rapid, disorganized way, so there is no coordinated contraction and no effective blood flow. The person becomes pulseless and unresponsive within seconds, making immediate defibrillation essential along with high-quality CPR while the defibrillator is ready. This is why VF is the primary rhythm targeted in early resuscitation for sudden cardiac arrest. Other rhythms can play a role in different scenarios—atrial fibrillation is a supraventricular rhythm and doesn’t typically cause sudden arrest on its own; ventricular tachycardia can lead to arrest if it becomes pulseless, but it’s less common as the immediate arrest rhythm than VF; and asystole reflects no electrical activity and has a poor prognosis, with defibrillation not being effective. The key take-home is that the most common arrest rhythm is the chaotic, nonperfusing ventricular activity seen in ventricular fibrillation, which is what drives the rapid push for defibrillation.