Which rhythms are considered shockable in ACLS?

• A. Ventricular fibrillation and pulseless ventricular tachycardia
• B. Asystole and pulseless electrical activity
• C. Atrial fibrillation with rapid ventricular response
• D. Normal sinus rhythm

Answer: (A)

In ACLS, only certain arrest rhythms are treated with defibrillation—the ones that are shockable. The shockable rhythms are ventricular fibrillation, where the heart’s electrical activity is chaotic and there’s no effective heartbeat, and pulseless ventricular tachycardia, a rapid rhythm that fails to produce a pulse. Delivering a defibrillating shock can reset the electrical activity and give the heart a chance to resume a coordinated, perfusing rhythm. The other rhythms listed—asystole and pulseless electrical activity—have no usable electrical activity guiding a pulse or have no mechanical output despite electrical activity; defibrillation won’t help here. Management focuses on high-quality CPR, vasopressors, and addressing reversible causes. Atrial fibrillation with rapid ventricular response isn’t treated as a shockable rhythm in this emergency context unless it deteriorates into a shockable arrest rhythm; normal sinus rhythm is simply normal and not shocked.