Which device is capable of defibrillation?

• A. Pacemaker
• B. Implantable cardioverter-defibrillator (ICD)
• C. External defibrillator
• D. None of the above

Answer: (B)

Defibrillation means delivering a high-energy shock to stop a dangerous heart rhythm and restore a normal heartbeat. An implantable cardioverter-defibrillator is placed in the chest and continuously monitors the heart. When it detects a life-threatening rhythm like ventricular fibrillation or a rapid VT, it delivers an internal shock to terminate the abnormal rhythm and can also provide pacing if needed. This makes it the device designed to perform defibrillation automatically within the body. A pacemaker primarily provides pacing to maintain heart rate and does not deliver shocks. An external defibrillator can deliver shocks as well, but it is not an implanted device.