Which device is designed to terminate lethal rhythms by detecting and delivering shocks?

• A. External defibrillator
• B. Pacemaker
• C. Defibrillator
• D. Implantable Cardioverter Defibrillator

Answer: (D)

An implantable cardioverter defibrillator is designed to continuously monitor the heart rhythm and automatically terminate lethal arrhythmias by delivering shocks when ventricular tachycardia or ventricular fibrillation is detected. It combines sensing, detection, and therapy in one implanted device, often with the option of anti-tachycardia pacing as well. A pacemaker mainly provides pacing to prevent too-slow heart rates and doesn’t typically terminate dangerous rhythms. An external defibrillator can shock to restore rhythm but is used in acute, external settings rather than as a chronic implanted therapy. The implanted device described here offers ongoing, automatic detection and shock delivery to prevent sudden cardiac death.