Which device is used to prevent sudden cardiac death in patients with heart failure with reduced ejection fraction (HFrEF) when indicated?

• A. Pacemaker
• B. Left ventricular assist device
• C. Implantable cardioverter-defibrillator (ICD)
• D. External defibrillator

Answer: (C)

In heart failure with reduced ejection fraction, the risk of sudden cardiac death from dangerous ventricular rhythms is a major concern. An implantable cardioverter-defibrillator is designed to address exactly this problem: it continuously monitors the heart rhythm and, if a malignant tachyarrhythmia like VT or VF is detected, it delivers a shock (or anti-tachycardia pacing) to restore a normal rhythm. This capability to terminate life-threatening arrhythmias is why the ICD is the device used to prevent sudden death in eligible HFrEF patients when indicated, typically after optimizing medical therapy.

Pacemakers mainly address slow heart rates or conduction problems, not malignant arrhythmias. Left ventricular assist devices support circulation in advanced HF and don’t prevent sudden death from arrhythmias. External defibrillators are used for acute, outside-the-body emergencies or temporary situations, not as a long-term preventive therapy.