Implantable cardioverter-defibrillators have proven efficacy in reducing mortality in patients with reduced left ventricular ejection fraction in both the primary and the secondary prevention settings. All randomized trials demonstrating this benefit have been conducted in outpatients with stable heart failure symptoms. Whether implantable cardioverter-defibrillators confer a benefit when implemented in patients with chronically reduced left ventricular ejection fraction in the acute heart failure setting is unknown. The purpose of this document is to review the existing literature related to this subject.