Controversies in Implantable Cardioverter-defibrillator Therapy
Implantable cardioverter-defibrillator (ICD) therapy is a mainstay in sudden cardiac death (SCD) prevention. Its efficacy has been proven in several conditions such as heart failure and reduced left ventricular ejection fraction (LVEF) and in familial SCD syndromes. In contrast to the fairly clear role of ICD therapy for secondary prevention, its role and indications for primary prevention of SCD has been more difficult to define. Many questions remain unresolved in this setting, such as the choice of the optimal time for implantation after a myocardial infarction and the degree of LVEF reduction that is able to predict future events and to justify the risks of ICD implant. The choice of ICD therapy may also be challenging in patients with different demographic features and comorbidities from that enrolled in clinical trials. Finally, the relative rarity of familial SCD syndromes seriously limits the data upon which recommendations are based and therefore many questions concerning the risk-benefit of ICD implantation remain unresolved.