EFFICACY OF IMPLANTABLE CARDIOVERTER-DEFIBRILLATORS IN REDUCING SUDDEN CARDIAC DEATH IN PATIENTS WITH NON-ISCHEMIC HEART FAILURE: A LITERATURE REVIEW

Abstract

Introduction: Nonischemic heart failure is associated with high morbidity and mortality, with sudden cardiac death representing an important cause of death in this population. The implantable cardioverter-defibrillator (ICD) is used as a primary prevention strategy in selected patients, although its benefit, particularly regarding overall mortality, remains controversial. Objective: To evaluate the efficacy of the implantable cardioverter-defibrillator in preventing sudden cardiac death and its impact on mortality in patients with nonischemic heart failure. Methods: A systematic literature review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) recommendations. The search was performed in April 2026 in the PubMed and Virtual Health Library (VHL) databases, considering studies published between January 2021 and March 2026 in Portuguese and English. Randomized clinical trials, observational studies, and cohort studies evaluating adult patients with nonischemic heart failure or cardiomyopathy treated with an ICD for primary prevention, with outcomes related to sudden cardiac death, arrhythmic death, or all-cause mortality, were included. Study selection and methodological assessment were independently performed by two reviewers, with disagreements resolved through discussion and consensus. Results:The included studies showed heterogeneous findings across the evaluated outcomes. Overall, evidence suggested a potential benefit of ICD therapy in preventing sudden cardiac death and fatal arrhythmic events. However, findings regarding all-cause mortality were inconsistent, with some studies demonstrating benefit while others did not identify a statistically significant reduction. The magnitude of benefit appeared to vary according to clinical characteristics, including age, comorbidities, competing risk of non-arrhythmic death, and markers associated with arrhythmic risk. Conclusion: The implantable cardioverter-defibrillator may provide benefit in preventing sudden cardiac death in patients with nonischemic heart failure. However, the heterogeneity of findings regarding overall mortality does not support the conclusion that ICD therapy uniformly reduces all-cause mortality. These findings reinforce the importance of individualized patient selection and appropriate arrhythmic risk stratification in the context of contemporary heart failure therapies.