Clinical Outcomes and Mortality in Patients with Implantable Cardioverter-Defibrillator for Primary Prevention

Background: Implantable cardioverter-defibrillator (ICD) is indicated for primary prevention in patients with left ventricular ejection fraction (LVEF) <= 35% and New York Heart Association class II or III heart failure despite 3 months of optimal medical therapy. However, studies that support this recommendation are over 20 years old, and they may not reflect modern heart failure patients' characteristics. Objectives: Retrospectively evaluate patients who received an ICD for primary prevention. Methods: All-cause and sudden death rates were compared in patients who received ICD between January 1, 2015 and March 1, 2020 and those who did not accept ICD. Variables were analyzed at a 95% confidence interval, and p < 0.05 was considered as significant. Results: When comparing mortality rates between patients with and without ICD, 67 of 228 patients (29.4%) in the ICD group and 39 of 150 patients (26%) in the control group died from all causes (p = 0.473). Age, LVEF, BNP value, and hospitalization were found to be independent predictors of all-cause mortality. Patients with BNP above 508.5, LVEF below 24.5%, and age over 68.5 years had a 25-fold increased all-cause mortality. Coronary artery disease was not found to be an independent risk factor. Survival in the control group was statistically significantly better in the first months. Although there was no statistical difference in the long term, survival was numerically better in the ICD arm. This could be attributed to the fact that ICD implantations were performed on patients with worse clinical conditions. The higher survival rate observed in patients with ICD may be due to the fact that they came in for device control and remained in follow-up. Conclusions: With advances in the treatment of heart failure, ICD implantation should be performed in selected patients.