Is primary prevention implantable cardioverter defibrillator implantation still warranted in the era of modern heart failure therapy? - a retrospective real-world cohort analysis

Abstract Background In recent years, the role of implantable cardioverter defibrillator (ICD) implantation for primary prevention in heart failure patients has been questioned. Emerging evidence suggests that its benefit may be reduced in the context of modern heart failure therapies, which have also contributed to a decline in the risk of sudden cardiac death in this patient population. Objective This study aimed to evaluate the clinical outcomes of heart failure patients with an indication for primary prevention ICD implantation. Methods We conducted a retrospective analysis of 150 patients who presented to our outpatient heart failure clinic in 2023. We assessed patient demographics, the performance of ICD therapy, and the incidence of ICD-related complications. Results Out of 150 analyzed patients 78 (52%) had an ICD. Of these, 57 (73%) were male and the mean age was 66.3 years. A total of 37 patients (47%) had an ischemic cardiomyopathy, while 41 (53%) had a non-ischemic cardiomyopathy. Contemporary medical heart failure therapy was wideliy utilized in the whole cohort: 16 patients (21%) were treated with angiotensin-converting enzyme (ACE) inhibitors, 57 patients (73%) received angiotensin-receptor neprilysin inhibitors (ARNI), 77 patients (99%) were on beta-blockers, 62 patients (79%) received aldosterone antagonists, and 56 patients (72%) were treated with sodium-glucose cotransporter-2 (SGLT2) inhibitors. All patients who had received an ICD had an ejection fraction (EF) of less than 35% at the time of implantation. However, during follow-up, only 48 patients (62%) continued to have an EF below 35%, with the mean EF across the cohort being 33.9%. 38 patients (49%) received cardiac resynchronization therapy. Among the 78 ICD recipients, 62 patients (79%) had the device implanted for primary prevention. Of these 62 patients, 12 (20%) experienced appropriate ICD therapy during follow-up. The average time from ICD implantation to the first appropriate therapy was 5.7 years. The overall ICD complication rate, including ICD-related interventions and revision surgeries (excluding routine upgrades or generator replacements), was 17% (13 of 78 patients). Conclusion In this long-term follow-up cohort, a significant proportion of patients with ICDs for primary prevention required appropriate therapy despite advanced heart failure treatments. Improved survival with contemporary therapies may extend the period at risk for sudden cardiac death, underscoring the continued importance of ICDs in future heart failure management.