A systematic review of acute and long-term outcomes in patients with non-transvenous implantable cardioverter-defibrillators

BACKGROUND: Non-transvenous implantable cardioverter-defibrillator (ICD) systems have been developed to address limitations of transvenous ICDs. This systematic literature review aimed to summarize periprocedural and long-term outcomes of non-transvenous ICD systems in adult patients with guideline-based indications for ICD therapy. METHODS: A systematic review was conducted in accordance with PRISMA guidelines (PROSPERO: CRD420261327618). Eligible studies enrolled adults (≥18 years) receiving a non-transvenous ICD for primary or secondary prevention. Outcomes included periprocedural and long-term endpoints and were summarized descriptively. The Newcastle-Ottawa Scale (NOS) and Joanna Briggs Institute (JBI) checklist for case series were used to assess risk of bias. Periprocedural complications were reported in 0%-5% of patients in most studies. Long-term complication rates ranged from 0%-8% at 0.5-1.5 years of follow-up and 1%-14% beyond 1.5 years. All-cause mortality ranged from 1%-5% within 6 months and increased to 16%-26% at 4-8 years. Clinical defibrillation success was consistently high (95%-100%). Incidence of inappropriate shock generally ranged from 7%-13% at 1 year and 2%-18% at later timepoints. Appropriate shock incidence ranged from 2% to 9% within 1 year and increased with longer follow-up. Risk of bias was predominantly moderate, with limited variation using NOS and greater discrimination observed with JBI. CONCLUSIONS: Non-transvenous ICD systems demonstrate favorable safety and effectiveness profiles, with high procedural and defibrillation success and acceptable complication and inappropriate shock rates across studies. Overall, the available evidence supports their use in appropriately selected adult patients with standard ICD indications.