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

Clinical Snapshot

Key Findings

• P Value: Not applicable - descriptive systematic review

• Effect Size: Defibrillation threshold testing success 89%-100% (≥96% in studies with n≥100)

• Primary Outcome: Procedural success ranged from 81%-100%, with rates ≥94% in all but one early-phase study

• Nnt Or Sensitivity: Clinical defibrillation success consistently high at 95%-100%

• Confidence Interval: Not reported - descriptive ranges provided

Clinical Application

Requires specialized electrophysiology expertise and appropriate patient selection; device availability dependent on regulatory approval TGA approval status unclear; would require PBS listing for cost-effectiveness; CSANZ guidelines would need updating to include recommendations Adults with standard Class I or IIa ICD indications who are unsuitable for or prefer alternatives to transvenous systems

Abstract

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. RESULTS: Twenty-five publications representing 18 unique studies and 4,633 patients were included. Most studies were single-arm (n = 13), while 2 were randomized controlled trials and 3 were nonrandomized comparative studies. Procedural success ranged from 81%-100%, with rates ≥94% of patients in all but one early-phase study; defibrillation threshold testing success ranged from 89%-100% (≥96% in studies with n ≥ 100). 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. Non-transvenous implantable cardioverter-defibrillators (ICDs) are devices placed outside the blood vessels and heart, designed to treat life-threatening heart rhythm problems while avoiding complications related to transvenous ICDs.This review summarized results from 25 published studies including 4,600 patients to understand how safe and effective these devices are.Across studies, non-transvenous ICDs showed high implant procedure success, effective therapy delivery, and had generally low rates of short- and long-term complications.

References

1. 1.Zweibel, S., Lanctin, D., Holbrook, R., & Kapur, S. (2026). A systematic review of acute and long-term outcomes in patients with non-transvenous implantable cardioverter-defibrillators. Journal of Medical Economics. https://doi.org/10.1080/13696998.2026.2667706