Design: Prospective, global post-approval registry
Population: 787 patients with an EV-ICD implant attempt
Primary outcome: Freedom from major system- or procedure-related complications at 1 year
Effect: 89.1% (95% CI 86.3–91.3); inappropriate shock 7.1%

The Enlighten post-approval registry followed 787 patients (mean age 49, 34% secondary prevention) in whom 168 implanters attempted an extravascular ICD with a substernal lead. It was published in Circulation this week.

Substernal lead placement succeeded in 99.2% and 96.3% remained implanted after defibrillation testing. One-year freedom from major system- or procedure-related complications was 89.1% (95% CI 86.3 to 91.3). All 61 discrete spontaneous episodes were terminated by shock, and antitachycardia pacing succeeded in 74.2% of monomorphic VT. The first inappropriate shock rate was 7.1% at one year, mostly from non-cardiac oversensing.

The device offers antitachycardia pacing without a transvenous lead, which matters for younger patients facing decades of lead risk. One inappropriate shock in about 14 patients a year is the figure to discuss before implant.

Consider the EV-ICD for younger patients who want to avoid a transvenous lead and do not need bradycardia pacing.
Counsel on a roughly 7% one-year risk of inappropriate shock.
Review sensing and programming at follow-up to reduce non-cardiac oversensing.
Compare with subcutaneous ICD where antitachycardia pacing is not required.

Why it matters

It confirms a lead-free option with antitachycardia pacing works outside expert trial centres.

The statistics, in plain English

This is a single-arm registry with no comparison group, so it describes performance rather than proving the device is better than alternatives. One year is short for lead and device longevity.