Skip to main content


Subcutaneous Implantable Defibrillator

S-ICD Clinical Data

Explore clinical study and real-world data on inappropriate shock rates, complication rates and more. Plus, learn about the ATLAS and PRAETORIAN trials which are both prospective, randomized, head-to-head, clinical trials comparing S-ICD to TV-ICD.

ATLAS Trial: Lead-related complication rates

ATLAS is the first prospective randomized controlled trial where the primary objective was to evaluate lead-related complication rates between the S-ICD and single chamber TV-ICD devices at six months after implant. Full results were published in 2022.


PRAETORIAN is the first prospective, randomized, head-to-head, non-inferiority clinical trial that compares S-ICD to TV-ICD. The trial followed 850 patients at 40 centers across Europe and the United States. Full results were published in 2020.

First results of the randomized PRAETORIAN-DFT trial

Prospective validation of the PRAETORIAN score for prediction of defibrillation test success after subcutaneous ICD implant

The findings from this first analysis demonstrate that a low (<90) PRAETORIAN score is 99% predictive for a successful DFT and a high (≥90) PRAETORIAN score is the strongest predictor for DFT-failure (odds ratio of 34 ).1

While the study investigators concluded their presentation by stating that the PRAETORIAN score could be used as an alternative for DFT in cases when DFT-testing is not possible or desirable, omitting DFT’s in S-ICD implants cannot be advised until the full PRAETORIAN-DFT results are available.

Analysis of the UNTOUCHED Study


The incidence of inappropriate shocks in primary prevention, LVEF ≤ 35% patients will be non-inferior to the rate in transvenous ICD patients with similar programming observed in MADIT-RIT Arms B and C.

Study Design

  • Follow-up for 18 months
  • Device programming with a conditional zone of 200 bpm and a shock zone of 250 bpm
  • Primary endpoint of inappropriate shock-free rate at 18 months
  • Secondary endpoints of all cause shock-free rate at 18 months and system and procedure complications at 30 days

Key Takeaways

1. In the UNTOUCHED study a subsequent sub-analysis demonstrated that the inappropriate shock rate with SMART Pass On was 1.8% at 1 year for EMBLEM™ S-ICDs. This is the lowest reported inappropriate shock rate for S-ICD, despite a cohort with more left ventricular dysfunction and heart failure.2,3

acute outcomes
2. The appropriate shock rate of 5.7% over 18 months was low with a high conversion success of 98.4%, similar to that reported with TV-ICD trials.2
S-ICD-Conversion Rates
3. Complication rates remain very low (95.8% complication free rate at 30 days, 92.7% at 18 months, and no systemic infections), despite enrolling a sicker patient population.2
EMBLEM complication rates

TV-ICD lead complications in the real world

The transvenous lead is the most common source of complications in a TV-ICD system. Data from over 40,000 patients from the OptumLabs Data Warehouse demonstrated that the incidence of mechanical and infectious complications of transvenous leads over long-term follow-up is much higher in the real world than in clinical studies. 
3-4% of patients with TV-ICD suffer lead malfunctions in the first year of implant10
About 25% mechanical failure rate for TV-ICD at 10 years10
4% infection rate for TV-ICD at 10 years10
freedom from complication
 Kaplan-Meier plot of lead revision associated with a diagnosis of infection or mechanical complication for patients with an implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator. 

Clinical Data Resources

The Impact of SMART Pass on IAS

S-ICD and Patients at High Risk for Infection

Bradycardia Pacing Need in ICD Patients


Training & Education

Explore continuing education courses, best practices modules and other training and resources for S-ICD.



Why S-ICD?

See how S-ICD helps protect patients at risk for sudden cardiac death while also eliminating the risk of TV-ICD lead complications.

Implant Procedure

Implant Procedure

Learn about advancements in the S-ICD implant procedure, including the 2-incision and intermuscular implant techniques.

Videos & Resources

Videos & Resources

Hear physician perspectives about S-ICD, find media information, and download product images, patient videos and more.