Clinical Overview

S-ICD Clinical Data

 Several landmark trials can confirm: S-ICD offers effective defibrillation while significantly reducing the risk of complications associated with transvenous leads.

ATLAS Randomized Controlled Trial: S-ICD Superior to TV-ICD14

Study overview

The ATLAS Trial is an investigator-sponsored research study (ISR) initiated, designed and led by Population Health Research Institute (PHRI), Jeff S. Healey MD, MSc, FHRS, and the ATLAS Steering Committee. It 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.


The trial hypothesis is that S-ICD is superior to TV-ICD with respect to serious lead-related complications*, including:

  • New moderate-severe or severe tricuspid insufficiency,
  • Hemothorax or pneumothorax
  • Cardiac perforation, tamponade, or pericardial effusion or pericarditis
  • Ipsilateral upper extremity deep venous thrombosis
  • Lead dislodgement or loss of sensing or pacing requiring revision


Sample Size and Timing

The trial randomized 503 patients, who passed electrocardiographic screening, from clinical centers across Canada between February 2017 and July 2021.

Primary Outcomes
Patients in the S-ICD group showed significantly fewer serious lead-related complications* than patients implanted with a single-chamber TV-ICD.
The ATLAS trial met its primary superiority endpoint demonstrating a highly significant 92% reduction in serious lead-related complications* at six months for the EMBLEM™ S-ICD compared to any manufacturer´s single chamber TV-ICD devices. p=0.00314
Serious lead-related complication* occurred in 12 times as many patients in the single chamber TV-ICD arm (4.8%) at six months compared to 1 patient** (0.4%) in the S-ICD arm.14
Watch the Data
92% reduction in serious
lead-related complications*
Graph of Serious lead-related complications



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Clinical Evolution of S-ICD

Over 100,000 patients implanted with S-ICDs worldwide - and counting

S-ICD History Timeline

Safety and Efficacy of the S-ICD System 

Spontaneous Conversion
Over a decade of clinical data have consistently demonstrated high spontaneous conversion rates for the S-ICD. Most recently, EFFORTLESS data demonstrated overall final shock efficacy of 98% over long term follow up of 5 years.1 The S-ICD has comparable success rates in treating VT/VF when compared to studies with TV-ICD and even higher success rates in some instances.

Safety and Efficacy of the S-ICD System

The spontaneous conversion rates for S-ICD are comparable to TV-ICD – and are even better in certain studies.1-8
Safety and Efficacy of the S-ICD System
In the PRAETORIAN trial (N=849) the mortality rate was low for both S-ICD and TV-ICD over 4 years. The number of sudden cardiac deaths was identical for S-ICD and TV-ICD despite enrolling a sicker patient population than in previous S-ICD studies.9

Avoiding Complications with the S-ICD System 

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 Warehouse12 demonstrated that the incidence 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

Complications - The PRAETORIAN Trial

Head-to-head landmark PRAETORIAN trial demonstrated fewer device and lead related complications when comparing S-ICD to TV-ICD over a 4 year follow-up period in more typical ICD patients.9
Fewer Lead Related Complications
Fewer Lead Related Complications
Fewer Device Related Complications
Fewer Device Related Complications


Low need for Brady/ATP 

Only 20 of 4,159 patients (0.4%) across four major S-ICD studies required a TV-ICD for ATP (10 pts. 0.2%) or pacing (10 pts., 0,2%).

Low need for Brady/ATP 

Decreasing IAS Rates in More Typical ICD Patient Population 

The IAS Rate of 2.4% at 1 Year for EMBLEM MRI S-ICD in UNTOUCHED is Lower than IAS Rates in TV-ICD Studies.

Decreasing IAS rates in more typical ICD patient population