Clinical Overview
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.
Hypothesis
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.
lead-related complications*
Clinical Evolution of S-ICD
Over 100,000 patients implanted with S-ICDs worldwide - and counting
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.
The spontaneous conversion rates for S-ICD are comparable to TV-ICD – and are even better in certain studies.1-8
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.
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
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%).
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.
