Subcutaneous Implantable Defibrillator

Study overview​

The pivotal MODULAR ATP trial is the basis for the commercialisation of the industry's first Modular CRM system and the EMPOWER Leadless Pacemaker (LP).1,2*​​

The components of the mCRM system are designed to work together wirelessly to coordinate intracardiac antitachycardia pacing (ATP) therapy, provide VVIR pacing and prevent sudden cardiac death2 without the risk of leads in the heart3-5 or under the sternum. 6,7​

Study design and overview​

The MODULAR ATP trial is a prospective, non-randomised, single arm, global study to demonstrate the safety, performance and effectiveness of the mCRM System and the EMPOWER LP and utilised performance goals to demonstrate these primary and secondary outcomes. In addition to evaluating the safety of the EMPOWER LP System, the MODULAR ATP trial evaluated the ability of the EMBLEM S-ICD to successfully communicate a wireless request to the EMPOWER LP to deliver intracardiac ATP.1,**​

Specific testing was also conducted to determine the performance and effectiveness of the EMPOWER LP to function as a standalone VVIR pacemaker.2†​

* The EMPOWER leadless pacemaker and mCRM system will pursue FDA approval in 2025. Caution: Investigational Device. Limited by US law to investigational use only.​
Not available for sale​
** The mCRM wireless communication is inductive, one-way communication from the S-ID to the LP to request ATP delivery. Communication testing, which assesed pass/fail of communication at the programmed S-ICD Telemetry Setting, was required at 6-month visit in 4 body postures. The test had to pass in >88% of communication attempts, across all postures, to be defined as successful.​
† Rate-response results will be reported in a future publication.​


From July 2021 through January 2024, 293 patients were enrolled at 38 centers. The study design included a pre-specified early analysis of the safety endpoint once 134 patients were implanted with the EMBLEM S-ICD and EMPOWER LP System and followed for 6 months. Because of variability in the 6-month follow up appointments, 162 patients were in this group for this early analysis of the safety endpoint. The mean age of this group was 60 years with a mean EF of 33%. 61% had ischemic cardiomyopathy and 54% were primary prevention patients.1,8​​

The MODULAR ATP trial enrolled patients with significant structural heart disease and implantation of the EMPOWER LP was successful in 100% of patients.1,8​


With 162 patients implanted, the mCRM System achieved all pre-specified safety and effectiveness 6-month endpoints from the MODULAR ATP trial.1  These results demonstrated the safety profile of the EMPOWER LP system.1
3 circles graphic

Intracardiac ATP

​​The EMPOWER LP is designed to deliver intracardiac ATP and brady pacing therapy that should not lead to pain or discomfort in contrast to extracardiac pacing.1,8,9 ATP conversion success rate was 61.3% and no patient in the MODULAR ATP trial requested leadless pacemaker therapy inactivation due to feelings of pain or discomfort. 1,8‡ ​
‡ ATP success rate defined as terminating ventricular arrhythmia.​
mCRM™ System Tachycardia Therapy: S-ICD and Leadless Pacemaker deliver ATP

Designed for the future of personalised patient care​​

Upon the EMPOWER LP and mCRM™ system receiving FDA approval, EMPOWER will be the first and only LP designed to be a standalone VVIR pacemaker that is compatible with all existing EMBLEM™ S-ICD devices as part of the mCRM system. The mCRM system is designed to deliver painless intracardiac ATP and/or brady pacing.2​​

Should patients currently implanted with an EMBLEM S-ICD device develop a need for ATP and/or bradycardia pacing, an upgrade pathway will be available once the EMPOWER LP and mCRM system receive FDA approval.2 ​​

The mCRM system is designed to provide upgrade pathways regardless if the EMBLEM S-ICD or EMPOWER LP is implanted first, providing physicians flexibility to tailor therapy to the individual patient's needs.2​

mCRM EMPOWER LP is pending CE Mark. Not available for sale.
NEJM requires a subscription to access the full publication.​


APPRAISE ATP: Assessment of primary prevention patients receiving an ICD-systematic evaluation of ATP​
Study design and overview 10

The APPRAISE ATP trial was a prospective, randomised, global, multicenter clinical trial to understand the role of ATP in primary prevention (PP) patients currently indicated for ICD therapy.​​

The objective of the trial was to determine if standard therapy (ATP prior to shock) is clinically equivalent to No ATP prior to shock when combined with contemporary programming in primary prevention TV-ICD indicated patients. The trial was designed to determine if programming ATP OFF in Zone 2 in PP patients is equivalent to programming ATP ON by measuring time to first all-cause shock. ​

Enrollment and randomisation 10,11​

The APPRAISE ATP trial is the largest head-to-head trial of ATP in primary prevention patients. The trial enrolled 2,626 primary prevention ICD indicated patients from 134 centers in North America, Europe, and Asia.11 Patients received a single- or dual-chamber transvenous ICD (TV-ICD) and 2,595 were randomized 1:1 to different therapy programming in an equivalence study design with sequential superiority analysis of each arm.​
ATP on off graphic

Results 11

The APPRAISE ATP trial demonstrated superiority with a 28% relative risk reduction in time to first all-cause shock for the ATP ON arm compared to the ATP OFF arm (Log-rank P-value=0.005). This represents an absolute all-cause shock reduction in 1% of PP ICD indicated patients per year.​​

There was a significant difference throughout follow up (p=0.005). The percentage of patients free from all-cause shocks at one year was 95.7% for ATP-plus-shock arm vs 94.7% for the shock-only arm.​​

At five years, the percent of patients free from all-cause shocks was 85.4% for the ATP-plus-shock arm vs 80.6% for the shock-only arm.11​

Kaplan Meier chart
This represents an absolute all-cause shock reduction in 1% of primary prevention ICD indicated patients per year (Log-rank P-value=0.005).11​

Inappropriate shock rates low in both arms​

Inappropriate shock rates were low in both TV-ICD programming arms due to the use of guideline recommended programming for PP patients.11, 12 While the overall difference between arms was significant (p=0.033), the absolute differences at 1 year and 5 years were 0.3% and 2.2% of patients, respectively.11​
Inappropriate shocks

The importance of shared decision making​

With an absolute all-cause shock reduction in 1% of PP patients with a TV-ICD per year11 this benefit of ATP should be discussed with PP patients eligible for an S-ICD during shared decision making and should also be compared to the lifetime risk of having a lead in the heart with a TV-ICD. 3-5,13 More data and time is needed to determine the risks associated with a substernal ICD lead.6,7​
absolute vs risk

Full follow-up results​

shock burden
 § Defined as all shocks over full follow-up period per 100 patients.​

Future upgrade pathway with the Modular CRM (mCRM) System*​

Should patients currently implanted with an EMBLEM S-ICD device develop a need for intracardiac ATP and/or bradycardia pacing, an upgrade pathway will be available once the EMPOWER Leadless Pacemaker (LP)* and mCRM system receive FDA approval. ​

The mCRM system is designed to provide upgrade pathways regardless if the EMBLEM S-ICD or EMPOWER LP is implanted first, providing physicians flexibility to tailor therapy to the individual patient's needs.2​
* The EMPOWER leadless pacemaker and mCRM system will pursue FDA approval in 2025. Caution: Investigational Device. Limited by US law to investigational use only. Not available for sale.​

Want More Info About the Study?

If you have questions about the MODULAR ATP Clinical Study and patient eligibility, please contact one of the coordinating principal investigators below.
Michael S. Lloyd, MD, FACC, FHRS

Michael S. Lloyd, MD, FACC, FHRS

Professor of Medicine, Program Director Emory EP Fellowship,​
 EUH Lab Director, Emory University Hospital, Atlanta, GA, USA​ | mlloyd2@emory.edu


Dr. Lluís Mont, MODULAR ATP Clinical Study Coordinating Principal Investigator

Lluís Mont, MD, PhD, FEHRA

Professor of Medicine, University of Barcelona, Head of the Arrhythmia Section, Cardiovascular Institute, Hospital Clínic, Barcelona, Catalonia, Spain | lmont@clinic.cat

Dr. R.E. Knops, MODULAR ATP Clinical Study Coordinating Principal Investigator

R.E. Knops, MD, PhD

Cardiologist, Department of Cardiology, Amsterdam University Medical Center, Amsterdam, the Netherlands | r.e.knops@amc.uva.nl

Dr. Vivek Y. Reddy, MODULAR ATP Clinical Study Coordinating Principal Investigator

Vivek Y. Reddy, MD

Professor of Medicine in Cardiac Electrophysiology, Director of Cardiac Arrhythmia Services, The Mount Sinai Hospital, New York, NY, USA | vivek.reddy@mountsinai.org

Clinical Trial Managers

For more information about the MODULAR ATP Clinical Study, please contact the clinical trial manager for your region.

North America

Julie West, MA


Ursula Appl

Study Eligibility

Study Eligibility

Explore patient inclusion and exclusion criteria and find resources to help you refer study candidates.

Pre-Clinical Data

Pre-Clinical Data

See the pre-clinical data evaluating the use of modular CRM technology in animal subjects.

mCRM Technology

mCRM Technology

Discover how a modular approach to ICD therapy may reduce the risks of TV leads while providing pacing if needed.