BOSTON, MA, MAY 19, 2024 – Today, the Heart Rhythm Society (HRS) announced new findings around several clinical trials showcasing recent advancements in cardiac implantable electronic device (CIED) technology and pharmacotherapy that overcome the limitations of traditional devices or address unmet therapeutic needs. Researchers presented the studies as late-breaking clinical science during Heart Rhythm 2024.

The emergence of complex stimulation systems and technical improvements in pacemakers, subcutaneous implantable cardioverter defibrillators (S-ICDs), and cardiac resynchronization therapy have led to accelerated innovations within the cardiac pacing field. CIEDs have evolved to be a common treatment option for patients with arrhythmias, with more than 300,000 individuals receiving new implants every year in the U.S. alone¹. Despite significant technological advances in CIED design and implantation, procedure- or device-related complications can occur, including infection, lead dislodgement, and damage to the heart and lungs².

The findings of the following studies demonstrate the safety and efficacy of novel or improved pacing methods and anticoagulation for secondary prevention of cardiovascular events.

• Assessment of Primary Prevention Patients Receiving an ICD- Systematic Evaluation of ATP: APPRAISE ATP: This study is the largest head-to-head trial of antitachycardia pacing (ATP) in patients with transvenous ICDs (TV-ICDs) using contemporary programming for primary prevention of sudden cardiac death. Researchers randomized patients to standard therapy (ATP and shock) or shock-only treatment to assess the role of ATP by measuring time to first all-cause shock. The trial found that the ATP and shock arm was superior to the shock-only arm: Data demonstrated a 28% relative risk reduction in time to first all-cause shock for the ATP and shock arm, which represents an absolute first all-cause shock reduction in approximately 1% of patients with primary prevention TV-ICDs per year.

“Data demonstrated the effectiveness of ATP in prolonging the time to first all-cause shock in primary prevention patients with TV-ICDs,” said Claudio Schuger, MD, University of Rochester, Rochester, New York, and lead investigator of the APPRAISE ATP clinical trial. “The benefit of ATP – compared to the known risk of having leads placed in the heart – should be discussed with patients who have a primary prevention indication for an ICD.”

• Tachycardia Therapy and Endpoint Results of the First Modular, Intra-body, Communicating Subcutaneous Defibrillator-Leadless Pacemaker System: MODULAR ATP Interim Cohort: The MODULAR ATP clinical trial evaluated the safety, performance, and effectiveness of the Boston Scientific mCRM™ System – the first modular cardiac rhythm management system that consists of the EMBLEM™ S-ICD System and the EMPOWER™ Leadless Pacemaker (LP)*. Pre-specified endpoint results demonstrated an LP complication-free rate of 97.5%, a communication success rate of 98.8% from the EMBLEM S-ICD System to the LP, and low and stable pacing capture thresholds (≤ 2.0 V at 0.4 ms) in 97.4% of patients, which indicate stable device fixation within the heart. Researchers also found an ATP success rate of 61.3%, with no patient requests for deactivation of ATP or bradycardia pacing due to pain or discomfort.

“Data demonstrated excellent overall clinical performance of the mCRM System in this study, including a low rate of major leadless pacemaker complications and a high rate of communication success from the S-ICD to the leadless pacemaker,” said Prof. Reinoud Knops, MD, PhD, Department of Cardiology and Electrophysiology, Amsterdam UMC, Amsterdam, Netherlands. “These findings are noteworthy, as they indicate both a potential upgrade pathway for patients currently implanted with an S-ICD who develop a need for ATP or pacing and support the use of the EMPOWER Leadless Pacemaker as a standalone therapy device.”

• Efficacy and Safety of Apixaban Versus Aspirin According to CHA2DS2-VASc Score in Patients with Subclinical Atrial Fibrillation in ARTESiA: The ARTESIA trial sought to determine if blood thinners could reduce the risk of stroke in patients with short-lasting atrial fibrillation (AF) that was detected only by an implanted pacemaker or similar device. Researchers found that the rate of stroke among such patients was low (about 1.2% per year) but was significantly reduced by treatment with apixaban, compared to aspirin. Study results also indicated that, in patients with more than four risk factors for stroke (27% of the overall study population), the annual risk of stroke was 2.3%; anticoagulation reduced this by more than half. The reduction in stroke was approximately double the increase in bleeding risk, indicating a clear benefit to using blood thinners for these patients. The opposite was true for patients with less than four risk factors for stroke (39% of the overall study population), where the increase in bleeding exceeded the reduction in stroke. For those with exactly four risk factors, the risks and benefits were similar, suggesting that physicians should take patient preference and other factors into account when considering treatment with blood thinners.

“Silent, subclinical, device-detected AF is extremely common in older individuals with stroke risk factors,” said Jeff Healey, MD, MSc, Yusuf Chair and Professor of Cardiology, Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada. “These results help inform the management of approximately one-third of patients with implanted pacemakers, defibrillators, and cardiac monitors. The results of this study also have important implications for the growing number of individuals with subclinical AF detected by consumer devices such as smart-watches, rings, and mobile phone applications.”

Researchers presented the trials at respective late-breaking clinical trial sessions on Friday, May 17, through Sunday, May 19.

*The EMPOWER LP is an investigational device and limited by U.S. law to investigational use only. It is not available for sale. Some device references are for informational purposes only and are pending CE Mark. Not available in the European Economic Area.

Session Details:

“Late Breaking Clinical Trials and Science - CIEDs: Assessment of Primary Prevention Patients Receiving an ICD- Systematic Evaluation of ATP: APPRAISE ATP” [Friday, May 17, 2024 at 11:45 am ET]

“Late Breaking Clinical Trials and Science - Innovation: Tachycardia Therapy and Endpoint Results of the First Modular, Intra-body, Communicating Subcutaneous Defibrillator-Leadless Pacemaker System: MODULAR ATP Interim Cohort” [Saturday, May 18, 2024 at 10:00 am ET]

“Late Breaking Clinical Trials and Science - CIEDs: Efficacy and Safety of Apixaban Versus Aspirin According to CHA2DS2-VASc Score in Patients with Subclinical Atrial Fibrillation in ARTESiA” [Sunday, May 19, 2024 at 10:15 am ET]

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About the Heart Rhythm Society

The Heart Rhythm Society is the international leader in science, education, and advocacy for cardiac arrhythmia professionals and patients and is the primary information resource on heart rhythm disorders. Its mission is to improve the care of patients by promoting research, education, and optimal healthcare policies and standards. Incorporated in 1979 and based in Washington, D.C., it has a membership of more than 8,200 heart rhythm professionals from 94 countries. For more information, visit www.HRSonline.org.

About Heart Rhythm 2024

The Heart Rhythm Society's annual Heart Rhythm meeting convenes 8,400+ of the world’s finest clinicians, scientists, researchers, and innovators in the field of cardiac pacing and electrophysiology. More than 1,200 international experts in the field will serve as faculty for the 200+ educational sessions, forums, symposia, and ceremonies, while 110+ exhibitors will showcase innovative products and services. For more information, visit www.HeartRhythm.com.

1. Greenspon AJ, Patel JD, Lau E, Ochoa JA, Frisch DR, Ho RT, Pavri BB, Kurtz SM. 16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States: 1993 to 2008. J Am Coll Cardiol. 2011 Aug 30;58(10):1001-6.

2. Kirkfeldt RE, Johansen JB, Nohr EA, Jørgensen OD, Nielsen JC. Complications after cardiac implantable electronic device implantations: an analysis of a complete, nationwide cohort in Denmark. Eur Heart J. 2014 May;35(18):1186-94.