Safety and Effectiveness of Left Bundle Branch Area Pacing Versus Conventional Cardiac Resynchronization Therapy in Heart Failure (SYNCHRONICITY)

This study will compare two different methods to pace the heart to treat heart failure including:

1. The current standard method of implanting a pacing lead in a vein on the surface of the left lower chamber of the heart (left ventricle) to deliver heart failure therapy. This method is called Cardiac Resynchronization Therapy (CRT).
2. The other method is using a lead implanted in the Left Bundle Branch Area (LBBA) of your heart. This method is called Left Bundle Branch Area Pacing or LBBAP. This lead is approved by the Food and Drug Administration (FDA) to be implanted in this area of the heart, but not to provide heart failure treatment.

Study Overview

• Status: Recruiting
• Conditions: Heart Failure - NYHA II - IV
• Intervention / Treatment: Device: CRT-D with a Quadripolar LV lead; Device: CRT-D with INGEVITY+ pace/sense lead

• Study Type: Interventional
• Enrollment (Estimated): 850
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jacqueline Beaulieu; Phone Number: 1-800-227-3422; Email: jacqueline.beaulieu@bsci.com

Study Locations

• United States
  • Alabama
    • Huntsville, Alabama, United States, 35801
      • Recruiting
      • Heart Center Research, LLC
      • Contact: John Jennings, Dr.
      • Principal Investigator: John Jennings, Dr.
    • Mobile, Alabama, United States, 36608
      • Recruiting
      • Mobile Infirmary Medical Center
      • Contact: Ernest Matthew Quin, Dr.
      • Principal Investigator: Ernest Matthew Quin, Dr.
  • Arkansas
    • Jonesboro, Arkansas, United States, 72401
      • Recruiting
      • Arrhythmia Research Group
      • Contact: Devi Nair, Dr.
      • Principal Investigator: Devi Nair, Dr.
  • California
    • La Jolla, California, United States, 92037
      • Recruiting
      • Scripps Memorial Hospital
      • Contact: Nicolas Olson, MD
      • Principal Investigator: Nicolas Olson, MD
    • Los Angeles, California, United States, 90048
      • Recruiting
      • Cedars Sinai Medical Center
      • Principal Investigator: Ashkan Ehdaie, MD
      • Contact: Ashkan Ehdaie, MD
    • Oakland, California, United States, 94609
      • Recruiting
      • Alta Bates Summit Medical Center
      • Contact: Rajan Shah, Dr.
      • Principal Investigator: Rajan Shah, Dr.
    • Santa Monica, California, United States, 90404
      • Recruiting
      • Pacific Heart Institute
      • Contact: Stephen Tang, MD
      • Principal Investigator: Stephan Tang, MD
    • Torrance, California, United States, 90505
      • Recruiting
      • Torrance Medical Center
      • Principal Investigator: Gene Kim, MD
      • Contact: Gene Kim, MD
    • Ventura, California, United States, 93003
      • Recruiting
      • Cardiology Associates Medical Group, Inc.
      • Contact: Jonathan Dukes, Dr.
      • Principal Investigator: Jonathan Dukes, Dr.
  • Florida
    • Sarasota, Florida, United States, 34239
      • Recruiting
      • Sarasota Memorial Hospital
      • Contact: Antonio Moretta, Dr.
      • Principal Investigator: Antonio Moretta, Dr.
  • Georgia
    • Atlanta, Georgia, United States, 30322
      • Recruiting
      • Emory University Hospital
      • Contact: Anand Shah, MD
      • Principal Investigator: Anand Shah, MD
  • Illinois
    • Hinsdale, Illinois, United States, 60521
      • Recruiting
      • University of Chicago
      • Contact: Shrinath Yeshwant, MD
      • Principal Investigator: Shrinath Yeshwant, MD
    • Naperville, Illinois, United States, 60540
      • Recruiting
      • Midwest Cardiovascular Institute
      • Contact: Moeen Saleem, Dr.
      • Principal Investigator: Moeen Saleem, Dr.
  • Indiana
    • Indianapolis, Indiana, United States, 46250
      • Recruiting
      • Community Heart and Vascular Hospital
      • Contact: Krishna Malineni, MD
      • Principal Investigator: Krishna Malineni, MD
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • Recruiting
      • University of Iowa Hospitals and Clinics
      • Principal Investigator: Paari Dominic, MD
      • Contact: Paari Dominic, MD
  • Kentucky
    • Louisville, Kentucky, United States, 40207
      • Recruiting
      • Baptist Hospital East Louisville
      • Principal Investigator: Kevin Parrott, MD
      • Contact: Kevin Parrott, MD
  • Massachusetts
    • Fall River, Massachusetts, United States, 02720
      • Recruiting
      • Southcoast Physicians Group
      • Contact: Arnoldas Giedrimas, MD
      • Principal Investigator: Arnoldas Giedrimas, MD
  • Michigan
    • Grand Rapids, Michigan, United States, 49525
      • Recruiting
      • Corewell Health
      • Contact: Jawad Wassim, MD
      • Principal Investigator: Jawad Wassim, MD
  • Minnesota
    • Duluth, Minnesota, United States, 55805
      • Recruiting
      • St. Mary's Duluth Clinic Regional Heart Center
      • Contact: Christopher Latanich, MD
      • Principal Investigator: Christopher Latanich, MD
    • Saint Cloud, Minnesota, United States, 56303
      • Recruiting
      • CentraCare Heart and Vascular Center
      • Contact: Hardik Doshi, Dr.
      • Principal Investigator: Hardik Doshi, Dr.
  • New Jersey
    • Morristown, New Jersey, United States, 07932
      • Recruiting
      • Morristown Medical Center
      • Contact: Michael Katz, MD
      • Principal Investigator: Michael Katz, MD
  • New York
    • Flushing, New York, United States, 11355
      • Recruiting
      • New York Hospital Queens
      • Contact: Seth Goldbarg, Dr.
      • Principal Investigator: Seth Goldbarg, Dr.
    • New York, New York, United States, 10021
      • Recruiting
      • Weill Cornell Medical University
      • Contact: Jim Cheung, Dr.
      • Principal Investigator: Jim Cheung, Dr.
    • New York, New York, United States, 14621
      • Recruiting
      • Rochester General Hospital
      • Contact: Dmitry Chuprun, MD
      • Principal Investigator: Dmitry Chuprun, MD
    • Syracuse, New York, United States, 13057
      • Recruiting
      • SUNY-Upstate Medical University
      • Contact: Jorge Romero, MD
      • Principal Investigator: Jorge Romero, MD
  • North Carolina
    • Durham, North Carolina, United States, 27710
      • Recruiting
      • Duke University Medical Center
      • Contact: Daniel Friedman, MD
      • Principal Investigator: Daniel Friedman, MD
  • Ohio
    • Columbus, Ohio, United States, 43219
      • Recruiting
      • Mount Carmel Health System
      • Contact: Kamel Addo, MD
      • Principal Investigator: Kamel Addo, MD
    • Columbus, Ohio, United States, 43214
      • Recruiting
      • OhioHealth Research and Innovation Institute-Riverside Methodist Hospital
      • Contact: Anish Amin, MD
      • Principal Investigator: Anish Amin, MD
  • South Dakota
    • Sioux Falls, South Dakota, United States, 57108
      • Recruiting
      • Avera Heart Hospital of South Dakota
      • Contact: Christopher Stanton, Dr.
      • Principal Investigator: Christopher Stanton, Dr.
  • Tennessee
    • Nashville, Tennessee, United States, 37205
      • Recruiting
      • St.Thomas Health
      • Contact: Ricardo Lugo, MD
      • Principal Investigator: Ricardo Lugo, MD
  • Texas
    • Plano, Texas, United States, 75093
      • Recruiting
      • Heart Hospital Baylor Plano
      • Contact: Mustafa Dohadwala, MD
      • Principal Investigator: Mustafa Dohadwala, MD
    • Tyler, Texas, United States, 75701
      • Recruiting
      • Christus Trinity Mother Frances Health System
      • Contact: Stanislov Weiner, Dr.
      • Principal Investigator: Stanislov Weiner, Dr.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Patient is age 18 years or above, or of legal age to give informed consent specific to state and national law
2. Patient meets a guideline-based indication for a de novo CRT-D device
3. Primary prevention indication for ICD therapy
4. Ischemic or nonischemic cardiomyopathy with LVEF ≤ 35% within 6 months of enrollment (LVEF must be assessed after the subject has been on GDMT for a minimum of 3 months) using an appropriate method of assessment (i.e. Echo, MRI, etc)

5. NYHA class II-IV despite maximally tolerated guideline directed medical therapy (GDMT)* for at least 3 months

   *GDMT is defined as all four drug classes listed below for at least 3 months prior to enrollment unless the investigator provides justification (e.g., contraindicated, not tolerated or cost): Renin Angiotensin System Inhibitors (ACE, ARB, or ARNI) Evidence based betablockers (metoprolol succinate, carvedilol, bisoprolol) Mineralocorticoid antagonists SGLT2 Inhibitor medications

6. Sinus rhythm with left bundle branch block (LBBB) defined as a QRS ≥ 140 ms in men and ≥ 130 ms in women with a predominantly negative deflection (QS or rS in lead V1 and mid QRS notching or slurring in at least two of the following leads: 1, aVL, V1, V2, V5, V6) within 3 months of enrollment
7. Patient is willing to participate in LATITUDE™ NXT remote patient monitoring
8. Patient is willing and capable of providing informed consent and participating in all testing associated with this investigation at an approved study site and at the protocol defined intervals (Note: Use of a legally authorized representative (LAR) is not allowed)
9. Patient plans to remain geographically stable (not permanently moving to another location) and can commit to all study participation requirements (procedure, follow-up visits and testing requirements)

Exclusion Criteria:

1. Persistent or permanent atrial fibrillation (AF) within 3 months prior to enrollment and documented in the medical record
2. Frequent premature ventricular contractions (PVCs), atrial arrhythmias, and/or other causes of expected percentage of cardiac physiologic pacing (CPP) delivery below 95% at the time of enrollment
3. Non-LBBB conduction abnormalities (including right bundle branch block (RBB) or intraventricular conduction delay (IVCD)) within 3 months prior to enrollment
4. Complete, second degree or high degree atrioventricular (AV) block, that requires pacing at the time of enrollment
5. Current or prior pacemaker, ICD or CRT implant (Also includes non-transvenous ICD technology and leadless pacemakers)
6. Prior or planned mechanical or bioprosthetic tricuspid valve replacement
7. Currently receiving or previously received positive inotrope therapy within 3 months prior to enrollment
8. Unstable angina, acute myocardial infarction, coronary artery bypass grafting, or percutaneous coronary intervention within 3 months prior to enrollment
9. History of heart transplantation or left ventricular assist device (LVAD) implantation
10. Less than 1 year of life expectancy at the time of enrollment
11. Anticipated heart transplantation or LVAD implantation within 1 year of enrollment
12. History of ventricular septal defect (VSD)
13. Complex congenital heart disease
14. Documented diagnosis of cardiac amyloidosis
15. Known occlusion or other reason limiting central venous access for transvenous leads
16. Women of childbearing potential who are, or plan to become, pregnant during the course of the study (assessment per investigator's discretion)
17. Patient currently requiring dialysis
18. Patient with known or suspected sensitivity to Dexamethasone Acetate (DXA)
19. Patient with contrast dye allergy or unwilling/able to undergo pre-treatment with steroids and/or diphenhydramine
20. Inability or refusal to comply with the follow-up schedule including subject living at such a distance from the investigational site that attending follow-up visits would be unusually difficult or burdensome
21. Patient is enrolled in any other concurrent study. Co-enrollment into other studies such as observational studies/registries needs prior written approval by BSC. Local mandatory governmental registries are accepted for co-enrollment without approval by BSC.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: CRT Cohort; Participants will be randomized, implanted with a BSC CRT-D device using a Quadripolar lead, and device programmed to the respective cohort.	Device: CRT-D with a Quadripolar LV lead; Participants randomized to this cohort will receive a BSC system: CRT-D, Right Atrial Lead (RA), Defibrillation Lead (RV), Quadripolar LV Lead.
Experimental: LBBA Cohort; Participants will be randomized, implanted with a BSC CRT-D using the INGEVITY+ pace/sense lead implanted in the LBBA, and device programmed to the respective cohort.	Device: CRT-D with INGEVITY+ pace/sense lead; Participants randomized to this cohort will receive a BSC system: CRT-D, Right Atrial Lead (RA), Defibrillation Lead (RV), INGEVITY+ pace/sense Lead (implanted in the LBBA)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Composite of reduction in all-cause mortality, heart transplant, left ventricular assist device, heart failure events, ventricular tachycardia/ventricular fibrillation requiring device therapy or external defibrillation/cardioversion.	The primary effectiveness endpoint is a composite of reduction in all-cause mortality, heart transplant, left ventricular assist device (LVAD), time to first heart failure (HF) events, time to first ventricular tachycardia (VT) / ventricular fibrillation (VF) requiring device therapy or external defibrillation/cardioversion.	Through study completion, up to maximum of 5 years
System-related complication-free rate	The primary safety endpoint is System-related complication-free rate of LBBAP at 12 months. This will be a single-arm analysis of the LBBAP group compared to a performance goal	12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Win ratio composite assessment	Win Ratio Ranking: 1) Death 2) Heart Transplant/LVAD 3) Number of Heart Failure (HF) events (includes in-patient, out-patient and HF re-admission 4) Number of VT/VF episodes requiring device therapy or external defibrillation/cardioversion (one episode per 24 hours 5) Change in MLHFQ (Minnesota Living with Heart Failure Questionnaire) quality of life	Through study completion, up to a maximum of 5 years
Composite of reduction in all-cause mortality, heart transplant, left ventricular assist device, heart failure events, ventricular tachycardia/ ventricular fibrillation requiring device therapy or external defibrillation/cardioversion.	The primary effectiveness endpoint is a composite of reduction in all-cause mortality, heart transplant, left ventricular assist device (LVAD), time to first heart failure (HF) events, time to first ventricular tachycardia (VT) / ventricular fibrillation (VF) requiring device therapy or external defibrillation/cardioversion.	Through study completion, up to a maximum of 5 years
System-related complication-free rate between randomized arms	System-related complication-free rate of LBBAP at 12 months. This will compare the two randomized arms.	12 months

Collaborators and Investigators

• Sponsor: Boston Scientific Corporation

Study record dates

Study Major Dates

• Study Start (Actual): October 22, 2025
• Primary Completion (Estimated): November 1, 2029
• Study Completion (Estimated): November 1, 2029

Study Registration Dates

• First Submitted: June 23, 2025
• First Submitted That Met QC Criteria: July 7, 2025
• First Posted (Actual): July 17, 2025

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: June 3, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Heart Failure; Cardiac Resynchronization Therapy; Primary Prevention; Left Bundle Branch Area Pacing; Conduction System Pacing
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Heart Diseases; Heart Failure
• Other Study ID Numbers: C2403

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes