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Abbott's Cardiac Rhythm Management News, Education, and Information Blog

Part 2: Continuing the Conversation – SyncAV™ Plus CRT Technology Achieves the Narrowest QRS for Improved Response1

Abbott Cardiac Rhythm Management | November 27, 2023

SyncAV technology

Blog 1 of this series told the story of why QRS narrowing is extremely important to patients, and included data demonstrating Abbott's proprietary technology, SyncAV, providing the most QRS narrowing options at implant for patients. SyncAV allows higher patient survival rates, and has demonstrated a 30% cumulative reduction of heart failure hospitalizations at two years.2


At APHRS last year in Singapore, a competitive SyncAV Plus CRT technology poster was presented comparing Abbott technology to Medtronic’s AdaptivCRT algorithm. AdaptivCRT is a rule-based algorithm that can be simulated with LV-only pacing and a dynamic AV delay fixed at 70% of the intrinsic PR interval (-30% SyncAV delta) when Paced AV (PAV) and Sensed AV (SAV) intervals are below 270/220 ms, respectively.* The poster depicts a direct comparison of QRS duration (QRSd) reduction of LV-only pacing with a fixed AV delay and biventricular simultaneous pacing with programmable AV offsets. 3


In the multicenter study, patients with indications for CRT device implantation, left bundle-branch block and intact AV conduction (n=50) were implanted with an Abbott CRT-D or CRT-P device and a quadripolar LV lead. Blinded QRSd measurements were taken from a 12-lead ECG at acute implant. Allied health professionals (AHPs) measured earlist onset of QRS deflection to latest offset with a 12-lead surface ECG.  The following pacing modes were tested:

  • Intrinsic conduction
  • LVSS (70% PR): LV-only single-site pacing with -30% SyncAV fixed AV delay
  • LVSS (SyncAV): LV-only single-site pacing with optimized SyncAV offset achieving minimal QRSd
  • BiV (SyncAV): Biventricular pacing with SyncAV pacing optimized for minimal QRSd.
LBBB QRS narrowing graph

The results emphasize the unique competitive edge SyncAV Plus CRT technology provides with percent delta offsets. 100% of the study cohort achieved their narrowest QRS with SyncAV pacing modes (LVSS and BIV), and the power of RV lead recruitment with fusion pacing and narrowing the QRS for LBBB CRT patients continue to be evident.

graph showing QRSd reduction

View the study here to learn more about achieving the narrowest QRS for patients.

Read more about Abbott's Implantable Cardioverter Defibrillators (ICDs) and Cardiac Resynchronization Therapy (CRT) devices.

Coming Soon: The series continues with key data points at two-year SyncAV follow-up.

Indicates a third-party trademark, which is property of its respective owner.

*AdaptivCRT LV-only pacing applies to cases in which the atrial paced ventricle sensed delay (PR) is below 270ms, atrial sensed ventricle sensed delay (AR) is below 220ms, and intrinsic heart rate is less than 100bpm.


  1. Varma N, O’Donnell D, Bassiouny M, et al. Programming Cardiac Resynchronization Therapy for Electrical Synchrony: Reaching Beyond Left Bundle Branch Block and Left Ventricular Activation Delay. Journal of the American Heart Association (JAHA). Accessed 1/9/2023. https://www.ahajournals.org/doi/full/10.1161/JAHA.117.007489.
  2. Varma, N., Gain in CRT Efficacy with Dynamic Electrical Optimization: Real World Effect of SyncAV™ CRT on Heart Failure Hospitalizations. Poster presented at EHRA. May 2020. Accessed February 1, 2023. https://pubmed.ncbi.nlm.nih.gov/33965608/.
  3. Thibault B, Chow A, Mangual J, et al. Electrical Synchrony Improvement with a Programmable Dynamic Atrioventricular Delay Algorithm. Poster presented at: APHRS; 2022; Singapore.


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