Impact of Atrioventricular Delay Optimization on Ventricular Function in Conduction System Pacing (OPTI-CSP)

The Effect Of Atrioventricular Delay Optimization On Ventricular Functions In Patients Undergoing Conduction System Pacing

Conduction system pacing has emerged as a physiological pacing strategy that preserves ventricular electrical activation and minimizes pacing-induced dyssynchrony. However, the optimal atrioventricular delay setting in patients undergoing conduction system pacing remains uncertain.

This study aims to evaluate the effects of individualized echocardiography-guided atrioventricular delay optimization on ventricular function and hemodynamic performance in patients with conduction system pacing. Echocardiographic parameters including global longitudinal strain, left ventricular ejection fraction, left ventricular outflow tract velocity-time integral, cardiac output, and diastolic function indices will be assessed before and after atrioventricular delay optimization.

The study will investigate whether optimization of atrioventricular timing provides additional mechanical and hemodynamic benefits beyond physiological ventricular activation achieved by conduction system pacing alone.

Study Overview

• Status: Completed
• Conditions: Atrioventricular Block; Conduction System Pacing
• Intervention / Treatment: Device: Echocardiography-Guided Atrioventricular Delay Optimization

Detailed Description

Conduction system pacing (CSP), including His bundle pacing and left bundle branch area pacing, has emerged as a physiological pacing strategy capable of preserving ventricular electrical activation and reducing pacing-induced dyssynchrony. Compared with conventional right ventricular pacing, CSP has been associated with improved electrical synchrony, ventricular function, and clinical outcomes.

Despite restoration of physiological ventricular activation, optimal atrioventricular (AV) coupling remains essential for maximizing ventricular filling, stroke volume, and overall cardiac performance. Inadequate AV timing may impair diastolic filling, reduce atrial contribution to ventricular preload, and limit the hemodynamic benefits achieved by physiological pacing. While AV delay optimization has been extensively investigated in cardiac resynchronization therapy, data regarding its role in patients undergoing CSP remain limited.

The present study evaluates the impact of individualized echocardiography-guided AV delay optimization on ventricular mechanical performance and hemodynamic parameters in patients with CSP implanted for atrioventricular block. Comprehensive transthoracic echocardiographic assessment will be performed before and after AV delay optimization. Measurements include left ventricular ejection fraction, global longitudinal strain, left ventricular outflow tract velocity-time integral, cardiac output, chamber dimensions, pulmonary artery systolic pressure, and diastolic function parameters.

The primary objective is to determine the effect of AV delay optimization on global longitudinal strain. Secondary objectives include assessment of changes in left ventricular systolic function, hemodynamic performance, and diastolic parameters. The study aims to provide additional evidence regarding the importance of individualized AV programming in patients undergoing conduction system pacing.

• Study Type: Interventional
• Enrollment (Actual): 39
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Yıldırım
    • Bursa, Yıldırım, Turkey (Türkiye)
      • University of Health Sciences Bursa Yuksek Ihtisas Training and Research Hospital

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

Age between 18 and 80 years Permanent conduction system pacing implantation for atrioventricular block At least 1 month elapsed since device implantation Sinus rhythm at the time of enrollment Left ventricular ejection fraction >40% Adequate echocardiographic image quality for comprehensive assessment Ability and willingness to provide informed consent

Exclusion Criteria:

Permanent or persistent atrial fibrillation Significant valvular heart disease Active malignancy Severe systemic illness with limited life expectancy Sinus node dysfunction requiring alternative pacing strategies Inadequate echocardiographic image quality Inability to comply with study procedures Refusal to participate in the study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Echocardiography-Guided AV Delay Optimization; Participants with conduction system pacing undergo individualized echocardiography-guided atrioventricular delay optimization. Echocardiographic and hemodynamic parameters are assessed before and after optimization.	Device: Echocardiography-Guided Atrioventricular Delay Optimization; Atrioventricular delay settings are individually optimized using echocardiographic assessment of transmitral inflow and ventricular filling patterns. Device programming is adjusted to achieve optimal atrioventricular coupling and ventricular performance.; Other Names: AV Delay Optimization

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Global Longitudinal Strain (GLS)	Assessment of left ventricular global longitudinal strain using two-dimensional speckle tracking echocardiography before and after atrioventricular delay optimization.	Immediately before and immediately after atrioventricular delay optimization.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Left Ventricular Outflow Tract Velocity-Time Integral (LVOT VTI)	Assessment of forward stroke volume using pulsed-wave Doppler measurements at the left ventricular outflow tract.	Immediately before and immediately after atrioventricular delay optimization.
Left Ventricular Ejection Fraction (LVEF)	Assessment of left ventricular systolic function using the biplane Simpson method.	Immediately before and immediately after atrioventricular delay optimization.

Collaborators and Investigators

• Sponsor: Bursa Yuksek Ihtisas Training and Research Hospital
• Investigators: Study Chair: Ahmet Tütüncü, Bursa Yuksek Ihtisas Training and Research Hospital

Publications and helpful links

General Publications

• Glikson et al. ESC Clinical Consensus Statement on Conduction System Pacing Glikson M, Vijayaraman P, Ellenbogen KA, et al. European Society of Cardiology (ESC) clinical consensus statement on indications for conduction system pacing. Europace. 2025;27(4):euaf050. Coluccia et al. Optimization of the Atrioventricular Delay in Conduction System Pacing Coluccia G, Padeletti L, Della Bella P, et al. Optimization of the atrioventricular delay in conduction system pacing. J Cardiovasc Electrophysiol. 2023;34(6):1441-1451. Pujol-López et al. LEVEL-AT Trial Secondary Findings Pujol-López M, et al. Longitudinal comparison of dyssynchrony correction and strain improvement by conduction system pacing: LEVEL-AT trial secondary findings. Eur Heart J Cardiovasc Imaging. 2024;25(10):1394-1404. Hua et al. Comparison of Left Bundle Branch and His Bundle Pacing Hua W, Fan X, Niu H, et al. Comparison of left bundle branch and His bundle pacing in bradycardia patients. JACC Clin Electrophysiol. 2020;6(10):1291-1299. Sweeney et al. Adverse Effect of Ventricular Pacing Sweeney MO, Hellkamp AS, Ellenbogen KA, et al. Adverse effect of ventricular pacing on heart failure and atrial fibrillation among patients with normal baseline QRS duration. Circulation. 2003;107(23):2932-2937.

Study record dates

Study Major Dates

• Study Start (Actual): October 6, 2025
• Primary Completion (Actual): February 17, 2026
• Study Completion (Actual): February 17, 2026

Study Registration Dates

• First Submitted: May 29, 2026
• First Submitted That Met QC Criteria: May 29, 2026
• First Posted (Actual): June 3, 2026

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: May 29, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Ventricular Function; Global Longitudinal Strain; Conduction System Pacing; Atrioventicular Block; Atrioventricular Delay Optimization; Mechanical Resynchronization
• Additional Relevant MeSH Terms: Cardiac Conduction System Disease; Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Heart Block; Pathological Conditions, Signs and Symptoms; Atrioventricular Block
• Other Study ID Numbers: BYIEAH-CSP-BMU-2025; 2024-TBEK 2025/07-12 (Other Identifier: SBÜ Bursa Yüksek İhtisas Eğitim ve Araştırma Hastanesi)

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: No