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NCT Number: NCT07032064

Evaluation of Electrical and Hemodynamic Effects of Different Pacing Strategies in CRT Candidates

Heart failure patients with delayed electrical activation of the heart often benefit from cardiac resynchronization therapy (CRT). However, traditional CRT using biventricular pacing is not effective in all patients. This study aims to evaluate the acute effects of pacing at different sites within the heart's conduction system-including His bundle pacing, deep septal pacing, left ventricular septal pacing, non-selective left bundle branch pacing, and selective left bundle branch pacing.

We will assess how these pacing strategies improve electrical synchrony and heart function by analyzing ECG parameters, such as QRS duration and QRS area, and measuring hemodynamic response using left ventricular pressure changes. The goal is to identify which pacing site provides the best improvement in heart performance. The study includes patients with left bundle branch block or intraventricular conduction delay, reduced heart function (ejection fraction <35%), and prolonged QRS duration (>150 ms).

This research may help improve the effectiveness of pacing therapy in heart failure patients who are not responding well to current CRT methods.

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Key information

Conditions

Heart Failure CRT and/or ICD Cardiovascular Diseases Heart Diseases

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Zhongshan Hospital, Fudan University

Shanghai, China

About this study

This is a prospective, single-center, crossover study designed to evaluate the acute hemodynamic and electrical effects of pacing at five distinct sites within the conduction system in patients with heart failure and wide QRS complexes. Each participant will undergo temporary pacing at the His bundle, deep septal, left ventricular septal, non-selective left bundle branch, and selective left bundle branch sites.

Pacing sites will be confirmed by fluoroscopic guidance and intracardiac electrogram criteria, including stimulus-to-R' interval and QRS morphology. Hemodynamic response during each pacing mode will be assessed non-invasively using a Finometer device, which continuously measures beat-to-beat blood pressure and provides derived parameters of cardiac function.

The primary objective is to compare the relative hemodynamic benefits and electrical synchrony achieved at each pacing location, with the aim of optimizing lead placement strategies for conduction system pacing in heart failure patients.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

NYHA class I to ambulatory IV despite optimized medical therapy for ≥3 months, LVEF ≤35%, and sinus rhythm with LBBB. LBBB was defined as QRS duration ≥130 ms, QS or rS in lead V1, broad/notched R waves in leads I, aVL, V5-V6, and absence of q waves in V5-V6

Exclusion criteria

second- or third-degree AV block, frequent PVCs, moderate-to-severe aortic stenosis, LV thrombus, or significant peripheral vascular disease

Treatment and study plan

Sequential ventricular pacing at five sites

Procedure

This intervention involves sequential temporary pacing at five distinct ventricular sites within the same patient during a single electrophysiological study. The pacing sites include:His bundle pacing (HBP),Deep septal pacing (DSP),Left ventricular septal pacing (LVSP),Non-selective left bundle branch pacing (NS-LBBP),Selective left bundle branch pacing (SLBBP).

Each pacing modality is tested under identical hemodynamic and electrophysiological conditions using a fixed output and AV delay. Electrical parameters and acute hemodynamic responses are recorded for each site. The study uses a within-subject crossover design, allowing direct intra-individual comparison of different pacing strategies in patients meeting standard CRT indications. No long-term device implantation is involved during this phase of the study.

Primary outcomes

  1. QRSd

    Time frame: within 30 minutes per patient

    QRSd was measured from the onset to the end of the QRS complex

  2. QRSa

    Time frame: within 30 minutes per patient

    QRSa was computed as the sum of the QRS area across three orthogonal vectorcardiographic leads reconstructed using the Kors transformation matrices

  3. Hemodynamic Evaluation

    Time frame: within 30 minutes per patient

    Continuous non-invasive blood pressure was monitored using a Finometer device

Sponsors and collaborators

Lead sponsor

Shanghai Zhongshan Hospital

Other

Registry information

Official study title

Electrical and Hemodynamic Assessment of Pacing Modalities in Patients With Indications for Cardiac Resynchronization Therapy

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Jun 22, 2025
Registry last updated
Jun 22, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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