Ablate and Pace HIS Study

Safety and Efficacy of Distal His Bundle Pacing Compared to Right Ventricular Pacing in Patients With Symptomatic Atrial Fibrillation Undergoing AV Node Ablation With Evidence of Heart Failure, a Randomised Control Study

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and estimates suggest its prevalence is increasing. Despite the advances in AF ablation strategies, the outcome of ablation procedures in persistent AF is still unsatisfactory. In addition, many patients are not candidates for ablation due to advanced age, comorbidities and previous failed ablation procedures.

It is well known that there is no mortality benefit from rhythm versus rate control strategy in AF, therefore the increased number of AV node ablation and pacemaker insertion for patients with symptomatic AF with uncontrolled heart rate. Following AV node ablation, it is understandable that these patients will be paced 100% of the time where the value of physiological pacing will be at its most.

The current standard practice is to pace the right ventricle for this cohort of patients unless they have severe LV systolic dysfunction when a biventricular pacing might be recommended. Previous data showed that RV pacing only can lead to deterioration of LV function, worsening of heart failure symptoms and increased mortality.

HIS bundle pacing is a novel technique of pacing through placing the pacemaker lead on the junction box between the top and bottom chamber of the heart. This will allow the utilisation of the normal/intrinsic HIS Purkinjie (eclectic cables) to stimulate the ventricles. This can offer a physiological pacing modality and reduce pacing induced cardiomyopathy specially in pacing dependent pacing.

The Ablate and Pace HIS Study proposes that the new method of HIS pacing is safe, effective and superior to the existing method of RV pacing in patients with atrial fibrillation who demonstrate signs of heart failure.

Study Overview

• Status: Recruiting
• Conditions: Atrial Fibrillation; HIS Bundle Pacing
• Intervention / Treatment: Procedure: Ablation and Pacemaker Implantation

Detailed Description

The Ablate and Pace HIS Study is a single-centre, prospective randomised single-blinded study, recruiting a sub-population of patients with AF who are deemed not fit for rhythm control strategy. These patients have been referred for a pacemaker implant and AVN node ablation as a symptomatic rate control option.

The study aims to randomise a total of 100 participants into either the RV only pacing arm or the HBP arm. All patients will be implanted with a pacemaker device with one lead positioned in the right ventricle, and only in the HBP arm will an additional lead be positioned on the distal HIS bundle in order to obtain direct HIS-bundle capture. The RV lead will be only be used as a back-up option for the HBP arm if needed.

Participants will undergo AVN ablation either at the same setting or 4-6 weeks later according to clinical indication and operator preference. A double-blinded design will then be employed to investigate the effect of HIS pacing. Endpoint measurements will be taken at Baseline, 4 weeks, 6 months and 12 months post randomisation. Treatment allocation will be blinded to the patients and endpoint assessor. All participants will be informed of their allocated treatment arm at the end of their 12 month follow up visit.

Funding has been provided by Medtronic. The study Sponsor is University Hospitals of Leicester.

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Mokhtar Ibrahim, Dr; Phone Number: 0116 2583887; Email: mokhtar.ibrahim@uhl-tr.nhs.uk

Study Locations

• United Kingdom
  • Leicestershire
    • Leicester, Leicestershire, United Kingdom, LE1 5WW
      • Recruiting
      • University Hospitals Of Leicester Nhs Trust

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Aged 18 or above
• Symptomatic AF, New York Heart Association (NYHA) class II-IV
• Willing to consent for the study

• AF regardless type, deemed not suitable for rhythm control strategy that has been referred for AVN ablation with one of the following:

  1. Impaired LV function, EF <50 %. And or
  2. Raised N-Terminal Pro B-type Natriuretic Peptide ( NT-ProBNP) >365 ng/L

Exclusion Criteria:

• Patient who has already got a pacemaker in situ
• Known severe LVSD when biventricular device is the thought to be the preferred pacing modality
• Females in child bearing period
• Lack of capacity to consent
• Other serious medical condition with life expectancy of less than 1 year
• Less than 18 years
• Unwilling to consent for the study

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Right Ventricular Only Pacing; All study participants will have an RV lead inserted, but this arm will have an RV lead only.	Procedure: Ablation and Pacemaker Implantation; All patients will be implanted with a pacemaker device with one lead positioned in right ventricle (control arm only) and an additional lead will be positioned on the distal (ventricular) HIS bundle if in intervention arm. All patients will undergo ablation.
Other: HIS Bundle Pacing; Participants in this group will have HIS bundle pacing, but in addition will have an RV lead inserted that will serve as a backup alternative in the event HIS bundle pacing is not effective.	Procedure: Ablation and Pacemaker Implantation; All patients will be implanted with a pacemaker device with one lead positioned in right ventricle (control arm only) and an additional lead will be positioned on the distal (ventricular) HIS bundle if in intervention arm. All patients will undergo ablation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants with 20% improvement in 6 minutes-walk distance, AFEQT questionnaire score, and number of steps and distance walked per day assessed by a Fitbit smart watch	20% improvement in all 3 areas	12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Improvement of LV function, LVESV assessed by echocardiogram	Improvement of LV function, LVESV assessed by echocardiogram	12 months
Change in NT-ProBNP level	Change in NT-ProBNP level	12 months
Incidence of hospitalisation for heart failure, need for device upgrade to biventricular pacemaker or mortality	Incidence of hospitalisation for heart failure, need for device upgrade to biventricular pacemaker or mortality	12 months
Pacing parameters	RV threshold/HIS bundle lead will be checked, and this will be documented if it has changed.	12 months
Fluoroscopy time during the device insertion	Fluoroscopy time during the device insertion	During device insertion
Safety consideration: rate of infection, lead failure, displacement or the need for a repeat procedure	Safety consideration: rate of infection, lead failure, displacement or the need for a repeat procedure	12 months

Collaborators and Investigators

• Sponsor: University Hospitals, Leicester
• Collaborators: Medtronic

Study record dates

Study Major Dates

• Study Start (Actual): October 24, 2023
• Primary Completion (Estimated): February 29, 2028
• Study Completion (Estimated): February 29, 2028

Study Registration Dates

• First Submitted: September 21, 2023
• First Submitted That Met QC Criteria: November 21, 2023
• First Posted (Actual): November 30, 2023

Study Record Updates

• Last Update Posted (Actual): January 5, 2026
• Last Update Submitted That Met QC Criteria: December 31, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Atrial Fibrillation; HIS Bundle Pacing
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Atrial Fibrillation
• Other Study ID Numbers: 153856

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

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