Atrial fibrillation ablation versus heart rate control using conduction system pacing with ablation of the atrioventricular node
| ISRCTN | ISRCTN65526476 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN65526476 |
| ClinicalTrials.gov (NCT) | NCT06207383 |
| Clinical Trials Information System (CTIS) | Nil known |
| Protocol serial number | SNF_2024-D0031 |
| Sponsor | University Hospital of Geneva |
| Funder | Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung |
- Submission date
- 25/07/2024
- Registration date
- 05/08/2024
- Last edited
- 09/06/2025
- Recruitment status
- Recruiting
- Overall study status
- Ongoing
- Condition category
- Circulatory System
Plain English summary of protocol
Background and study aims
Atrial fibrillation (AF) impacts heart function by causing a loss of contraction and deteriorating pump function due to the irregular and often rapid heart rate. The coexistence of AF with heart failure (HF) increases the risk of hospitalization and death. Treatment strategies involve drugs to slow down heart rate or to maintain normal rhythm, catheter intervention to maintain normal rhythm (AF ablation by pulmonary vein isolation), or implantation of a pacemaker with catheter ablation of the atrioventricular node (AVNA) to allow the pacemaker to regulate the heart rate. Conduction system pacing (CSP) involves implanting the pacemaker lead directly into the heart's natural electrical conduction system, maintaining a close to normal contraction of the heart (which allows preservation of pump function).
This study evaluates a strategy of AF ablation against CSP combined with AVNA in patients with AF and HF, as these treatments have never been directly compared. The aim is to determine whether CSP with AVNA has similar rates of heart failure hospitalization and death compared to AF ablation.
Who can participate?
Patients aged 60 years and over who have persistent AF (which is continuously present for over 7 days) and HF (with at least one hospitalization or emergency room / HF clinic visit for HF in the past 2 years and elevated blood markers for HF during this interval)
What does the study involve?
Patients are randomly allocated to either AF ablation or to pacemaker implantation with CSP and AVNA. Both these treatments are performed in routine clinical practice. The patients are then followed up for at least 1 year for clinical events (hospitalizations, deaths), as well as other criteria such as quality of life.
What are the possible benefits and risks of participating?
Participants will be closely followed up. The risks involved are those of the routine procedures of the study.
Where is the study run from?
University Hospital of Geneva (Switzerland)
When is the study starting and how long is it expected to run for?
August 2022 to October 2028
Who is funding the study?
Swiss National Science Fund (Switzerland)
Who is the main contact?
Prof. Haran Burri, haran.burri@hug.ch
Contact information
Public, Scientific, Principal investigator
Cardiology Departement
University Hospital of Geneva
Rue Gabrielle Perret Gentil 4
Geneva
1211
Switzerland
 ORCID ID |
0000-0002-4393-5338 |
|---|---|
| Phone | +41 (0)22 372 72 00 |
| haran.burri@hug.ch |
Study information
| Primary study design | Interventional |
|---|---|
| Study design | Investigator-initiated prospective randomized controlled open-label multicentre study |
| Secondary study design | Randomised controlled trial |
| Study type | Participant information sheet |
| Scientific title | Catheter ABlation of Atrial fibrillation versus atrioventricular nodal ablation with CondUction System pacing in persistent atrial fibrillation and heart failure (ABACUS) |
| Study acronym | ABACUS |
| Study objectives | The investigation seeks primarily to determine whether Conduction System Pacing + Atrioventricular Nodal Ablation (CSP+AVNA) is superior to atrial fibrillation (AF) ablation to reduce the incidence of cardiovascular hospitalization (CVH) or mortality, and whether it is non-inferior to reduce heart failure hospitalization (HFH) or mortality, in patients with persistent atrial fibrillation (AF) and heart failure (HF). |
| Ethics approval(s) |
1. Approved 16/10/2024, Commission cantonale d'éthique de la recherche (CCER) / Cantonal research ethics commission (Rue Adrien-Lachenal 8, Geneva, 1227, Switzerland; +41 (0)22 546 51 01; ccer@etat.ge.ch), ref: 2024-D0031 2. Approved 26/06/2024, HUS Regional Medical Research Ethics Committee (HUS Central Archives, PO Box 200, Marjaniementie 74, Iiris Centre, Helsinki, 00029 HUS, Finland; -; keskuskirjaamo@hus.fi), ref: HUS/4385/2024 |
| Health condition(s) or problem(s) studied | Persistent atrial fibrillation and heart failure |
| Intervention | AF ablation is a routine procedure and may be performed according to the operator’s preference (e.g. radiofrequency ablation, cryoablation, pulsed-field ablation etc) but should include pulmonary vein isolation (PVI) and restoration of sinus rhythm as a goal. Patients may be included in the trial if they have had a single previous PVI, but any further redo procedures during the course of the trial are considered CVH endpoints. Rate and/or rhythm control medical therapy may be continued after the ablation procedure, as deemed necessary. Randomization will be 1:1 using RedCAP with the alternative intervention of CSP + AVNA. CSP implantation with His bundle pacing (HBP) or left bundle branch area pacing (LBBAP) is currently available in routine clinical practice and may be performed according to the operator’s preference but should include conduction system capture or left ventricular septal pacing (LVSP) as a goal. All hardware to be used are commercially available and some will soon receive regulatory approval for CSP. AVNA is a standard procedure which may be performed during the implantation or as a staged procedure, according to operator preference. |
| Intervention type | Procedure/Surgery |
| Primary outcome measure(s) |
The following primary endpoints are assessed at the last follow-up/study closure: |
| Key secondary outcome measure(s) |
The following secondary endpoints are measured using patient medical records at the last follow-up/study closure unless specified otherwise: |
| Completion date | 01/10/2028 |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Senior |
| Lower age limit | 60 Years |
| Upper age limit | 100 Years |
| Sex | All |
| Target sample size at registration | 220 |
| Key inclusion criteria | 1. Persistent AF with symptomatic HF despite medical therapy, considered to be suitable for AF ablation, with at most one previous PVI procedure 2. At least one prior hospital admission, or emergency room / HF clinic visit for HF in the past 2 years, with NT-pro-BNP >1000 pg/ml or BNP >250 pg/ml measured at any timepoint during this interval 3. Previous or current rate or rhythm control drug therapy 4. Considered eligible for CSP implantation as an alternative to AF ablation 5. Age > or = 60 years |
| Key exclusion criteria | 1. NYHA Class IV and systolic blood pressure ≤80 mmHg despite optimized therapy 2. Life expectancy <2 years 3. Need for major surgical intervention 4. Myocardial infarction, stroke or percutaneous coronary intervention within the previous 3 months 5. Previously implanted or planned implantation of CRT device or pacemaker. Implantable cardioverter defibrillator (ICD) implantation without a pacing indication is acceptable. 6. Participation in another controlled trial 7. Inability to sign an informed consent form |
| Date of first enrolment | 24/10/2024 |
| Date of final enrolment | 20/08/2027 |
Locations
Countries of recruitment
- United Kingdom
- England
- Austria
- Belgium
- Bulgaria
- Czech Republic
- Finland
- France
- Germany
- Hungary
- Italy
- Netherlands
- Poland
- Spain
- Switzerland
Study participating centres
Geneva
1211
Switzerland
Bern
3010
Switzerland
Zurich
8091
Switzerland
Basel
4031
Switzerland
Bologna
40138
Italy
Rovigo
45100
Italy
Novara
28100
Italy
Cona
8-44124
Italy
Leipzig
04289
Germany
Bad Oeynhausen
32545
Germany
Bremen
28277
Germany
Valencia
46026
Spain
Barcelona
08036
Spain
Zaragoza
50009
Spain
Madrid
28046
Spain
Prag
100 00
Czech Republic
Budapest
1085
Hungary
Edegem
2650
Belgium
Gent
9000
Belgium
Bruges
8000
Belgium
Krakow
30-688
Poland
Rzeszów
35-623
Poland
Helsinki
FI-00029
Finland
Linz
4020
Austria
Graz
8036
Austria
Sofia
1407
Bulgaria
Maastricht
6229
Netherlands
London
SW3 6LY
United Kingdom
Rouen
76031
France
Results and Publications
| Individual participant data (IPD) Intention to share | Yes |
|---|---|
| IPD sharing plan summary | Stored in publicly available repository |
| IPD sharing plan | The datasets generated during and/or analysed during the current study will be stored in a publicly available repository (Yareta) without personal data identifiers. |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | Participant information sheet | 11/11/2025 | 11/11/2025 | No | Yes |
Editorial Notes
09/06/2025: Internal review.
06/11/2024: The recruitment start date was changed from 01/09/2024 to 24/10/2024.
05/11/2024: Ethics approval details added.
05/08/2024: Study's existence confirmed by the Swiss National Science Foundation.
