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NCT Number: NCT06657170

Hidden Slow Conduction Ablation for Recurrent Atrial Fibrillation: Unmasking the Arrhythmogenic Substrate (Unmask-AF)

Over recent years, pulmonary vein isolation (PVI) procedures have demonstrated progressively enhanced efficacy and safety, resulting in a substantial increase in the number of atrial fibrillation ablations, not only as a first-line treatment but also for repeat procedures. However, there is still a notable lack of randomized evidence in this area, which limits guidance and decision-making in clinical practice. Recently, the investigators found that employing short-coupled atrial extrastimuli revealed highly fragmented or double atrial evoked electrograms (EGMs) in AF patients, termed as hidden slow conduction (HSC). Identifying HSC sites may provide insight into the early identification of the arrhythmogenic substrate, offering a potential target for ablation This multi-center, prospective, randomized, controlled trial will include two arms: one investigational (PV reconnection + HSC) and one control (PV reconnection). All the subjects will be followed for 12 months after the ablation procedure.

The aim of our study is to investigate the impact of ablating HSC sites on arrhythmia recurrence in repeat ablation procedures. The hypothesis is that the additional ablation of HSC zones may improve the freedom from atrial arrhythmia recurrence after repeat ablation procedure.

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Key information

Conditions

Atrial Fibrillation Arrhythmias, Cardiac Cardiovascular Diseases Heart Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms

Age range

40 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Recurrent paroxysmal AF (continuous AF episode lasting longer than 30 s but terminating spontaneously or with intervention within 7 days of onset), recurrent persistent AF (continuous AF episode lasting longer than 7 days but < 1 year) and recurrent long standing persistent AF (continuous AF ≥1 year in duration, in patients where rhythm control management is being pursued)
  • Previous PVI procedure
  • Age > 40 years
  • Willing and capable of providing consent
  • Able and willing to comply with all follow-up testing and requirements

Exclusion criteria

  • Additional left atrial ablations during the previous procedures (es. posterior wall isolation, anterior line, roof line, CFAE and others)
  • Acute illness, active systemic infection, or sepsis
  • Presence of intracardiac thrombus, myxoma, tumor, interatrial baffle or patch or other abnormality that precludes catheter introduction or manipulation.
  • Severe mitral regurgitation
  • Women who are pregnant, lactating, or who are planning to become pregnant during the course of the clinical investigation

Treatment and study plan

Pulmunary veins reconnection plus hidden slow conduction ablation

Procedure

Ablation of pulmonary veins reconnections plus the search and ablation of hidden slow conductions sites (HSC) in the left atrium.

HSC sites are defined as EGMs showing highly fragmented or double electrograms in response atrial triple extrastimulus, presenting normal or fractionated electrogram in the sinus rhythm.

After checking for PV's conduction breakthroughs, point-by point ablation targeting HSC-EGMs will be performed.

The end point for HSC+ ablation will be reached with loss of local capture at a given lesion, pacing from the ablation catheter at high output (10V·2ms).

Pulmunary veins (PV) reconnection ablation only

Procedure

Each vein will be re-assessed by observing PV potentials along the PV ostia and by pacing from the distal bipole of the ablation catheter (10mA at 2ms) within the lesion set with failed capture of the left atrium. In case of PVs reconnection touch-up applications will be performed at the earliest potential site, identified by comparing far-field atrial EGM to near-field local EGM timing, until isolation will be achieved (entrance and exit block).

Primary outcomes

  1. Atrial arrhythmias recurrence

    Time frame: up to 12 moths

    The primary endpoint of the study aims to establish the impact of targeting HSC sites alongside PV gaps in repeat ablation procedures for patients with recurrent AF. Specifically evaluating the freedom from atrial tachyarrhythmia recurrence (documented AF/AT/AFL lasting at least 30s).

Secondary outcomes

  1. Burden of atrial arrhythmias

    Time frame: up to 12 moths

    Arrhythmic burden (average percentage of time in AF/AT in 24h Holter)

  2. incidence of periprocedural complications (pericardial effusion)

    Time frame: up to 12 months

    incidence of periprocedural complications such as pericardial effusion

  3. Use of antiarrhythmic drugs

    Time frame: up to 12 months

    Use of antiarrhythmic drugs after the blanking period of 60 days.

  4. incidence of periprocedural complications (peripheral complication)

    Time frame: up to 12 moths

    incidence of periprocedural complications such as peripheral complication

  5. incidence of periprocedural complications (transient ischemic attack or stroke)

    Time frame: up to 12 months

    incidence of periprocedural complications such as transient ischemic attack or stroke

Other outcomes

  1. Concentration of intramyocardial fat (inFAT) into the HSC points

    Time frame: up to 12 months

    Concentration of intramyocardial fat (inFAT) into the atrial area where we found the HSC points

  2. Procedure features

    Time frame: up to 12 months

    procedure time

  3. Atrial arrhythmias first recurrence

    Time frame: up to 12 months

    Evaluation of the atrial arrhythmias recurrence in patients with isolated PVs underwent HSC sites ablation

  4. Left atrial wall thickness (LAWT) measurement into the HSC points

    Time frame: up to 12 months

    Left atrial wall thickness (LAWT) measurement into the atrial areas where we found the HSC points

  5. procedure features

    Time frame: up to 12 months

    fluoroscopy time

  6. procedure features

    Time frame: up to 12 months

    fluoroscopy dose

  7. procedure features

    Time frame: up to 12 months

    number of radiofrequency (RF) applications

  8. procedure times

    Time frame: up to 12 months

    radiofrequency (RF) total delivery time

Study contacts

Contact information is provided by the study sponsor or research team.

Antonio Berruezo Sanchez, MD, PHD

CONTACT

[email protected]

3384090290

Sponsors and collaborators

Lead sponsor

Centro Medico Teknon

Other

Registry information

Official study title

Hidden Slow Conduction Ablation for Recurrent Atrial Fibrillation: Unmasking the Arrhythmogenic Substrate

Important dates

Study start
2024
Primary completion
2026
Study completion
2027
First posted
Oct 24, 2024
Registry last updated
Dec 12, 2024

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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