Atrial Fibrillation (AF)COSMICNCT07889440
Conduction Breakthrough in the Coronary Sinus Post Endocardial Mitral Isthmus Ablation
An observational study of Atrial Fibrillation (AF) and Atrial Tachycardia, run by Sebastien Knecht.
Trial summary
The goal of this observational study is to learn more about how doctors can create a complete electrical block in the heart during catheter ablation procedures used to treat certain abnormal heart rhythms. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Atrial Fibrillation (AF), Atrial Tachycardia, Paroxysmal AF
- How many people
- 50 participants
- Where
- No sites listed yet
- Study dates
- Oct 2026to Dec 2027
- How long will I take part?
- 1 Day
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: The study population comprises adult patients (≥18 years) with symptomatic AF (paroxysmal, persistent) or perimitral atrial tachycardia (PMAT) undergoing left atrial catheter ablation with a planned first-time mitral isthmus line. Both sexes are eligible without restriction on body weight, BMI, or ethnicity. Patients must have sufficient procedural documentation to allow complete lesion-level data extraction.
Who may be able to join
- Age ≥18 years at the time of the ablation procedure.
- Diagnosis of paroxysmal AF, persistent AF, or perimitral atrial tachycardia.
- Catheter ablation with a planned and performed first-time MI line (lateral mitral annulus to left inferior pulmonary vein) during the index procedure.
- Procedure performed at AZ Sint-Jan Brugge AV.
- Complete and interpretable procedural documentation (electrophysiology system data, fluoroscopy, procedural report).
- For prospective patients: written informed consent obtained prior to the procedure.
Who cannot join
- Subjects meeting any of the following criteria will be excluded:
- Age <18 years.
- No attempted MI line during the index procedure.
- Prior MI line ablation (redo MI line procedures).
- Incomplete or non-interpretable procedural documentation precluding lesion-level analysis.
- Absence of written informed consent (prospective cohort only).
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
The goal of this observational study is to learn more about how doctors can create a complete electrical block in the heart during catheter ablation procedures used to treat certain abnormal heart rhythms. The main questions it aims to answer are:
- How often do electrical signals continue to travel through a blood vessel around the heart after ablation?
- Which ablation applications are most important for achieving a successful electrical block?
- How do different procedural factors affect the success of the treatment?
Participants who undergo a catheter ablation procedure as part of their normal medical care may take part in this study. No additional tests, visits, or procedures will be required. Researchers will collect information that is routinely recorded during the procedure to better understand how electrical signals travel in the heart and how ablation procedures can be improved.
- Conditions
- Atrial Fibrillation (AF), Atrial Tachycardia, Paroxysmal AF, Persisent Atrial Fibrillation
- Keywords
- Catheter Ablation, Mitral Isthmus Ablation, Coronary Sinus Conduction, Paroxysmal Atrial Fibrillation, Persisent Atrial Fibrillation, Perimitral Atrial Tachycardia
- Medical subject headings
- Atrial Fibrillation
What is being measured
The primary outcome is the main question the study is designed to answer.
Anatomical Zone of the Effective Coronary Sinus RF Application
Anatomical location of the first epicardial radiofrequency (RF) application within the coronary sinus that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: categorical variable (Superior, Anterior, Inferior, or Posterior zone).
Measured: During the index ablation procedure
RF Power of the Effective Coronary Sinus RF Application
RF power delivered during the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: Watts (W).
Measured: During the index ablation procedure
Duration of the Effective Coronary Sinus RF Application
Duration of the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: seconds (s).
Measured: During the index ablation procedure
Contact Force of the Effective Coronary Sinus RF Application
Mean contact force recorded during the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: grams (g).
Measured: During the index ablation procedure
Ablation Index of the Effective Coronary Sinus RF Application
Ablation Index value of the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block.
Measured: During the index ablation procedure
Cumulative Epicardial RF Time to Mitral Isthmus Block
Total cumulative duration of epicardial coronary sinus RF applications delivered up to and including the first application associated with achievement of bidirectional mitral isthmus conduction block. Unit: seconds (s).
Measured: During the index ablation procedure
Relative Order of the Effective Coronary Sinus RF Application
Sequence number of the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: lesion number (n).
Measured: During the index ablation procedure
Secondary outcomes (12)
Number of Epicardial Coronary Sinus RF Applications
Total number of epicardial radiofrequency (RF) applications delivered within the coronary sinus during the ablation procedure. Unit: number of RF applications (n).
Measured: During the index ablation procedure
Distribution of Epicardial Coronary Sinus RF Applications
Number of epicardial RF applications delivered within each of the 8 predefined anatomical coronary sinus zones. Unit: number of RF applications per anatomical zone (n).
Measured: During the index ablation procedure
Cumulative Epicardial Coronary Sinus RF Time
Total cumulative duration of all epicardial RF applications delivered within the coronary sinus. Unit: seconds (s).
Measured: During the index ablation procedure
Total Procedure RF Time
Total duration of radiofrequency energy delivery during the entire ablation procedure. Unit: seconds (s).
Measured: During the index ablation procedure
Total Fluoroscopy Time
Total fluoroscopy time during the ablation procedure. Unit: minutes (min).
Measured: During the index ablation procedure
Total Procedure Duration
Total duration of the ablation procedure. Unit: minutes (min).
Measured: During the index ablation procedure
Achievement of Bidirectional Mitral Isthmus Block Without Epicardial Coronary Sinus Ablation
Proportion of procedures in which bidirectional mitral isthmus (MI) conduction block is achieved without delivery of epicardial RF applications within the coronary sinus. Unit: percentage of procedures (%).
Measured: During the index ablation procedure
Number of Coronary Sinus RF Applications According to VOM-EI Success
Difference in the total number of epicardial coronary sinus RF applications between procedures with successful Vein of Marshall ethanol infusion (VOM-EI) and procedures with failed or absent VOM-EI. Unit: number of RF applications (n).
Measured: During the index ablation procedure
Distribution of Coronary Sinus RF Applications According to VOM-EI Success
Difference in the distribution of epicardial coronary sinus RF applications across the 8 predefined anatomical zones between procedures with successful VOM-EI and procedures with failed or absent VOM-EI. Unit: number of RF applications per anatomical zone (n).
Measured: During the index ablation procedure
Cumulative Epicardial RF Time According to VOM-EI Success
Difference in cumulative epicardial coronary sinus RF time between procedures with successful VOM-EI and procedures with failed or absent VOM-EI. Unit: seconds (s).
Measured: During the index ablation procedure
Time to Mitral Isthmus Block According to VOM-EI Success
Difference in time to achievement of bidirectional mitral isthmus conduction block between procedures with successful VOM-EI and procedures with failed or absent VOM-EI. Unit: seconds (s).
Measured: During the index ablation procedure
Incidence of Periprocedural Complications
Incidence of periprocedural complications related to mitral isthmus ablation, epicardial coronary sinus RF ablation, or Vein of Marshall ethanol infusion (VOM-EI), including pericardial effusion or cardiac tamponade, coronary sinus dissection or perforation, coronary artery injury or spasm, stroke or transient ischemic attack (TIA), phrenic nerve palsy, steam pop, and complications specifically related to VOM-EI. Unit: percentage of participants with at least one periprocedural complication (%).
Measured: During the index ablation procedure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Oct 2026
- Study startOct 2026 (estimated)
- Primary completionDec 2027 (estimated)
- Study completionDec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Atrial Fibrillation (AF)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 50 participants (estimated)
- Target duration
- 1 Day
Sponsor and investigators
- Lead sponsor
- Sebastien Knecht
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Sebastien Knecht, AZ Sint-Jan AV
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07889440
- Sponsor's protocol ID
- COSMIC
- Acronym
- COSMIC
- Status last verified
- Sep 2026
- First submitted
- 16 Oct 2026
- Last updated
- 22 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Conduction Breakthrough in the Coronary Sinus Post Endocardial Mitral Isthmus Ablation
- ClinicalTrials.gov ID
- NCT07889440
- Acronym / sponsor ID
- COSMIC / COSMIC
- Conditions
- Atrial Fibrillation (AF), Atrial Tachycardia, Paroxysmal AF, Persisent Atrial Fibrillation
- Keywords
- Catheter Ablation, Mitral Isthmus Ablation, Coronary Sinus Conduction, Paroxysmal Atrial Fibrillation, Persisent Atrial Fibrillation, Perimitral Atrial Tachycardia
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- Sebastien KnechtUniversity, hospital or other
- Study start
- Oct 2026 (estimated)
- Primary completion
- Dec 2027 (estimated)
- Study completion
- Dec 2027 (estimated)
- First posted
- 22 Oct 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this observational study is to learn more about how doctors can create a complete electrical block in the heart during catheter ablation procedures used to treat certain abnormal heart rhythms. The main questions it aims to answer are:
- How often do electrical signals continue to travel through a blood vessel around the heart after ablation?
- Which ablation applications are most important for achieving a successful electrical block?
- How do different procedural factors affect the success of the treatment?
Participants who undergo a catheter ablation procedure as part of their normal medical care may take part in this study. No additional tests, visits, or procedures will be required. Researchers will collect information that is routinely recorded during the procedure to better understand how electrical signals travel in the heart and how ablation procedures can be improved.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 1 Day
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- The study population comprises adult patients (≥18 years) with symptomatic AF (paroxysmal, persistent) or perimitral atrial tachycardia (PMAT) undergoing left atrial catheter ablation with a planned first-time mitral isthmus line. Both sexes are eligible without restriction on body weight, BMI, or ethnicity. Patients must have sufficient procedural documentation to allow complete lesion-level data extraction.
Key inclusion criteria (6 listed)
- Age ≥18 years at the time of the ablation procedure.
- Diagnosis of paroxysmal AF, persistent AF, or perimitral atrial tachycardia.
- Catheter ablation with a planned and performed first-time MI line (lateral mitral annulus to left inferior pulmonary vein) during the index procedure.
- Procedure performed at AZ Sint-Jan Brugge AV.
- Complete and interpretable procedural documentation (electrophysiology system data, fluoroscopy, procedural report).
Key exclusion criteria (6 listed)
- Subjects meeting any of the following criteria will be excluded:
- Age <18 years.
- No attempted MI line during the index procedure.
- Prior MI line ablation (redo MI line procedures).
- Incomplete or non-interpretable procedural documentation precluding lesion-level analysis.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Anatomical Zone of the Effective Coronary Sinus RF Application
Time frame: During the index ablation procedure
Anatomical location of the first epicardial radiofrequency (RF) application within the coronary sinus that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: categorical variable (Superior, Anterior, Inferior, or Posterior zone).
RF Power of the Effective Coronary Sinus RF Application
Time frame: During the index ablation procedure
RF power delivered during the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: Watts (W).
Duration of the Effective Coronary Sinus RF Application
Time frame: During the index ablation procedure
Duration of the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: seconds (s).
Contact Force of the Effective Coronary Sinus RF Application
Time frame: During the index ablation procedure
Mean contact force recorded during the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: grams (g).
Ablation Index of the Effective Coronary Sinus RF Application
Time frame: During the index ablation procedure
Ablation Index value of the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block.
Cumulative Epicardial RF Time to Mitral Isthmus Block
Time frame: During the index ablation procedure
Total cumulative duration of epicardial coronary sinus RF applications delivered up to and including the first application associated with achievement of bidirectional mitral isthmus conduction block. Unit: seconds (s).
Relative Order of the Effective Coronary Sinus RF Application
Time frame: During the index ablation procedure
Sequence number of the first epicardial coronary sinus RF application that is temporally associated with achievement of bidirectional mitral isthmus conduction block. Unit: lesion number (n).
12 secondary outcomes
Number of Epicardial Coronary Sinus RF Applications
Time frame: During the index ablation procedure
Distribution of Epicardial Coronary Sinus RF Applications
Time frame: During the index ablation procedure
Cumulative Epicardial Coronary Sinus RF Time
Time frame: During the index ablation procedure
Total Procedure RF Time
Time frame: During the index ablation procedure
Total Fluoroscopy Time
Time frame: During the index ablation procedure
Total Procedure Duration
Time frame: During the index ablation procedure
Achievement of Bidirectional Mitral Isthmus Block Without Epicardial Coronary Sinus Ablation
Time frame: During the index ablation procedure
Number of Coronary Sinus RF Applications According to VOM-EI Success
Time frame: During the index ablation procedure
Distribution of Coronary Sinus RF Applications According to VOM-EI Success
Time frame: During the index ablation procedure
Cumulative Epicardial RF Time According to VOM-EI Success
Time frame: During the index ablation procedure
Time to Mitral Isthmus Block According to VOM-EI Success
Time frame: During the index ablation procedure
Incidence of Periprocedural Complications
Time frame: During the index ablation procedure
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Oct 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Questions about this trial
What is this clinical trial studying?
An observational study of Atrial Fibrillation (AF) and Atrial Tachycardia, run by Sebastien Knecht.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 22 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Emma Christiaen (+3250453293, SM-SJ-Cardiologie-Studies@azsintjan.be), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Anatomical Zone of the Effective Coronary Sinus RF Application (time frame: During the index ablation procedure). The study lists 7 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Oct 2026.