Atrial FibrillationPHENOTYPE-AFNCT03394404
ECG-I Phenotyping of Persistent AF Based on Driver Distribution to Predict Response to Pulmonary Vein Isolation
A study testing ECG-I mapping and PVI in people with Atrial Fibrillation, run by Barts & The London NHS Trust at 1 site in United Kingdom.
Trial summary
Atrial fibrillation (AF) is an irregular heart rhythm associated with significant morbidity and mortality. The pulmonary veins (the blood vessels carrying blood from the lungs into the left atrium) have been shown to send electrical signals into the heart that can cause and maintain AF. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Atrial Fibrillation
- What is being tested?
- ECG-I mapping and PVI
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 140 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 8 Jan 2018to 31 Mar 2021
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients diagnosed with Persistent AF (i.e. episodes of AF that are continuous for > 1 week or have required DC cardioversion)
- Willing for ablation.
- Age between 18 to 80.
- left atrial diameter <5 cm
- left ventricular function >40%.
- New York Heart Association class < 3.
Who cannot join
- Persistent AF diagnosed > 2 years ago
- left atrial diameter > 5 cm
- Severe left ventricular impairment (EF < 40%)
- New York Heart Association class 3 or 4 heart failure
- Known hypertrophic cardiomyopathy, cardiac sarcoid, or arrythmogenic ventricular cardiomyopathy.
- Known inherited arrhythmia such as Brugada or long QT syndromes
Show all 20Show fewer
- Valvular disease that is more than moderate
- History of valve replacement (metallic or tissue)
- History of congenital heart disease (other than patent foramen ovale)
- Previous left atrial ablation (percutaneous or surgical)
- Cardiac surgery or percutaneous coronary intervention within the last 3 months.
- Myocardial infarction or unstable angina within the last 3 months.
- Unwillingness for ablation
- Unwillingness to be involved in study
- Suspected reversible cause of AF
- Any other contraindication to catheter ablation
- Age < 18 yrs or > 80 years
- Pregnancy
- Morbid obesity (defined as BMI >40)
- Any other medical problem likely to cause death within the next 18 months
Trial locations and contacts
1 site in 1 country.
About this study
Atrial fibrillation (AF) is an irregular heart rhythm associated with significant morbidity and mortality. The pulmonary veins (the blood vessels carrying blood from the lungs into the left atrium) have been shown to send electrical signals into the heart that can cause and maintain AF. Pulmonary vein Isolation (PVI) is an established treatment where catheters are passed into the atria of the heart to deliver lines of scar to electrically isolate the pulmonary veins preventing them from transmitting these electrical signals into the left atrium.
The ECG-I is a system which involves wearing a jacket with many ECG electrodes to record electrical activity from the surface of the body. A CT scan then shows where these electrodes are relative to the atria, and computer modelling is used to reconstruct the movements of electricity on the surface of the heart and therefore identifying where the drivers (tissue causing and maintaining AF) are located.
Read more
Unfortunately, not all patients respond to PVI due to the drivers of AF being located in areas other than within the Pulmonary Veins. Identifying the drivers of AF is very difficult and the role they play has yet to be proved scientifically.
The investigators intend to enroll 100 patients with persistent AF and perform atrial mapping using the ECG-I system. Solely pulmonary vein isolation will be performed. Patients will be followed up to see if the distribution of drivers as predicted by the ECG-I predicts outcomes. This may improve patient selection for this procedure.
Read the detailed description
Atrial Fibrillation (AF) is the commonest heart rhythm disturbance and is associated with significant morbidity and mortality. Catheter ablation (CA) is a procedure where catheters (leads) are passed into the heart and energy is used to disrupt and isolate (by freezing or cauterising) heart tissue causing AF. CA is an established therapy for AF. Success rates for CA for paroxysmal AF lies in the region of 70% or better. However, success rates for persistent AF is much lower and estimates lie in the region of 30-60%.
Current CA protocols for AF centre on isolating the pulmonary veins (the pulmonary veins drain into the left atrium) which have been proven to trigger AF. Pulmonary Vein Isolation (PVI) ablation alone seems sufficient to remove the trigger for the vast majority of patients with paroxysmal AF. However, in patients with persistent AF it is common for AF to continue after the pulmonary veins have been electrically isolated.
The difference in success rates between the paroxysmal and persistent form of AF is thought to be due to changes within the heart atria after AF has been established for some time. In persistent AF the atria dilate and remodel structurally and electrically, and therefore the maintenance of persistent AF differs from paroxysmal AF.
Persistent AF is thought to be maintained by focal sources, whether rotors or sites of radial activation. Currently, targeting other sites within the atria in addition to PVI such as fractionated electrograms (areas of electrical activity) are thought to be imprecise and require extensive ablation. Often AF will persist despite targeting additional sites within the atria.
One particular challenge is to select patients likely to benefit from CA. CA carries an approximate less than 1% risk of life threatening complication. Therefore being able to select suitable patients is desirable in order to prevent unnecessary procedures.
Currently clinical characteristics of patients or structural imaging have limited accuracy in selecting patients likely to benefit from CA. Mapping studies have shown that patients with persistent AF who have higher frequency signals near the pulmonary veins than being distributed in the left atrial body are more likely to terminate to sinus rhythm (normal heart rhythm) with PVI alone and to maintain sinus rhythm.
Studies have suggested that patients undergoing standard PVI ablation procedures for persistent AF who have coincidental interruption of drivers have a far better long term outcome. This suggests that the characteristics of atrial heart tissue and electrical activation patterns maintaining AF are likely to determine the response to ablation therefore it may be possible to determine more directly and accurately the likelihood of success by performing non-invasive mapping of the atria using the ECG-I.
It appears that a proportion of patients with persistent AF will maintain sinus rhythm long term after undergoing AF CA with standard PVI protocols alone. PVI can now be achieved quickly and safely using technologies such as the Cryoballoon (A freezing technology). Identification of patients that are likely to respond to PVI alone is therefore of great interest as it (1) identifies patients that may respond to a conservative strategy, and (2) in the absence of an effective strategy beyond PVI may allow de-selection of patients unlikely to benefit from ablation at all.
- Conditions
- Atrial Fibrillation
- Being tested
- ECG-I mapping and PVI
- Keywords
- ECG-I Mapping Pulmonary Vein Isolation
- Medical subject headings
- Atrial Fibrillation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
ECG-I mapping and PVIDevice
ECG-I mapping and PVI
| Study group | Role | What they receive |
|---|---|---|
| ECG-I mapping and PVI | Experimental | ECG-I mapping and PVI Receives: Device: ECG-I mapping and PVI |
What is being measured
The primary outcome is the main question the study is designed to answer.
Freedom from Atrial Arrhythmia and association with distribution of drivers of AF
All patients will undergo mapping with ECG-I during their procedure. The number of drivers and their locations will be collected. Patients who remain free from AF at 12 months will be compared to patients who relapsed comparing the number and location of these drivers.
Measured: Performed 12-14 months post procedure
Secondary outcomes (1)
Impact of pulmonary vein isolation on drivers of AF
Patients will undergo ECG-I mapping of their AF at baseline and then immediately after pulmonary vein isolation. The number of drivers and locations will be collected at both points and these will be compared to assess the impact of PVI.
Measured: During AF Catheter Ablation
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Jan 2018
- Study start8 Jan 2018
- Primary completion31 Mar 2021
- Study completion31 Mar 2021
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Atrial FibrillationStudies 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 140 participants (actual)
Sponsor and investigators
- Lead sponsor
- Barts & The London NHS Trust
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Ross Hunter, Principal investigator, Barts Heart Centre
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03394404
- Sponsor's protocol ID
- 218367-1
- Acronym
- PHENOTYPE-AF
- Status last verified
- Oct 2024
- First submitted
- 4 Dec 2017
- Last updated
- 22 Oct 2024
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Undecided
Publications
Dhillon GS, Honarbakhsh S, Graham A, Abbass H, Welch S, Daw H, Sporton S, Providencia R, Chow A, Earley MJ, Lowe M, Lambiase PD, Schilling RJ, Hunter RJ. ECG-I phenotyping of persistent AF based on driver burden and distribution to predict response to pulmonary vein isolation (PHENOTYPE-AF). J Cardiovasc Electrophysiol. 2022 Nov;33(11):2263-2273. doi: 10.1111/jce.15644. Epub 2022 Aug 16.
PubMed 35924481Dhillon GS, Ahluwalia N, Honarbakhsh S, Graham A, Creta A, Abbass H, Chow A, Earley MJ, Lambiase PD, Schilling RJ, Hunter RJ. Impact of adenosine on mechanisms sustaining persistent atrial fibrillation: Analysis of contact electrograms and non-invasive ECGI mapping data. PLoS One. 2021 Mar 25;16(3):e0248951. doi: 10.1371/journal.pone.0248951. eCollection 2021.
PubMed 33765054Dhillon GS, Schilling RJ, Honarbakhsh S, Graham A, Abbass H, Waddingham P, Sawhney V, Creta A, Sporton S, Finlay M, Providencia R, Chow A, Earley MJ, Lowe M, Lambiase PD, Hunter RJ. Impact of pulmonary vein isolation on mechanisms sustaining persistent atrial fibrillation: Predicting the acute response. J Cardiovasc Electrophysiol. 2020 Apr;31(4):903-912. doi: 10.1111/jce.14392. Epub 2020 Mar 1.
PubMed 32048786
Study at a glance
From the registry record, last updated by the sponsor on 22 Oct 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- ECG-I Phenotyping of Persistent AF Based on Driver Distribution to Predict Response to Pulmonary Vein Isolation
- ClinicalTrials.gov ID
- NCT03394404
- Acronym / sponsor ID
- PHENOTYPE-AF / 218367-1
- Conditions
- Atrial Fibrillation
- Keywords
- ECG-I Mapping Pulmonary Vein Isolation
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 140 participants (actual)
- Lead sponsor
- Barts & The London NHS TrustUniversity, hospital or other
- Study start
- 8 Jan 2018 (actual)
- Primary completion
- 31 Mar 2021 (actual)
- Study completion
- 31 Mar 2021 (actual)
- First posted
- 9 Jan 2018 (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.
Atrial fibrillation (AF) is an irregular heart rhythm associated with significant morbidity and mortality. The pulmonary veins (the blood vessels carrying blood from the lungs into the left atrium) have been shown to send electrical signals into the heart that can cause and maintain AF. Pulmonary vein Isolation (PVI) is an established treatment where catheters are passed into the atria of the heart to deliver lines of scar to electrically isolate the pulmonary veins preventing them from transmitting these electrical signals into the left atrium.
The ECG-I is a system which involves wearing a jacket with many ECG electrodes to record electrical activity from the surface of the body. A CT scan then shows where these electrodes are relative to the atria, and computer modelling is used to reconstruct the movements of electricity on the surface of the heart and therefore identifying where the drivers (tissue causing and maintaining AF) are located.
Unfortunately, not all patients respond to PVI due to the drivers of AF being located in areas other than within the Pulmonary Veins. Identifying the drivers of AF is very difficult and the role they play has yet to be proved scientifically.
The investigators intend to enroll 100 patients with persistent AF and perform atrial mapping using the ECG-I system. Solely pulmonary vein isolation will be performed. Patients will be followed up to see if the distribution of drivers as predicted by the ECG-I predicts outcomes. This may improve patient selection for this procedure.
Detailed description
Atrial Fibrillation (AF) is the commonest heart rhythm disturbance and is associated with significant morbidity and mortality. Catheter ablation (CA) is a procedure where catheters (leads) are passed into the heart and energy is used to disrupt and isolate (by freezing or cauterising) heart tissue causing AF. CA is an established therapy for AF. Success rates for CA for paroxysmal AF lies in the region of 70% or better. However, success rates for persistent AF is much lower and estimates lie in the region of 30-60%.
Current CA protocols for AF centre on isolating the pulmonary veins (the pulmonary veins drain into the left atrium) which have been proven to trigger AF. Pulmonary Vein Isolation (PVI) ablation alone seems sufficient to remove the trigger for the vast majority of patients with paroxysmal AF. However, in patients with persistent AF it is common for AF to continue after the pulmonary veins have been electrically isolated.
The difference in success rates between the paroxysmal and persistent form of AF is thought to be due to changes within the heart atria after AF has been established for some time. In persistent AF the atria dilate and remodel structurally and electrically, and therefore the maintenance of persistent AF differs from paroxysmal AF.
Persistent AF is thought to be maintained by focal sources, whether rotors or sites of radial activation. Currently, targeting other sites within the atria in addition to PVI such as fractionated electrograms (areas of electrical activity) are thought to be imprecise and require extensive ablation. Often AF will persist despite targeting additional sites within the atria.
One particular challenge is to select patients likely to benefit from CA. CA carries an approximate less than 1% risk of life threatening complication. Therefore being able to select suitable patients is desirable in order to prevent unnecessary procedures.
Currently clinical characteristics of patients or structural imaging have limited accuracy in selecting patients likely to benefit from CA. Mapping studies have shown that patients with persistent AF who have higher frequency signals near the pulmonary veins than being distributed in the left atrial body are more likely to terminate to sinus rhythm (normal heart rhythm) with PVI alone and to maintain sinus rhythm.
Studies have suggested that patients undergoing standard PVI ablation procedures for persistent AF who have coincidental interruption of drivers have a far better long term outcome. This suggests that the characteristics of atrial heart tissue and electrical activation patterns maintaining AF are likely to determine the response to ablation therefore it may be possible to determine more directly and accurately the likelihood of success by performing non-invasive mapping of the atria using the ECG-I.
It appears that a proportion of patients with persistent AF will maintain sinus rhythm long term after undergoing AF CA with standard PVI protocols alone. PVI can now be achieved quickly and safely using technologies such as the Cryoballoon (A freezing technology). Identification of patients that are likely to respond to PVI alone is therefore of great interest as it (1) identifies patients that may respond to a conservative strategy, and (2) in the absence of an effective strategy beyond PVI may allow de-selection of patients unlikely to benefit from ablation at all.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| ECG-I mapping and PVI | Experimental | Device: ECG-I mapping and PVIECG-I mapping and PVI |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Patients diagnosed with Persistent AF (i.e. episodes of AF that are continuous for > 1 week or have required DC cardioversion)
- Willing for ablation.
- Age between 18 to 80.
- left atrial diameter <5 cm
- left ventricular function >40%.
Key exclusion criteria (20 listed)
- Persistent AF diagnosed > 2 years ago
- left atrial diameter > 5 cm
- Severe left ventricular impairment (EF < 40%)
- New York Heart Association class 3 or 4 heart failure
- Known hypertrophic cardiomyopathy, cardiac sarcoid, or arrythmogenic ventricular cardiomyopathy.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| ECG-I mapping and PVIECG-I mapping and PVI | Device | ECG-I mapping and PVI |
Primary outcome
Freedom from Atrial Arrhythmia and association with distribution of drivers of AF
Time frame: Performed 12-14 months post procedure
All patients will undergo mapping with ECG-I during their procedure. The number of drivers and their locations will be collected. Patients who remain free from AF at 12 months will be compared to patients who relapsed comparing the number and location of these drivers.
1 secondary outcome
Impact of pulmonary vein isolation on drivers of AF
Time frame: During AF Catheter Ablation
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Oct 2024.
- Derived from this study: PubMed 35924481Dhillon GS, Honarbakhsh S, Graham A, Abbass H, Welch S, Daw H, Sporton S, Providencia R, Chow A, Earley MJ, Lowe M, Lambiase PD, Schilling RJ, Hunter RJ. ECG-I phenotyping of persistent AF based on driver burden and distribution to predict response to pulmonary vein isolation (PHENOTYPE-AF). J Cardiovasc Electrophysiol. 2022 Nov;33(11):2263-2273. doi: 10.1111/jce.15644. Epub 2022 Aug 16.
- Derived from this study: PubMed 33765054Dhillon GS, Ahluwalia N, Honarbakhsh S, Graham A, Creta A, Abbass H, Chow A, Earley MJ, Lambiase PD, Schilling RJ, Hunter RJ. Impact of adenosine on mechanisms sustaining persistent atrial fibrillation: Analysis of contact electrograms and non-invasive ECGI mapping data. PLoS One. 2021 Mar 25;16(3):e0248951. doi: 10.1371/journal.pone.0248951. eCollection 2021.
- Derived from this study: PubMed 32048786Dhillon GS, Schilling RJ, Honarbakhsh S, Graham A, Abbass H, Waddingham P, Sawhney V, Creta A, Sporton S, Finlay M, Providencia R, Chow A, Earley MJ, Lowe M, Lambiase PD, Hunter RJ. Impact of pulmonary vein isolation on mechanisms sustaining persistent atrial fibrillation: Predicting the acute response. J Cardiovasc Electrophysiol. 2020 Apr;31(4):903-912. doi: 10.1111/jce.14392. Epub 2020 Mar 1.
- Individual participant dataSharing planned: Undecided
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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. This study is not recruiting at the moment.
Ross Hunter principal investigator
Barts Heart Centre
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing ECG-I mapping and PVI in people with Atrial Fibrillation, run by Barts & The London NHS Trust at 1 site in United Kingdom.
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 20 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: finished, as of the sponsor's last update on 22 Oct 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Freedom from Atrial Arrhythmia and association with distribution of drivers of AF (time frame: Performed 12-14 months post procedure). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03394404, which also lists 3 linked publications.
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 2024.