Atrial Fibrillation, PersistentCOOL-PERNCT05507749
Cyroablation for Pulmonary Vein Isolation Alone in Patients With Early Persistent AF Assessed by Continuous Monitoring
A study testing cryoballoon ablation and implantable loop recorder insertion in people with Atrial Fibrillation, Persistent, run by Seoul National University Hospital at 1 site in South Korea.
Trial summary
This study aimed to evaluate the efficacy of Cryoablation in patients with early persistent atrial fibrillation as a first index procedure using continuous cardiac rhythm monitoring. Read more about this study
- Who is it for?
- Ages 20 to 79 years
- Conditions the study is for
- Atrial Fibrillation, Persistent
- What is being tested?
- cryoballoon ablation and implantable loop recorder insertion
- Type of treatment
- Medical device, Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 130 participants
- Where
- 1 siteSouth Korea
- Study dates
- 27 Nov 2020to 31 Dec 2027
- Phase
- Interventional
- 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 20 to 79 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Drug refractory symptomatic persistent atrial fibrillation diagnosed within 3 years
- Either two conditions
- atrial fibrillation episode lasting longer than 7 days, but less than 3 years documented by consecutive electrocardiogram recordings of 100% atrial fibrillation greater than 7 days apart or
- atrial fibrillation episode requiring electrical or pharmacological cardioversion after 24 hours of atrial fibrillation documented by continuous recording
- Willing to comply with study requirements and give informed consent to participate in this clinical study
Who cannot join
- Long-standing persistent atrial fibrillation more than 3 years
- Sinus rhythm at enrollment
- Recurrent sinus rhythm after electrical cardioversion
- Severe left ventricular dysfuncion (left ventricle ejection fraction < 30%)
- Previous ablation procedure or surgery for atrial fibrillation
- Contraindication to chronic anticoagulation therapy or heparin
Show all 14Show fewer
- Documented left atrial diameter >50 mm from parasternal long-axis view
- A percutaneous coronary intervention or myocardial infarction ≤3 months
- A stroke or transient ischemic attack ≤6 months
- Planned cardiovascular intervention
- Mental or physical inability to participate in the study
- Participation in another randomized clinical trial
- Uncontrolled hypertension, untreated hypothyroidism or hyperthyroidism
- Requirement for dialysis due to terminal renal failure
Trial locations and contacts
1 site in 1 country.
South Korea1 site
Seoul National university Hostpital
Seoul, Jongno-gu, 03080
About this study
This study aimed to evaluate the efficacy of Cryoablation in patients with early persistent atrial fibrillation as a first index procedure using continuous cardiac rhythm monitoring.
Read the detailed description
Atrial fibrillation is the most common cardiac arrhythmia. With the population aging, the prevalence of atrial fibrillation is increasing globally. Recently, Cryoablation has been demonstrated non-inferior efficacy and safety compared with catheter ablation in atrial fibrillation patients. Cryoablation with the simplicity of the procedure brought the substantial shortening of the total procedure time compared to catheter ablation with comparable long-term atrial fibrillation free survival and procedure-related adverse events. However, most of the previous studies that reported non-inferior efficacy and safety of Cryoablation versus catheter ablation were only included patients with paroxysmal atrial fibrillation. The long-term efficacy of Cryoablation in patients with persistent atrial fibrillation is controversial.
In patients with persistent atrial fibrillation, pulmonary vein isolation alone showed comparable atrial fibrillation recurrence rate compared to pulmonary vein isolation with additional ablation, including linear ablation or ablation of complex fractionated electrograms.
In a recent study, Cryoablation was safe and had good outcomes in patients with persistent and long-standing persistent atrial fibrillation within relatively short procedure time; atrial fibrillation recurrence rate was 36% in persistent atrial fibrillation and 43% in long-standing persistent atrial fibrillation. Among patients with persistent atrial fibrillation ≤1 year, pulmonary vein isolation using cryoballoon had 39% of any atrial fibrillation/atrial tachycardia recurrence rate during a 1-year follow-up. Pre-predictor such as smaller left atrium size or atrial fibrillation history less than three years was associated with a better outcome of atrial fibrillation cryoablation. Therefore, early ablation of persistent atrial fibrillation using Cryoablation may be related to a good outcome that is nearly comparable to those with paroxysmal atrial fibrillation. Namely, pulmonary vein isolation by Cryoablation could be reasonable as the first procedure in patients with early persistent atrial fibrillation. Based on the results of the STOP Persistent atrial fibrillation trial, the Arctic Front Advance cryoablation system (Medtronic) was granted an expanded indication by the US Food and Drug Administration for the treatment of recurrent, drug-refractory, symptomatic, persistent atrial fibrillation. It is the first ablation catheter in the United States to receive an indication for persistent-as opposed to paroxysmal-atrial fibrillation.
Not only atrial fibrillation recurrence merely defined as any atrial fibrillation episode lasting 30 seconds or more, but the atrial fibrillation burden is also a relevant indicator for evaluation of procedure success. Among patients with paroxysmal atrial fibrillation, a recent prospective study reported that atrial fibrillation burden dramatically decreased after Cryoablation by 99% . There was limited data about the efficacy of Cryoablation in patients with early persistent atrial fibrillation evaluated by actual atrial fibrillation burden using continuous cardiac rhythm monitoring.
- Conditions
- Atrial Fibrillation, Persistent
- Being tested
- cryoballoon ablation, implantable loop recorder insertion
- Keywords
- Cryoablation
- Medical subject headings
- Atrial Fibrillation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
cryoballoon ablationProcedure or surgery
Cryoballoon ablation for the treatment of atrial fibrillation
implantable loop recorder insertionDevice
The device called a implantable loop recorder, is placed just under the skin of one's chest during a minor surgery.
| Study group | Role | What they receive |
|---|---|---|
| a group of participants receive implantable loop recorder before cryoballoon ablation | Experimental | Following enrollment, an implantable loop recorder is implanted in all participants for the purpose of arrhythmia (any atrial fibrillation or atrial tachycardia) detection (Reveal LINQ, Medtronic, Minneapolis, MN). Receives: Procedure: cryoballoon ablation; Device: implantable loop recorder insertion |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change of implantable cardiac monitor-detected atrial fibrillation/atrial flutter burden.
The percentage of time spent in atrial fibrillation (hours of atrial fibrillation/hours of monitoring) during the first year after pulmonary vein isolation (excluding a 3-month window) compared to pre-ablation atrial fibrillation/atrial flutter burden.
Measured: After cryoablation (between 3-month and 1-year) and pre-ablation
Secondary outcomes (5)
Time to the first recurrence of atrial fibrillation/atrial flutter
Atrial fibrillation/atrial flutter recurrence, defined as an episode of atrial arrhythmia beyond the first 3 months post-ablation (blanking period), lasting for 30 seconds or more
Measured: From 3-month after cryoablation to the removal of the implantable loop recorder, up to 3years.
Recurrence nature of atrial fibrillation
paroxysmal atrial fibrillation or persistent atrial fibrillation
Measured: From 3-month after cryoablation to the removal of the implantable loop recorder, up to 3years.
36-Item Short Form Health Survey composite scores
Quality of life assessed with the use of the Medical Outcomes Study 36-Item Short-From Health Survey [SF-36]; range 0 to 100, with higher scores indicating better quality of life
Measured: Pre-ablation and 1-year after ablation
European Heart Rhythm Association score
The European Heart Rhythm Association score of atrial fibrillation (or EHRA score) is a classification system for the extent of atrial fibrillation. It places patients in one of four categories based on how much they are limited during physical activity; the limitations/symptoms are in regard to normal breathing and varying degrees in shortness of breath and/or angina.
EHRA Class / Symptoms I- No symptoms. II- Mild symptoms; normal daily activity not affected. III- Severe symptoms; normal daily activity affected. IV- Disabling symptoms; normal daily activity discontinued.
Measured: Pre-ablation and 1-year after ablation
Atrial fibrillation/atrial flutter recurrence and changes in atrial fibrillation/atrial flutter burden
Atrial fibrillation/atrial flutter recurrence and changes in AF/AT burden from 3-month after cryoablation to the removal of the implantable loop recorder
Measured: From 3-month after cryoablation to the removal of the implantable loop recorder, up to 3years.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Aug 2022
- Study start27 Nov 2020
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Atrial Fibrillation, PersistentStudies of the same condition, open and under way.
- More trials run by Seoul National University HospitalThe sponsor's other registered studies.
- 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
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 130 participants (actual)
Sponsor and investigators
- Lead sponsor
- Seoul National University Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Seoul National University Bundang Hospital, Samsung Medical Center, Hallym University Medical Center, Asan Medical Center
- Responsible party
- Principal investigator, Eue-Keun Choi, Seoul National University Hospital
- Investigators
- Eue-Keun Choi, M.D. Ph.D., Principal investigator, Seoul National University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05507749
- Sponsor's protocol ID
- COOL PER
- Acronym
- COOL-PER
- Status last verified
- Nov 2025
- First submitted
- 8 Aug 2022
- Last updated
- 20 Aug 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Lee SR, Choi EK, Lee KY, Choi J, Ahn HJ, Kwon S, On YK, Lee JH, Cho Y, Oh IY, Lim HE, Cho MS, Nam GB, Lip GYH, Oh S. Reduction of AF Burden After Cryoballoon Ablation in Patients With Early Persistent AF: The COOL-PER Trial. JACC Clin Electrophysiol. 2025 Jun;11(6):1234-1247. doi: 10.1016/j.jacep.2025.02.006. Epub 2025 Mar 26.
PubMed 40146092
Study at a glance
From the registry record, last updated by the sponsor on 20 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Cyroablation for Pulmonary Vein Isolation Alone in Patients With Early Persistent AF Assessed by Continuous Monitoring
- ClinicalTrials.gov ID
- NCT05507749
- Acronym / sponsor ID
- COOL-PER / COOL PER
- Conditions
- Atrial Fibrillation, Persistent
- Keywords
- Cryoablation
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 130 participants (actual)
- Lead sponsor
- Seoul National University HospitalUniversity, hospital or other
- Collaborators
- Seoul National University Bundang Hospital, Samsung Medical Center, Hallym University Medical Center, Asan Medical Center
- Study start
- 27 Nov 2020 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 19 Aug 2022 (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.
This study aimed to evaluate the efficacy of Cryoablation in patients with early persistent atrial fibrillation as a first index procedure using continuous cardiac rhythm monitoring.
Detailed description
Atrial fibrillation is the most common cardiac arrhythmia. With the population aging, the prevalence of atrial fibrillation is increasing globally. Recently, Cryoablation has been demonstrated non-inferior efficacy and safety compared with catheter ablation in atrial fibrillation patients. Cryoablation with the simplicity of the procedure brought the substantial shortening of the total procedure time compared to catheter ablation with comparable long-term atrial fibrillation free survival and procedure-related adverse events. However, most of the previous studies that reported non-inferior efficacy and safety of Cryoablation versus catheter ablation were only included patients with paroxysmal atrial fibrillation. The long-term efficacy of Cryoablation in patients with persistent atrial fibrillation is controversial.
In patients with persistent atrial fibrillation, pulmonary vein isolation alone showed comparable atrial fibrillation recurrence rate compared to pulmonary vein isolation with additional ablation, including linear ablation or ablation of complex fractionated electrograms.
In a recent study, Cryoablation was safe and had good outcomes in patients with persistent and long-standing persistent atrial fibrillation within relatively short procedure time; atrial fibrillation recurrence rate was 36% in persistent atrial fibrillation and 43% in long-standing persistent atrial fibrillation. Among patients with persistent atrial fibrillation ≤1 year, pulmonary vein isolation using cryoballoon had 39% of any atrial fibrillation/atrial tachycardia recurrence rate during a 1-year follow-up. Pre-predictor such as smaller left atrium size or atrial fibrillation history less than three years was associated with a better outcome of atrial fibrillation cryoablation. Therefore, early ablation of persistent atrial fibrillation using Cryoablation may be related to a good outcome that is nearly comparable to those with paroxysmal atrial fibrillation. Namely, pulmonary vein isolation by Cryoablation could be reasonable as the first procedure in patients with early persistent atrial fibrillation. Based on the results of the STOP Persistent atrial fibrillation trial, the Arctic Front Advance cryoablation system (Medtronic) was granted an expanded indication by the US Food and Drug Administration for the treatment of recurrent, drug-refractory, symptomatic, persistent atrial fibrillation. It is the first ablation catheter in the United States to receive an indication for persistent-as opposed to paroxysmal-atrial fibrillation.
Not only atrial fibrillation recurrence merely defined as any atrial fibrillation episode lasting 30 seconds or more, but the atrial fibrillation burden is also a relevant indicator for evaluation of procedure success. Among patients with paroxysmal atrial fibrillation, a recent prospective study reported that atrial fibrillation burden dramatically decreased after Cryoablation by 99% . There was limited data about the efficacy of Cryoablation in patients with early persistent atrial fibrillation evaluated by actual atrial fibrillation burden using continuous cardiac rhythm monitoring.
Study design
- Primary purpose
- Other
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| a group of participants receive implantable loop recorder before cryoballoon ablation | Experimental | Procedure: cryoballoon ablation, Device: implantable loop recorder insertionFollowing enrollment, an implantable loop recorder is implanted in all participants for the purpose of arrhythmia (any atrial fibrillation or atrial tachycardia) detection (Reveal LINQ, Medtronic, Minneapolis, MN). |
Who may qualify
- Ages
- 20 to 79 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Drug refractory symptomatic persistent atrial fibrillation diagnosed within 3 years
- Either two conditions
- Willing to comply with study requirements and give informed consent to participate in this clinical study
Key exclusion criteria (14 listed)
- Long-standing persistent atrial fibrillation more than 3 years
- Sinus rhythm at enrollment
- Recurrent sinus rhythm after electrical cardioversion
- Severe left ventricular dysfuncion (left ventricle ejection fraction < 30%)
- Previous ablation procedure or surgery for atrial fibrillation
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 |
|---|---|---|
| cryoballoon ablationCryoballoon ablation for the treatment of atrial fibrillation | Procedure or surgery | a group of participants receive implantable loop recorder before cryoballoon ablation |
| implantable loop recorder insertionThe device called a implantable loop recorder, is placed just under the skin of one's chest during a minor surgery. | Device | a group of participants receive implantable loop recorder before cryoballoon ablation |
Primary outcome
Change of implantable cardiac monitor-detected atrial fibrillation/atrial flutter burden.
Time frame: After cryoablation (between 3-month and 1-year) and pre-ablation
The percentage of time spent in atrial fibrillation (hours of atrial fibrillation/hours of monitoring) during the first year after pulmonary vein isolation (excluding a 3-month window) compared to pre-ablation atrial fibrillation/atrial flutter burden.
5 secondary outcomes
Time to the first recurrence of atrial fibrillation/atrial flutter
Time frame: From 3-month after cryoablation to the removal of the implantable loop recorder, up to 3years.
Recurrence nature of atrial fibrillation
Time frame: From 3-month after cryoablation to the removal of the implantable loop recorder, up to 3years.
36-Item Short Form Health Survey composite scores
Time frame: Pre-ablation and 1-year after ablation
European Heart Rhythm Association score
Time frame: Pre-ablation and 1-year after ablation
Atrial fibrillation/atrial flutter recurrence and changes in atrial fibrillation/atrial flutter burden
Time frame: From 3-month after cryoablation to the removal of the implantable loop recorder, up to 3years.
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 20 Aug 2026.
- Derived from this study: PubMed 40146092Lee SR, Choi EK, Lee KY, Choi J, Ahn HJ, Kwon S, On YK, Lee JH, Cho Y, Oh IY, Lim HE, Cho MS, Nam GB, Lip GYH, Oh S. Reduction of AF Burden After Cryoballoon Ablation in Patients With Early Persistent AF: The COOL-PER Trial. JACC Clin Electrophysiol. 2025 Jun;11(6):1234-1247. doi: 10.1016/j.jacep.2025.02.006. Epub 2025 Mar 26.
- Individual participant dataSharing planned: No
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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.
Eue-Keun Choi, M.D. Ph.D. principal investigator
Seoul National University Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing cryoballoon ablation and implantable loop recorder insertion in people with Atrial Fibrillation, Persistent, run by Seoul National University Hospital at 1 site in South Korea.
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 5 inclusion and 14 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: under way, not looking for participants, as of the sponsor's last update on 20 Aug 2026. 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 South Korea. 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?
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?
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?
Change of implantable cardiac monitor-detected atrial fibrillation/atrial flutter burden. (time frame: After cryoablation (between 3-month and 1-year) and pre-ablation). 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 NCT05507749, which also lists 1 linked publication.
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 20 Aug 2026.