Freezing vs burning: which heart procedure works best for AFib?
NCT ID NCT01490814
First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This study compared two ways to treat paroxysmal atrial fibrillation (AFib) — a heart rhythm problem. One method uses a freezing balloon (cryoballoon), the other uses heat (radiofrequency). About 769 patients took part. The goal was to see if the freezing method works as well and is as safe as the heat method. Both aim to stop faulty electrical signals in the heart.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- catheter ablation procedure (cryoballoon or radiofrequency)
- What this could lead to
- If successful, this could confirm that cryoballoon ablation is as safe and effective as standard radiofrequency ablation for treating atrial fibrillation, offering patients another option.
- What could go wrong
- This is a completed non-inferiority trial, so results are already known. The main risks are typical for any heart ablation: bleeding, stroke, or heart rhythm issues. The study does not test a cure, only symptom control.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Not a phased trial
Phase numbers describe drug development. The registry uses this when they do not apply, as it does for trials of devices, procedures or behaviour changes, and for observational studies.
- Participants
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769 people
The number who actually took part.
- Start date
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Dec 2011
- Finished
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Jan 2016
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 to 75 years
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * Symptomatic PAF with at least two episodes and at least one episode documented (30 seconds episode length, documented by ECG within last 12 months). * Documented treatment failure for effectiveness of at least one anti-arrhythmic drug(AAD Type I or III, including β-blocker and AAD intolerance). * ≥ 18 and ≤ 75 years of age. * Patients who are mentally and linguistically able to understand the aim of the trial and to show sufficient compliance in following the trial protocol. * Patient is able to verbally acknowledge and understand the associated risks, benefits, and treatment alternatives to therapeutic options of this trial: cryoballoon ablation system or standard RF ablation technique. The patients, by providing informed consent, agree to these risks and benefits as stated in the patient informed consent document. All the details have been presented to him and he has signed the informed consent form for the trial. Exclusion Criteria: General exclusion criteria * Any disease that limits life expectancy to less than one year. * Participation in another clinical trial (of a drug, device or biologic), either within the past two months or ongoing. * Pregnant women or women of childbearing potential not on adequate birth control: only women with a highly effective method of contraception \[oral contraception or intrauterine device (IUD)\] or sterile women can be randomized. * Breastfeeding women. * Substance misuse. * Active systemic infection. * Cryoglobulinaemia. * Previous participation in this clinical trial. * Employment by the sponsor or by the department of any of the investigators. * Close relatives of any of the investigators. Exclusion criteria related to a cardiac condition * Patients with prosthetic valves. * Any previous LA ablation or surgery. * Any cardiac surgery or percutaneous coronary intervention (PCI) within three months prior to enrollment. * Unstable angina pectoris. * Myocardial infarction within three months prior to enrollment. * Symptomatic carotid stenosis. * Chronic obstructive pulmonary disease with detected pulmonary hypertension. * Any condition contraindicating chronic anticoagulation. * Stroke or transient ischemic attack within six months prior to enrollment. * Any significant congenital heart defect corrected or not (including atrial septal defects or PV abnormalities) but not including patent foramen ovale. * New York Heart Association (NYHA) class III or IV congestive heart failure. * EF \< 35 % (determined by echocardiography within 60 days of enrollment as documented in patient medical history). * Anteroposterior LA diameter \> 55 mm (by trans-thoracic echocardiography (TTE or TEE) within three months to prior enrollment). * LA thrombus (TEE diagnostic performed on admission). * Intracardiac thrombus. * PV diameter \> 26 mm in right sided PVs. * Mitral prosthesis. * Hypertrophic cardiomyopathy (see Appendix IX) * 2° (Type II) or 3° atrioventricular block. * Brugada syndrome or long QT syndrome. * Arrhythmogenic right ventricular dysplasia. * Sarcoidosis. * PV stent. * Myxoma. Exclusion criteria based on laboratory abnormalities * Thrombocytosis (platelet count \> 600,000 / µl), thrombocytopenia (platelet count \< 100,000 / µl). * Any untreated or uncontrolled hyperthyroidism or hypothyroidism. * Severe renal dysfunction (stage V, requiring or almost requiring dialysis, glomerular filtration rate (GFR) \< 15 ml / min).
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Arrhythmia Unit Hospital Clinico San Carlos
Madrid, 28040, Spain
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Asklepios Klinik St. Georg
Hamburg, 20099, Germany
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CHU Lyon, Départment de Rythmologie, Hospital Cardiologique Pradel
Lyon, 69677, France
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Cardiac Arrhythmia Research Centre Department of Cardiovascular Medicine Centro Cardiologico Monzino University of Milan
Milan, 20138, Italy
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Cardioangiologisches Centrum Bethanien - CCB
Frankfurt, 60431, Germany
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Centre Chirurgical Ambroise Paré
Neuilly-sur-Seine, 92200, France
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Herz-Zentrum Bad Krozingen
Bad Krozingen, 79189, Germany
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Herz-Zentrum-Bodensee Konstanz
Konstanz, 78464, Germany
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Hospital Clinic, University of Barcelona
Barcelona, 08036, Spain
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Hospital Clinico Universtitario, Cardiology Department Arrhythmia Unit
Valencia, 46014, Spain
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Hospital Henri Mondor CHU, Service de Cardiologie
Créteil, 94010, France
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Hospital Universitario Virgen de la Victoria, Department of Cardiology, Campus Teatinos sn
Málaga, 29010, Spain
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Isala Klinieken loc. Weezenlanden Diagram Clinical Resarch
Zwolle, 8011, Netherlands
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Klinik für Kardiologie II mit interventioneller Elektrophysiologie
Bad Neustadt/Saale, 97616, Germany
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La Clinique Pasteur, 45 Avenue de Lombez
Toulouse, 31076, France
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Na Homolce Hospital, Cardiology
Prague, 515030, Czechia
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Semmelweis University of Medicine, Kardiovaskuläres Zentrum
Budapest, 1122, Hungary
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Universitätsklinikum Greifswald Elektrophysiologie
Greifswald, 17475, Germany
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Universitätsspital Basel, Elektrophysiologie/ Kardiologie
Basel, 4031, Switzerland