Atrial FibrillationMERCYNCT05805189
Prospective Evaluation of Biophysical Parameters as Long-term Predictors of Pulmonary Vein Isolation
A study testing pulmonary vein (PV) isolation in people with Atrial Fibrillation, run by Maria Cecilia Hospital at 1 site in Italy.
Trial summary
Current, worldwide assessments of the prevalence of AF estimate that 33 million people are affected by this cardiac arrhythmia. As the most common sustained atrial arrhythmia, AF has a well-established association with systemic embolic events, stroke, heart failure, and increased mortality. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Atrial Fibrillation
- What is being tested?
- pulmonary vein (PV) isolation
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteItaly
- Study dates
- 9 Feb 2023to 30 Sep 2026
- 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 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- The following criteria must be met for subjects to be eligible for inclusion into the study
- Subjects indicated for the treatment of paroxysmal AF with the RF ablation system according to current and future Guidelines and system indications for use
- Subjects who are willing and capable of providing informed consent
- Patients who have stopped amiodarone for at least one month
- Subjects whose age is > 18 years old
- Subjects whose age is < 80 years old
- Subjects who are willing and capable of participating in all testing associated with this clinical study at an approved clinical investigational center
Who cannot join
- Subjects who meet any one of the following criteria will be excluded from this clinical study
- Patients who had already undergo an AF ablation procedure
- Any known contraindication to an AF ablation or anticoagulation, including those listed in the instructions for use
- Subjects with indication for treatment of AF that is not according to current and future Guidelines and system indications for use
- Presence of an intracavitary thrombus
- Subjects that are unable or not willing to complete follow-up visits and examination for the duration of the study
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- Patients with left ventricular ejection fraction < 35%
- Women of childbearing potential who are, or plan to become, pregnant during the time of the study (method of assessment upon investigator's discretion)
- Hematological contraindications to ionizing radiation exposure
- Presence of complex congenital heart disease, and cardiac surgery within 1 month from enrollment
- Uncontrolled heart failure
- Subjects with severe valvular disease OR with a prosthetic - mechanical or biological- heart valve (not including valve repair and annular rings)
- Contraindications to general anesthesia
- Subjects who are currently enrolled in another investigational study or registry that would directly interfere with the current study
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Prospective Evaluation of Biophysical Parameters as Long-term Predictors of PVI With Multi-Electrode Radiofrequency Catheter: Comparison Between CARTO Guided and Fluoroscopy Guided Approach (MERCY Study)
Current, worldwide assessments of the prevalence of AF estimate that 33 million people are affected by this cardiac arrhythmia. As the most common sustained atrial arrhythmia, AF has a well-established association with systemic embolic events, stroke, heart failure, and increased mortality. Current treatment guidelines and consensus statements for patients with AF suggest that most patients should be first managed with a pharmaceutical drug therapy; however, when a patient becomes drug refractory (intolerant or non-responsive), catheter ablation by PV isolation (PVI) is recommended.
The aim of PVI is abolishment of all conducted electrical activity beyond the isolating lesions.
The recent NICE guidelines have established that today RF point-by-point ablation is the most cost-effective treatment approach over a lifetime after failure of 1 or more anti-arrhythmic drugs5, but until now a new technology, HELIOSTAR, RF Balloon, has not been included in this cost-effectiveness analysis
Read the detailed description
The multi-electrode RF Balloon catheter (HELIOSTAR, Biosense Webster) is a compliant Balloon with 10 circularly orientated electrodes bonded to its surface. It has been designed to be used in conjunction with the Carto3 system (Biosense Webster, CA). It is able to deliver RF energy directly forming a continuous circular ablation lesion around the PV ostia. With HELIOSTAR, each individual electrode can sense temperature and can be controlled separately. The electrodes can be used for visualization, stimulation, recording and ablation. The compliance of the Balloon allows conformation to the anatomy of the PVs and therefore maximizing tissue contact. The advantages of the RF Balloon include the ease of use to the operator that is associated with Balloon delivery systems, possibility of single shot PVI with tailored RF energy delivery, potentially shorter procedure times and avoidance of collateral damage to non-PVI structures, due to the capacity to individually select and deselect electrodes during ablation.6,7 To date, retrospective analyzes conducted in the RADIANCE and SHINE studies have shown the pre-ablation indicators of optimal electrode positioning and post-RF indicators associated with better outcomes; specifically, baseline impedance range 90-110 Ohms, impedance variability across ten electrodes ≤20 Ohms, baseline electrode temperature ≤31°C, baseline temperature variability ≤3°C and the post-RF indicators (impedance drop ≥12 Ohm and temperature rise ≥6°C) seem to independently predict a durable PVI. To the best of our knowledge, no studies have investigated prospectively the performance of impedance drop and temperature rise of HELIOSTAR ablation in terms of feasibility, acute PVI and post-procedural outcomes.
- Conditions
- Atrial Fibrillation
- Being tested
- pulmonary vein (PV) 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.
pulmonary vein (PV) isolationProcedure or surgery
The settings used during ablation will be for both groups: 15W, unipolar; 5ml/min baseline irrigation, 35ml/min irrigation during inflation/RF application; 55°C target electrode temperature; RF application time 60s for anterior electrodes, 20s for posterior electrodes. The catheter insertion in Pulmonary vein and ablation workflow will be different for two groups.
| Study group | Role | What they receive |
|---|---|---|
| Heliostar group A | Experimental | In this group the achievement of isolation of the pulmonary veins is evaluated with one shot tecnology Heliostar, multielecrode radiofrequency ballon catheter guided by the impedance level measured in the veins Receives: Procedure: pulmonary vein (PV) isolation |
| Carto Group B | Active comparator | In this group the achievement of isolation of the pulmonary veins is evaluated with classic method guided by fluoroscopy Receives: Procedure: pulmonary vein (PV) isolation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Pulmonary vein single shot isolation
The primary objective of this study is PV single shot isolation in acute and at 1-3-6-12 months follow up with stringent monitoring including medical examination (Echo, ECG, and 24h-Holter)..
It will be assessed the time necessary to reach the isolation, the number of erogations, the fluoroscopy dose and any use of contrast medium and they will be compared between the two arms.
Our aim is to demonstrate that, even in the case of equivalent relapse rates during the follow up, the CARTO guided approach allows patients to benefit from a faster and less invasive procedure compared to the fluoroscopy guided method. This occurs because the former doesn't require contrast medium and the fluoroscopy time is notably reduced.
Measured: 12 months
Secondary outcomes (1)
Correlation of biophysical parameters, procedural, and ablation times
correlation of biophysical parameters, procedural, and ablation times between two groups. Therefore the following parameters will be collected: Balloonballoon dwelling time, impedance drop, and temperature rise of each RF sessions, rate of bonus and segmental applications, rate of reconnection. One of the endpoint is the recurrence of atrial tachycardia (AT) and AF after the blanking period (3 months), as measured by ECG and 24h-holter. It will be evaluated by the failure-free rate at 12 months post-index procedure in each cohort.
Measured: 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Apr 2023
- Study start9 Feb 2023
- Primary completion30 Sep 2025
- Study completion30 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- 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
- Randomised
- Intervention model
- Sequential
- Model description
- This is a prospective, single-center, randomized study, designed to evaluate the acute achievement of pulmonary vein isolation with HELIOSTAR Balloon catheter. In this study, patients will be treat using prospectively the pre-ablation indicators of optimal electrode positioning in comparison with standard positioning evaluated by fluoroscopy visualization and contrast injection and the optimized biophysical parameters as predictors of long-term efficacy.
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Maria Cecilia Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Saverio Iacopino, MD, Principal investigator, Maria Cecilia Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05805189
- Sponsor's protocol ID
- MERCY
- Acronym
- MERCY
- Status last verified
- May 2026
- First submitted
- 28 Mar 2023
- Last updated
- 8 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: The Investigator must document in the subject's medical chart that informed consent has been obtained. The signed Informed Consent Form must be kept in the hospital/clinic medical chart or with the study subject documentation and be available for monitoring and auditing.
Study at a glance
From the registry record, last updated by the sponsor on 8 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prospective Evaluation of Biophysical Parameters as Long-term Predictors of PVI With Multi-Electrode Radiofrequency Catheter: Comparison Between CARTO Guided and Fluoroscopy Guided Approach (MERCY Study)
- ClinicalTrials.gov ID
- NCT05805189
- Acronym / sponsor ID
- MERCY / MERCY
- Conditions
- Atrial Fibrillation
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Maria Cecilia HospitalUniversity, hospital or other
- Study start
- 9 Feb 2023 (actual)
- Primary completion
- 30 Sep 2025 (actual)
- Study completion
- 30 Sep 2026 (estimated)
- First posted
- 7 Apr 2023 (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.
Current, worldwide assessments of the prevalence of AF estimate that 33 million people are affected by this cardiac arrhythmia. As the most common sustained atrial arrhythmia, AF has a well-established association with systemic embolic events, stroke, heart failure, and increased mortality. Current treatment guidelines and consensus statements for patients with AF suggest that most patients should be first managed with a pharmaceutical drug therapy; however, when a patient becomes drug refractory (intolerant or non-responsive), catheter ablation by PV isolation (PVI) is recommended.
The aim of PVI is abolishment of all conducted electrical activity beyond the isolating lesions.
The recent NICE guidelines have established that today RF point-by-point ablation is the most cost-effective treatment approach over a lifetime after failure of 1 or more anti-arrhythmic drugs5, but until now a new technology, HELIOSTAR, RF Balloon, has not been included in this cost-effectiveness analysis
Detailed description
The multi-electrode RF Balloon catheter (HELIOSTAR, Biosense Webster) is a compliant Balloon with 10 circularly orientated electrodes bonded to its surface. It has been designed to be used in conjunction with the Carto3 system (Biosense Webster, CA). It is able to deliver RF energy directly forming a continuous circular ablation lesion around the PV ostia. With HELIOSTAR, each individual electrode can sense temperature and can be controlled separately. The electrodes can be used for visualization, stimulation, recording and ablation. The compliance of the Balloon allows conformation to the anatomy of the PVs and therefore maximizing tissue contact. The advantages of the RF Balloon include the ease of use to the operator that is associated with Balloon delivery systems, possibility of single shot PVI with tailored RF energy delivery, potentially shorter procedure times and avoidance of collateral damage to non-PVI structures, due to the capacity to individually select and deselect electrodes during ablation.6,7 To date, retrospective analyzes conducted in the RADIANCE and SHINE studies have shown the pre-ablation indicators of optimal electrode positioning and post-RF indicators associated with better outcomes; specifically, baseline impedance range 90-110 Ohms, impedance variability across ten electrodes ≤20 Ohms, baseline electrode temperature ≤31°C, baseline temperature variability ≤3°C and the post-RF indicators (impedance drop ≥12 Ohm and temperature rise ≥6°C) seem to independently predict a durable PVI. To the best of our knowledge, no studies have investigated prospectively the performance of impedance drop and temperature rise of HELIOSTAR ablation in terms of feasibility, acute PVI and post-procedural outcomes.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Sequential
- Masking
- Single blind (participant)
- Number of arms
- 2
- Model description
- This is a prospective, single-center, randomized study, designed to evaluate the acute achievement of pulmonary vein isolation with HELIOSTAR Balloon catheter. In this study, patients will be treat using prospectively the pre-ablation indicators of optimal electrode positioning in comparison with standard positioning evaluated by fluoroscopy visualization and contrast injection and the optimized biophysical parameters as predictors of long-term efficacy.
| Arm | Type | Receives |
|---|---|---|
| Heliostar group A | Experimental | Procedure: pulmonary vein (PV) isolationIn this group the achievement of isolation of the pulmonary veins is evaluated with one shot tecnology Heliostar, multielecrode radiofrequency ballon catheter guided by the impedance level measured in the veins |
| Carto Group B | Active comparator | Procedure: pulmonary vein (PV) isolationIn this group the achievement of isolation of the pulmonary veins is evaluated with classic method guided by fluoroscopy |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- The following criteria must be met for subjects to be eligible for inclusion into the study
- Subjects indicated for the treatment of paroxysmal AF with the RF ablation system according to current and future Guidelines and system indications for use
- Subjects who are willing and capable of providing informed consent
- Patients who have stopped amiodarone for at least one month
- Subjects whose age is > 18 years old
Key exclusion criteria (14 listed)
- Subjects who meet any one of the following criteria will be excluded from this clinical study
- Patients who had already undergo an AF ablation procedure
- Any known contraindication to an AF ablation or anticoagulation, including those listed in the instructions for use
- Subjects with indication for treatment of AF that is not according to current and future Guidelines and system indications for use
- Presence of an intracavitary thrombus
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 |
|---|---|---|
| pulmonary vein (PV) isolationThe settings used during ablation will be for both groups: 15W, unipolar; 5ml/min baseline irrigation, 35ml/min irrigation during inflation/RF application; 55°C target electrode temperature; RF application time 60s for anterior electrodes, 20s for posterior electrodes. The catheter insertion in Pulmonary vein and ablation workflow will be different for two groups. | Procedure or surgery | Carto Group B, Heliostar group A |
Primary outcome
Pulmonary vein single shot isolation
Time frame: 12 months
The primary objective of this study is PV single shot isolation in acute and at 1-3-6-12 months follow up with stringent monitoring including medical examination (Echo, ECG, and 24h-Holter).. It will be assessed the time necessary to reach the isolation, the number of erogations, the fluoroscopy dose and any use of contrast medium and they will be compared between the two arms. Our aim is to demonstrate that, even in the case of equivalent relapse rates during the follow up, the CARTO guided approach allows patients to benefit from a faster and less invasive procedure compared to the fluoroscopy guided method. This occurs because the former doesn't require contrast medium and the fluoroscopy time is notably reduced.
1 secondary outcome
Correlation of biophysical parameters, procedural, and ablation times
Time frame: 12 months
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 8 May 2026.
- Individual participant dataSharing planned: No. The Investigator must document in the subject's medical chart that informed consent has been obtained. The signed Informed Consent Form must be kept in the hospital/clinic medical chart or with the study subject documentation and be available for monitoring and auditing.
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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.
Saverio Iacopino, MD principal investigator
Maria Cecilia 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 pulmonary vein (PV) isolation in people with Atrial Fibrillation, run by Maria Cecilia Hospital at 1 site in Italy.
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 7 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 8 May 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 Italy. 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?
Pulmonary vein single shot isolation (time frame: 12 months). 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 8 May 2026.