Paroxysmal Atrial FibrillationNCT05996159
Pulmonary Vein Isolation Strategy of Very High Power Short Duration in Patients With Paroxysmal Atrial Fibrillation
A study testing QDOT MicroTM catheter and AI-guided ablation only for PVI in people with Paroxysmal Atrial Fibrillation, run by Seoul National University Hospital at 1 site in South Korea.
Trial summary
This study aims to investigate the effect of reducing ablation time for a hybrid approach of vHPSD and AI-guided ablation using the QDOT Micro catheter in PVI among patients with PAF. Read more about this study
- Who is it for?
- Ages 19 years and older
- Conditions the study is for
- Paroxysmal Atrial Fibrillation
- What is being tested?
- QDOT MicroTM catheter and AI-guided ablation only for PVI
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 150 participants
- Where
- 1 siteSouth Korea
- Study dates
- 7 Nov 2023to 1 May 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 19 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patients undergoing PVI for PAF
Who cannot join
- Aged less than 19 years
- Patients with persistent AF
- Patients with previous ablation or surgery for AF
- Patients with intracardiac thrombus or thromboembolic events within the previous 90 days
- Patients with cardiac surgery or acute coronary syndrome within the previous 90 days
- Patients with contraindication(s) for using oral anticoagulants
Show all 10Show fewer
- Patients with LA anteroposterior diameter of more than 55 mm
- Patients with left ventricular ejection fraction less than 35%
- Pregnants or those who plan to become pregnant during the study
- Life expectancy less than a year
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
South Korea1 site, 1 recruiting
- Recruiting
Seoul National University Hospital
Seoul
Eue-Keun Choi, MD, PhD, choiek17@snu.ac.kr
About this study
Official title: Pulmonary Vein Isolation Strategy of Very High Power Short Duration in Patients With Paroxysmal Atrial Fibrillation: Q-INDEX Trial
This study aims to investigate the effect of reducing ablation time for a hybrid approach of vHPSD and AI-guided ablation using the QDOT Micro catheter in PVI among patients with PAF.
Read the detailed description
Radiofrequency catheter ablation has become a cornerstone strategy for the rhythm control of AF. During the last decade, catheter technology has revolutionized and, accordingly, clinical outcomes after the ablation and procedural efficacy have been improved.
In recent years, the use of the CLOSE protocol employing contiguous, closely spaced applications and targeted ablation index (AI) values has translated into robust acute and long-term success rates for PVI, typically with the power delivery of up to 35 W, and more recently with 40 to 50 W, in power and temperature-controlled mode.
Contiguous ablation using very high-power, short-duration ablation at 90 W over 4 seconds is expected to shorten procedure time. However, changes in lesion geometry and the altered impact of catheter stability on lesion quality may influence procedural efficiency, safety, and effectiveness.
The Q-FFICIENCY trial showed that the vHPSD (90 W, 4 sec), temperature-controlled radiofrequency ablation (25/50 W) has comparable efficacy to conventional-power temperature-controlled ablation.
However, the efficacy of vHPSD ablation may depend on PV thickness due to its lesion characteristics. Therefore, AI-guided ablation may have merits over vHPSD ablation in thickened PV segments. According to the POWER PLUS trial, the proportion of 1st-pass PVI with vHPSD ablation was numerically lower than that of the conventional ablation, although there was marginal significance; 83.9% vs. 90.0%, p-value =0.085.
According to the OPTIMUM trial, a study conducted by our group, roof and anterior walls of the left atrium often require higher AI targets due to their thickness.
Therefore, a hybrid approach that combines both vHPSD and AI-guided ablations according to PV segments may achieve both high efficacy and short ablation time for PVI. The investigators of the POWER PLUS trial also speculated that the hybrid approach based on tissue thickness might offer the optimal balance of procedural efficacy.
However, up to date, no studies have investigated the efficacy and safety of the hybrid approach for PVI. More data is needed to suggest that the hybrid approach could be useful for PVI.
Therefore, this study aims to investigate the effect of reducing ablation time for a hybrid approach of vHPSD and AI-guided ablation using the QDOT Micro catheter in PVI among patients with PAF.
- Conditions
- Paroxysmal Atrial Fibrillation
- Being tested
- QDOT MicroTM catheter, AI-guided ablation only for PVI
- Medical subject headings
- Atrial Fibrillation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
QDOT MicroTM catheterDevice
Novel high power-short duration ablation catheter for atrial fibrillation
AI-guided ablation only for PVIDevice
Ablation is the removal or destruction of something from an object by vaporization, chipping, erosive processes, or by other means.
| Study group | Role | What they receive |
|---|---|---|
| vHPSD ablation only for PVI | Experimental | Pulmonary vein encirclement is achieved using contiguous applications of very high power and short duration (90 W over 4 seconds). The inter-lesion distance is set at 3-4mm for the roofs and anterior segments, and 5-6mm for other segments. If the esophageal temperature rises > 38 for segments near the esophagus, encirclement will be applied at 25 W for 15 seconds. Receives: Device: QDOT MicroTM catheter |
| vHPSD and AI-guided ablation for PVI | Experimental | At the anterior segments, pulmonary vein encirclement is achieved through contiguous applications using AI-guided ablation (40-50 W, AI target 500, and an inter-lesion distance of 4mm).
In the other segments, pulmonary vein encirclement is achieved through contiguous applications using very high-power and short-duration techniques (90 W over 4 seconds, inter-lesion distance of 3-4mm; if the segments are near the esophagus, encirclement will be applied at 25 W for 15 seconds). Receives: Device: QDOT MicroTM catheter; Device: AI-guided ablation only for PVI |
| AI-guided ablation only for PVI | Experimental | Pulmonary vein encirclement is achieved through contiguous applications using AI-guided ablation (40-50 W, AI target 500 for anterior segments and 400 for other segments, with an inter-lesion distance of 4mm; if the segments are near the esophagus, encirclement will be applied at 25 W for 15 seconds) Receives: Device: AI-guided ablation only for PVI |
What is being measured
The primary outcome is the main question the study is designed to answer.
Time for AF ablation
Including total PVI time, total ablation time, fluoroscopic time, and total procedure time.
Measured: up to 12 months
Secondary outcomes (5)
Acute PV reconnection rate
Including residual PV potential and early reconnection after 1st pass PVI.
Measured: up to 12 months
The segment of residual PV potential
Descript as RSPV roof/anterior/posterior/carina, RIPV anterior/posterior/inferior/carina, LSPV roof/anterior(ridge)/posterior/carina, LIPV anterior(ridge)/posterior/inferior/carina.
Measured: up to 12 months
The segment of early reconnection
Descript as RSPV roof/anterior/posterior/carina, RIPV anterior/posterior/inferior/carina, LSPV roof/anterior(ridge)/posterior/carina, LIPV anterior(ridge)/posterior/inferior/carina.
Measured: up to 12 months
1-year AF recurrence
Using single lead 3-day holter monitoring.
Measured: up to 12 months
30-day complication associated with procedure
Including puncture site hematoma, puncture site pseudoaneurysm, puncture site AV fistula, stroke, TIA, thromboembolism, and others.
Measured: up to 12 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Aug 2023
- Study start7 Nov 2023
- Primary completion30 Jul 2026 (estimated)
- Study completion1 May 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Paroxysmal Atrial FibrillationStudies 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
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 150 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Seoul National University Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Eue-Keun Choi, M.D. Ph.D., Principal investigator, Seoul National University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05996159
- Sponsor's protocol ID
- Q-INDEX
- Status last verified
- May 2025
- First submitted
- 1 Aug 2023
- Last updated
- 20 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pulmonary Vein Isolation Strategy of Very High Power Short Duration in Patients With Paroxysmal Atrial Fibrillation: Q-INDEX Trial
- ClinicalTrials.gov ID
- NCT05996159
- Acronym / sponsor ID
- Q-INDEX
- Conditions
- Paroxysmal Atrial Fibrillation
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 150 participants (estimated)
- Lead sponsor
- Seoul National University HospitalUniversity, hospital or other
- Study start
- 7 Nov 2023 (actual)
- Primary completion
- 30 Jul 2026 (estimated)
- Study completion
- 1 May 2027 (estimated)
- First posted
- 18 Aug 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.
This study aims to investigate the effect of reducing ablation time for a hybrid approach of vHPSD and AI-guided ablation using the QDOT Micro catheter in PVI among patients with PAF.
Detailed description
Radiofrequency catheter ablation has become a cornerstone strategy for the rhythm control of AF. During the last decade, catheter technology has revolutionized and, accordingly, clinical outcomes after the ablation and procedural efficacy have been improved.
In recent years, the use of the CLOSE protocol employing contiguous, closely spaced applications and targeted ablation index (AI) values has translated into robust acute and long-term success rates for PVI, typically with the power delivery of up to 35 W, and more recently with 40 to 50 W, in power and temperature-controlled mode.
Contiguous ablation using very high-power, short-duration ablation at 90 W over 4 seconds is expected to shorten procedure time. However, changes in lesion geometry and the altered impact of catheter stability on lesion quality may influence procedural efficiency, safety, and effectiveness.
The Q-FFICIENCY trial showed that the vHPSD (90 W, 4 sec), temperature-controlled radiofrequency ablation (25/50 W) has comparable efficacy to conventional-power temperature-controlled ablation.
However, the efficacy of vHPSD ablation may depend on PV thickness due to its lesion characteristics. Therefore, AI-guided ablation may have merits over vHPSD ablation in thickened PV segments. According to the POWER PLUS trial, the proportion of 1st-pass PVI with vHPSD ablation was numerically lower than that of the conventional ablation, although there was marginal significance; 83.9% vs. 90.0%, p-value =0.085.
According to the OPTIMUM trial, a study conducted by our group, roof and anterior walls of the left atrium often require higher AI targets due to their thickness.
Therefore, a hybrid approach that combines both vHPSD and AI-guided ablations according to PV segments may achieve both high efficacy and short ablation time for PVI. The investigators of the POWER PLUS trial also speculated that the hybrid approach based on tissue thickness might offer the optimal balance of procedural efficacy.
However, up to date, no studies have investigated the efficacy and safety of the hybrid approach for PVI. More data is needed to suggest that the hybrid approach could be useful for PVI.
Therefore, this study aims to investigate the effect of reducing ablation time for a hybrid approach of vHPSD and AI-guided ablation using the QDOT Micro catheter in PVI among patients with PAF.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| vHPSD ablation only for PVI | Experimental | Device: QDOT MicroTM catheterPulmonary vein encirclement is achieved using contiguous applications of very high power and short duration (90 W over 4 seconds). The inter-lesion distance is set at 3-4mm for the roofs and anterior segments, and 5-6mm for other segments. If the esophageal temperature rises > 38 for segments near the esophagus, encirclement will be applied at 25 W for 15 seconds. |
| vHPSD and AI-guided ablation for PVI | Experimental | Device: QDOT MicroTM catheter, Device: AI-guided ablation only for PVIAt the anterior segments, pulmonary vein encirclement is achieved through contiguous applications using AI-guided ablation (40-50 W, AI target 500, and an inter-lesion distance of 4mm). In the other segments, pulmonary vein encirclement is achieved through contiguous applications using very high-power and short-duration techniques (90 W over 4 seconds, inter-lesion distance of 3-4mm; if the segments are near the esophagus, encirclement will be applied at 25 W for 15 seconds). |
| AI-guided ablation only for PVI | Experimental | Device: AI-guided ablation only for PVIPulmonary vein encirclement is achieved through contiguous applications using AI-guided ablation (40-50 W, AI target 500 for anterior segments and 400 for other segments, with an inter-lesion distance of 4mm; if the segments are near the esophagus, encirclement will be applied at 25 W for 15 seconds) |
Who may qualify
- Ages
- 19 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Patients undergoing PVI for PAF
Key exclusion criteria (10 listed)
- Aged less than 19 years
- Patients with persistent AF
- Patients with previous ablation or surgery for AF
- Patients with intracardiac thrombus or thromboembolic events within the previous 90 days
- Patients with cardiac surgery or acute coronary syndrome within the previous 90 days
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 |
|---|---|---|
| QDOT MicroTM catheterNovel high power-short duration ablation catheter for atrial fibrillation | Device | vHPSD ablation only for PVI, vHPSD and AI-guided ablation for PVI |
| AI-guided ablation only for PVIAblation is the removal or destruction of something from an object by vaporization, chipping, erosive processes, or by other means. | Device | AI-guided ablation only for PVI, vHPSD and AI-guided ablation for PVI |
Primary outcome
Time for AF ablation
Time frame: up to 12 months
Including total PVI time, total ablation time, fluoroscopic time, and total procedure time.
5 secondary outcomes
Acute PV reconnection rate
Time frame: up to 12 months
The segment of residual PV potential
Time frame: up to 12 months
The segment of early reconnection
Time frame: up to 12 months
1-year AF recurrence
Time frame: up to 12 months
30-day complication associated with procedure
Time frame: up to 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 20 May 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.
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 QDOT MicroTM catheter and AI-guided ablation only for PVI in people with Paroxysmal Atrial Fibrillation, 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 1 inclusion and 10 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: looking for participants now, as of the sponsor's last update on 20 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 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?
Contact Eue-Keun Choi, M.D. Ph.D. (82-2-2072-0688, choiek417@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Time for AF ablation (time frame: up to 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 20 May 2026.