Pulmonary Vein Isolation Strategy of Very High Power Short Duration in Patients With Paroxysmal Atrial Fibrillation

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.

Study Overview

• Status: Recruiting
• Conditions: Paroxysmal Atrial Fibrillation
• Intervention / Treatment: Device: QDOT MicroTM catheter; Device: AI-guided ablation only for PVI

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 Type: Interventional
• Enrollment (Estimated): 150
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Eue-Keun Choi, M.D. Ph.D.; Phone Number: 82-2-2072-0688; Email: choiek417@gmail.com

Study Locations

• South Korea
  • Seoul, South Korea
    • Recruiting
    • Seoul National University Hospital
    • Contact: Eue-Keun Choi, MD, PhD; Email: choiek17@snu.ac.kr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients undergoing PVI for PAF

Exclusion Criteria:

• 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
• 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: vHPSD ablation only for PVI; 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.	Device: QDOT MicroTM catheter; Novel high power-short duration ablation catheter for atrial fibrillation
Experimental: vHPSD and AI-guided ablation for PVI; 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).	Device: QDOT MicroTM catheter; Novel high power-short duration ablation catheter for atrial fibrillation; Device: AI-guided ablation only for PVI; Ablation is the removal or destruction of something from an object by vaporization, chipping, erosive processes, or by other means.
Experimental: AI-guided ablation only for PVI; 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)	Device: AI-guided ablation only for PVI; Ablation is the removal or destruction of something from an object by vaporization, chipping, erosive processes, or by other means.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time for AF ablation	Including total PVI time, total ablation time, fluoroscopic time, and total procedure time.	up to 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Acute PV reconnection rate	Including residual PV potential and early reconnection after 1st pass PVI.	up to 12 months
1-year AF recurrence	Using single lead 3-day holter monitoring.	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.	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.	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.	up to 12 months

Collaborators and Investigators

• Sponsor: Seoul National University Hospital
• Investigators: Principal Investigator: Eue-Keun Choi, M.D. Ph.D., Seoul National University Hospital

Study record dates

Study Major Dates

• Study Start (Actual): November 7, 2023
• Primary Completion (Estimated): July 30, 2026
• Study Completion (Estimated): May 1, 2027

Study Registration Dates

• First Submitted: August 1, 2023
• First Submitted That Met QC Criteria: August 13, 2023
• First Posted (Actual): August 18, 2023

Study Record Updates

• Last Update Posted (Actual): May 20, 2026
• Last Update Submitted That Met QC Criteria: May 18, 2026
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cardiovascular Diseases; Pathologic Processes; Heart Diseases; Arrhythmias, Cardiac; Pathological Conditions, Signs and Symptoms; Atrial Fibrillation
• Other Study ID Numbers: Q-INDEX

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No