Risk of Asymptomatic Cerebral Embolism During AF Ablation With AI-HPSD Strategy Versus Standard Settings

Risk of Asymptomatic Cerebral Embolism During AF Ablation With AI-HPSD Strategy Versus Standard Settings

Risk of Asymptomatic Cerebral Embolism During Atrial Fibrillation Ablation Using Smart Touch SF Catheter With Ablation Index Guided High-power Short-duration Strategy Versus Smart Touch Catheter With Standard Settings Evaluated by High-resolution Diffusion-weighted Magnetic Resonance Imaging Technique (REDUCE-IT Study)

The purpose of this prospective randomized controlled study is to evaluate the risk of asymptomatic cerebral embolism during catheter ablation of atrial fibrillation (AF) with AI-HPSD strategy versus standard radiofrequency ablation settings, with the diagnosis of asymptomatic cerebral embolism is determined by brain high-resolution diffusion-weighted magnetic resonance imaging technique.

Radiofrequency catheter ablation is increasingly performed in patients with paroxysmal and persistent atrial fibrillation (AF) in recent decade. However, catheter ablation of AF is associated with the occurrence of procedure-related thromboembolic events, especially the risk of asymptomatic cerebral embolism detected by brain high-resolution diffusion-weighted magnetic resonance imaging (hDWI). Meanwhile, ablation index guided high-power short-duration (AI-HPSD) strategy with the advanced SmartTouch SurroundFlow (STSF) catheter is an increasingly used technique for catheter ablation of AF, which is proposed to be associated with relatively wider and superficial lesions, less risk of esophageal injury, and shorter procedure time plus higher rate of first-pass pulmonary vein isolation. Moreover, the advanced STSF catheter in AI-HPSD strategy features with the Surround Flow entire tip irrigation system, which is a wide-spread distribution of the irrigating solution (56 irrigation holes), resulting in homogenous cooling and protection from thrombus formation and reduced incidence of steam pops. Thus, comparing with the standard radiofrequency ablation technique using the SmartTouch (ST) catheter, the AI-HPSD strategy may associate with much lower risk of periprocedural asymptomatic cerebral embolism, with the application of advanced STSF catheter and shorter procedure time. Therefore, this study is designed as a prospective randomized controlled study to evaluate the risk of asymptomatic cerebral embolism during catheter ablation of AF with AI-HPSD strategy versus standard radiofrequency ablation settings, with the diagnosis of asymptomatic cerebral embolism is determined by brain hDWI.

This study is a single center prospective single-blinded randomized controlled trial. Enrolled AF patients planning clinically-indicated catheter ablation is randomly assigned with 1:1 ratio to undergo catheter ablation with ablation index guided high-power short-duration strategy or the standard radiofrequency ablation technique. Besides the evaluation at baseline, all the participants will be followed up at 24-72 hours, 1 month and 3 months post ablation.

For patients assigned to undergo AF ablation with ablation index guided high-power short-duration strategy, point-by-point circumferential pulmonary vein ablation will be performed using the advanced STSF catheter under ablation index guided high power short duration strategy (Radiofrequency energy is set up at a power of 50 W, temperature of 43 °C, contact force of 5-20 gram, and flow rate of 20 mL/min; Target ablation index is set to 500 at the anterior wall and 350 at the posterior wall of left atrium).

For patients assigned to undergo AF ablation with standard radiofrequency ablation group, point-by-point circumferential pulmonary vein ablation will be performed using the ST catheter under standard radiofrequency ablation settings (Radiofrequency energy is set up at a power of 30 to 35 W, temperature of 43 °C, contact force of 5-20 gram, and flow rate of 17 to 30 mL/min. Target ablation index is set to 500 at the anterior wall and 350 at the posterior wall of left atrium).

Point-by-point circumferential pulmonary vein ablation will be performed using the advanced STSF catheter under ablation index guided high power short duration strategy (Radiofrequency energy is set up at a power of 50 W, temperature of 43 °C, contact force of 5-20 gram, and flow rate of 20 mL/min; Target ablation index is set to 500 at the anterior wall and 350 at the posterior wall of left atrium).

Point-by-point circumferential pulmonary vein ablation will be performed using the ST catheter under standard radiofrequency ablation settings (Radiofrequency energy is set up at a power of 30 to 35 W, temperature of 43 °C, contact force of 5-20 gram, and flow rate of 17 to 30 mL/min. Target ablation index is set to 500 at the anterior wall and 350 at the posterior wall of left atrium).

The brain hDWI should be performed within 3 days prior to the ablation procedure to investigate previous cerebral lesions and reevaluated within 24-72 hours post ablation to determine the occurrence of new asymptomatic cerebral embolic lesions. The acute cerebral embolic lesion is typically defined as a new focal hyper-intense area detected on the diffusion-weighted sequence, and a hyper-intense signal intensity in the fluid-attenuated inversion recovery sequence, and meantime confirmed by apparent diffusion coefficient mapping as corresponding area of restricted diffusion to rule out a shine-through artifact.

The Montreal Cognitive Assessment (MoCA) is known as a brief cognitive screening tool with a high sensitivity and specificity for detecting a mild cognitive impairment. All enrolled patients undergo a prospective assessment of their cognitive function using the MoCA test at 1 day before and 24-72 hours and 3 months after the catheter ablation procedure.

Inclusion Criteria: Patients≥18 years of age prior to obtaining the written informed consent. Patients with electrocardiographically documented, symptomatic atrial fibrillation. Patients is scheduled to undergo circumferential pulmonary vein antrum radiofrequency ablation. Patient or patient's legal representative is able and willing to give informed consent. Exclusion Criteria: Moderate to severe valvular heart disease. Contraindication for anticoagulation therapy. Contraindication for Diffusion-Weighted MRI. Ischemic stroke or transient ischemic attack within 6 months prior to the consent date. Acute coronary syndrome within 3 months prior to the consent date. Prior left atrial appendage occlusion device. Prior septal occlusion device. Left atrial size greater than 55 mm. Conditions that prevent patient's participation in neurocognitive assessment (at physician's discretion). Female patients who are pregnant or breast feeding or plan a pregnancy during the course of the study. Simultaneous participation in another study. Unwilling or unable to comply fully with the study procedures and follow-up requirements.

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