Lesion Characteristics After Pulsed-Field Ablation in Patients With Atrial Fibrillation and a Left Common Ostium

Study Overview
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Brief Summary
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This study aims to investigate the lesion characteristics after pulmonary vein isolation using pulsed-field ablation in patients with atrial fibrillation and a common of the left pulmonary veins. The main question it aims to answer is: In which percentage of the patients will pulsed field ablation result in successful isolation of the left common ostium? Nineteen patients will be prospectively included in OLVG. All patients will be treated with pulsed-field ablation (routine care). After the ablation procedure, an electro-anatomical map will be created using the ablation catheter and a mapping system. This map will display the left atrium and the lesion in detail. After the procedure, three experienced operators are asked to draw a line around the LCO in the anatomical map where they would have ablated if conventional radiofrequency ablation was used. The distance between the drawn line and the ablation lesion will be measured at three predefined points. The lesion is considered successful if the mean distance is within ±10mm at all measurement points.

Detailed Description
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Atrial fibrillation (AF) is the most common arrhythmia affecting millions worldwide with increasing prevalence. Patients with AF tend to have more comorbidity and an increased stroke and mortality risk. Pulmonary vein isolation (PVI) has become the cornerstone in the invasive treatment of atrial fibrillation (AF). It has been shown that PVI is more effective in maintaining sinus rhythm and improving quality of life compared to antiarrhythmic drugs. Although PVI results in a 98% burden reduction, an AF recurrence is observed in about half of the patients. AF type, comorbidity, and anatomical pulmonary vein variants affect arrhythmia-free survival. Eighteen per cent of the patients undergoing PVI have a left common ostium (LCO) of the pulmonary veins.(16) A large ostium characterises an LCO, and single-shot devices tend to have worse arrhythmia-free survival than conventional radiofrequency (C-RF) ablation. A proper pulmonary vein occlusion is crucial during cryoballoon ablation. A large ostium can form a distal lesion with the possibility of pulmonary vein potentials proximal to the lesion resulting in AF recurrence. Wide antrum isolation has been shown to improve outcomes, and a distally located lesion can explain the higher AF recurrence rate.(18) Farapulse (Boston Scientific, MA, US) pulsed-field ablation (PFA) was recently introduced. PFA uses short pulses of high voltages to achieve electroporation and irreversible cell membrane damage.(19) This technique is tissue-specific and limits collateral damage. While PV reconnection has been observed in 47% of patients who underwent cryoballoon or radiofrequency ablation, PFA ablation creates durable lesions in 86% of patients.(19, 20) Tissue contact is less critical during PFA than conventional RF or cryoballoon ablation. Therefore one could hypothesise that, in patients with an LCO, PFA can be performed at the actual pulmonary vein ostium and that the lesion location is comparable to conventional RF ablation. Reddy et al. included patients with an LCO and presented an electro-anatomical map showing antral isolation. However, it is still being determined how many patients with an LCO were included, and a comprehensive description of the lesion still needs to be provided. Because no studies investigated the lesion characteristic in patients with AF and an LCO after PFA ablation, this study is designed to examine the lesion location in detail with an electro-anatomical map. This single-centre study will be conducted prospectively in OLVG, Amsterdam, the Netherlands. Patients are eligible for this study if they are admitted for AF ablation because of symptomatic and drug-resistant/intolerant AF and have an LCO (identified by computer tomography (CT) or magnetic resonance imaging (MRI)). All inclusion and exclusion criteria are described in the paragraph ELIGIBILITY. The operator will map the left atrial voltage in nineteen patients using the Ensite Precision (Abbott inc. IL, US) and the Farawave ablation catheter. First, all patients will be treated with pulsed-field ablation (routine care). Then, when all pulmonary veins are considered isolated, an electro-atomical map of the left atrium will be created. After the procedure, three experienced operators are asked to draw a line in the anatomical map where they would have performed ablation if C-RF had been used - again, blinded for voltage. Next, the investigators will measure the distance between the line the operators drew and the ablation lesion at three points. The lesion is considered within range if the mean difference is ±10mm at all measurement points. All study outcomes are specified in the paragraph OUTCOME MEASURES.

Official Title
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Lesion Characteristics After Pulsed-Field Ablation in Patients With Atrial Fibrillation and a Left Common Ostium

Conditions
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Atrial Fibrillation, Pulmonary Vein Isolation, Ablation Therapy

Intervention / Treatment
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* Other: Creating an electro-anatomical map


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age > 18 years of age on the day of enrolment of either sex Willing to the sign informed consent Left atrial volume index measured < 60 ml/m2 within last 12 months Documented atrial fibrillation Admitted and accepted for PVI A left common ostium of the pulmonary veins identified by CT or MRI Accepted to receive general anaesthesia Exclusion Criteria: Patients aged < 18 Body mass index > 35kg/m2 Left atrial volume index ≥ 60 ml/m2 within 12 months on MRI or cardiac echo New York Heart Association heart failure class III or IV Myocardial infarction within three months before the procedure Unstable angina pectoris Percutaneous coronary interventions within three months before the procedure Sudden cardiac death event within three months before the procedure A life expectancy of less than one year Presence of an atrial tachycardia other than cavotricuspid isthmus-dependent atrial flutter History of blood clotting or bleeding abnormalities History of a thromboembolic event within six months before the procedure A contraindication to anticoagulant Clinical significant infection Unstable clinical significant medical condition Previous left atrium ablation, except successful accessory pathway ablation Presence of a left appendage closure device Presence of an atrial septum occluder Presence of a prosthetic heart valve Occlusion of the inferior venous tract Enrolment in another study that would interfere with this study

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: Creating an electro-anatomical map|After the routine pulsed-field ablation procedure, the operator will create an electro-anatomical map using the ablation catheter and a 3D mapping system.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Successful left common ostium isolation after pulsed-field ablation in patients with atrial fibrillation | The distance between the lesion and the line drawn in the electro-anatomical map by three operators will be measured at three predefined points. The lesion is considered successful if the mean distance is within 10mm at all points. | Within one week after the procedure | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Successful isolation at each measuring point | The mean distance between the lesion and line in the electro-anatomical map for each measuring point. (Superior roof, mid posterior, and inferior) | Within one week after the procedure | 
| Distance between the left and right lesion | Distance between the left and right lesion measured at the superior roof, mid posterior, and inferior | Within one week after the procedure | 
| Correlation between posterior wall conduction speed and the left and right lesion distance | Conduction speed at the posterior wall will be measured with an activation map. All the activation data will be collected simultaneously with the electro-anatomical map. | Within one week after the procedure | 
| Safety outcomes within the hospital stay | The occurrence of procedural-related complications, including: Vascular complication (defined as a major or minor vascular complication from the Valve Academic Research Consortium-2) Bleeding complication (defined as Bleeding Academic Research Consortium type 2 or higher) Tamponade, for which an intervention is required Transient phrenic nerve palsy (lasting < 24 hours) Persistent phrenic nerve palsy (lasting ≥ 24 hours) Thromboembolic event Admission for more than 24 hours post-procedure and the reason for prolonged admission. | 24 hours | 
| Number of patients with successful same-day discharge | The number of patients who were successfully discharged and data on hospital prolongation will be collected. | 24 hours | 
| Interoperator variability of the line drawn in the anatomical map | The investigators will investigate the variation of the line drawn by three operators | Within one week after the procedure | 
| True pulmonary vein isolation demonstrated with the Boston Farawave and Ensite Precision | Here the investigators will investigate whether all pulmonary veins are isolation based on the information from the electro-anatomical map. | During the procedure | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Atrial fibrillation, Pulmonary vein isolation, Left common ostium, Pulsed-field ablation