Patient-TAILORed Ablation of Persistent AF Guided by Instantaneous Amplitude and Frequency Modulation Maps (TAILOR-AF)

Study Overview
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Brief Summary
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Pulmonary vein isolation (PVI) is still considered the cornerstone of catheter ablation for patients with persistent atrial fibrillation (AF). However, ablation outcomes in patients with persistent AF are suboptimal with high recurrence rates after a single PVI procedure. Recently, the investigators developed a new strategy, which enables precise identification of the driver regions allegedly responsible for the maintenance of persistent AF outside the pulmonary veins. This approach uses a conventional electroanatomical mapping system and novel single-signal algorithms based on automatic and accurate analysis of the instantaneous amplitude and frequency modulations displayed by atrial signals during AF (iAM and iFM, respectively) to locate the spatiotemporally stable regions that drive persistent AF (leading drivers). This strategy also enables to identify highly complex substrates in which targeting leading driver regions with catheter-based ablation may not be feasible or could be potentially associated with a significantly higher risk of complications. In such patients, the iAM/iFM maps obtained in the index catheter mapping and ablation procedure will be used to guide an additional patient-specific, minimally invasive surgical ablation approach via thoracoscopy, aiming to completely but specifically target all leading driver regions. The main objective of the TAILOR-AF study is to identify (via iAM/iFM maps), target and ablate AF leading drivers in patients with symptomatic persistent AF recurrences despite ≥2 previous PVI procedures. The methods include a percutaneous catheter mapping and ablation approach followed by a minimally invasive surgical approach via thoracoscopy, if necessary. As a secondary objective we will study the association of underlying blood biomarkers, atrial imaging and surface ECG parameters, with advanced remodeling stages requiring a surgical approach to target leading driver regions. This is a single center study (Hospital Clínico San Carlos, Madrid, Spain) that will recruit 25 patients with symptomatic persistent AF episodes despite having been submitted to ≥2 PVI prior procedures. All patients will undergo subcutaneous implantable loop recorder (ILR) implantation to address AF burden 1 month before the ablation procedure and at least 1 year after the ablation procedure. The primary outcome of the study will be AF freedom after one year of follow-up off antiarrhythmic drugs.

Detailed Description
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The study is co-sponsored by the Fundación para la Investigación Biomédica del Hospital Clínico San Carlos (Madrid, Spain) and the Centro Nacional de Investigaciones Cardiovasculares Carlos III (F.S.P.) (Madrid, Spain). Dr. David Filgueiras-Rama (MD, PhD, affiliation: Hospital Clínico San Carlos) and Dr. Jorge G. Quintanilla (MScEng, PhD, affiliation: Centro Nacional de Investigaciones Cardiovasculares [CNIC]) are Co-Principal Investigators of the study.

Official Title
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Patient-TAILORed Ablation of Atrial Fibrillation Drivers in Persistent Stages Based on Instantaneous Amplitude and Frequency Modulation Criteria (TAILOR-AF)

Conditions
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Persistent Atrial Fibrillation

Intervention / Treatment
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* Device: Subcutaneous implantable loop recorder (ILR) implantation
* Procedure: Mapping and catheter ablation
* Procedure: Minimally invasive surgical ablation via thoracoscopy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with symptomatic persistent AF (defined as a sustained episode lasting ≥ 7 days) despite ≥2 previous PVI, with or without other atrial anatomical targets isolated in previous procedures (e.g. superior vena cava, coronary sinus or others). AF episodes refractory to ≥1 antiarrhythmic drug (flecainide, propofenone, amiodarone or droneradore) or adverse events related to antiarrhythmic drugs that do not allow long-term drug therapy. Age between 18-75 years old. Patients must be willing and able to comply with all peri-ablation and follow-up requirements. Signed informed consent. Confirmed pulmonary vein isolation in the index (in current protocol) procedure. Exclusion Criteria: Patients with paroxysmal AF (defined as a sustained episode lasting < 7 days). Patients for whom cardioversion or sinus rhythm will never be attempted/pursued. Patients with AF secondary to an obvious reversible cause. Patients with contraindications to systemic anticoagulation with heparin or coumadin or a direct thrombin inhibitor. Non-sustained AF during the mapping procedure. Severe underlying systemic disease (e.g. dementia, any end-disease stage, sepsis, etc). Severe left atrial dilation (left atrial volume >73 ml/m2). Severe underlying cardiac disease (e.g. left ventricular ejection fraction ≤35%, severe non-corrected valvular disease, severe non-corrected coronary artery disease, hypertrophic cardiomyopathy, other inherited arrhythmia syndromes, severe dilated cardiomyopathy with NYHA functional class III, IV). Hemodynamic instability due to any cardiac or non-cardiac disease. Pregnancy.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Case group<br>Patients with symptomatic persistent AF episodes after previous failure of ≥2 pulmonary vein isolation procedures | Device: Subcutaneous implantable loop recorder (ILR) implantation<br>* All patients will undergo subcutaneous implantable loop recorder (ILR) implantation to quantify AF burden 1 month before the ablation procedure and at least 1 year after the ablation procedure.<br>Procedure: Mapping and catheter ablation<br>* Driver regions will be identified during persistent AF using a conventional electroanatomical mapping system, multielectrode mapping catheters, and leading-driver maps generated by novel single-signal algorithms based on an automatic and accurate analysis of the instantaneous amplitude and frequency modulations displayed by atrial signals (iAM and iFM, respectively). Such maps enable the location of the spatiotemporally stable regions that drive persistent AF (leading drivers). Leading-driver regions that can be reasonably targeted/isolated with catheter ablation without high-risk of complications upon radiofrequency delivery will be targeted for ablation.<br>Procedure: Minimally invasive surgical ablation via thoracoscopy<br>* This procedure will be performed only in those patients whose leading-driver maps in the previous mapping and catheter ablation procedure fulfill the following requirements: Extensive atrial remodeling who will not likely get any benefit from catheter-based ablation due to too large atrial leading driver areas (≥10-15% of atrial surface), or Leading drivers located at regions with high-risk of complications upon radiofrequency delivery (e.g. left and right atrial appendages, coronary sinus, in the vicinity [≤5 mm] of the cardiac specific conduction system). In such patients, the leading-driver regions not completely targeted or not targeted at all in the previous index mapping and catheter ablation procedure, will be specifically ablated/isolated by minimally invasive surgical ablation techniques via thoracoscopy.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Freedom from Atrial Fibrillation without antiarrhythmic drugs | Number/Percentage of participants with freedom from Atrial Fibrillation without antiarrhythmic drugs | After one year of follow-up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Acute termination of Atrial Fibrillation during the procedure/s | Number/Percentage of participants with acute termination of Atrial Fibrillation during the procedure/s | During catheter ablation and/or minimally invasive thoracoscopic surgical procedures | 
| Freedom from Atrial Fibrillation with or without antiarrhythmic drugs | Number/Percentage of participants with freedom from Atrial Fibrillation with or without antiarrhythmic drugs | After one year of follow-up | 
| Freedom from Atrial Tachycardia/Flutter with or without antiarrhythmic drugs | Number/Percentage of participants with freedom from Atrial Tachycardia/Flutter with or without antiarrhythmic drugs | After one year of follow-up |