Additional Low Voltage Area Ablation in Older Patients With Paroxysmal Atrial Fibrillation

Study Overview
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Brief Summary
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The primary objective of this investigation is to compare the efficacy of two different AF ablation strategies in older patients with paroxysmal AF: Pulmonary vein isolation alone versus additional low-voltage substrate modification during sinus rhythm

Detailed Description
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BACKGROUND: Atrial fibrillation (AF) is the most common cardiac rhythm disorder. Catheter ablation to the pulmonary veins isolation (PVI) electrically from the left atrium (LA) has been shown to be an effective treatment for paroxysmal AF (PAF). The consensus is that PVI alone is the main strategy for PAF ablation. Based on the results from our pilot study and STABLE-SR trial, that low-voltage modification beyond CPVI is very promising for persistent AF ablation. Whether the low voltage area modification combined with PVI improves outcomes is unclear in older patients with PAF. AIM OF THE STUDY: The primary objective of this investigation is to compare the efficacy of two different AF ablation strategies in older patients with PAF: PVI alone versus additional low-voltage substrate modification during sinus rhythm. The primary endpoint is freedom from AF and/or ATs with or without antiarrhythmic drugs (AADs) at 12 months after a single-ablation procedure. AF and/or AT occurring in the first 3 months after the ablation (blanking period) was censored. Each atrial tachyarrhythmia episode lasts > 30 seconds monitored by ECG, 24-Holter or 7 days-Holter was defined as recurrence. The secondary endpoint are incidence of periprocedural complications, including stroke, PV stenosis, cardiac perforation, esophageal injury and death; procedure time; fluoroscopy time (including the total fluoroscopy time, during CPVI and after CPVI); the occurrence of the conversion from AF to AT, and its relationship with long-term outcome; the scar distribution and the relationship of success rate in older PAF patients. STUDY DESIGN: This is a randomized, prospective, parallel, single-blind multicenter design. The expected freedom from atrial fibrillation in older patients after one ablation procedure was 75% for PVI. Previous study did not include a group assigned to isolation plus additional low-voltage substrate modification during sinus rhythm, so freedom form AF for this procedure was estimated from the literature at 85%. A log-rank test was used for sample-size calculation. To test whether the isolation plus low-voltage substrate modification was superior to isolation only. Then the 369 patients were needed, with a randomization ratio of 1:1, for the study to have a power of 90% at a two-sided alpha level of 0.05. Assuming a dropout rate of 15%, we need 434 patients. Patients are randomized in a 1:1 fashion into one of the investigation arms: CPVI plus low-voltage substrate modification in the left atrium during SR and CPVI alone. Follow-up for these patients includes visits at 3 m, 6 m, 9 m, 12 m.

Official Title
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Additional Low Voltage Area Ablation in Older Patients With Paroxysmal Atrial Fibrillation: a Randomized Control Trial of STABLE-SR-III

Conditions
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Paroxysmal Atrial Fibrillation

Intervention / Treatment
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* Procedure: CPVI plus low-voltage substrate modification
* Procedure: CPVI alone


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients age is 65-80 years; Patients with paroxysmal AF; Patients can sign the written informed consent for the study; Patients can endure the required follow-up. Exclusion Criteria: Patients with previous radiofrequency ablation; Patients with PLT count less than 80×109/L, or with contraindications to systemic anticoagulation with heparin or Coumadin or a direct thrombin inhibitor; Patients with left atrial size ≥ 55 mm (2D echocardiography, parasternal long-axis view); Patients with thromboemboli in LA (TEE or MSCT); Patients with severe structural cardiac disease (medium or severe mitral regurgitation, DCM, HCM, or other severe valvular heart diseases); Patients with abnormal thyroid function; Patients with severe liver or renal dysfunction (AST or ALT > 3-fold of upper limit value; the SCr > 3.5 mg/dl or Ccr < 30 ml/min); Previous surgery history in last 3 months; Patients with life expectancy < 12 months

Ages Eligible for Study
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Minimum Age: 65 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Study Group<br>PVI with additional low-voltage substrate modification | Procedure: CPVI plus low-voltage substrate modification<br>* CPVI plus low-voltage substrate modification in the left atrium during SR<br>* Other names: CPVI plus additional low-voltage substrate modification;|
| Active Comparator: Control Group<br>PVI only | Procedure: CPVI alone<br>* circumferential pulmonary vein isolation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Freedom from AF and/or ATs with or without antiarrhythmic drugs (AADs) | Freedom from AF and/or ATs with or without antiarrhythmic drugs (AADs) at 12months after a single-ablation procedure. AF and/or AT occurring in the first 3 months after the ablation (blanking period) was censored. Each episode lasts > 30 seconds. | at least 12 months follow up] | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of peri-procedural complications | stroke, cardiac perforation, and death | 1 week after patient enrollment | 
| complications during the follow-up | PV stenosis, esophageal injury | 1month to 12 months | 
| Procedure time | time that the patient spend in the procedure room | 1 week after patient enrollment | 
| Fluoroscopy time | the total fluoroscopy time, during PVI alone or PVI plus low-voltage substrate modification | 1 week after patient enrollment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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substrate modification, pulmonary vein isolation, ablation, Paroxysmal Atrial Fibrillation