Catheter Ablation Therapy for Persistent Atrial Fibrillation

Study Overview
=================
Brief Summary
-----------------
Use of catheter ablation for persistent atrial fibrillation (PerAF) remains controversial due to unsatisfactory long-term success rates (15% - 28.4%). The investigators' previous study indicated that the upper area of the left atrium (LA) plays an important role in PerAF, with the LA roof and mitral isthmus appearing to serve as main substrate in progression from PAF to PerAF and maintenance of fibrillatory activities. The investigators therefore hypothesized that AF should not be initiated or sustained if the latter crucial regions for AF maintenance are abolished. This study aimed to describe the efficacy and safety of additional linear ablation on the left atrial anterior wall for PerAF.

Detailed Description
-----------------
Although studies and guidelines have helped establish catheter ablation as preferred treatment for patients suffering from paroxysmal atrial fibrillation (PAF), use of catheter ablation for persistent atrial fibrillation (PerAF) remains controversial due to unsatisfactory long-term success rates (15% - 28.4%). The investigators' study indicated that the upper area of the left atrium (LA) plays an important role in PerAF, with the LA roof and mitral isthmus appearing to serve as main substrate in progression from PAF to PerAF and maintenance of fibrillatory activities. The investigators therefore hypothesized that AF should not be initiated or sustained if the latter crucial regions for AF maintenance are abolished. This was confirmed using a stepwise pure linear ablation protocol, consisting of a line across the LA roof and extending along the anterior wall of pulmonary veins (PV) antrum to mitral valve annulus (MVA) without PV isolation; the approach appeared safe and effective with long-term (5.2 years) follow-up success rate of 40% for PerAF. This study will evaluate efficacy and safety of circumferential pulmonary vein isolation (CPVI) + LA roof linear ablation + LA anterior wall (LAAW) linear ablation combined with high density mapping and contact force sensing techniques for perAF. This study is expected to provide a practical and guided catheter ablation strategy with maximized safety and efficacy through use of contact force sensing technique, which will be accepted by other qualified electrophysiology laboratories.

Official Title
-----------------
Catheter Ablation Therapy for Persistent Atrial Fibrillation: Value of Additional Linear Ablation on Left Atrial Anterior Wall

Conditions
-----------------
Persistent Atrial Fibrillation

Intervention / Treatment
-----------------
* Procedure: Additional LAAW linear ablation


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: - The main inclusion criterion is patients suffering from drug refractory persistent atrial fibrillation and referred to catheter ablation therapy. Persistent AF is defined as continuous AF for over 7 days, or lasting no more than 7 days but requiring pharmacological or electrical cardioversion. Exclusion Criteria: Patients without spontaneous ongoing AF at the beginning of the procedure; Age: <18 years or >70 years; LA size > 55mm measured on echocardiogram; Previous AF ablation history including surgical ablation; Documented LA thrombus; Severe pulmonary diseases; Previous cardiac surgical history.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: With additional LAAW linear ablation<br>Patients who undergo CPVI+LA roof linear ablation+/ MI linear ablation, and additional LAAW linear ablation using ThermoCool SmartTouch catheter. | Procedure: Additional LAAW linear ablation<br>* Additional linear ablation on LAAW using ThermoCool SmartTouch ablation catheter.<br>|
| Active Comparator: Without additional LAAW linear ablation<br>Patients who undergo CPVI+LA roof +/ MI linear ablation using ThermoCool SmartTouch catheter, without LAAW linear ablation. | Procedure: Additional LAAW linear ablation<br>* Additional linear ablation on LAAW using ThermoCool SmartTouch ablation catheter.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| AF recurrence | Freedom from AF at 1 year without any anti-arrhythmic drugs. Recurrent AF is defined as documented AF (through 12-lead ECG or Holter) period lasting >30 seconds after a 3-month blanking period. | From August, 2016 to July 2019. The overall Time Frame for AF recurrence is being assessed up to 36 months. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Acute success rate of AF termination during ablation procedure |  | From August, 2016 to July 2017. The overall Time Frame for AF termination during ablation procedure is being assessed up to 12 months. | 
| Frequency of complications |  | From August, 2016 to July 2017. The overall Time Frame for frequency of complications is being assessed up to 12 months. | 
| Average radiation exposure |  | From August, 2016 to July 2017. The overall Time Frame for average radiation exposure is being assessed up to 12 months. | 
| Frequency of redo procedures |  | From August, 2016 to July 2019. The overall Time Frame for frequency of redo procedures is being assessed up to 12 months. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
atrial fibrillation, catheter ablation