ICE Based Atrial Flutter Ablation Vs Conventional Fluoroscopy/Anatomical Mapping Based Ablation - ICE Flutter Study

Study Overview
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Brief Summary
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Intracardiac echocardiography (ICE), has been an essential component of Radiofrequency (RF) ablations for AF given its association with decreased fluoroscopy time and complication rates, and therefore it is logical that this can be applied to CTI ablations for AFL as well. There are however no studies to date that directly focused on the benefits of adding ICE during CTI dependent AFL ablation. Currently it is not required that operators use ICE in every case of AFL ablation. Investigators intended to study the routine use of ICE in such cases and to see if there is a significant benefit in routine use of ICE.

Detailed Description
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Atrial flutter (AFL) is a re-entrant tachyarrhythmia that involves the atria that leads to both rapid ventricular rates as well as a loss of effective contractility of the atrial making them vulnerable to formation of thrombi similar to atrial fibrillation (AF). Incidence rates ranges between 5/100,000 in those <50 years old to 587/100,000 in subjects older than 80. AFL often coexists or precedes AF. In a longitudinal study, 56% of patients with lone AFL eventually developed AF. A variety of atrial flutters have been described apart from the classic cavotricuspid isthmus (CTI) dependent flutters. These include left atrial flutters and scar based reentry flutters. Atrial flutter is often a persistent rhythm that requires electrical cardioversion or radiofrequency catheter ablation for termination. While AFL may recur after cardioversion with or without antiarrhythmic therapy, ablation offers a more curative approach for this rather intolerant arrhythmia. 3D electroanatomical mapping in combination with fluoroscopy has been traditionally used in conventional CTI ablation for AFL. However, there are instances when ablation of the CTI is challenging as a result of various factors including a thick Eustachian ridge, presence of a sub-Eustachian pouch, or prominent pectinate muscles. Isthmus anatomy has been shown to affect the parameters of ablation procedure. 3D mapping to overcome difficult anatomy may not be the answer for difficult situations as shown by some operators . These anatomical challenges can not only lengthen procedural times but also lead to increased risk of complications such as perforation, effusion, or cardiac tamponade. Intracardiac echocardiography (ICE), has been an essential component of Radiofrequency (RF) ablations for AF given its association with decreased fluoroscopy time and complication rates, and therefore it is logical that this can be applied to CTI ablations for AFL as well. There are however no studies to date that directly focused on the benefits of adding ICE during CTI dependent AFL ablation. Currently it is not required that operators use ICE in every case of AFL ablation. Investigators intend to study the routine use of ICE in such cases and to see if there is a significant benefit in routine use of ICE.

Official Title
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Prospective Comparison of ICE Based Atrial Flutter Ablation Vs Conventional Fluoroscopy/Anatomical Mapping Based Ablation

Conditions
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Atrial Flutter

Intervention / Treatment
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* Procedure: 3D electroanatomical mapping alone guided CTI ablation
* Procedure: ICE plus 3D electroanatomical mapping guided CTI ablation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients undergoing typical CTI dependent AFL who give informed consent for participation in the study will be included. Exclusion criteria: Patients in whom placement of an ICE catheter in the right atrium for adequate atrial visualization is technically not feasible. Patients who cannot give an informed consent will be excluded. Patients in who vascular access for the 11F sheath is not feasible will be excluded. Those with left iliac vein stenosis or left groin arteriovenous (AV) fistulas or prior left groin access complications will be excluded. Patients who on the EP (Electrophysiology) study are found to have a left sided arrhythmia needing transseptal access will be excluded. Patients who during EP study are found to have atypical flutter pathways including Left Atrial (LA)/Left sided flutter as above, atypical pathways outside of the CTI, and scar based- reentry pathways.

Ages Eligible for Study
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Minimum Age: 18 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: Total 60 patients will be studied. St.Jude View Flex ICE catheter and Siemens AcuNav ICE catheter are used routinely for all left sided ablation procedures which require transeptal puncture. ICE imaging catheter is typically introduced through an 11-F hemostatic sheath and positioned under fluoroscopic guidance in right atrium. After catheter coupling to the imaging platform, imaging frequency is optimized using adjunctive gain, depth, and focal length controls to define anatomic structures and minimize noise.Imaging is performed at different levels in right atrium, if needed. Imaging targets included right atrium, coronary sinus orifice, fossa ovalis, interatrial septum(IAS), tricuspid valve,left atrium, left atrial appendage, orifice of all pulmonary veins,mitral valve, papillary muscles, aortic and pulmonary valve leaflets, right ventricle, right ventricular outflow tract(RVOT),pericardial space,esophagus,aorta and adjoining left ventricular and right ventricular myocardium.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: 3D electroanatomical mapping alone<br>Patients who are diagnosed with typical right sided flutter who are scheduled for an ablation procedure will be enrolled. Informed consent will be obtained from each of them prior to the procedure. Patients will be randomly assigned to undergo either 3D electroanatomical mapping alone vs ICE plus 3D electroanatomical mapping guided CTI ablation. Operators will plan to alternate each case with the use of ICE + 3D mapping and 3D mapping alone with one method followed by the other for randomization. All patients will have the standard access sheaths placed in the right femoral vein. | Procedure: 3D electroanatomical mapping alone guided CTI ablation<br>* 3D electroanatomical mapping in combination with fluoroscopy has been traditionally used in conventional CTI ablation for AFL.<br>|
| Experimental: ICE plus 3D electroanatomical mapping<br>Patients who are diagnosed with typical right sided flutter who are scheduled for an ablation procedure will be enrolled. Informed consent will be obtained from each of them prior to the procedure. Patients will be randomly assigned to undergo either 3D electroanatomical mapping alone vs ICE plus 3D electroanatomical mapping guided CTI ablation. Operators will plan to alternate each case with the use of ICE + 3D mapping and 3D mapping alone with one method followed by the other for randomization. All patients will have the standard access sheaths placed in the right femoral vein. The group randomized to ICE catheter placement will have a left femoral 11F sheath placed in addition. | Procedure: ICE plus 3D electroanatomical mapping guided CTI ablation<br>* ICE imaging catheter is typically introduced through an 11-F hemostatic sheath and positioned under fluoroscopic guidance in the right atrium. After catheter coupling to the imaging platform, imaging frequency is optimized by the operator using adjunctive gain, depth, and focal length controls to define anatomic structures and minimize noise. Imaging is performed at different levels in the right atrium, if needed. Imaging targets included the right atrium, coronary sinus orifice, fossa ovalis, interatrial septum (IAS), tricuspid valve, left atrium, left atrial appendage, orifice of all pulmonary veins, mitral valve, papillary muscles, aortic and pulmonary valve leaflets, right ventricle, RVOT, pericardial space, esophagus, aorta and adjoining left ventricular and right ventricular myocardium.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Procedural duration, fluoroscopy time, and RF time assessment | To assess the procedural duration, fluoroscopy time, and RF time of patients undergoing CTI dependent flutter ablation using ICE catheter along with 3D anatomical plus fluoroscopy imaging guidance compared to the same parameters in patients undergoing CTI dependent flutter ablation using only 3D anatomical plus fluoroscopy imaging guidance alone. | These are all intraprocedural characteristics | 
| Post procedural complications | To assess the incidence of post procedural complications such as incidence of perforation, pericardial effusion, cardiac tamponade, and pericarditis. | Post-operative Day#0-7 | 
| Procedural success - Number of patients with bidirectional block (entrance block and exit block) at the end of the procedure. | To assess the procedural success of ablation procedures in terms of achieving bidirectional block. | End of procedure marker of success | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Atrial Flutter, Ablation, Intra-cardiac echocardiogram (ICE)