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

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.

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.

Eligibility Criteria:
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.