Cavotricuspid Isthmus Flutter Research Articles

Catheter ablation in Asian patients with atrial fibrillation and hypertrophic cardiomyopathy: electrophysiological characteristics of recurrence and long-term clinical outcomes.

Catheter ablation (CA) is a treatment strategy for atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM). We investigated the electrophysiological characteristics of recurrence in a tertiary referral center and compared long-term clinical outcomes after CA therapy with patients who did not undergo CA. Patients with HCM and AF who underwent CA (group 1, n = 60) or pharmacological treatment (group 2, n = 298) between 2006 and 2021 were enrolled in this study. The baseline characteristics and electrophysiological characteristics of group 1 patients were examined to elucidate the reason for the recurrence of AF after CA therapy. The clinical results of the patients in Group 1 and Group 2 were compared using a propensity score (PS)-matched method. The most common cause of recurrence was pulmonary vein reconnection (86.5%), followed by non-pulmonary vein triggers (40.5%), cavotricuspid isthmus flutter (29.7%), and atypical flutter (24.3%). Thyroid disease (HR, 14.713; P < 0.01), diabetes (HR, 3.074; P = 0.03), and non-paroxysmal AF (HR, 4.012; P = 0.01); these factors independently predicted recurrence. After the first recurrence, patients who underwent repeat CA showed a better arrhythmia-free state (74.1%) than those who underwent drug escalation therapy (29.4%, P < 0.01). After matching, PS-group 1 patients showed significantly better outcomes in all-cause mortality, heart failure hospitalization, and left atrial reverse remodeling than PS-group 2 patients. Patients who underwent CA showed better clinical outcomes than those who underwent drug therapy. The main predictors of recurrence were thyroid disease, diabetes, and non-paroxysmal AF.

AB-452666-3 CATHETER ABLATION IN ASIAN PATIENTS WITH ATRIAL FIBRILLATION AND HYPERTROPHIC CARDIOMYOPATHY: ELECTROPHYSIOLOGICAL CHARACTERISTICS OF RECURRENCE AND LONG-TERM CLINICAL OUTCOMES

Catheter ablation (CA) is an effective and safe strategy for treating atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM). We investigated the electrophysiological characteristics of recurrence at a tertiary referral center and compared the long-term clinical outcomes after CA therapy with patients who did not receive CA. Patients with HCM and AF who underwent CA (group 1, n=60) or pharmacological treatment (group 2, n=298) from 2006 to 2021 were enrolled. The patients’ baseline characteristics and electrophysiological features were examined to elucidate the reason for AF recurrence after CA in part I of the study (group 1). The clinical outcomes of group 1 and group 2 patients were compared using a propensity score (PS)-matched method in part II. In part I, the most common cause of recurrence was pulmonary vein (PV) reconnection (86.5%), followed by non-PV triggers (40.5%), cavotricuspid isthmus flutter (29.7%), and atypical flutter (24.3%). Thyroid disease (HR: 14.713, p<0.001), diabetes (HR: 3.074, p=0.034), and non-paroxysmal AF (HR: 4.012, p=0.007) independently predicted recurrence. After the first recurrence, the patients who underwent repeat CA demonstrated better arrhythmia-free status (74.1%) compared to those who underwent drug-escalation therapy (29.4%, p=0.004). In part II, after matching, PS-group 1 patients had significantly better outcomes in all-cause mortality, heart failure hospitalization, and left atrium reverse remodeling than PS-group 2 patients. Patients who underwent CA had better clinical outcomes than those who did not receive CA. The main recurrence predictors were thyroid disease, diabetes, and non-paroxysmal AF.

Atrial Arrhythmia Ablation in Patients With D-Transposition of the Great Arteries and Atrial Switch.

Patients with D-transposition of the great arteries and atrial switch have a high incidence of atrial arrhythmias. We sought to analyze the arrhythmia substrate, ablation strategies, and outcomes for catheter ablation in this population. An in-depth analysis of all clinical and procedural data in patients with D-transposition of the great arteries, atrial baffles, and atrial arrhythmia ablation was performed. A cohort of 32 patients (72% male, mean age 38±7 years) underwent ablation for non-AV nodal reentrant tachycardia atrial arrhythmias, and 4 patients underwent AV nodal reentrant tachycardia ablation. Cavotricuspid isthmus flutter (CTI-flutter) was the most common arrhythmia, encountered in 75% of patients, followed by scar-related intraatrial reentrant tachycardia (non-CTI intraatrial reentrant tachycardia, 53%) and focal atrial tachycardia (focal atrial tachycardia, 6%). Among the 32 patients, 26 underwent 31 procedures at our institution. For patients with prior outside intervention, the index ablation at our institution revealed CTI-dependent flutter in 3/5 cases. However, redo ablation after an index ablation with demonstrated bidirectional CTI block revealed different/new arrhythmia substrates (80% non-CTI intraatrial reentrant tachycardia, 40% focal atrial tachycardia). Achieving bidirectional block across the CTI often required ablating on both sides of the baffle (retroaortic access, 81%; using a baffle leak, 11.5%; or transbaffle puncture, 7.7%). Combined approaches were necessary in 19% to reach the critical tissue. Acute procedural success was 81%, and recurrence was documented in 58% of patients. Despite recurrence, clinical arrhythmia burden was significantly reduced post-ablation (P<0.001), with rare episodes, amenable to antiarrhythmic therapy. Redo ablation was required in 5 (19%) patients and uncovered new arrhythmia substrates. AV nodal reentrant tachycardia ablation also required transbaffle approaches in 3/4 patients. CTI-dependent flutter was the most common arrhythmia in patients with Dextro-Transposition of the Great Arteries and atrial switch. Transbaffle approaches were often necessary, and, provided that bidirectional CTI block was achieved at the index ablation, late recurrence was due to different arrhythmia mechanisms. Despite recurrence, ablation was associated with significant clinical improvement.

PO-623-01 ABLATION STRATEGIES IN PATIENTS WITH CONGENITAL HEART DISEASE AND ATRIAL BAFFLES

Patients with D-Transposition of the Great Arteries (D-TGA) palliated with atrial switch have a high incidence of atrial arrhythmias and pose a particular challenge for ablation. We sought to analyze ablation strategies in this population. An in-depth analysis of ablation data in patients with D-TGA, atrial baffles, and atrial arrhythmia ablations performed at a large tertiary care institution. A cohort of 26 patients with D-TGA and atrial switch (73% male; systemic RV EF 35±11%, mean age at first ablation 37.4±7.2 years) underwent a total of 31 procedures, 26 de novo and 5 redo ablations. For patients with no prior intervention (21, 81%), ablation revealed cavotricuspid isthmus dependent flutter (CTI-flutter, 71%), scar-related intra-atrial reentry (IART, 57%), and focal atrial tachycardia (FAT, 9.5%) (Figure A). Patients with prior outside interventions for CTI-flutter (5, 29%) demonstrated conduction across the CTI in 3/5 (60%) cases. However, patients requiring redo ablation after an index ablation at our institution (5, 29%) demonstrated bi-directional block across the CTI and different, new arrhythmia substrates at the next procedure (80% IART, 40% FAT). Intracardiac echocardiography and electroanatomic mapping were used in all contemporary cases. A screw-in atrial lead was used in 4 procedures as a stable fiduciary reference for mapping, as the coronary sinus ostium was inaccessible. Achieving bi-directional block across the CTI often required ablating on both sides of the baffle (retroaortic access, 81%; using a baffle leak, 11.5%; trans-baffle puncture, 7.7%, or using a VSD, 3.8%). Combined approaches were necessary in 23% of patients to reach critical tissue and achieve optimal contact force (Figure B). Irrigated contact force sensing catheters were used, targeting a significant effect on the electrograms and demonstration of bi-directional CTI block (Figure C). Despite the complex anatomy and atrial reconstruction, cavotricuspid isthmus flutter is still the most common arrhythmia in this population, and bi-directional block often requires additional ablation approaches to reach the target tissue on either side of the baffle. Once CTI block is achieved, further recurrences are due to different, new arrhythmia substrates- IART and FAT.

Immuno-Electrophysiological Mechanisms of Functional Electrical Connections Between Recipient and Donor Heart in Patients With Orthotopic Heart Transplantation Presenting With Atrial Arrhythmias.

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Algorithm for cavo-tricuspid isthmus flutter on surface ECGs: the ACTIONS study

ObjectiveCavo-tricuspid isthmus atrial flutter (CTI-AFL) is an important arrhythmia to recognise because there is a highly effective and relatively low-risk ablation strategy. However, clinical experience has demonstrated that providers often...

Feasibility of complex transfemoral electrophysiology procedures in patients with inferior vena cava filters

The presence of inferior vena cava filters (IVCFs) has been considered a relative contraindication to electrophysiology (EP) procedures that require transfemoral venous placement of multiple catheters and/or long sheaths. There are inadequate data related to complex EP procedures in this population. The purpose of this study was to describe the experience of a single high-volume center with respect to complex EP procedures in patients with IVCFs. Patients with IVCFs undergoing complex EP procedures between 2004 and 2018 were identified. Clinical characteristics, IVCF type, procedural findings, and complications were analyzed. Fifty complex ablation procedures were performed in 40 patients (mean age 63.8 ± 10.9 years; 68% men). The mean IVCF dwell time was 69.1 ± 19.1 months, and 48 patients (96%) were on chronic oral anticoagulation. Procedures included ablation of atrial fibrillation (n = 21), ventricular tachycardia (n = 20), supraventricular tachycardia (n = 3), cavotricuspid isthmus flutter (n = 3), supraventricular tachycardia and cavotricuspid isthmus flutter (n = 1), and transvenous lead extraction (n = 3). Twenty procedures included quadripolar catheters (mean 1.4 ± 0.75), and 33 procedures involved deflectable decapolar catheters (mean 1.7 ± 0.47). Long sheaths were used in 35 cases (mean 1.63 ± 0.49) and intracardiac echocardiography in 38. In 4 cases (involving 3 patients), the IVCF was occluded and could not be crossed. There were no procedural complications related to the IVCF. The substantial majority of IVCFs in patients presenting for complex EP procedures were patent and easily crossed under fluoroscopic guidance. The presence of an IVCF should not discourage operators from performing procedures that require transfemoral deployment of multiple catheters and/or sheaths.

Challenges and Pitfalls of Entrainment Mapping of Ventricular Tachycardia: Ten Illustrative Concepts.

The use and interpretation of entrainment mapping, or continuous resetting, of a reentrant tachycardia has been regarded as the gold standard for delineation of the components of a reentrant circuit.1,2 The response during and after overdrive pacing, whereby 2 wavefronts enter the circuit antidromically (with fusion) and orthodromically, is used to confirm reentry as the arrhythmia mechanism and determine the relationship of the pacing site to the circuit. The fulfillment of classical criteria outlined by Waldo and colleagues3,4 were synthesized into an anatomic concept for scar-related ventricular tachycardia (VT) by Stevenson et al5 to portray the structural and architectural basis of circuit conduction meandering between regions of fibrosis. In this construct, a central corridor, or protected isthmus, is bordered between 2 regions of dense scar with a single entrance that is distinct from a single exit, which yields the QRS morphology.6 This reentrant model has been central to our current mechanistic understanding of scar-mediated VT and is critically important for differentiating critical sites from bystander sites and regions that are unlikely to interrupt or eliminate reentry.7 However, the nature of reentrant VT in man is more complex than our idealized working construct for many reasons. In clinical practice, the majority of VT is hemodynamically unstable, which precludes the ability to perform entrainment mapping and activation mapping of the entire circuit.8 Differences in the circuit between patients with untolerated and tolerated VT are not well understood. VT circuits are 3 dimensionally complex with transmural conduction and circuit conduction is unlikely to be planar, as depicted by electroanatomic mapping of the myocardial surface. Exits may be multiple9,10 and patterns other than loop reentry around scar are likely. Channels of preserved myocardium are frequently not “normal” in voltage (>1.5 mV) …

Termination of persistent atrial fibrillation during pulmonary vein isolation: insight from the MAGIC-AF trial.

Controversy on the optimal ablation strategy for persistent atrial fibrillation (AF) exists with limited work evaluating a strategy of pulmonary vein isolation (PVI) alone when AF terminates during PVI. Thirty-five patients had AF termination during PVI in the Modified Ablation Guided by Ibutilide Use in Chronic Atrial Fibrillation (MAGIC-AF; ClinicalTrials.gov number: NCT01014741) study. The objective of the current study is to report the 1-year outcome after PVI alone in this unique patient group. The 1-year single procedure freedom from atrial arrhythmia off anti-arrhythmic drugs was reported for the 35 patients in the MAGIC-AF study with persistent AF termination during or upon completion of PVI. Freedom from recurrent atrial arrhythmia was achieved in 60% of patients where AF terminated during PVI. Cavotricuspid isthmus flutter was common when AF terminated to a macro re-entrant flutter during PVI, and responsible for 92% of all flutter circuits with AF termination. Persistent AF termination during PVI may identify a subgroup of patients who experience a similar long-term clinical outcome with PVI ablation alone when compared with other more extensive persistent AF ablation strategies. Pulmonary vein isolation alone may be an appropriate tactic in this subgroup of persistent AF patients.

Abstract 16580: Safety and Efficacy of Cryoballoon Ablation in Patients With Congestive Heart Failure

Background: Irrigated radiofrequency ablation of atrial fibrillation (AF) is challenging in patient with severe systolic congestive heart failure due to large fluid load. The use of cryoballoon ablation in patients with low ejection fraction (EF) and NYHA class II-IV congestive heart failure has not been well described, and may benefit from the lack of fluid bolus and restoration of sinus rhythm. Method: To evaluate the efficacy and safety of cryoballoon ablation for systolic heart failure patients with atrial fibrillation (AF). Single center retrospective review of 832 patients with AF ablation using Arctic Front Advance Cryoballoon (Medtronic, Minneapolis, MN) was performed, and 188 patients has EF less than 35% (24 paroxysmal, 122 persistent, and 42 long-standing persistent, average EF 28%) was analyzed. Procedural tolerance, complications, and impact on congestive heart failure were reviewed over a 12 months follow up. Results: All 188 patients (Average age 68, LA size 5.8 cm) with systolic CHF and atrial fibrillation underwent successful pulmonary vein (PV) isolation and extra-pulmonary vein lesions sets applied using cryoballoon. Non-irrigated radiofrequency ablation was used in (22%) for cavo-tricuspid isthmus flutter ablation. Acute procedural success rate was 100% with length of hospitalization of 1.1 days. Average procedural time was 2.6 hours, and fluid infusion of 0.3 liters, no significant complications was noted. Atrial fibrillation burden was monitored by implantable pacemaker or defibrillator in 118 of 188 patients (63%), and others were monitoring via wearable looping recorders every 3 months. Significant AF burden (&lt;10% atrial high rate burden) was observed in over 67% of the patients, and improvement CHF symptoms were reported in all of the patients with reduction of atrial fibrillation burden. Conclusions: Cryoballoon of AF in systolic CHF population is well tolerated with high procedural success rate and low complication rate. Significant clinical improvement of CHF class was observed in patient with reduction of atrial fibrillation burden. Ongoing collection of data is needed to quantify long-term benefit.

Importance of ablating all potential right atrial flutter circuits in postcardiac surgery patients

ObjectivesIn patients with atrial flutter (AFL) and postoperative right atrial incisional scars, we sought to assess if the use of additional ablative lesions that targeted all potential re-entrant circuits, regardless of the presenting type of flutter, would prevent long-term recurrence. BackgroundPatients with AFL and incisional scars have a complex atrial substrate that may promote multiple mechanisms of intra-atrial re-entry. MethodsTwenty-nine patients with single right atrial incisional scars undergoing ablation for scar-dependent (n = 15) and cavotricuspid isthmus (CTI)-dependent (n = 14) flutter were studied. ResultsIn the scar-dependent group, 9 of 15 (60%) patients had inducible or spontaneous CTI-dependent flutter immediately after ablation. In the group with CTI flutter, 7 of 14 (50%) patients had scar-related flutter immediately after ablation. If a second type of flutter was found during the initial ablation, a second ablation was performed either along the isthmus (scar-dependent group) or from the scar to another anatomic boundary (isthmus-dependent group). Patients were followed for 24 ± 5 months and 18 ± 6 months in the scar- and CTI-dependent groups, respectively. In the scar-dependent group, five of six (83%) who underwent only a single flutter line had recurrence at 3 ± 1 months. In the isthmus-dependent group, three of seven (42%) patients who had only one flutter line performed had recurrence at 5 ± 3 months. There was no flutter recurrence in patients who initially received two different flutter lines or in patients who subsequently underwent a second flutter line at follow-up. ConclusionsIn patients with postoperative right atrial incisional scar and flutter, multiple ablation lines that target both scar-related and classic isthmuses appear necessary to prevent long-term recurrence.