Left Atrial Flutter Research Articles

A comparison of 8-mm and open-irrigated gold-tip catheters for typical atrial flutter ablation: Data from a prospective multicenter registry.

BackgroundCavotricuspid isthmus (CTI) radiofrequency (RF) catheter ablation is the standard treatment for patients suffering from CTI‐dependent atrial flutter (AFL). The aim of this study was to compare the use in clinical practice of 8‐mm gold‐tip catheter (8mmRFC) and open‐irrigated gold‐tip catheter (irrRFC) for RF typical AFL ablation.MethodsPatients with typical AFL were treated with 8mmRFC or irrRFC catheters according to investigator preferences. The primary endpoint was the cumulative radiofrequency time (CRFT). Fluoroscopy time, acute and 6‐month success rates were secondary endpoints.ResultsAfter excluding 3 patients with left AFL, 157 of the enrolled patients (median age 71.8 [interquartile range, 64.1‐76.2], 76% men, 91% in NYHA class ≤II, 65% with no structural heart disease) were analyzed: 74 (47%) subjects were treated with the 8mmRFC and 83 (53%) with the irrRFC. The median CRFT was 3 [2‐6] minutes in the 8mmRFC group and 5 [3‐7] minutes in the irrRFC group (P = .183). There were no significant differences in ablation success rates, intraprocedural CTI reconnections, audible steam pops, and procedural times. In the 8mmRFC group, a significantly lower fluoroscopy time was observed as compared to the irrRFC group (8 [5‐12] vs 15 [10‐20] minutes, P < .001). During the follow‐up period, AFL recurrences were documented in 3 patients in the 8mmRFC group and 2 in the irrRFC group (P = .655).ConclusionsThe 8mmRFC and the irrRFC performed similarly in routine practice for CTI ablation in terms of cumulative RF time, acute and 6‐month success rates. Fluoroscopy time was significantly lower in the 8mmRFC group.

Three-year follow-up of hybrid ablation for atrial fibrillation.

The single-step hybrid atrial fibrillation (AF) ablation procedure combines a transvenous endocardial and thoracoscopic epicardial approach in 1 procedure. Short-term results are encouraging, but long-term outcome data are not available. Hybrid AF ablation was successfully performed in 64 consecutive patients (53% with persistent AF). The mean follow-up period was 1732 ± 353 days. Perprocedural endocardial touch-up of incomplete epicardial lesions was performed in 17 (26%) patients. In paroxysmal AF patients, arrhythmia-free cumulative survival rates after 1 hybrid AF ablation without Class I or III antiarrhythmic drugs procedure and without redo catheter ablation were 83%, 80% and 80% after 1, 2 and 3 years, respectively. In (long-standing) persistent AF patients, these were 82%, 79% and 79% after 1, 2 and 3 years. Thirteen (20%) patients had at least 1 recurrent episode of supraventricular arrhythmia lasting longer than 30 s: the most frequent recurrent arrhythmias were left atrial flutter and AF. No mortality or conversion to cardiopulmonary bypass, no phrenic nerve palsy and no pacemaker implantation were reported. Hybrid AF ablation, combining a transvenous endocardial and thoracoscopic epicardial approach in a single procedure, results in a cumulative 3-year freedom from arrhythmia without Class I or III antiarrhythmic drugs and without redo catheter ablation of 80% in paroxysmal AF (24 of 30 patients) and 79% in non-paroxysmal AF (26 of 33 patients).

Subxiphoid Minimally Invasive Epicardial Ablation (Convergent Procedure) With Left Thoracoscopic Closure of the Left Atrial Appendage

The Convergent Procedure is a combined epicardial and endocardial ablation performed by a cardiac surgeon and electrophysiologist to treat symptomatic persistent and long standing persistent atrial fibrillation. The epicardial ablation is performed on the entire width of the posterior left atrial wall using monopolar radiofrequency via a subxiphoid incision. There is no sternotomy and cardiopulmonary bypass is not utilized. The surgical ablation is then followed by endocardial voltage mapping and ablation, allowing for complete lesion set creation. Left atrial appendage exclusion can be performed via left thoracoscopic approach at the same time as the surgical ablation. The Convergent Procedure is a truly hybrid, collaborative procedure which combines the strengths of minimally invasive cardiac surgery and percutaneous electrophysiologic techniques to treat a challenging disease process.

P939Catheter ablation of atrial flutter: (typical) right atrial and (atypical) left atrial flutter occur in similar patients but have different outcome of ablation

P939Catheter ablation of atrial flutter: (typical) right atrial and (atypical) left atrial flutter occur in similar patients but have different outcome of ablation

P1455Remote Magnetic Navigation for ablation of macro-reentrant left atrial flutters

P1455Remote Magnetic Navigation for ablation of macro-reentrant left atrial flutters

USE OF DABIGATRAN ETEXILATE TO PREVENT STROKE AND THROMBOEMBOLISM IN PATIENTS UNDERGOING LEFT ATRIAL CATHETER ABLATION PROCEDURES FOR PAROXYSMAL OR PERSISTENT (NON-PERMANENT) ATRIAL FIBRILLATION AND LEFT ATRIAL FLUTTER

Background: Optimal dosing of dabigatran in patients undergoing left atrial (LA) ablation procedures for atrial fibrillation (AF) or LA flutter is unknown. Retrospective data suggest increased bleeding risk with continuous dabigatran, and increased embolic risk when interrupted. We sought to confirm

96-17: Atrial tachycardias in patients with long-standing persistent atrial fibrillation undergoing thoracoscopic epicardial RF ablation

Introduction: Surgical epicardial thoracoscopic RF ablation (SETA) was shown to be more effective in terms of clinical results than catheter based procedures in patients with atrial fibrillation (AF). However, neither surgery nor catheter ablation alone can achieve 100% complete and durable transmural lesions. The aim of this study was to determine mechanisms and localization of atrial tachycardias found after epicardial ablation. Methods: Patients with long-standing persistent AF underwent SETA with aim to create circumferential lesions around the ipsilateral pulmonary veins (PVs) using bipolar RF clamps, to complete linear connecting lesions and to ablate ganglionated plexi using linear pen. As a second step, a detailed 3D electroanatomical mapping (EAM) of both atria using CARTO3 system was performed within 6-8 weeks following surgical procedure. All spontaneous or induced atrial tachycardias (ATs) were mapped and ablated. Results: Sixty patients (mean age 62 years, LA diameter 49 ± 6 mm) were studied. Forty-five patients (75%) had sinus rhythm in the beginning of EAM. Six patients (10%) had typical CTI-dependent right atrial flutter; two patients (5.1%) had right atrial (RA) tachycardia, one patient (2.6%) had focal tachycardia arising from the middle CS, three patients (5%) had perimitral left atrial (LA) flutter, and finally, four patients (6.7%) had AF. All spontaneous ATs were successfully mapped and ablated. As a part of protocol, incremental atrial pacing was performed after finalization of all lines and PV isolations at the end of procedure. In 46 patients (76.7%), no sustained AF and/or AT was induced, in three patients (5%), AF lasting > 30 s was induced, but spontaneously terminated. Non self-terminating AF was induced in two patients (3.3%). In the remaining 9 patients (15%), 13 ATs were induced: 6 arising from the RA and 7 arising from the LA. All but 2 ATs were successfully abolished by RF ablation. Mean procedure and fluoroscopic times of the whole procedure reached 132 ± 37 min and 8 ± 2 min, respectively. 84% of patients maintained stable SR off antiarrhythmic therapy at 12-month follow-up. Reasonable arrhythmia control was achieved in 94% of patients. Conclusion: At least one quarter of patients are suffering from spontaneous ATs and/or AF after SETA. Catheter ablation of ATs following surgery is safe and highly effective. Sequential hybrid approach seems to achieve normal SR in vast majority of patients with previously long-standing persistent AF.

Feasibility of using patient-specific models and the “minimum cut” algorithm to predict optimal ablation targets for left atrial flutter

Left atrial flutter (LAFL) occurs in patients after atrial fibrillation ablation. Identification of optimal ablation targets to terminate LAFL remains challenging. The purpose of this study was to use patient-specific models to simulate LAFL and predict optimal ablation targets using a novel approach based on flow network theory. Late gadolinium-enhanced cardiac magnetic resonance scans from 10 patients with LAFL were used to construct atrial models incorporating fibrosis by investigators blinded to procedural findings. Rapid pacing was applied in silico to induce LAFL. In each LAFL, we represented reentrant wave propagation as an electric flow network and identified the "minimum cut" (MC), which was the smallest amount of tissue that separated the flow into 2 discontinuous components. In silico ablation was applied at MCs, and targets were compared to those that terminated LAFL during catheter ablation. Patient-specific atrial models were successfully generated from patient scans. LAFL was induced in 7 of 10 models. Ablation of MCs terminated LAFL in 4 models and produced new, slower LAFL morphologies in the other 3. For the latter cases, flow analysis was repeated to identify MCs of emergent LAFLs. Ablation of these MCs terminated emergent LAFLs. The MC-based ablation lesions in simulations were similar in length and location to ablation targets that terminated LAFL during catheter ablation for these 7 patients. Personalized atrial simulations can predict ablation targets for LAFL. These simulations provide a powerful tool for planning ablation procedures and may reduce procedural times and complications.

Repeat Procedures After Hybrid Thoracoscopic Ablation in the Setting of Longstanding Persistent Atrial Fibrillation: Electrophysiological Findings and 2-Year Clinical Outcome.

In order to increase success rates of invasive treatment of persistent atrial fibrillation, the hybrid approach was developed, combining video-assisted thoracoscopic epicardial procedure with conventional endocardial catheter ablation. Currently, there are no reports of electrophysiological findings and clinical outcomes of repeat procedures after the hybrid approach. Out of 64 patients who were treated by hybrid ablation for persistent atrial fibrillation (AF), 14 underwent the repeat catheter ablation and were selected for this study. All 14 patients initially presented with longstanding persistent atrial fibrillation and markedly dilated atria. The hybrid procedure was performed in a single act and the mean time to redo procedure was 346 ± 227 days. In 57% of patients indication for redo procedure was regular atrial tachycardia, and the rest presented with recurrent atrial fibrillation. In 36% of patients, recovered conduction was found along the previous ablation lesions. Only 9% of pulmonary veins were reconnected (0.36 veins per patient) and 7% of box lesions were not complete. The overall success rate at 2 years follow-up after the repeat procedure, including second repeat procedure and patients taking antiarrhythmic drugs, was 64% (57% without drugs and further ablation). One case of moderate pulmonary vein stenosis was detected as a consequence of hybrid procedure. Hybrid atrial fibrillation ablation results in durable lesions and high rates of chronic pulmonary vein isolation even after long-term follow-up. Most of the repeat procedures after the hybrid approach are related to left atrial flutters that could be successfully treated by catheter ablation.

Predictors of early and late left atrial tachycardia and left atrial flutter after catheter ablation of atrial fibrillation: long-term follow-up.

The aim of the study was identification of the predictors of left atrial tachycardia and left atrial flutter (LATAFL) after radiofrequency catheter ablation of atrial fibrillation (CAAF). We followed 598 patients (71% male, 41% paroxysmal AF; median follow-up: 36 months) after a single step-wise CAAF procedure. The time to first documented LATAFL lasting longer than 30 s, documented in any kind of electrocardiography (ECG), was defined as an end-point. A single CAAF procedure resulted in LATAF in 58 (10%) patients. Additional lesions were performed in 275 (46%) patients. Early LATAFL recurrence (£ 3 months since the index procedure) was observed in 11 (2%) patients. Late LATAFL (> 3 months) was noted in 47 (8%) patients. The univariate predictors of LATAFL recurrence were: type of AF (p = 0.003), the size of LA (p = 0.002) and the type of procedure (p = 0.0001). The identified single independent predictors of LATAFL recurrence were enlarged LA (p = 0.001) and mul-tiple (≥ 2) additional lesions performed during the index procedure (p < 0.0001). Higher rate of LATAFL recurrence was observed in patients with non-paroxysmal AF, enlarged LA and any additional lesions performed. Two independent predictors of LATAFL recurrence after CAAF were: the enlarged LA and multiple (≥ 2) additional lesions performed during the index procedure.

LEFT ATRIAL APPENDAGE CLOSURE UNDER LOCAL ANESTHESIA GUIDED BY INTRA-CARDIAC ECHOCARDIOGRAPHY FROM THE LEFT ATRIUM

bridged warfarin in patients undergoing radiofrequency ablation for AF, at our centre. METHODS: Two-hundred and forty-nine consecutive patients undergoing radiofrequency ablation for AF or left atrial flutter, between January 2011 to July 2013, were included. Periprocedural anticoagulation with dabigatran (n1⁄4112) was compared with bridged warfarin (n1⁄4137). Primary outcome was a composite of complications including major and minor bleeding, stroke and systemic embolism. RESULTS: Mean age was 58.6 10.6; warfarin group compared to 56.9 10.7 in the dabigatran group. Mean CHADS2 score was 0.8 0.9 in the warfarin group vs. 0.7 0.9 in the dabigatran group. Mean CHA2DS2VASc score was 1.4 1.2 in the warfarin group vs 1.3 1.2 in the dabigatran group. Major bleeding occurred in 5 (3.6%) patients in the warfarin group compared to none in the dabigatran group (p1⁄4 0.06). Groin hematoma was reported in 5 (3.6%) patients in warfarin group and 2 (1.8%) in the dabigatran group (p1⁄40.46). No patient had stroke and 1 (0.7%) patient in the warfarin group developed TIA (p1⁄40.36). Pericardial effusion not requiring drainage was observed in 3 (2.7%) patients in the dabigatran group vs. 1 (0.7%) in the warfarin group (p1⁄40.33). Combined end point occurred in 12 patients in the warfarin group vs, 6 in the dabigatran group (p1⁄40.20). CONCLUSION: Periprocedural complications with oral anticoagulants post AF ablation are rare. Dabigatran appears to be a safe and effective alternative to bridged warfarin in patients at low risk of stroke and bleeding undergoing radiofrequency ablation for AF. 200 LEFT ATRIAL APPENDAGE CLOSURE UNDER LOCAL ANESTHESIA GUIDED BY INTRA-CARDIAC ECHOCARDIOGRAPHY FROM THE LEFT ATRIUM

Association of left atrial function with incident atypical atrial flutter after atrial fibrillation ablation

Symptomatic left atrial (LA) flutter (LAFL) is common after atrial fibrillation (AF) ablation. The purpose of this study was to examine the association of baseline LA function with incident LAFL after AF ablation. The source cohort included 216 patients with cardiac magnetic resonance (CMR) before initial AF ablation between 2010 and 2013. Patients who underwent cryoballoon or laser ablation, patients with AF during CMR, and those with suboptimal CMR, or missing follow-up data were excluded. Baseline LA volume and function were assessed by feature-tracking CMR analysis. The final cohort included 119 patients (mean age 58.9 ± 11 years; 76.5% men; 70.6% patients with paroxysmal AF). During a median follow-up of 421 days (interquartile range 235-751 days), 22 patients (18.5%) had incident LAFL. Baseline LA volume was similar between the 2 groups. In contrast, baseline reservoir, conduit, and contractile function of the LA were significantly impaired in patients with incident LAFL. Baseline global peak longitudinal atrial strain (PLAS) <22.65% predicted incident LAFL with 86% sensitivity and 68% specificity (C statistic 0.76). In a multivariable model adjusting for age, heart failure, and LA volume, PLAS (hazard ratio 0.9 per % increase in PLAS; P = .003) and LA linear lesions (hazard ratio 2.94; P = .020) were independently associated with incident LAFL. The coexistence of PLAS <22.65% and linear lesions was associated with 9-fold increased hazard of incident LAFL. Baseline LA function and linear lesions were independently associated with incident LAFL after AF ablation. Linear lesions should be limited to selected cases, especially in patients with impaired LA function.

Effectiveness of integrating delayed computed tomography angiography imaging for left atrial appendage thrombus exclusion into the care of patients undergoing ablation of atrial fibrillation

Computed tomography angiography (CTA) can identify and rule out left atrial appendage (LAA) thrombus when delayed imaging is also performed. In patients referred for CTA to evaluate pulmonary vein anatomy before the ablation of atrial fibrillation (AF) or left atrial flutter (LAFL), we sought to determine the effectiveness of a novel clinical protocol for integrating results of CTA delayed LAA imaging into preprocedure care. After making delayed imaging of the LAA part of our routine preablation CTA protocol, we integrated early reporting of preablation CTA LAA imaging results into clinical practice as part of a formal protocol in June 2013. We then analyzed the effectiveness of this protocol by evaluating 320 AF/LAFL ablation patients with CTA imaging during the time period 2012-2014. In CTA patients with delayed LAA imaging, the sensitivity and negative predictive values for LAA thrombus using intracardiac echocardiography or transesophageal echocardiography (TEE) as the reference standard were both 100%. Intracardiac echocardiography during ablation confirmed the absence of thrombus in patients with negative CTA or negative TEE results. No patients with either negative CTA results or equivocal CTA results combined with negative TEE results had strokes or transient ischemic attacks. Overall, the need for TEE procedures decreased from 57.5% to 24.0% during the 3-year period because of the CTA protocol. Clinical integration of CTA delayed LAA imaging into the care of patients having catheter ablation of AF or LAFL is feasible, safe, and effective. Such a protocol could be used broadly to improve patient care.

Surface ECG characteristics of right and left atrial flutter

Atrial tachycardia in virtually all areas of both atria has become more important in the clinical management of patients with previous complex atrial fibrillation ablation. Accurate interpretation of surface electrocardiogram (ECG) characteristics is of paramount importance to localize the origin of atrial tachycardia, particularly for planning interventional treatment. This article highlights the ECG features of different types of right and left atrial tachycardia. Typical right atrial flutter through the cavotricuspid isthmus conducts septally in a cranial direction and demonstrates sawtooth-like flutter waves which start negative in II, III and aVF and then show a steep slope upwards to the isoelectric line. The flutter rate typically ranges between 240-250 beats/min. In contrast, right atrial flutter in a clockwise rotation, flutter around the vena cava inferior or superior and around a scar (e.g. after cardiac surgery) show positive or biphasic flutter waves (lower or upper loop reentry). Left atrial flutter waves (e.g. around the mitral valve or around the pulmonary veins) are very heterogeneous and are typically positive in V1 as the left atrium is located in the posterior mediastinum. Specific knowledge of flutter wave morphology in surface ECG facilitates planning and performance of the ablation strategy.

Pulmonary Vein Isolation Using the Visually Guided Laser Balloon: Results of the U.S. Feasibility Study.

Visually guided laser balloon (VGLB) ablation is unique in that the operator delivers ablative energy under direct visual guidance. In this multicenter study, we sought to determine the feasibility, efficacy, and safety of performing pulmonary vein isolation (PVI) using this VGLB. Patients with symptomatic, drug-refractory paroxysmal atrial fibrillation (AF) underwent PVI using the VGLB with the majority of operators conducting their first-ever clinical VGLB cases. The primary effectiveness endpoint was defined as freedom from treatment failure that included: Occurrence of symptomatic AF episodes ≥1 minutes beyond the 90-day blanking, the inability to isolate 1 superior and 2 total PVs, occurrence of left atrial flutter or atrial tachycardia, or left atrial ablation/surgery during follow-up. A total of 86 patients (mean age 56±10 years, 67% male) were treated with the VGLB at 10 US centers. Mean fluoroscopy, ablation, and procedure times were 39.8±24.3 minutes, 205.2 ± 61.7 minutes, and 253.5±71.3 minutes, respectively. Acute PVI was achieved in 314/323 (97.2%) of targeted PVs. Of 84 patients completing follow-up, the primary effectiveness endpoint was achieved in 50 (60%) patients. Freedom from symptomatic or asymptomatic AF was 61%. The primary adverse event rate was 16.3% (8.1% pericarditis, phrenic nerve injury 5.8%, and cardiac tamponade 3.5%). There were no cerebrovascular events, atrioesophageal fistulas, or significant PV stenosis. This multicenter study of operators in the early stage of the learning curve demonstrates that PVI can be achieved with the VGLB with a reasonable safety profile and an efficacy similar to radiofrequency ablation.

Efficacy of ablation at the anteroseptal line for the treatment of perimitral flutter

BackgroundLeft atrial flutter following atrial fibrillation (AF) ablation is increasingly common and difficult to treat. We evaluated the safety and efficacy of ablation of the anteroseptal line connecting the right superior pulmonary vein (RSPV) to the anteroseptal mitral annulus (MA) for the treatment of perimitral flutter (PMF). MethodsWe systematically studied patients who were previously treated with AF ablation and who presented to the electrophysiology laboratory with atrial tachyarrhythmias between January 2000 and July 2010. The diagnosis of PMF was confirmed by activation mapping and/or entrainment. After re-isolation of any recovered pulmonary vein, a linear radiofrequency (RF) ablation was performed on the line that connected the RSPV to the anteroseptal MA. In this analysis, we included only patients who were treated with an anteroseptal line for their PMF. ResultsAblation was performed at the anteroseptal line in 27 PMF patients (63±13 years; 9 women) who had undergone prior ablation for paroxysmal (n=3) or persistent (n=24) AF, using electroanatomic activation mapping (70% CARTO, 30% NavX). The anteroseptal ablation line was effective in 22/27 (81.5%) patients in the acute-care setting. Termination of AF to sinus rhythm occurred in 15/22 (68.2%) patients, and 7/22 (31.8%) patients׳ AF converted to another right or left atrial flutter. At the 6-month follow-up, 20% of patients demonstrated recurrent left atrial tachyarrhythmia. Only one patient required repeat ablation, and the remaining patients׳ condition was controlled with antiarrhythmic medications. No major procedural complications or heart block occurred. ConclusionAblation at the left atrial anteroseptal line is safe and efficacious for the treatment of PMF. Unlike ablation at the traditional mitral isthmus line, ablation at the left atrial anteroseptal line does not require ablation in the coronary sinus.

Incidence, Risk Factors, Prognosis, and Electrophysiological Mechanisms of Atrial Arrhythmias After Lung Transplantation

ObjectivesThe purpose of this study was to investigate the incidence and timing, risk factors, prognostic significance, and electrophysiological mechanisms of atrial arrhythmia (AA) after lung transplantation. BackgroundAlthough new-onset AA is common after thoracic surgery and is associated with poorer outcomes, prognostic and mechanistic data are sparse in lung transplant populations. MethodsA total of 293 consecutive isolated lung transplant recipients without known AA were reviewed retrospectively. Mean follow-up was 28 ± 17 months. Electrophysiology studies (EPS) were performed in 25 patients with AA. ResultsThe highest incidence of new-onset AA after lung transplantation occurred within 30 days after transplantation (25% of all patients). In multivariable analysis, post-operative AA was associated with double-lung transplantation (odds ratio: 2.79; p = 0.005) and lower mean pulmonary artery pressure (odds ratio: 0.95; p = 0.027). Patients with post-operative AA had longer hospital stays (21 days vs. 12 days; p < 0.001). Post-operative AA was independently associated with late AA (hazard ratio: 13.52; p < 0.001) but not mortality (hazard ratio: 1.55; p = 0.14). On EPS, there were 14 patients with atrial flutter alone and 11 with atrial flutter and fibrillation. Among all EPS patients, 20 (80%) had multiple AA mechanisms, including peritricuspid flutter (48%), perimitral flutter (36%), right atrial incisional re-entry (24%), focal tachycardia from recipient pulmonary vein (PV) antrum (32%), focal PV fibrillation (24%), and left atrial roof flutter (20%). Left atrial mechanisms were present in 80% of EPS patients (20 of 25) and originated from the anastomotic PV antrum. ConclusionsPost-operative AA was independently associated with longer length of stay and late AA but not mortality. Pleomorphic PV antral arrhythmogenesis from native PV antrum is the main cause of AA after lung transplantation.

Left atrial catheter ablation subsequent to Watchman® left atrial appendage device implantation: a single centre experience.

Left atrial appendage device occlusion is an increasingly accepted therapy for stroke prevention in atrial fibrillation. The feasibility and safety of left atrial catheter ablation procedures in the presence of a left atrial appendage device implant is unclear. We report on 10 cases of successful left atrial catheter ablation therapy for atrial fibrillation in patients with an implanted Watchman® device. Consecutive patients with an existing Watchman® left atrial appendage implant and symptomatic antiarrhythmic-drug refractory atrial fibrillation or atrial tachycardias requiring left atrial catheter ablation therapy were included. Open irrigated tip ablation and circular mapping catheters were positioned in the left atrium via double transseptal access. Ten patients underwent successful left atrial geometry creation and complex atrial arrhythmia mapping and ablation in the presence of a chronically implanted Watchman® device. Arrhythmia targets included left atrial flutters, a focal tachycardia, left atrial CFAE zones, and pulmonary vein electrical isolation. The appearances of the Watchman® device position and device integrity were confirmed to be satisfactory in all patients at the end of the procedure based on fluoroscopy and intracardiac echocardiography imaging. There were no procedural complications. Left atrial catheter ablation therapy in the presence of an implanted Watchman® left atrial appendage occlusion device was efficacious and uncomplicated in our small single centre experience.

Noninvasive pacing study via pacemakers and implantable cardioverter-defibrillators for differentiating right from left atrial flutter.

Patients with atrial flutter who are implanted with a pacemaker (PM) or implantable cardioverter-defibrillator (ICD) present with the opportunity to perform a noninvasive pacing study (NIPS) using the right atrial pacing lead to differentiate right from left atrial flutter. The purpose of this study was to study the feasibility and accuracy of NIPS to distinguish right from left atrial flutter. We enrolled consecutive patients scheduled for an electrophysiological study or ablation procedure who were in atrial flutter and who were implanted with a PM or ICD with a functional atrial lead in the right atrial appendage. Flutter tachycardia cycle lengths (TCLs) and postpacing intervals (PPIs) were measured noninvasively via the device during the procedure. A total of 48 (67%) patients were studied. Right atrial flutter was present in 32 patients (of whom 29 had typical cavotricuspid isthmus-dependent flutter) and 16 (33%) patients had left atrial flutter. A PPI-TCL interval of >100 ms was 100% specific and 81% sensitive to identify left atrial flutter, with an overall accuracy of 94% and a c statistic of 0.94 (95% confidence interval 0.87-1.00). A PPI-TCL interval of ≤100 ms had a positive predictive value of 86% for diagnosing typical flutter. NIPS via PMs and ICDs with a PPI-TCL interval of >100 ms can reliably identify left atrial flutter (although we have only validated this cutoff for leads implanted in the right atrial appendage). This simple maneuver may allow planning for left-sided access and may avoid an unnecessary invasive electrophysiological study if left atrial flutter ablation is not to be considered.

A safe, simple technique for transseptal catheterization.

Transseptal catheterization is required for atrial fibrillation ablation and many ablations for atrial tachycardias, left atrial flutters, and accessory pathways. Using a Brockenbrough needle or other specialized device adds time, expense, and risk of potential complications such as atrial or aortic perforation, pericardial effusion, and tamponade to these procedures. We present a simple, low-risk technique for transseptal catheterization.