Complex Atrial Arrhythmias Research Articles

Recurrent atrial flutter after radiofrequency ablation for atrial fibrillation in a patient with hypertrophic obstructive cardiomyopathy undergoing repetitive transcoronary ablation of septal hypertrophy

IntroductionWe described the clinical characteristics of a patient with hypertrophic obstructive cardiomyopathy (HOCM) who had undergone transcoronary ablation of septal hypertrophy (TASH) twice and developed atrial flutter after radiofrequency ablation for atrial fibrillation (AF) due to pulmonary vein reconnection. This case of HOCM is unique because of its complex complications and multiple complex atrial arrhythmias. The treatment of HOCM was successful and the postoperative follow-up results was good.Methods and resultsA 71-year-oldfemale, developed exertional dyspnea with palpitations 12 years ago, with a valid diagnosis of HOCM according to the echocardiography which showed an absolute increase in the interventricular septum thickness (22.8 mm). She underwent two rounds of TASH and only the second round was successful. During a visit due to recurrent palpitations, the patient was diagnosed with AF based on electrocardiographic examination. Circumferential pulmonary vein isolation (CPVI) was performed to treat AF. However, the recurrence of atrial flutter was detected on her electrocardiograms (ECGs) three years after the operation. Since the patient had an interstitial lung injury, there were relative contraindications for antiarrhythmic drugs. Due to restrictive use of antiarrhythmic drugs and continuous palpitation, the patient agreed to receive a second radiofrequency ablation. Left-sided macroreentrant circuits were identified via high-density mapping and successful ablation was performed at the isthmus.ConclusionsPerforming catheter ablation and TASH respectively in patients with HOCM associated with AF would be tricky. But taking such a comprehensive and respective clinical treatment would be beneficial to patients in the long term.

High Density grid catheter mapping for complex atrial arrhythmias

High Density grid catheter mapping for complex atrial arrhythmias

Treatment of Complex Atrial Arrhythmias in Lamin Heart Disease

Treatment of Complex Atrial Arrhythmias in Lamin Heart Disease

Non-invasive electrocardiographic imaging for the characterization of complex atrial tachyarrhythmias

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This work was supported by the European Union NextGenerationEU/PRTR. Background – The non-invasive characterization of complex atrial tachyarrhythmias, including atrial flutter (AFL) and focal atrial tachycardia (AT) is challenging. Conventional 12-lead electrocardiogram (ECG) faces several limitations. Planning a precise and preprocedural strategy for complex tachyarrhythmias catheter ablation (CA) is not easy. Purpose To evaluate the diagnostic capacity of a novel electrocardiographic imaging (ECGI) system that does not require previous CT/MRI thoracic imaging. Methods – 42 patients (27 males, CHA2DS2-VASc score 2±1, LVEF 54.5 ± 11.0 % and LA area 31.3 ± 7.0 cm2) undergoing CA for focal AT or AFL were prospectively included in the study. A preprocedural ECGI was managed based on a 64-electrode vest, a torso reconstruction using a 3D real-time acquisition camera, and an artificial intelligence-based method to estimate the patient atrial geometry. The differential diagnostic capacities of non-invasive 12-lead ECG and ECGI were assessed compared with endocavity electroanatomical mapping (EAM) regarding three endpoints: 1) the identification of the involved atrial cavity, 2) the mechanism (focal/micro-reentry or macro-reentry), and (3) the ablation target site defined as the area where the earliest activation was located for focal/micro re-entrant arrhythmias, and the precise anatomical pathway for macro re-entrant tachyarrhythmias. Regarding the ECG, the three endpoints were assessed based on validated algorithms by 2 different observers blinded from the diagnosis. Results – 48 atrial tachyarrhythmias of which 59.5% occurred in the context of a history of CA were evaluated. The non-invasive characterization of complex atrial arrhythmias using this novel ECGI system was possible in 94% of the cases (Figure A): directly for 36 arrhythmias and after decreasing ventricular response using vagal maneuvers for 9. ECGI obtained global accuracy to identify the involved atrial cavity of 91.7%, the mechanism of 89.6%, and the ablation target of 83.3%. In challenging cases, such as in patients with history of CA for AF (n = 27) and in patients without a final diagnosis of counterclockwise typical AFL (n=38) the diagnosis capacity of ECGI is consistent compared to the whole study population. The ECGI diagnostic capacity significantly outclassed the ECG one regarding the identification of the involved cavity (p<0.001), the mechanism (p<0.05), and the ablation target (p<0.001). ECGI was able to prevent the totality of unnecessary transseptal punctures (n=7), representing 28% of the overall punctures. Conclusions (Figure B) – This novel non-invasive ECGI system that does not require CT/MRI thoracic imaging accurately characterizes complex atrial tachyarrhythmia and outclasses ECG, the current noninvasive diagnostic tool of reference.

PO-04-032 UTILIZATION OF OMINPOLAR TECHNOLOGY IN COMPLEX ATRIAL FLUTTERS

Complex atrial flutters are a common occurrence that are found post cardiac surgeries or ablations, and account for a significant percentage of repeat procedures. However, due to scar density and disease progression, wavefront directionality of these complex circuits can often make traditional techniques and algorithms struggle to identify these circuits’ critical isthmus. The purpose of this abstract is to assess the utilization of omnipolar signal technology in terms of map point density in the setting of complex atrial flutters. This was a prospective observational case series with retrospective map and signal analysis of patients who underwent an ablation procedure for complex atrial flutter wherein omnipolar signal technology was primarily utilized for mapping. Omnipolar signals are acquired using a combination of three unipoles and two bipoles whereas in the traditional electrode configuration signals are acquired using orthogonal bipoles. The primary endpoint of this series was to assess the significance of map point density using omnipolar signal technology vs the traditional electrode configuration of the same high density grid catheter in the setting of complex atrial flutters. Eight patients were included, and seven out of the eight patients had prior ablation procedures. The mean recorded mapping points utilizing omnipolar signal technology was higher compared to that of the traditional electrode configuration (22000.38 vs 14412.12, p < 0.05). Total activation mapping time, which included geometry creation for all eight, had a mean of 10.6 minutes. At 3 months follow up, there were no repeat ablations or cardioversions on all eight patients. Two out of the eight patients who had prior CIED implantation recorded mode switch episodes of <1% and all eight had recorded sinus rhythm on follow up in office EKGs. The utilization of omnipolar signal technology in complex atrial arrhythmias produces higher point density maps vs the traditional electrode configuration of the same high density grid catheter. This results in reproducible maps that accurately identifies a flutter’s critical isthmus resulting in efficient, often single burn, termination of these complex flutters. Furthermore, we observed that due to the density of the map and the way onmipolar signals are acquired, the area of the isthmus is more defined vs maps rendered using the traditional electrode configuration

Novel filamin C (FLNC) variant causes a severe form of familial mixed hypertrophic-restrictive cardiomyopathy.

Variants of filamin C (FLNC) have been identified as rare genetic substrate for hypertrophic cardiomyopathy (HCM). Data on the clinical course of FLNC-related HCM are conflicting with some studies suggesting mild phenotypes whereas other studies have reported more severe outcomes. In this study, we present a novel FLNC variant (Ile1937Asn) that was identified in a large family of French-Canadian descent with excellent segregation data. FLNC-Ile1937Asn is a novel missense variant characterized by full penetrance and poor clinical outcomes. End stage heart failure requiring transplantation occurred in 43% and sudden cardiac death in 29% of affected family members. Other particular features of FLNC-Ile1937Asn include an early disease onset (mean age of 19 years) and the development of a marked atrial myopathy (severe biatrial dilatation with remodeling and multiple complex atrial arrhythmias) that was present in all gene carriers. The FLNC-Ile1937Asn variant is a novel, pathogenic mutation resulting in a severe form of HCM with full disease penetrance. The variant is associated with a high proportion of end-stage heart failure, heart transplantation, and disease-related mortality. Close follow-up and appropriate risk stratification of affected individuals at specialized heart centers is recommended.

Catheter Ablation in Complex Atrial Arrhythmias: Pilot Study Evaluating a 3D Wide-Band Dielectric Imaging System.

BackgroundCryoballoon ablation (CBA) for pulmonary vein isolation (PVI) is a standard in atrial fibrillation (AF) ablation but might not be enough in complex atrial arrhythmias (AA). An open three-dimensional wide-band dielectric imaging system (3D-WBDIS) has been introduced to guide CBA.Material and MethodsPilot study evaluating feasibility and safety of 3D-WBDIS in combination with CBA and optional radiofrequency ablation (RFA) in patients with complex AA defined as (1) history of persistent AF, (2) additional atrial tachycardia/flutter, or (3) previous left atrial ablation.ResultsProspectively, seventeen patients, 68.9 ± 12.2 years of age, with complex AA were enrolled. In 70 pulmonary veins (PV), balloon positioning maneuvers (n = 129) were guided additionally by the occlusion tool (1.84/PV). Compared to angiography, its sensitivity and specificity was 94.5, and 85%, respectively. CBA-PVI was achieved in 100% of PVs including variants. In 68 maps, the median number of mapping points was 251.0 (interquartile range (IQR) 298.0) with a median map volume of 52.8 (IQR 83.9) mL. Following CBA, six additional arrhythmias (two right and two left atrial flutter, one left atrial appendage tachycardia, and one atrioventricular nodal reentry tachycardia) were identified and successfully ablated by means of RFA in five patients (29.4%). Left atrial and fluoroscopy times were 88 (IQR 40) and 20 (IQR 10) minutes, respectively. Dose area product was 1,100 (IQR 1252) cGyxcm2. Freedom from AA after 6 months follow-up time and 90 days blanking period was documented in 10/17 (59%) patients, and 8/17 (47%) without a blanking period. No major complication was observed.ConclusionThe combined use of CBA with optional RFA guided by a novel 3D-WBDIS is feasible and safe in patients suffering from complex AA. The occlusion tool shows high sensitivity and specificity for assessment of the balloon occlusion. Additional arrhythmias were successfully mapped and ablated. Short-term outcome is promising, and subsequent prospective, larger outcome studies are necessary to confirm our observations.

Clinical utility of non-contact charge density 'SuperMap' algorithm for the mapping and ablation of organized atrial arrhythmias.

AimsSuperMap is a novel non-contact algorithm for the mapping of organized atrial arrhythmias. We prospectively evaluated SuperMap during mapping and ablation of atrial tachycardias (ATs) and paced rhythms and compared to conventional high-density contact mapping.Methods and resultsConsecutive patients undergoing SuperMap guided ablation of pre-existing ATs or AT developed during atrial fibrillation ablation procedures were included together with maps obtained during pacing to assess block in linear lesions. The time taken to obtain diagnostic maps was measured together with the number of electrogram (EGM) points and accuracy compared to the arrhythmia diagnosis confirmed using a combination of map findings, entrainment, and response to ablation. In a subgroup of patients, concurrent contact mapping was performed with contact and SuperMap analysed by separate operators blinded to the other technique. The time taken to generate a diagnostic map, EGM number, and map accuracy was compared. Thirty-one patients (62 maps) were included with contact mapping performed in 19 [39 maps (33 for AT)]. SuperMap acquisition time was 314 s [interquartile range (IQR) 239–436]. The median number of EGM points used per map was 5399 (IQR 3279–8677). SuperMap was faster than contact mapping [394 ± 219 s vs. 611 ± 331 s; difference 217 s, 95% confidence interval (CI) 116–318, P < 0.0005]. The number of EGM points used per map was higher for SuperMap (7351 ± 5054 vs. 3620 ± 3211; difference 3731, 95% CI 2073–5388, P < 0.0005). SuperMap and contact mapping were accurate in 92% and 85% of maps, respectively, P = 0.4805.ConclusionSuperMap non-contact charge density mapping is a rapid and reliable approach to guide the ablation of complex atrial arrhythmias.

A novel noncontact high-resolution charge density mapping system to guide ablation of complex atrial arrhythmias: overview of device technology and application

ABSTRACT Introduction: Despite advances in imaging technology to guide ablative therapies, catheter ablation of more complex arrhythmias continues to be a challenge in part due to suboptimal mechanistic understanding of these arrhythmias by conventional mapping systems. A novel noncontact charge density mapping system has been designed to overcome some of these limitations. Areas covered: Hereby, we present an overview of this novel, charge density-based global chamber mapping approach. We initially highlight the concept of charge density, describe further the device technology and finally summarize the clinical application of this system. Expert opinion: Noncontact charge density mapping provides a more localized, high-resolution global panoramic assessment of cardiac activation. This might contribute to uncover the mechanisms of more complex arrhythmias such as persistent atrial fibrillation or unstable atrial tachycardias with the ultimate goal to guide the ablation therapy.

Catheter ablation of complex atrial tachyarrhythmias in adult patients with cor triatriatum.

Reports concerning clinical characteristics of cor triatriatum and approaches for catheter ablation of complex atrial tachyarrhythmias remain limited. Here, we describe successful catheter ablation treatments for complex atrial tachyarrhythmias in patients with cor triatriatum and address the clinical caveats. Demographic characteristics, electrophysiologic findings, and ablation results in four patients with cor triatriatum were described. Catheter ablation was performed in four patients with cor triatriatum (three sinister and one dexter) and complex atrial arrhythmias (three with persistent atrial fibrillation (AF) and one with atypical left atrial flutter). A transseptal puncture was selectively directed into the accessory compartment containing the pulmonary veins. A comprehensive preview involving transthoracic echocardiography, transesophageal echocardiography, and computed tomography of the pulmonary veins was critical for proper positioning of ablation catheters. The pulmonary veins remain the major triggers or initiators for AF, and four pulmonary vein isolation procedures were sufficient to achieve successful results with negative inducibility test in the patients with AF. Heterogeneous conduction and complex fractionated signals were observed on the fibromuscular membrane. Atypical flutter was terminated during ablation over the connection between membrane and left atrial roof. The procedure was successfully performed on all patients without complications. No acute recurrences of atrial tachyarrhythmias were observed in any of the patients during short-term follow-up. Catheter ablation is a feasible and efficient therapeutic strategy for treating complex atrial tachyarrhythmias in patients with cor triatriatum. Atrial remodeling due to anatomical obstruction or heterogeneous conduction of the fibromuscular membrane may serve as an arrhythmic substrate.

Initial multicenter experience with a new high-density coloring module: impact for complex atrial arrhythmias interpretation.

High-density automated mapping of complex atrial tachycardias (ATs) requires accurate assessment of activation maps. A new local activation display module (HD coloring, Biosense Webster®) provides higher map resolution, a better delineation of potential block reducing color interpolation, and a new propagation display. We evaluated the accuracy of a dedicated local activation display compared with standard algorithm. High-density maps from 10 AT were collected with a multipolar catheter and were displayed with standard activation or HD coloring. Six expert operators retrospectively analyzed activation maps and were asked to define (1) the tachycardia mechanism, (2) ablation target, and (3) level of difficulty to interpret those maps. Using HD coloring, operators were able to reach a correct diagnosis in 93% vs. 63%, p < 0.05 compared to standard activation maps. Time to diagnosis was shorter 1.9 ± 1.0min vs. 3.9 ± 2.1min, p < 0.05. Confidence level would have allowed ablation without necessity for entrainment maneuvers in 87% vs. 53%, p < 0.05. Operators would have needed to remap or proceed with multiple entrainments in 3% vs. 13% of cases, p < 0.05. Finally, ablation strategy was more accurately identified in 97% vs. 67%, p < 0.05. Activation mapping with the new HD coloring module allowed a more accurate, reliable, and faster interpretation of complex ATs mechanisms compared to standard activation maps.

Benefit of ultra-high-density mapping-guided radiofrequency reablation in pulmonary vein isolation non-responders after initial cryoballoon procedure.

Symptomatic atrial arrhythmias despite complete pulmonary vein isolation (PVI) are common. The purpose was to evaluate ultra-high-density multi-electrode electroanatomical mapping-guided radiofrequency ablation (RFA) in PVI non-responders. Ultra-high-density multi-electrode electroanatomical mapping-guided RFA in consecutive symptomatic atrial fibrillation (AF) patients after initial cryoballoon PVI was performed. Patients were included if all pulmonary veins (PVs) were still isolated. Radiofrequency targets were atrial tachycardia (AT), extra-PV trigger, and/or substrate. Procedural results and outcome were evaluated. Of 95 patients, 67 (70.5%) with complete PVI were included (70 years, CHA2DS2Vasc 2.9, left atrium 45 mm, persistent AF 45%, AT 45%). The median time to reablation was 26 months. One hundred and seven maps (1.6/patient) and 11.890 ± 9.018 electrograms were acquired in 33 ± 12 min. Twenty-eight percent of the left atrial (LA) wall showed pathological voltage signals, predominantly at the anterior (37%) and septal wall (26%). Atrial tachycardia (49 left, 4 right) were ablated in 35 patients (52%), extra-PV trigger in two patients (3%). One atrioventricular nodal re-entry tachycardia and seven right atrial isthmus ablation (10%) were performed. In 32 patients (48%), no AT was present and substrate-based ablation was performed. Mean LA area ablated was 7 ± 6 cm2 (7%). No major complication occurred. The mean follow-up time was 772 ± 317 days. Freedom from atrial arrhythmia recurrence off antiarrhythmic drugs was 49% at 12 months. Pulmonary vein isolation non-responders are older, mainly suffering from complex atrial arrhythmias. Left atrial substrate is predominantly located at the anterior and septal wall. Ultra-high-density multi-electrode electroanatomical mapping-guided RFA is safe and effective. At 1 year, 5 out of 10 patients were in stable sinus rhythm off antiarrhythmic drugs.

Multi-electrode mapping of complex macroreentry atrial tachycardia

BackgroundMulti-electrode mapping (MEM) is increasingly applied in ablation of complex atrial arrhythmias. This study aimed to evaluate MEM for analysis and treatment of complex macroreentry atrial tachycardia (MAT). MethodsPatients with MAT related to scarring, history of heart surgery or atrial linear ablation were studied. Patients were mapped with conventional activation mapping (CAM) or MEM. After characterizing the mechanism of atrial tachycardia (AT), the ablation was performed. ResultsThe study consisted of 114 eligible patients, 74 in the CAM and 40 in MEM. Compared with CAM, MEM had a shorter procedure duration (156.7 ± 59.1 ms vs. 127.3 ± 59.3 ms, P = 0.003) and mapping duration (62.6 ± 35.7 ms vs. 30.5 ± 15.3 ms, P < 0.001) and more mapping points (1364.9 ± 828.7 points vs. 148.3 ± 79.6 points, P < 0.001). There were no significant differences between CAM and MEM in acute ablation success rate, complication, postoperative AADs, and ablation duration. The mean disease-free survival time in CAM versus MEM was 20.8 (95% CI: 17.6–24.1) months versus 26.6 (95% CI: 22.7–30.4) months. The median disease-free survival time in the CAM versus MEM was 20.0 (95% CI: 13.9–26.1) months versus 30.0 (95% CI: 26.7–36.3) months. The AT recurrence risk of MEM was 0.522 times that of CAM (HR 95% CI: 0.282–0.968; P = 0.039). ConclusionMEM is strongly recommended in ablation of complex MAT.

Extensive Use of 3D Nonfluoroscopic Mapping Systems for Reducing Radiation Exposure during Catheter Ablation Procedures: An Analysis of 10 Years of Activity.

Purpose 3D nonfluoroscopic mapping systems (NMSs) are generally used in the catheter ablation (CA) of complex ventricular and atrial arrhythmias. The aim of this study was to evaluate the efficacy, safety, and long-term effect of the extended, routine use of NMSs for CA. Methods Our study involved 1028 patients who underwent CA procedures from 2007 to 2016. Initially, CA procedures were performed mainly with the aid of fluoroscopy. From October 2008, NMSs were used for all procedures. Results The median fluoroscopy time of the overall CA procedures fell by 71%: from 29.2 min in 2007 to 8.4 min in 2016. Over the same period, total X-ray exposure decreased by 65%: from 58.18 Gy⁎cm2 to 20.19 Gy⁎cm2. This reduction was achieved without prolonging the total procedure time. In AF CA procedures, the median fluoroscopy time fell by 85%, with an 86% reduction in total X-ray exposure. In SVT CA procedures, the median fluoroscopy time fell by 93%, with a 92% reduction in total X-ray exposure. At the end of the follow-up period, the estimated probability of disease-free survival was 67.7% at 12 months for AF CA procedures and 97.2% at 3 months for SVT CA, without any statistically significant difference between years. Conclusions Our study shows the feasibility of using NMSs as the main imaging modality to guide CA. The extended, routine use of NMSs dramatically reduces radiation exposure, with only slight fluctuations due to the process of acquiring experience on the part of untrained operators, without affecting disease-free survival.

Multifocal atrial and ventricular premature contractions with an increased risk of dilated cardiomyopathy caused by a Nav1.5 gain-of-function mutation (G213D)

Background: SCN5A mutations can lead to different cardiac diseases. Recently, SCN5A mutations have been linked to the clinical entity multifocal ectopic Purkinje-related premature contractions (MEPPC) characterized by ventricular ectopy and dilated cardiomyopathy.Methods & Results: A family with a uniform MEPPC-like phenotype, associated with complex atrial and ventricular arrhythmias and dilated cardiomyopathy caused by a high frequency of ventricular ectopy was clinically assessed. Screening of the SCN5A gene revealed a missense mutation in the linker between segments 3 and 4 in domain 1 of the Nav1.5 protein, resulting in a glycine to aspartate substitution at position 213 (G213D). The phenotype co-segregated with the missense mutation. Electrophysiological studies of wild type (WT) hNav1.5 and hNav1.5_G213D expressed in CHO-K cells showed that the voltage of half-maximal activation (V½) was significantly more negative for hNav1.5_G213D compared to WT (V½=−38.7±0.5mV for WT and V½=−42.4±0.5mV for G213D; P<0.001). This suggests activation of Nav1.5_G231D at more negative potentials. The V½ of steady-state inactivation was significantly shifted towards more positive values for Nav1.5_G213D (V½=−86.7±0.2mV for WT and −82.2±0.3mV for G213D; P<0.001), also contributing to a gain-of-function phenotype. Flecainide and amiodarone markedly reduced premature atrial and ventricular contractions in four patients.Conclusion: The Nav1.5_G213D mutation is associated with a gain-of-function phenotype, multifocal atrial and ventricular ectopy and dilated cardiomyopathy. Since patients with a MEPPC-like phenotype may specifically benefit from Class-1 antiarrhythmic drugs or amiodarone, clinical identification of this disease entity is important.

Characterization of a NaV1.5 Gain-of-Function Mutation (G213D) causing Multifocal Atrial and Ventricular Premature Ectopies and an Increased Risk of Dilated Cardiomyopathy

Background: Mutations in SCN5A have been linked to different cardiac diseases including multifocal ectopic Purkinje-related premature contractions (MEPPC) characterized by ventricular ectopy and dilated cardiomyopathy (DCM). Here we characterize the Nav1.5 G213D variant found in a large Danish family with frequent premature ventricular and atrial contractions, frequent nonsustained ventricular tachycardia and DCM. Methods and Results: The family was clinically assessed and an MEPPC-like phenotype including complex atrial and ventricular arrhythmias and dilated cardiomyopathy was found. Genetic screening revealed a G213D Nav1.5 missense mutation in the link of segment 3 and 4 in domain 1 of the Nav1.5 protein. The MEPPC-like phenotype co-segregated with G213D. Electrophysiological studies of wild type (WT) hNav1.5 and hNav1.5_G213D expressed in CHO-K cells was performed using conventional patch clamp and a SynchoPatch 384PE (Nanion Technologies) high throughput automatic patch clamp. The half-maximal inactivation (V½) was significantly more negative for hNav1.5_G213D compared to WT and the V½ of steady-state inactivation was shifted towards more positive values for hNav1.5_G213D, resulting in increased window-currents. This suggests that hNav1.5_G213D activates at more negative potentials and a larger fraction of channels will recover from inactivation during the diastole resulting in a gain-of-function phenotype. A combination of wild type and G213D mimicking the heterozygote state exhibited an intermediate phenotype. Flecainide or amiodarone resulted in a markedly reduced number of premature atrial and ventricular contractions in patients. Conclusions: The G213D Nav1.5 variant is associated with a gain-of-function and is associated with multifocal atrial and ventricular ectopy and dilated cardiomyopathy.

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.

Comparison of Computer Tomography and 3D Rotational Angiography of the Left Atrium before Atrial Fibrillation Catheter Ablation; Radiation Exposure, Contrast Agent Consumption and Cost Effectiveness

Background: Catheter ablation of complex atrial arrhythmias guided by 3D models of the left atrium (LA) derived from CT/MRI or 3D rotational angiography of the heart (3DRA) is currently a common practice. Our aim is to compare radiation dose, consumption of contrast agent and cost of these methods. Materials and methods: Over the period from October 2011 to October 2014, either 3DRA or CT of the LA was performed in 314 patients referred to complex atrial arrhythmias ablation. 3DRA (157 patients) was done according to the LA protocol using the X-ray system Philips Allura FD 10, CT (157 patients) using 64-slice CT GE Light speed VCT. All procedures were monitored for average effective dose and dose of the contrast agent. For both methods, analysis of the financial costs was conducted. Results: The average effective radiation dose for 3DRA was 2.11 ± 0.392 mSv compared to 10.52 ± 2.093 mSv for CT. The contrast agent consumption was 22.2 mg of iodine compared to 48.4 mg of iodine in CT. Total price per procedure is 123 € for 3DRA and 162 € for CT. Conclusion: Consumption of the contrast agent and radiation burden for 3DRA of the left atrium is significantly lower than most currently used CT scan methods. The advantage of a lower X-ray dose and contrast agent compared to CT of the heart is relative and with new generations of CT devices, both methods will be comparable. Cost of the both methods is comparable; 3DRA is slightly less expensive than CT.

Left atrial enlargement causing dysphagia and weight loss: A rare contraindication for catheter ablation therapy in a patient with complex atrial arrhythmia

Left atrial enlargement causing dysphagia and weight loss: A rare contraindication for catheter ablation therapy in a patient with complex atrial arrhythmia

40Dot mapping: a novel technique for dual electrophysiological dataset representation facilitates recognition of complex intra-atrial re-entrant tachycardia substrate in repaired adult congenital heart disease

Introduction: Adult congenital heart disease (ACHD) patients have a high lifetime prevalence of reentrant atrial arrhythmia, secondary to both the anatomic lesion and surgical repair. Catheter ablation is an effective treatment for atrial tachycardia (AT), however current electroanatomical mapping (EAM) systems permit the display of only a single data modality per shell at a given time. Localised voltages can reveal prior structural information critically related to arrhythmia mechanisms. A bipolar voltage threshold of <0.05mV has traditionally been accepted for the annotation of scar (based on the noise threshold of the Carto system), with voltage <0.5mV taken to represent abnormal atrial tissue. We sought to assess the feasibility of dual representation of activation time (LAT) and voltage on the atrial shell of patients with repaired congenital heart disease. Methods: Surface shading was used to represent LAT and finely spaced dots (‘Dot Mapping’) were utilized to represent voltage. Low voltages are represented by high dot density and the cloud overlaid on the activation map (see Figure 1). Dot positions are randomized within triangular (surface meshes) or tetrahedral (volumetric meshes) simplices making the approach directly transferrable to contemporary EAM systems. In order to assess the feasibility of co-representation, users (n=10) completed a 5-point Likert scale questionnaire covering three domains (diagnostic accuracy, display fidelity and dataset co-registration) for both Dot Maps and traditional color maps. Subsequently, the technique was applied to seventeen patients with repaired ACHD who had undergone catheter ablation procedure for AT using CARTO3. Voltage and activation time datasets were exported for offline co-display using Matlab. Results: With 5 items in each domain, the maximum score per domain is 25. Dot Mapping out-performed color maps in the “Dataset co-registration” domain (median score 24.5 vs 10, p<0.05, Wilcoxon two-sample signed rank), “Diagnostic accuracy” (17 vs 21) and “Display fidelity” (18 vs 20) scored similarly, indicating that the Dot Mapping software faithfully represents the input datasets. Conclusion: Dot mapping facilitates co-display of complimentary data sets. Interpretation of activation time maps in the context of structural arrhythmia substrate may improve diagnosis of mechanisms of complex atrial arrhythmias in repaired ACHD. ![Graphic][1] Figure 1 Demonstrates a representative example of a repaired congenital heart disease dataset with voltage information overlaid on a localized activation time map. [1]: /embed/inline-graphic-1.gif