3-dimensional Electroanatomic Mapping System Research Articles

Longitudinal reduction in fluoroscopy with continued use of 3-dimensional electroanatomic mapping systems in catheter ablation of supraventricular tachycardia – then and now

BackgroundCatheter ablation is a first-line treatment for symptomatic, recurrent supraventricular tachycardia (SVT). This study aims to demonstrate if 3D-electroanatomic mapping (EAM) during SVT ablation reduces fluoroscopy time (FT) and determine if further reductions in FT are observed longitudinally. MethodsAll cases of SVT ablation between May 2011–May 2022 at a single tertiary centre were prospectively recruited. FT between the cohorts with and without EAM were compared. Within the EAM subset, the trend of FT across the years was analysed. ResultsThere were 1758 cases included, 563 without EAM, 1195 with EAM. EAM was associated with a longer procedure time (mean + 8.8 min, p = 0.001), but with mean reductions in FT and dose area product (DAP) by 19.6 min and 18 621 mGy*cm2 respectively (p < 0.001). There was comparable efficacy without any increase in complication rates. Over time (2011–2022), further reduction in FT of 0.9 min year on year was observed (p = 0.001). Between 2011 and 2017, there was a significant reduction in FT of 1.1 min year on year (p = 0.019), which was not observed from 2017 onwards (p = 0.061). The greatest reduction in FT was after the first year of adoption. ConclusionEAM in SVT ablation reduces fluoroscopy use. FT was initially observed to reduce further over time before plateauing, likely due to increased operator experience. While there is increased interest in zero fluoroscopy SVT ablation, complementary use of fluoroscopy may still be necessary in complex cases.

Assessment of Esophageal Shifts during Catheter Ablation of Atrial Fibrillation Using Intracardiac Ultrasound Integrated with 3-Dimensional Electroanatomical Mapping System.

Purpose: Atrioesophageal fistula is one of the most feared complications of radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) as it is associated with high mortality. Determining the esophagus location during RFCA might reduce the risk of esophageal injury. The present study aims to evaluate the feasibility of using intracardiac echocardiography integrated into a 3-dimensional electroanatomical mapping system (ICE/3D EAM) for the assessment of esophageal position and shifts in response to ablation. Methods: We prospectively enrolled 20 patients that underwent RFCA of AF under conscious analgosedation. The virtual anatomy of the left atrium, the pulmonary vein (PV) ostia, and the esophagus was created with ICE/3D EAM. The esophageal positions were obtained at the beginning of the procedure and then after left and right PV isolation (PVI). Esophageal shifts were measured offline after the procedure using the tools available in the 3D EAM system. Results: Most esophagi moved away from the ablated PV ostia. After the left PVI, the median of the shifts was 2.8 mm (IQR 1.0-6.3). In 25% of patients, the esophagus shifted by >5.0 mm (max. 13.4 mm). After right PVI, the median of shifts was 2.0 mm (IQR 0.7-4.9). In 10% of patients, the esophageal shift was >5.0 mm (max. 7.8 mm). Conclusions: ICE/3D EAM enables the intraprocedural visualization of baseline esophageal position and its shifts after PVI. The shifts are variable, but they tend to be small and directed away from the ablation site. Repeated intraprocedural visualization of the esophagus may be needed to reduce the risk of esophageal injury.

Impact of 3-dimensional electroanatomic mapping systems on fluoroscopy reduction in catheter ablation of supraventricular tachycardia - then and now

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation is an effective first-line treatment for symptomatic and recurrent supraventricular tachycardia (SVT). The advent of 3D electroanatomic mapping (EAM) has led to a reduction in fluoroscopy use and consequently lower radiation exposure for patients and staff during SVT ablation. Purpose The aims of this study are to demonstrate if the use of EAM during SVT ablation reduces fluoroscopy time (FT), and determine if further reductions in FT are observed longitudinally. We hypothesise that over time, with continued use and wider adoption of EAM, greater operator experience, and technological advancements in EAM, there will be further reductions in radiation exposure as estimated by FT. Methods All cases of atrioventricular nodal re-entry tachycardia (AVNRT), atrioventricular re-entry tachycardia (AVRT), and/or atrial tachycardia (AT) ablation between May 2011 to May 2022 at a tertiary centre were prospectively recruited. FT between the groups with and without EAM were compared. Within the EAM subset, the trend of FT across the years was also analysed. Results Over this 11-year period, there were 1758 cases of SVT ablation (565 without EAM; 1193 with EAM). Between the two groups, there were no significant differences (p &amp;gt; 0.05) in age, sex, history of structural heart disease and/or ischaemic heart disease, stereotaxis use, and diagnosis (AVNRT, AVRT, AT). Cases using EAM were more likely to have &amp;gt;1 SVT ablated during the procedure (0.04) and require intracardiac echocardiography (ICE) (p &amp;lt; 0.001). The use of EAM was associated with mean reductions in FT and dose area product (DAP) by 19.6 minutes and 18 581 mGy*cm2 respectively (both p &amp;lt; 0.001). EAM was also associated with a longer procedure time (mean +8.8 minutes, p &amp;lt; 0.001). There was no difference in radiofrequency application time between the two groups (p = 0.143). After controlling for potential confounding factors including age, sex, use of stereotaxis, use of ICE, type and number of SVT, history of prior ablation, and structural heart disease and/or ischaemic heart disease, we found over time (2011-2022), further reduction in FT was observed, with a mean reduction of 0.9 minutes year on year (p &amp;lt; 0.001). EAM was gradually adopted through the years with the number of cases per year plateauing after 2017. Between 2011-2017, there was a significant reduction in FT (mean of -1.1 minute year on year, p = 0.020), which was not observed from 2017 onwards (p = 0.088). The greatest reduction in FT was observed after the first year of adoption, with a mean reduction of 6.9 minutes between 2012-2013. Conclusion This demonstrates that use of EAM in SVT ablation reduces FT and fluoroscopy DAP. There was no incremental benefit observed after 6 years of EAM adoption likely related to operator experience. While there is increased interest in zero fluoroscopy SVT ablation, complementary use of fluoroscopy may still be necessary in select complex cases.

PO-01-074 USE OF ELECTRO-ANATOMIC MAPPING TO REDUCE THE NUMBER OF LEAD DEPLOYMENT ATTEMPTS FOR OPTIMAL LEFT BUNDLE AREA PACING: A CASE SERIES

Left bundle area pacing (LBP) often requires multiple lead deployments into the interventricular septum to find an ideal site with left bundle capture. Evaluate the use of 3-dimensional electro-anatomical mapping system (3D map) to aid in the identification of the correct implant site to achieve optimal left bundle branch capture. Three consecutive patients requiring pacing for AV block with LVEF 40-45% are included in this case series. After ultrasound-guided axillary vein access, a decapolar catheter was advanced and visualized using Carto (DecaNav, Biosense Webster). Intracardiac anatomy was defined using fast activation mapping in the region of the bundle of His and right ventricular septum. High- and low-output pacing was delivered from each of the electrode pairs of the decapolar catheter while it abutted the septum. Ideal deployment site was chosen from among the electrode pair sites based on W-pattern in V1, R wave axis in inferior leads, and aVL/aVR relationship. After this site was marked on the 3D map, the catheter was removed and the pacing lead (Biotronik Solia S60) was advanced under 3D mapping guidance and deployed. Please see Table 1 for patient characteristics and procedure details. Please see figure for EAM Utilization of 3D mapping to select the ideal site of LBP capture can allow for (1) improved procedural efficiency, (2) decreased fluoroscopy usage, and (3) successful LBP capture with a single deployment.Tabled 1Patient characteristics and Procedure detailsPatient 1Patient 2Patient 3Age (years)645577GenderMaleMaleFemaleBody Mass Index (Kg/m2)273421Number of implant attempts111Fluoroscopy time2 minutes 25 secs1 min 47 secs2 minutes 50 secsComplicationsNoneNoneNone Open table in a new tab

Pulmonary vein size is associated with reconnection following cryoballoon ablation of atrial fibrillation.

The second-generation cryoballoon (CB) has proven to be a highly effective ablative strategy in patients with symptomatic atrial fibrillation (AF). This study sought to investigate the anatomical characteristics of pulmonary veins (PVs) and the relationship between their size, ovality, and late reconnections in a large cohort of patients undergoing repeat ablation for recurrence of atrial arrhythmias. A total of 152 consecutive patients (98 males, 64.5%; mean age 64.9 ± 9.6years) underwent a repeat ablation for recurrent atrial tachyarrhythmias after a median time of 6.5months [IQR 11] from the index CB ablation. All repeat ablations were performed using a 3-dimensional electro-anatomical mapping system. Among all 593 PVs, 134 (22.6%) showed a late PV reconnection in 95 patients (0.88 per patient), at the time of repeat ablation procedure. There was a significant difference in ovality between left- and right-sided PVs (p < 0.001). Greater diameters of left superior PV, left inferior PV, and right inferior PV ostia (both maximum and minimum) and higher index ovality were significantly associated with late PV reconnection. The rate of late PV reconnection after CB ablation was low (0.88 PVs/patient). Left-sided PVs were more oval than septal PVs. Larger PV dimensions and higher ovality index were significantly associated with reconnections in all PVs except for RSPV.

Durability of pulmonary vein isolation following cryoballoon ablation: lessons from a large series of repeat ablation procedures

Abstract Funding Acknowledgements Type of funding sources: None. Background The cryoballoon technology has been widely proven to be effective in achieving acute pulmonary vein (PV) isolation and favorable clinical outcome. To date, little information is still available about occurrence of late PV reconnection after cryoballoon ablation. Purpose To assess the rate of durable PV isolation following cryoballoon ablation of atrial fibrillation in the setting of repeat procedures. Methods and Results A total of 154 consecutive patients (90 male, 58.4%; mean age 60.6±12.6 years) underwent a repeat procedure, after a mean 21.5±12.4 months (median 14 months), after index ablation using the 28-mm second-generation cryoballoon. All repeat ablations were performed using a 3-dimensional electro-anatomical mapping system. Among all 590 PVs, including 26 left common ostiums (LCOs), 99 (16.8%) showed a PV reconnection in 86 patients (1.15 per patient). Persistent PV isolation could be documented in 491 of 590 PVs (83.2%). In 68 of 154 patients (44%), all PVs were electrically isolated. In the multivariable analysis, balloon nadir temperature (p&amp;lt;0.01) and time to PV isolation (P=0.02) independently predicted late PV reconnection. Conclusions The rate of late PV reconnection after second-generation cryoballoon ablation was low (1.15 PVs/patient). Globally, the rate of durable PV isolation assessed during repeat procedures was 83.2%. The balloon nadir temperature and faster time to isolation were independently associated with durable PV isolation.

Comparison of ostial versus very wide antral circumferential pulmonary vein isolation using pulsed field ablation

Abstract Funding Acknowledgements Type of funding sources: None. Background Pulmonary vein isolation (PVI) is the gold standard for first-time atrial fibrillation (AF) ablation procedures. Wide antral circumferential ablation (WACA) in comparison to ostial PVI has been attributed to an improved rhythm outcome after AF ablation. Pulsed field ablation (PFA) is a novel energy source with promising safety and efficacy advantages over existing ablation methods due to its unique myocardial tissue specificity. Feasibility of PFA for very WACA has not been investigated so far. Objective To evaluate procedural characteristics and lesion formation during wide antral circumferential PVI in comparison to ostial PVI using a PFA system. Methods Thirty-seven consecutive AF patients underwent first-time PFA under deep sedation. Patients eighter received ostial (ostial group; N = 15: 66 % paroxysmal AF; age: 69 years; 66 % male) or very wide antral (vWACA group; N = 22: 59 % paroxysmal AF; age: 62 years; 73 % male) PFA. Pre and post ablation LA voltage maps were acquired using a 20-pole spiral catheter together with a 3-dimensional electroanatomic mapping system (voltage cutoff ≤0.5 mV). On post ablation maps, lesion size by encircling the ablated area was measured. In all patients, 8 pulse trains (2kV/2.5 sec, bipolar, biphasic, 4x basket/flower configuration each) were delivered to each pulmonary vein (PV). In the vWACA-group, extra pulse trains in flower configuration were added to each PV in a wide antral position continuous intraluminal esophageal temperatures (TESO) were monitored with an S-shaped esophageal temperature probe. Results A median of 8 [IQR 8;8] and 10 [IQR 10;11] pulse trains per PV for ostial and vWACA PVI were applied. vWACA PFA resulted in significant larger lesion formation (47.3 cm2 [IQR 39.1; 52.0]) in comparison to ostial PFA (35.5 cm2 [IQR 30.3; 38.1], p=0.013) with consecutive posterior LA wall isolation in 19/22 (86 %) patients (Figure 1). In the vWACA group, median TESO increased by 0.7 °C (TESOmax 36.5 °C [IQR 36.0;36.9]). However, the vWACA approach was not associated with a significant increase in procedure time, sedation dosage or exposure to radiation. Conclusion Very wide antral circumferential PFA of the PVs is feasible and was associated with significant larger lesion formation in comparison to conventional ostial PFA. Concomitant posterior LA wall isolation occurred in the majority of patient and did not result in a clinically significant increase of intraluminal esophageal temperatures, procedure time, sedation and radiation dosage.

Durability of pulmonary vein isolation following cryoballoon ablation: Lessons from a large series of repeat ablation procedures.

IntroductionThe second-generation cryoballoon (CB) has emerged in the last decade as an effective treatment for atrial fibrillation (AF). This study sought to analyze the rate of PV reconnection following CB ablation, evaluate the most frequent PV sites of conduction recovery and finally to assess procedural and biophysical indicators of reconnection in a large cohort of patients undergoing repeat ablation for recurrence of atrial arrhythmias.Methods and ResultsA total of 300 consecutive patients (189 males, 63%; mean age 63.0 ± 11.1 years) underwent a repeat ablation after 18.2 ± 10.8 months from the index CB ablation. All repeat ablations were performed using a 3-dimensional electro-anatomical mapping system. Among all 1178 PVs, 209 (17.7%) showed a late PV reconnection in 177 patients (1.18 per patient), at the time of repeat ablation procedure. Overall, persistent PV isolation could be documented in 969 of 1178 PVs (82.3%). In 123 of 300 patients (41%), persistent isolation could be demonstrated in all PVs, whereas PV reconnection could be documented in 177 patients (59%). In the multivariable analysis, nadir temperature (p = 0.03), time to PV isolation (p = 0.01) and failure to achieve − 40 °C within 60 s (p = 0.05) were independently associated with late PV reconnection.ConclusionsThe rate of late PV reconnection after CB ablation was low (1.18 PVs/patient). The most frequent sites of reconnections were the superior-anterior portions for the upper PVs and the inferior-posterior portions for the lower PVs. Faster time to isolation, colder nadir temperatures and achievement of − 40 °C within 60 s were associated with durable PV isolation.

Mapping the Conduction System in Patients Undergoing Transcatheter Device Closure of Perimembranous Ventricular Septal Defect: A Proof-of-Concept Study.

Earlier studies that investigated the relation of atrioventricular (AV) conduction system to perimembranous ventricular septal defect (pmVSD) were based on cardiopathological specimens. To study the relationship of conduction system to pmVSD using 3-dimensional electroanatomic mapping system (EAMS) in patients undergoing device closure. Fifteen consecutive cases of pmVSD from January 2014 to July 2017 (age > 2years and weight > 8kg) were included in the study. The course of conduction system and its relationship with the pmVSD was mapped before and after device closure, with the use of EAMS. Median age and weight of the cohort was 10years (range 4-21years) and 25kg (range 13-55) respectively. Device implantation was successful in all patients except 1. The course and relation of the conduction system were posteroinferior to the pmVSD in all cases (100%), and away from the defect in 67% (10/15). In patient with baseline RBBB, the right-sided conduction system was in close proximity to the pmVSD. Two patients had part of left-sided conduction system in close proximity to pmVSD or device edges. Two patients developed RBBB following device deployment, which reverted to normal on follow up. No patient developed high grade AV block during the median follow-up of 34months (range 24-62). This experimental study has shown the feasibility of 3D EAM of conduction system during device closure of pmVSD. This novel concept can be utilized to understand the anatomy of conduction system in other congenital heart diseases.

Three-dimensional guided selective right ventricular septal pacing preserves ventricular systolic function and synchrony in pediatric patients

Nonfluoroscopic 3-dimensional (3D) electroanatomic mapping systems (EAMs) have been developed to guide cardiac catheter navigation and reduce fluoroscopy. Selective right ventricular (RV) septal pacing could prevent pacing-induced left ventricular (LV) dysfunction. The purpose of this study was to determine whether EAM-guided selective RV septal pacing preserves LV contractility/synchrony in pediatric patients with complete atrioventricular block (CAVB) and no other congenital heart defects. Prospective analysis of children/adolescents who underwent EAM-guided selective RV pacing was performed. A 3D pacing map guided ventricular lead implantation at septal sites with narrow paced QRS. Serial echocardiograms were obtained after pacemaker implantation to monitor for function (volumes, ejection fraction [EF], global longitudinal/circumferential strain) and synchrony (interventricular mechanical delay, septal to posterior wall motion delay, systolic dyssynchrony index). Data are reported as median (25th-75th percentile). Thirty-two CAVB patients (age 9.8 [7.0-14.0] years; 11 with a previous pacing system) underwent selective RV septal pacing (13 DDD, 19 VVIR pacemaker; midseptum 22, parahisian 7, RV outflow tract 3) with narrow paced QRS (110 [100-120] ms) and low radiation exposure. Follow-up over 24 (5-33) months showed preserved LV function and synchrony, without significant differences between pacing sites (midseptum-parahisian) and mode (VVIR-DDD). EF decreased after implantation in patients without previous pacing, although values were mainly within normal limits. Three parahisian patients underwent early lead repositioning. EAM-guided selective RV septal pacing is a feasible technique associated with preserved LV systolic function and synchrony and low radiation exposure in pediatric patients with CAVB.

Prediction of premature ventricular complex origins using artificial intelligence–enabled algorithms

BackgroundCatheter ablation is a standard therapy for frequent premature ventricular complex (PVCs). Predicting their origin from a 12-lead electrocardiogram (ECG) is crucial but it requires specialized knowledge and experience.ObjectiveThe objective of the present study was to develop and evaluate machine learning algorithms that predicted PVC origins from an ECG.MethodsWe developed the algorithms utilizing a support vector machine (SVM) and a convolutional neural network (CNN). The training, validating, and testing data consisted of 116 PVCs from 111 patients who underwent catheter ablation. The ECG signals were labeled with the PVC origin, which was confirmed using a 3-dimensional electroanatomical mapping system. We classified the origins into 4 groups: right or left, outflow tract, or other sites. We trained and evaluated the model performance. The testing datasets were also evaluated by board-certified electrophysiologists and an existing classification algorithm. We also developed binary classification models that predicted whether the origin was on the right or left side of the heart.ResultsThe weighted accuracies of the 4-class classification were as follows: SVM 0.85, CNN 0.80, electrophysiologists 0.73, and existing algorithm 0.86. The precision, recall, and F1 in the machine learning models marked better than physicians and comparable to the existing algorithm. The SVM model scored among the best accuracy in the binary classification (the accuracies were 0.94, 0.87, 0.79, and 0.90, respectively).ConclusionArtificial intelligence–enabled algorithms that predict the origin of PVCs achieved superior accuracy compared to the electrophysiologists and comparable accuracy to the existing algorithm.

Predictors of silent cerebral infarction associated with catheter ablation for atrial fibrillation

Abstract Introduction Cather ablation (CA) has been identified as an effective and safe treatment option for patients with atrial fibrillation (AF). One of the serious complications associated AF is cerebral infarction (CI). Recent studies reported that CA was associated with lower incidence of ischemic stroke in patients with AF. However, CA for AF itself has a potential risk of CI. Several previous studies showed that the incidence of silent CI (SCI) assessed by magnetic resonance imaging (MRI) of the brain occurred 5 to 18% during CA for AF. Recently, CA for AF made a remarkable progress in technology. However, there are few information available that the impact of 3-dimensional electroanatomical mapping system on the incidence of SCI. This study aimed to clarify the prevalence and predictors of SCI during CA for AF. Methods We enrolled 893 consecutive patients (male 534, age 71±10 years), who underwent CA for AF and MRI of brain 1 day after the procedure. We collected patients data such as physical examinations, blood sampling, echo cardiography, and CA data. A brain MRI was performed the next day following the procedure to identify any CIs. One-hundred and forty-six of patients used the Rhythmia® mapping system catheter, and the other mapping system such as CARTO or EnSite system used in the remaining 747 patients. Results The MRI depicted acute micro-CIs in 144 (16%) patients, but neither symptoms nor abnormal neurological findings were present in these patients. Patients with SCI had significantly higher prevalence of persistent AF (60 vs 43%, p=0.0002), CHADS2 Score (2 (1–3) vs 1 (1–2), p=0.0001), higher prevalence of previous stroke (19 vs 12%, p=0.02), larger left atrial (LA) diameter (43.2±6.4 vs 41.7±6.5mm, p=0.01), lower left ventricular ejection fraction (LVEF) (59.0±13.2 vs 64.2±11.3%, p≤0.0001), higher B-type natriuretic peptide level (221±236 vs 163±225 pg/dl, p≤0.0001), more Rhythmia® mapping system use (30 vs 8%, p&amp;lt;0.0001), and longer procedure time (129±46 vs 108±39 min, p≤0.0001) than those without SCI, while there were no significant differences in age, LA appendage flow velocity, kind of anti-coagulant agent between the two groups. Multivariate regression analysis identified Rhythmia® use [odds ratio (OR) 4.26, (95% CI 2.32–7.84), p=0.0001], LVEF (OR 1.02, p=0.0059), CHADS2 score (OR 1.27, p=0.009), and procedure time (OR 1.005, p=0.04) as independent risk factors of acute SCI during CA for AF. Conclusion Acute SCI occurred about 16% after CA for AF. Rhythmia® mapping system use exhibited a higher incidence of acute SCI after catheter ablation for AF than the other mapping system use. Rhythmia® mapping system use, LVEF, CHADS2 score, and procedure time are associated with SCI relating CA for AF. Funding Acknowledgement Type of funding source: None

Risk Factors for Early Recurrence Following Ablation for Accessory Pathways: The Role of Consolidation Lesions.

Atrioventricular reentrant tachycardia is common in children. Catheter ablation is increasingly used as a first-line therapy with a high acute success rate, but recurrence during follow-up remains a concern. The aim of this study was to identify risk factors for recurrence after accessory pathway (AP) ablation. Retrospective cohort study including patients who underwent AP ablation between 2013 and 2018. Cox proportional hazards model was used to examine the association between patient and procedural characteristics and recurrence during follow-up. From 558 AP ablation procedure, 542 (97%) were acutely successful. During a median follow-up of 0.4 (interquartile range, 0.1-1.4) years, there were 42 (8%) patients with documented recurrence. On univariate analysis, early recurrence was associated with younger age, congenital heart disease, multiple AP, AP location (right sided and posteroseptal versus left sided), cryoablation (versus radiofrequency), empirical ablation, the lack of full power radiofrequency lesions (<50 W), radiofrequency consolidation time <90 seconds and the use of fluoroscopy without a 3-dimensional electroanatomic mapping system. On multivariable analysis, only multiple AP (hazard ratio, 2.78 [95% CI, 1.063-4.74]) and radiofrequency consolidation time < 90 seconds (hazard ratio, 4.38 [95% CI, 1.92-9.51]) remained significantly associated with early recurrence; this association remained true when analyzed in subgroups by pathway location for right and left free wall AP. In our institutional experience, radiofrequency consolidation time <90 seconds after ablation of AP was associated with an increased risk of early recurrence.

Evidence of 2 conduction exits of the moderator band: Findings from activation and pace mapping study

The moderator band (MB) is an endocavitary structure with only 2 exits to the bulk of the ventricular myocardium. Whether this may lead to specific electrophysiological characteristics remains unknown. The purpose of this study was to investigate electrocardiographic (ECG), activation, and pace mapping characteristics of MB-originated ventricular arrhythmias (VAs). Mapping and ablation of MB-VAs were performed in 12 patients under the guidance of a 3-dimensional electroanatomic mapping system and intracardiac echocardiography and ECG, and mapping data were analyzed. Of these patients, 11 underwent pace mapping study of 6 sites around the MB and the QRS morphology was compared. The earliest activation site was free wall (FW) insertion in 8 patients (66.7%) and MB body in 4 patients (33.3%), preceding the QRS onset by 17.8±4.7 ms, and Purkinje-like potential was observed in 6 (50.0%). VAs were eliminated at the earliest activation site in the procedure, but recurrence was documented in 2 cases (16.7%) during a follow-up of 13.4±7.8 months. Pacing QRS complex from the MB was characterized by short QRS duration (P<.001), short intrinsicoid deflection time (P<.001), later precordial transition (P=.025), and notch on the descending limb of the inferior leads (P<.001) as compared with pacing from the adjacent anterior-lateral FW, and that notch could also differentiate MB from the anterior papillary muscle (P=.027). However, pacing QRS is identical between the MB body and the FW insertion in 11 of 11 patients and between the septal insertion and the MB body in 7 of 11 patients. Bidirectional conduction via the 2 exits during MB-VAs contributed to distinct ECG and electrophysiological characteristics, while pace mapping is of limited value in defining the ablation target.

P377Zero-fluoroscopy ablation with ultrasound-guided sheath insertion

Abstract Background Radiation exposure during catheter ablation procedures is a risk for both the patient and electrophysiology staff. Recently, the feasibility and effectiveness of zero-fluoroscopy ablation have been shown. However, ensuring a safe sheath insertion through the venous system toward the heart is a concern in catheter ablation using the zero-fluoroscopy technique. Purpose The objective of this study was to confirm feasibility and safety for zero-fluoroscopy ablation using ultrasound-guided sheath insertion. Methods Zero-fluoroscopy catheter ablation was performed in 220 patients (185 patients with atrial fibrillation (AF), 26 patients with supraventricular tachycardia (SVT), and nine patients with ventricular arrhythmias (VA)) using a 3-dimensional electro-anatomical mapping system, contact force monitoring, and intracardiac echocardiography (ICE) imaging. In all cases, ultrasound-guided sheath insertion was performed through the femoral vein. In 6 cases of VA, the retrograde approach through the femoral artery was performed with ICE imaging and contact-force monitoring. The endpoint of ablation for AF was pulmonary vein ablation in all cases and addition of left atrial posterior wall isolation in persistent AF cases. The endpoint of ablation for SVT and VA was noninducibility after ablation. Results The endpoints of ablation were achieved in all cases. The fluoroscopic time during ablation procedures was 0 seconds. There were two complications (one cardiac tamponade and one acute heart failure). There were no complications related to sheath insertion. Conclusions Zero-fluoroscopy catheter ablation with ultrasound-guided sheath insertion may be feasible and can be performed safely. This method eliminates exposure radiation safely, which is a concern of zero-fluoroscopy endocardial catheter ablation.

Atrial tachycardia eliminated at the ventricular side in patients with congenitally corrected transposition of the great arteries: Electrophysiological findings and anatomical concerns

The unique malformation of congenitally corrected transposition of the great arteries (cc-TGA) makes the pulmonary outflow tract (POT) a possible origin of atrial tachycardia (AT). The purpose of this study was to investigate the mapping characteristics of ATs successfully ablated at the POT in patients with cc-TGA. Patients with cc-TGA with AT eliminated at the POT were analyzed. Activation mapping of the atria and POT was performed under the guidance of a 3-dimensional electroanatomic mapping system. The activation pattern of these chambers was investigated, with the local activation time (LAT; using coronary sinus ostium as a reference) of the earliest activation site (EAS) being compared. AT eliminated at the POT was documented in 5 of 6 patients with cc-TGA. The EAS was at the right anteroseptal region with a LAT of 33 (21-120) ms in the right atrium and at the septal wall with a comparable LAT (26, 47, and 26 ms; P = .604) in the left atrium. The EAS of the POT was in the vicinity of the left-facing pulmonary sinus cusp in 3 cases and the nonfacing pulmonary sinus cusp in 2 cases, with a LAT of 106 (28-134) ms preceding both atria. Ablation at this site successfully eliminated AT in all 5 cases. AT arising adjacent to the POT is not an uncommon tachycardia in patients with situs solitus-type cc-TGA and can be safely eliminated by ablation targeting the EAS in the POT.

A Practical Method for Ablation Catheter Reintroduction into the Left Atrium via Prior Transseptal Puncture, without Radiation.

We evaluated the feasibility and safety of reintroducing an ablation catheter (ABL) into the left atrium (LA) through a previously punctured interatrial septum under guidance of the show-catheter image-track function of the CARTO 3 3-dimensional (3D) electroanatomic mapping system. One hundred consecutive paroxysmal or persistent drug-refractory atrial fibrillation (AF) patients (men: 55; mean age, 64.7 ± 12.1 years) who had undergone 2 fluoroscopy-guided transseptal punctures and anatomical LA reconstruction under CARTO 3-guidance, and required ABL reinsertion into the LA during mapping or ablation, were included. They were randomized 1:1 to the show-catheter (reintroduction under the CARTO 3 show-catheter image-track function) or fluoroscopy group (reintroduction under conventional fluoroscopy). Although the reconstructed 3D anatomy map was displaced in 21/100 patients (21.0%), the ABL was successfully reintroduced in all patients. In the show-catheter and fluoroscopy groups, model displacement incidence (18% versus 24%), tachyarrhythmias (46.0% versus 52.0%), complications (2% versus 4%), and number of ABLs reintroduced into the LA (3.3 ± 0.8 versus 3.1 ± 0.9) were similar (all P > .05). The show-catheter group displayed shorter ABL reintroduction time (9.5 ± 5.5 s versus 156.4 ± 35.5 s, P < .01), ABL reintroduction X-ray exposure time (0 s versus 39.3 ± 13.8 s, P < .01), and total X-ray exposure time (4.1 ± 1.4 min versus 4.7 ± 0.8, P < .05). During AF ablation, the catheter can be safely reintroduced into the LA, without additional fluoroscopy, under guidance of the CARTO 3 show-catheter image track function.

Impact of the type of electroanatomic mapping system on the incidence of cerebral embolism after radiofrequency catheter ablation of left atrial tachycardias

Left atrial tachycardias (ATs) often occur after left atrial ablation. The incidence of symptomatic and silent cerebral embolism after radiofrequency catheter ablation of left ATs and the impact of the type of 3-dimensional electroanatomic mapping (3D-EAM) system on the incidence of cerebral embolism remain unclear. This study aimed to investigate the incidence of cerebral embolism after a 3D-EAM system-guided left AT ablation procedure and compare that between the different 3D-EAM systems. We prospectively enrolled 59 patients who underwent left AT ablation and brain magnetic resonance imaging after the procedure: 30 were guided by the Rhythmia system (Boston Scientific, Marlborough, MA) and 29 by the CARTO system (Biosense Webster, Diamond Bar, CA) (groups R and C, respectively). One transient ischemic attack occurred in group R, and no symptomatic embolism occurred in group C. Silent cerebral ischemic lesions (SCILs) were observed in 35 patients (59.3%), and group R had a significantly higher incidence of SCILs than did group C (86.2% vs 33.3%; P < .001). In multivariate analysis, group R and left atrial linear ablation were independent positive predictors of SCILs (odds ratio 12.822 and 8.668; P = .001 and P = .005). The incidence of bleeding complications was comparable between groups R and C (0% vs 3.3%; P = .508). Group R exhibited a higher incidence of postablation cerebral embolism than did group C. The use of the high-resolution 3D-EAM system with a mini-basket catheter to guide radiofrequency ablation of left atrial macroreentrant tachycardias may markedly increase the risk of silent cerebral embolism. The present results require further validation in a randomized study.

Prevalence and predictors of low voltage zones in the left atrium in patients with atrial fibrillation.

To describe the extent and distribution of low voltage zones (LVZ) in a large cohort of patients undergoing ablation for paroxysmal and persistent atrial fibrillation (AF), and to explore baseline predictors of LVZ in these patients. Consecutive patients who underwent a bipolar voltage map guided AF ablation, were enrolled. Voltage maps were conducted for each patient using 3-dimensional electroanatomical mapping system and LVZ were defined as areas of bipolar voltage < 0.5 mV. A total of 539 patients (309 male, age 65 ± 10 years) were included. Low voltage zones was present in 58 out of 292 patients with paroxysmal and 134 out of 247 persistent AF (P < 0.001). The area of LVZ was larger in patients with persistent as compare to paroxysmal AF, 5 cm2 (IQR 3-18.6) vs. 12.1 cm2 (IQR 3.6-28.5), P = 0.026, respectively. In the multivariate analysis age (OR 1.07, 95%CI 1.05-1.10, P < 0.001), female gender (OR 2.18, 95%CI 1.38-3.43, P = 0.001), sinoatrial node dysfunction (OR 3.90, 95%CI 1.24-12.21, P = 0.020), larger surface area of left atrium pr. cm2 (OR 1.01, 95%CI 1.00-1.02, P = 0.016), and persistent AF (OR 5.03, 95%CI 3.20-7.90, P<0.001) were associated with presence of LVZ. In a large cohort of patients undergoing ablation for AF, the prevalence of LVZ was higher and LVZ areas larger in patients with persistent as compared with paroxysmal AF. The most frequent localization of LVZ was anterior wall, septum and posterior wall. Presence of LVZ was associated with higher age, female gender, larger LA surface area, and sinoatrial node dysfunction.

Incidence and Factors Associated With the Occurrence of Pulmonary Vein Narrowing After Cryoballoon Ablation.

In contrast with traditional radiofrequency ablation, little is known about the influence of cryoballoon ablation on the morphology of pulmonary veins (PVs). We evaluated the influence of cryoballoon ablation on the PV dimension (PVD) and investigated the factors associated with a reduction of the PVD. Seventy-four patients who underwent cryoballoon ablation for paroxysmal atrial fibrillation were included in the present study. All subjects underwent contrast-enhanced computed tomography both before and at 3 months after the procedure. The PVD (cross-sectional area) was measured using a 3-dimensional electroanatomical mapping system. Each PV was evaluated according to the PVD reduction rate (ΔPVD), which was calculated as follows: (1-post-PVD/pre-PVD)×100 (%). Ninety-two percent of the PVs (271/296) were successfully isolated only by cryoballoon ablation; the remaining 8% of the PVs required touch-up ablation and were excluded from the analysis. Mild (25%-50%), moderate (50%-75%), and severe (≥75%) ΔPVD values were observed in 87, 14, and 3 PVs, respectively, including 1 case with severe left superior PV stenosis (ΔPVD: 94%) in a patient who required PV angioplasty. In multivariable analysis, a larger PV ostium and lower minimum freezing temperature during cryoballoon ablation were independently associated with PV narrowing (odds ratio, 1.773; P=0.01; and odds ratio, 1.137; P<0.001, respectively). A reduction of the PVD was often observed after cryoballoon ablation for atrial fibrillation. A larger PV ostium and lower minimum freezing temperature during cryoballoon ablation were associated with an increased risk of PVD reduction.