Comparison between conventional approach and three-dimensional mapping system in the catheter ablation of accessory pathway associated with coronary sinus diverticulum: A single-center experience.

BACKGROUND: Posteroseptal accessory pathways (APs) associated with coronary sinus (CS) diverticulum present a rare and challenge for ablation. This study aimed to compare the safety and efficacy of conventional approach and three-dimensional (3D) mapping system in the catheter ablation. METHODS AND RESULTS: This was a retrospective study of all patients (from January 2013 to July 2022) who underwent catheter ablation of posteroseptal AP associated with CS diverticula in our center. Patients who underwent catheter ablation using the traditional fluoroscopy method were included in the conventional method group (n = 13). Patients who underwent catheter ablation using the 3D mapping method were included in the 3D mapping group (n = 11). Clinical characteristics, ablation procedure, and outcomes were recorded and analyzed between the two groups. Out of 669 patients with posteroseptal APs, 24 of them (3.6%) were associated with CS diverticula. All patients in both groups successfully completed the electrophysiological study. In the conventional method group, two patients experienced complications (one patient with pericardial effusion and the other patient with femoral arterial hematoma), and two patients had recurrence. However, no patients suffered from complications or recurrence during follow-up. The procedure time and fluoroscopy time in the conventional method group were significantly longer than those in the 3D mapping method group. CONCLUSIONS: The utilization of 3D mapping led to reduced fluoroscopy time, shorter procedure duration, enhanced acute success rates, and decreased incidence of complications.

Combining conventional technique with fluoroscopy integration module in accessory pathway ablation.

INTRODUCTION: Accessory pathway (AP) ablation is a straightforward approach with high success rates, but the fluoroscopy time (FT) is significantly longer in conventional technique. Electroanatomical mapping systems (EMS), reduce the FT, but anatomical and activation mapping may prolong the procedure time (PT). The fluoroscopy integration module (FIM) uses prerecorded fluoroscopy images and allows ablation similar to conventional technique without creating an anatomical map. In this study, we investigated the effects of combining the FIM with traditional technique on PT, success, and radiation exposure. METHODS: A total of 131 patients who had undergone AP ablation were included in our study. In 37 patients, right and left anterior oblique (RAO-LAO) images were acquired after catheter placement and integrated with the FIM. The ablation procedure was then similar to the conventional technique, but without the use of fluoroscopy. For the purpose of acceleration, anatomical and activation maps have not been created. Contact-force catheters were not used. 94 patients underwent conventional ablation using fluoroscopy only. RESULTS: FIM into AP ablation procedures led to a significant reduction in radiation exposure, lowering FT from 7.4 to 2.8 min (p < .001) and dose-area product from 12.47 to 5.8 µGym² (p < .001). While the FIM group experienced a reasonable longer PT (69 vs. 50 min p < .001). FIM reduces FT regardless of operator experience and location of APs CONCLUSION: Combining FIM integration with conventional AP ablation offers reduced radiation exposure without compromising success rates and complication.

Successful ablation of a right concealed epicardial accessory pathway using ethanol infusion.

INTRODUCTION: This study describes a rare case of concealed epicardial accessory pathway (AP) successfully ablated using ethanol infusion (EI) through a variant vessel connecting the right atrium (RA) and the right ventricle (RV) surface. METHODS AND RESULTS: A 58-year-old male referred to our hospital for prior failed AP ablation. Cardiac-enhanced computerized tomography scan showed there was a variant vessel at the tip of right atrial appendage and a pulmonary artery (PA)-RA fistula at the roof of RA. The earliest activation was present at the site of the PA-RA fistula. A selective angiography showed that a small branch of the variant vessel covered the earliest excitation site of the AP. EI into this branch successfully repressed the AP without any recurrences within a follow-up period of 3 months. CONCLUSION: Endocardial ablation is challenging for epicardial APs related to cardiac structural variations. If small vascular branches near the earliest activation site can be found, EI can successfully ablate these types of epicardial APs.

Using 2D speckle-tracking echocardiography to localize the accessory pathway and evaluate cardiac function and dyssynchrony in pediatric patients with Wolf-Parkinson-White syndrome.

Wolf-Parkinson-White (WPW) accessory pathway (AP) may be associated with reentry supraventricular tachycardia (SVT) in addition to ventricular dyssynchrony and cardiac dysfunction. Electrophysiological studies (EPS) are the gold standard for the localization of the AP; however, 2D speckle-tracking echocardiography (2D-STE) may help in the localization of the AP noninvasively. Our study aims to evaluate the capability of 2D-STE for AP localization and the identification of AP-related contractile abnormalities and dyssynchrony in pediatric patients with WPW syndrome. This prospective multicenter cohort study involved 18 pediatric patients with ventricular preexcitation from January 2021 to January 2023. Tissue Doppler imaging (TDI), conventional echocardiography, and 2D-STE were done. Myocardial velocities, myocardial performance index (MPI), the global and segmental longitudinal strain of the left ventricle (LV), and time-to-peak longitudinal strain (TPLS) were measured before and after ablation. The longitudinal strain of the LV segments supplied by the AP, or the nearby segments close to the AP, was significantly impaired and improved after ablation (P = 0.0001). The abnormal strain pattern in the affected segments could predict the location of the AP. The TPLS of the affected segments significantly increased after ablation (P = 0.0001), denoting improved dyssynchrony. The ejection time and the LV MPI measured at the basal septum improved significantly after ablation. CONCLUSIONS: 2D STE may be used for noninvasive localization of the AP and to evaluate cardiac function and dyssynchrony in patients with WPW. Further research on more patients is necessary to validate this method for AP localization. WHAT IS KNOWN: • Accessory pathways (AP) associated with the Wolf-Parkinson-White (WPW) syndrome have been linked to supraventricular tachycardia (SVT). Even without SVT, WPW can cause left ventricular dyssynchrony, contractile dysfunction, and cardiomyopathy. • Electrophysiology study is the gold standard for the localization of the AP in WPW syndrome. WHAT IS NEW: • The combination of 2D-speckle-tracking echocardiography (2D-STE) and the modified Arruda algorithm can precisely localize the AP associated with WPW syndrome. • 2D-STE can potentially assess cardiac function and dyssynchrony related to WPW syndrome. Additionally, 2D-STE can be utilized to evaluate the effectiveness of ablation in restoring cardiac function and dyssynchrony.

Successful ablation of a right epicardial accessory pathway via the right ventricular diverticulum in a patient with Wolff-Parkinson-White syndrome.

INTRODUCTION: We describe one rare case of successful ablation of a right epicardial accessory pathway (AP) via the right ventricular diverticulum in a patient with Wolff-Parkinson-White syndrome. METHODS: A 42-year-old woman was referred to the hospital for a catheter ablation of Wolf-Parkinson-White syndrome. The earliest activation was shown to be present in the region of the tricuspid annulus. However, ablation had no effect on the AP. RESULTS: We decided to do a selected angiography, in which a big diverticulum near the right tricuspid annulus was shown to be present. Ablation in this region successfully repressed the AP without any recurrences within a follow-up period of 12 months. CONCLUSION: The ventricular diverticulum-mediated AP is a novel variant of pre-excitation. It can serve as an anatomical substrate of supraventricular tachycardia, and can be ablated endocardially using an irrigation tip catheter within the diverticulum.

Intracardiac echocardiography as an adjunctive tool for accessory pathway ablation in Ebstein anomaly.

BACKGROUND: Accessory pathway (AP)-related arrhythmias are frequent in patients with Ebstein anomaly (EA), and arrhythmia recurrence after catheter ablation remains high despite current technological developments. METHODS: Case series report of patients with EA who were taken to an accessory pathway ablation procedure and where clinical, procedure, and follow-up data are described. In all cases, mapping of the true tricuspid annulus guided by intracardiac ultrasound was used. RESULTS: Six patients with EA underwent an ablation procedure using ICE to delineate the true tricuspid annulus. The duration of the procedure was 253.33 ± 60.92 min, with an acute success of 100%. After a mean follow-up of 16.16 ± 7.7 months, no recurrences of tachycardia were documented, and all patients were free of antiarrhythmic medications. CONCLUSION: Intraprocedural ICE helps to delineate the true tricuspid annulus that contains the APs, facilitating mapping and ablation. We hypothesize that the systematic use of ICE in this scenario improves ablation efficacy while reducing complications, but this must be verified in prospective studies.

Ultrahigh density atrio-ventricular dual-chamber mapping as a next generation tool for ablation of accessory pathways.

INTRODUCTION: Detailed three-dimensional (3D) mapping has been useful for effective radiofrequency catheter ablation. The Rhythmia system can create atrio-ventricular dual-chamber mapping, which reveals the atrial and ventricular potentials all at once in the same map. The aim of this study was to investigate the utility of mapping the atrium and ventricle simultaneously with a high-density 3D mapping system for the ablation of accessory pathways (AP). METHODS: From July 2015 to August 2020, 111 patients underwent ablation of APs. Dual-chamber maps were created in 50 patients (median age 15 [10-54], 32 male [64.0%]), while 61 patients underwent radiofrequency (RF) ablation with conventional single-chamber 3D maps. The background characteristics and procedural details were compared between the dual-chamber mapping group and the conventional single-chamber mapping group. RESULTS: The number of RF applications (median [IQR]; 1.0 [1.0-3.0] vs. 3.0 [1.0-6.0], p = .0023), RF time (median [IQR], s; 9.2 [2.0-95.7] vs. 95.6 [4.1-248.7], p = .0107), and RF energy (median [IQR], J; 248.4 [58.7-3328.2] vs. 2867.6 [134.2-7728.4], p = .0115) were significantly lower in the dual-chamber group. The fluoroscopy time (median [IQR], min; 19.9 [14.2-26.1] vs. 26.5 [17.7-43.4], p = .0025) and fluoroscopy dose (median [IQR], mGy; 52.5 [31.3-146.0] vs. 119.0 [43.7-213.5], p = .0249) were also significantly lower in the dual-chamber than single-chamber mapping group. CONCLUSION: The dual-chamber mapping was useful for ablating accessory pathways and reducing the number of RF applications, total RF energy, and radiation exposure as compared with traditional mapping techniques.

Segmental septal dyskinesia associated with an accessory pathway and preexcitation in two Golden Retriever dogs.

Ventricular preexcitation secondary to anterograde conduction through an accessory pathway was diagnosed in two Golden Retriever dogs. Both dogs demonstrated similar segmental myocardial thinning and systolic dyskinesia of the basal interventricular wall on echocardiography. These changes are widely recognised in people with ventricular preexcitation but have not been previously described in dogs. Ventricular preexcitation should be considered as a potential cause for segmental wall motion abnormalities in these two dogs.

A unique mapping strategy for localization and ablation of the atrial input of an antegrade only conducting accessory pathway.

The standard technique for accessory pathway ablation involves mapping along the mitral and tricuspid annulus to localize the regions of earliest ventricular activation during antegrade pathway conduction, earliest atrial activation during retrograde conduction or detection of an accessory pathway potential. In some cases despite what appears to be appropriate mapping, catheter positioning and adequate power delivery the ablation is not successful. In many of these cases, the pathway is felt to be inaccessible because of a location remote from the mitral or tricuspid annulus that cannot be affected by endocardial power delivery along the annulus. In the case of difficult left sided pathways, some may be reached and ablated via the coronary sinus or its branches. Right sided pathways cannot be approached in this fashion since there is no venous structure analogous to the coronary sinus around the tricuspid annulus. Alternative mapping and ablation techniques for these difficult pathways have included epicardial mapping via direct pericardial access or attempts to localize pathway insertion areas remote from the valve annulus which may be amenable to endocardial ablation. We describe the use of post-pacing interval mapping to localize the atrial input of a right sided antegrade only accessory pathway that was resistant to conventional mapping and ablation strategies.

Fluoroless catheter ablation of accessory pathways in adult and pediatric patients: a single centre experience.

Catheter radio-frequency ablation (RFA) and cryo-ablation (CRA) procedures are an effective and safe treatment options for adult and pediatric patients with accessory pathway (AP) mediated tachycardias. Non-fluoroscopic techniques during catheter ablation (CA) procedures reduce potentially harmful effects of radiation. Our aim was to investigate the efficacy and safety of completely fluoroless RFA and CRA procedures in pediatric and adult patients with APs. Consecutive patients with AP-related tachycardia and high risk asymptomatic ventricular pre-excitation were assessed in retrospective analysis. Three-dimensional (3D) electro-anatomical mapping (EAM) and intra-cardiac echocardiography (ICE) were used as principal imaging modalities. Fluoroscopy was not used during any stage of the procedures. Among 116 included patients (22.76 ± 16.1 years, 68 patients < 19 years), 60 had left-sided APs, 16 right-sided APs and 40 septal APs. Altogether, 96 had RFA and 20 CRA procedures. The acute success rates (ASR) of RFA and CRA were 97.9% and 95%, respectively (p = 0.43), with recurrence rates (RR) of 8.33% and 40%, respectively (p < 0.0001). The outcome difference was principally driven by lower RR with RFA in septal APs (9.1% vs. 38.9%, p = 0.025). Pediatric patients with APs (12.21 ± 3.76 years) had similar procedural parameters and outcomes compared to adult patients. There were no procedure-related complications. In adult and pediatric patients with AP-related tachycardias, both CRA and RFA can be effectively and safely performed without the use of fluoroscopy. In addition, RFA resulted in better outcomes compared to CRA.

Ablation of manifest septal accessory pathways: a single-center experience.

BACKGROUND: Ablation of septal accessory pathways (SAPs) is associated with an increased risk of heart block. Data on outcomes of SAP ablation in adults are limited. OBJECTIVES: To describe outcomes of SAP ablation in our center. METHODS: Patients with Wolff-Parkinson-White syndrome (WPW) undergoing an EP study at our center between January 2008 and August 2019 were identified from our institutional database. Location of the pathway was noted as anteroseptal (AS), midseptal (MS), or posteroseptal (PS). Outcomes of the ablation including success, complication rates, and recurrences were also recorded. RESULTS: Thirty-three patients with SAP underwent 35 EP studies: AS (n = 13), MS (n = 5), and PS (n = 15). Thirty pathways were targeted for ablation, two of which required a 2nd procedure resulting in 32 attempts at ablation in 30 patients. In the remaining 3 patients, SAP did not have malignant features and were not targeted for ablation. Single-procedure success rate was 28/30 (93.33%): 9/10 AS, 5/5 MS, and 14/15 PS ablations. One AS pathway was successfully ablated during a 2nd procedure. Two complications were observed: 1 pericardial effusion in a patient who underwent epicardial mapping and ablation of both PS and right free wall APs. Additionally, transient 2:1 AV block occurred during an MS pathway ablation that recovered during follow-up and did not require permanent pacing procedure. CONCLUSION: In this single-center experience, ablation of manifest SAP was associated with high success rates and low complication rates. No instances of permanent heart block requiring pacing occurred.

Outcomes of ablation in Wolff-Parkinson-White-syndrome: Data from the German Ablation Registry.

AIMS: Catheter ablation is recommended for symptomatic WPW-syndrome. Commonly perceived low recurrence rates were challenged recently. We sought to identify patient strata at increased risk. METHOD: Of 12,566 patients enrolled at 52 German Ablation Registry sites from 2007 to 2010, 789 were treated for WPW-syndrome. Patients were included for symptomatic palpitations and tachycardia documentation. Follow-up duration was one year. Overall complications were defined as serious, access-related, and ablation-related. We adjudicated WPW-recurrence for re-ablation during follow-up. Risk strata included: admission for repeat ablation at registry entry; accessory pathway localization; antiarrhythmic medical treatment before the ablation. RESULTS: WPW-syndrome patients were 42.8 ± 16.2 years on average; 39.9% were women. A majority of 95.9% was symptomatic; in 84.4%, a tachycardia was documented. Seventy-six (9.6%) patients presented for repeat procedures. Accessory pathways were located in the left atrium (71.4%), right atrium (21.1%), septum (4.4%), or coronary sinus diverticula (2.1%). Prior antiarrhythmic medication was used in 43.7% of patients. No serious events occurred. The overall complication rate was 2.5% (ablation related 1.2%, access-related 1.3%). Major determinants for complications were presentation for re-ablation as registry index procedure (6.9% vs 2.2%; p = 0.016) and septal pathway location (left 2.0% vs septal 9.1%, p = 0.014). The overall re-ablation rate was 9.7%. Usage of prior antiarrhythmic medication was associated with higher recurrence rates (12.2% vs. 7.6%; p = 0.035). CONCLUSIONS: Patients at higher complication risk may be identified by repeat procedure and septal pathway location. Prior antiarrhythmic medication was associated with higher recurrence rates. Our findings may help improving peri-procedural patient management and information.

Ultra-high resolution mapping and ablation of accessory pathway conduction.

BACKGROUND: Detailed mapping studies of accessory pathway (AP) conduction have not been previously performed using ultra-high resolution mapping systems. We sought to evaluate the clinical utility of ultra-high resolution mapping systems and the novel "Lumipoint" algorithm in AP ablation. METHODS: This study included 17 patients who underwent AP mapping using minielectrode basket catheters and Rhythmia systems. Ablation was performed with 4-mm irrigated-tip catheters. RESULTS: Antegrade and retrograde AP conduction was observed in 6 and 16 patients. Atrial activation map was obtained during orthodromic tachycardia and ventricular pacing in 13 (76.5%) and 14 (82.3%) patients, and the earliest activation area was identical. Ventricular activation maps were created during atrial pacing in 3 patients. All maps showed focal activation patterns on global activation histograms, and the valley on the histogram highlighted the earliest activation area. "Complex activation" features further highlighted limited areas with continuous electrical activity during the time period in the majority. APs were located at the mitral and tricuspid annuli in 15 and 2 patients, and all were successfully eliminated with 3.4 ± 0.6 s applications. No patients had recurrences during a median follow-up of 15 [10.5-22.5] months. At successful ablation sites, the local atrial and ventricular electrogram amplitudes and ratio tended to be greater, and fusion or continuous electrical activity between the atrial and ventricular components was more frequently observed on the minielectrode than ablation catheter (17/17 vs. 12/17, p = 0.005). CONCLUSIONS: Ultra-high resolution activation mapping and a novel algorithm facilitated the AP localization. The local electrogram characteristics differed between the minielectrode and ablation catheters.

Open-window mapping of accessory pathways utilizing high-density mapping.

PURPOSE: Accessory pathway (AP) mapping is currently based on point-by-point mapping and identifying if a local electrogram's origin is atrial, pathway, or ventricular, which is time-consuming and prone to insufficient mapping. We sought to determine the feasibility of automated and high-density mapping to define AP location using open-window mapping (OWM), which does not rely on defining the electrogram's origin but simply detects the sharpest local signal at each point. METHODS: We enrolled 23 consecutive patients undergoing catheter ablation for atrioventricular reentrant tachycardia. High-density mapping was performed using OWM and ablation was performed. The successful site of ablation was determined by the loss of pathway function. RESULTS: OWM was 100% effective at identifying the successful site of ablation (average mapping time 7.3 ± 4.3 min.) Permanent AP elimination was achieved using a mean radiofrequency energy time of 18.5 ± 24.5 s/patient. Transiently successful ablations were 4.0 ± 1.8 mm from permanently successful sites and had lower contact force (5.1 ± 2.5 g vs. 11.7 ± 9.0 g; P = 0.041). Unsuccessful sites had similar contact force to permanently successful sites (12.2 ± 9.2 g vs. 11.7 ± 9.0 g; P = 0.856) but were 6.4 ± 2.0 mm away from successful sites. CONCLUSION: A novel technique of high-density, automated, and open-window mapping (OWM) effectively localizes APs without the need to differentiate the signal's site of origin. These findings suggest that OWM can be used to rapidly and successfully map and ablate APs. Both distances from the pathway and contact force were shown to be important for pathway ablation.

Successful integration of a three-dimensional transthoracic echocardiography-derived model with an electroanatomic mapping system to guide catheter ablation of WPW.

Three-dimensional transthoracic echocardiography (3DE)-derived heart models have not previously been utilized to guide catheter ablation. In this case report, we describe the creation of a 3DE model from transthoracic echocardiography, import of the model into CARTO3, and successful use of the model as a guide during mapping and ablation of a right lateral accessory pathway. We believe this technique represents a valuable alternative to the integration of computed tomography or magnetic resonance imaging-derived anatomic data, and that it has the potential to improve the definition of the atrioventricular valve annuli during catheter ablation of accessory pathways.

Intra-cardiac ultrasound guided approach for catheter ablation of typical right free wall accessory pathways.

BACKGROUND: Right free wall accessory pathways (AP) are difficult to treat with catheter ablation as ablation catheter (AC) instability at the tricuspid annulus often precludes successful procedure. The aim of our study was to test a novel intra-cardiac echocardiography (ICE) guided technique for AC placement. Feasibility and success rates were observed. METHODS: Eight consecutive patients (aged 29 ± 21 years, 4 female) with Wolff-Parkinson-White syndrome and a right free wall AP were included in the study. ICE, three-dimensional (3D) electro-anatomic mapping (EAM) system, and a steerable long sheath were used together with either an irrigated or a non-irrigated tip radio-frequency AC to achieve a "loop" manoeuvre which provided AC tip stability at the ventricular aspect of the tricuspid annulus. X-ray fluoroscopy was not used. RESULTS: Three patients had an anterior and five had a lateral location of the right free wall AP. Procedures were successful in all patients, without recurrences during the mean follow-up of 397 ± 363 days. Average procedural duration was 90 ± 31 min. On average, 6.6 ± 5.7 ablations were needed. Average time to terminate AP conduction after the start of ablation was 4.8 ± 4.2 s. In five patients (62%) AP conduction was successfully terminated with the first ablation. There were no procedural complications. CONCLUSIONS: The novel ICE-guided approach with concomitant use of the steerable sheath and the 3D EAM system for zero-fluoroscopy mapping and ablation of the right free wall APs proved feasible and resulted in excellent acute and long-term outcomes.

Estimation of the accessory pathway location of the manifest Wolf-Parkinson-White syndrome using synthesized right-sided chest leads.

PURPOSE: The classification using QRS morphology of V1 lead is a useful simple predictor of accessory pathway location (type A, R or Rs pattern; type B, rS pattern; type C, QS or Qr pattern), but often leads to misdiagnosis of accessory pathway location, especially in types B and C. The synthesized 18-lead electrocardiography (ECG) derived from standard 12-lead ECG can provide virtual waveforms of right-sided chest leads. This study aimed to evaluate the usefulness of the right-sided chest lead ECG for prediction of accessory pathway location. METHODS: This retrospective study included 44 patients in whom successful ablation of manifest Wolff-Parkinson-White (WPW) syndrome was performed. Synthesized ECG waveforms were automatically generated, and ECG data obtained before the procedure. RESULTS: There were 26, 4, and 14 patients with left, right, and septal accessory pathways, respectively. All left accessory pathway cases have type A in V1 and syn-V4R leads. Of the 4 right accessory pathway cases, 2 have type B in V1 and syn-V4R leads. Other 2 of 4 cases have type C. In V1 lead, 5 of 14 septal accessory pathway cases have type C, 7 of 14 cases have type B, and 2 of 14cases have type A. In syn-V4R lead, all 14 septal accessory pathway cases have type C. The QRS morphology of V1 and syn-V4 leads could predict the site of accessory pathway with overall accuracy of 79% and 95%, respectively. CONCLUSIONS: QRS morphology of syn-V4R lead may be useful for predicting accessory pathway location of manifest WPW syndrome.