Accessory Pathway Ablation Research Articles

Administration of Adenosine Triphosphate Provides Additional Value Over Programmed Electrophysiologic Study in Confirmation of Successful Ablation of Atrioventricular Accessory Pathways.

Objectives: To study the benefit of adenosine triphosphate (ATP) in evaluating ablation endpoints of accessory pathways (AP) and subsequent long-term prognosis.Methods: We reviewed consecutive patients with supraventricular tachycardias due to APs that underwent radiofrequency catheter ablation (RFCA) from January 2016 to September 2018 in our center. The patients were divided into two groups: the ATP group (who had passed both the ATP test and PES after ablation as the endpoint) and the non-ATP group (who had passed PES only after ablation as the endpoint). We reviewed the patients' intra-cardiac electrograms and analyzed their long-term outcomes.Results: In total, 1,343 patients underwent successful RFCA. There were 215 patients in the ATP group with one lost to follow-up. There were 1,128 patients in the non-ATP group with 39 lost to follow-up. Twenty-three patients in the ATP group demonstrated additional electrophysiological entities due to ATP administration, including reappearance of the ablated APs in 16 patients, discovery of PES-undetected APs in 5, induction of atrial fibrillation in 5, premature atrial contractions in 1, and premature ventricular contractions in another. During the 7 to 39 months (average 24.4 ± 9.5 months) follow-up, the recurrence rate was 8.41% (18/214) in the ATP group and 6.80% (74/1,084) in the non-ATP group. In subjects with recurrence, 14 patients (14/18 = 77.8%) in the ATP group and 50 patients (50/74 = 67.6%) in the non-ATP group accepted redo ablations. Among the ATP-group, all the 14 redo APs were the old ones as before. Among the non-ATP-group, redo ablations confirmed that 39 APs were the old ones, while 20 APs were newly detected ones which had been missed previously. The difference in recurrent AP locations confirmed by redo procedures between the two groups was significant (p = 0.008). In the non-ATP group, 20 (40%) of redo cases were proven to have multiple APs, while 33 (3.3%) cases who did not suffer from recurrence had multiple APs. Existences of multiple APs in recurred cases were significantly higher than that in non-recurred ones in the non-ATP group (p < 0.001), while there was no such difference in the ATP group (p = 0.114).Conclusions: The existence of multiple APs was more common in recurrent cases if ATP was not used for confirmation of ablation endpoints. ATP probably has additional value over PES alone by detecting weak AP conductions. ATP can evoke atrial and ventricular arrhythmias.

Accessory pathway ablation in Ebstein anomaly: A challenging substrate.

Catheter ablation of accessory pathways (APs) in Ebstein anomaly (EA) has been associated with a high recurrence risk. The purpose of this study was to compare outcomes of AP ablation in EA in an early (1990-2004) vs a recent (2005-2019) era and identify variables associated with recurrence. A retrospective review of all catheter ablations for supraventricular tachycardia in EA at our institution was performed. We identified 76 patients with median (25th-75th quartiles) age 9 (2.6-13.3) years. Of these patients, 52 had AP alone, 12 had atrial flutter, 3 had atrioventricular nodal reentrant tachycardia, and 9 had AP plus at least 1 additional arrhythmia. Of the 61 patients with APs, a total of 78 separate APs were identified: 40 right-sided, 37 septal, and 1 left-sided. Acute success for AP first procedure was 89% and did not differ between early and recent eras (89% vs 88%; P = .48). However, 19 patients (31%) required repeat procedures (average 1.4 per patient) due to AP recurrence or ablation failure at first attempt. In comparison to early era, recent era ablations had significantly lower recurrence rates at 1 year (62% vs 19%; P = .005). At median follow-up of 2.5 (0.2-7) years, ultimate AP elimination after all procedures was 93%. Younger age at time of electrophysiological study (<2 vs 12-47 years: hazard ratio [HR] 7.3; P = .003) and ablation era (early era vs recent era: HR 3.65; P = .009) predicted recurrence. Outcomes for AP ablation in patients with EA have improved, but there is still a relatedly high recurrence risk requiring repeat procedures.

Ventricular ectopy following accessory pathway ablation in WPW syndrome

IntroductionMany Authors already described automatic activity arising from accessory pathways, but the underlying mechanism has not been clarified yet. They may be due to embryogenetic features of myocardium or may be related to specific excitability during radiofrequency ablation. CaseOur report shows that ventricular accelerated rhythm may transiently arise from the ventricular edge of a common myocardium made accessory pathway right after the ablation. No further action were required in our experience, since the phenomenon self extinguished in approximately hour. ConclusionsIf this manifestation represents the effect of thermal injury or if it is a real intrinsic automaticity is not fully documented and may need further reporting and investigation.

Six-Year Follow-Up Outcomes of Catheter Ablation of Para-Hisian Accessory Pathways.

Background: Ablation of para-hisian accessory pathways (APs) remains challenging due to anatomic characteristics, and a few studies have focused on the causes for recurrence of radiofrequency ablation of para-hisian APs.Objective: This retrospective single center study aimed to explore the risk factors for recurrence of para-hisian APs.Methods: One hundred thirteen patients who had para-hisian AP with an acute success were enrolled in the study. In the 6-year follow-up, 15 cases had a recurrent para-hisian AP. Therefore, 98 patients were classified into the success group, while 15 patients were classified into the recurrence group. Demographic and ablation characteristics were analyzed.Results: Gender difference was similar in two groups. The median age was 36.2 years old and was younger in the recurrence group. Maximum ablation power was significantly higher in the success group (29 ± 7.5 vs. 22.9 ± 7.8, p < 0.01). Ablation time of final target sites was found to be markedly higher in the success group (123.4 ± 53.1 vs. 86.7 ± 58.3, p < 0.05). Ablation time <60 s was detected in 12 (12.2%) cases in the success group and 7 (46.7%) cases in the recurrence group (p < 0.01). Occurrence of junctional rhythm was significantly higher in the recurrence group (25.5% vs. 53.3%, p < 0.05). No severe conduction block, no pacemaker implantation, and no stroke were reported. Junctional rhythm during ablation (OR = 3.833, 95% CI 1.083–13.572, p = 0.037) and ablation time <60 s (OR = 5.487, 95% CI 1.411–21.340, p = 0.014) were independent risk factors for the recurrence of para-hisian AP.Conclusions: With careful and accurate mapping, it is relatively safe to ablate para-hisian AP. If possible, proper extension of ablation time could reduce the recurrence rate of para-hisian APs.

Ebstein Anomaly Focusing on Pre-excited Atrial Fibrillation Management

Introduction: Ebstein’s anomaly is a rare abnormality of the heart associated with atrialization right ventricle and apical (downward) displacement of the tricuspid valve functional annulus. Twenty percents of patients with Ebstein’s anomaly accompanied with accessory pathway. The dilatation of atrium and aging process may develop atrial fibrillation (AF).Case Description: A 35 years old patient with recurrency palpitation, accompanied with dizziness and epigastric discomfort. He had history of taking propafenone 3 x 150 mg for long time while the palpitation recurrent. He was hospitalization due to propafenone could not suppress the palpitation. During monitor in hospital revealed haemodynamic stable with heart rate 160-180 beats/minute irregularly irregular. The electrocardiography showed atrial fibrillation with pre-excitation WPW syndrome. We performed electrical cardioversion 100 joule. Then the atrial fibrillation was convert to sinus rhythm with WPW pattern. The propafenone 3 x 150mg was continued. The patient was performed catheter radiofrequency ablation of the accessory pathway. Electrophysiology showed AV fusion at right anteroseptal pathway and preexcited atrial fibrillation with shortest RR interval 220 ms that converted by cardioversion. The ablation was successfully performed. Discussion: The accessory pathway is a complication of ebstein anomaly. Digoxin, beta-blockers, diltiazem, verapamil, and amiodarone are potentially harmful in pre-excited atrial fibrillation. Propafenone reduces fast inward potential by sodium channels, reduces spontaneous automaticity and prolongs the effective refractory periode so could be used in this case. Catheter ablation of accessory pathway in Ebstein anomaly with WPW syndrome was class I recommendation. In our case, the accessory pathway was successfully ablated.

Left atrial \u0131ntramural hematoma after radiofrequency catheter ablation of left lateral accessory pathway

We report a case of left atrial hematoma after ablation of left lateral concealed accessory pathway. A 46-year-old male patient experienced chest pain after radiofrequency ablation. Transthoracic echocardiography and computed tomography revealed the intramural mass consistent with hematoma in the left atrium. He was hemodynamically stable, and conservative approach was decided. Atrioventricular groove is a vulnerable part of left atrium, and ablation of left free wall accessory pathway may require targeting both atrial and ventricular surfaces of the mitral annulus. Avoidance of forceful catheter manipulation during the electrophysiological procedure is important for prevention of this complication. Optimal periprocedural anticoagulation might reduce the risk of procedure-related thromboembolic complications, but electrophysiologists should always pay attention to an intramural hematoma that may occur after radiofrequency catheter ablation.

Contemporary procedure characteristics and outcomes of accessory atrioventricular pathway ablations in an integrated community-based health care system using a tiered approach

BackgroundSince the early descriptions of large series of accessory atrioventricular pathway ablations in adults and adolescents over 20 years ago, there have been limited published reports based on more recent experiences of large referral centers. We aimed to characterize accessory pathway distribution and features in a large community-based population that influence ablation outcomes using a tiered approach to ablation.MethodsRetrospective analysis of 289 patients (age 14–81) who underwent accessory ablation from 2015–2019 was performed. Pathways were categorized into anteroseptal, left freewall, posteroseptal, and right freewall locations. We analyzed patient and pathway features to identify factors associated with prolonged procedure time parameters.ResultsInitial ablation success rate was 94.7% with long-term success rate of 93.4% and median follow-up of 931 days. Accessory pathways were in left freewall (61.6%), posteroseptal (24.6%), right freewall (9.6%), and anteroseptal (4.3%) locations. Procedure outcome was dependent on pathway location. Acute success was highest for left freewall pathways (97.1%) with lowest case times (144 ± 68 min) and fluoroscopy times (15 ± 19 min). Longest procedure time parameters were seen with anteroseptal, left anterolateral, epicardial-coronary sinus, and right anterolateral pathway ablations.ConclusionsIn this community-based adult and adolescent population, majority of the accessory pathways are in the left freewall and posteroseptal region and tend to be more easily ablated. A tiered approach with initial use of standard ablation equipment before the deployment of more advance tools, such as irrigated tips and 3D mapping, is cost effective without sacrificing overall efficacy.

Two decades of experience on ablation in children with Ebstein's anomaly.

Accessory pathways are commonly seen due to delamination of tricuspid valve leaflets. In addition to accessory pathways, an enlarged right atrium due to tricuspid regurgitation and incisional scars creates substrates for atrial re-entries and ectopic tachycardia. We sought to describe our experience with catheter ablation in children with Ebstein's anomaly. During the study period, of 89 patients diagnosed with Ebstein's anomaly, 26 (30.9%) of them who underwent 33 ablation procedures were included in the study. Accessory pathways were observed in the majority of procedures (n = 27), whereas atrial flutter was observed in five, atrioventricular nodal reentrant tachycardia in five, and atrial tachycardia in two procedures. Accessory pathways were commonly localised in the right posteroseptal (n = 10 patients), right posterolateral (n = 14 patients), septal (n=two patients), and left posteroseptal (n=one patient) areas. Multiple accessory pathways and coexistent arrhythmia were observed in six procedures. All ablation attempts related to the accessory pathways were successful, but recurrence was observed in five (19%) of the ablations. Ablation for atrial flutter was performed in five patients; two of them were ablated successfully. One of the atrial tachycardia cases was ablated successfully. Ablation in patients with Ebstein's anomaly is challenging, and due to nature of the disease, it is not a rare occasion in this group of patients. Ablation of accessory pathways has high success, but also relatively high recurrence rates, whereas ablation of atrial arrhythmias has lower success rates, especially in operated patients.

The efficacy and safety of non-fluoroscopic catheter ablation of arrhythmias in pregnancy after mid-long-term follow-up: a single- center experience

Abstract Funding Acknowledgements Type of funding sources: None. Background Despite the incidence of arrhythmias in pregnancy data on non-fluoroscopic catheter ablation in pregnant women and perinatal outcomes is limited. Purpose the aim of this study is to prospectively assess the efficacy and safety of non-fluoroscopic catheter ablation in pregnant women with arrhythmias. Methods 44 pregnant women (mean age of 28,2 ± 4,2 years, mean gestation age 24,4 ±3,8 weeks) indicated for catheter ablation were enrolled. The ablation was performed under the guidance of CARTO (n = 20; 45%) and Ensite Precision systems (n = 24; 55%) without fluoroscopy. Ablation characteristics, procedure-related complications and clinical outcomes were evaluated during 18 months follow-up. Results all 44 cases of ablation were successful. There were 14 (31,8%) ablation of accessory pathways - in left free wall (n = 8), in right free wall (n = 5), posteroseptal (n = 1). 19 patients (43,2%) underwent ablation for atrioventricular nodal reentrant tachycardia. In 3 cases (6,8%) were combination of accessory pathways with slow conduction ways. Ablation of the right ventricular outflow tract was performed in 8 cases (18,2%) of frequent premature ventricular contractions and idiopathic ventricular tachycardia. The median procedural time was 71 minutes (interquartile range 54-97). Procedural complication was documented in 1 patient (2,3%), who developed an ileofemoral thrombosis. Perinatal outcomes: spontaneus vaginal (n = 35; 79.5%) or vaginal-assisted (n = 4; 9.1%) delivery were in the majority. Five pregnancies (11.4%) were delivered by cesarean section. Mean median gestational age at delivery was 39 ± 1,12 weeks. In one case was placental abruption (2,3%). Maternal cardiac events was none declared. There were 44 live births (in all pregnancies). Fetal birth weight was 3324,39 ± 625,1 grams, 5 minute Apgar was 8,81 ± 1,9. There were no maternal and fetal mortality. During follow-up there were no arrhythmia recurrence. Conclusions non-fluoroscopic catheter ablation of arrhythmias is feasible and can be safety performed in pregnancy. Our data suggests that these pregnancies were with good perinatal and neonatal outcomes.

11-year follow-up outcomes of catheter ablation of para-hisian accessory pathways

Abstract Funding Acknowledgements Type of funding sources: None. Background Ablation of para-hisian accessory pathways (APs) remains challenging due to anatomic characteristics and few studies have focused on the causes for recurrence of radiofrequency ablation of para-hisian APs. Objective This retrospective single center study was aimed to explore the risk factors for recurrence of para-hisian APs. Methods 113 patients who had a para-hisian AP with an acute success were enrolled in the study. In the 11-year follow-up, 15 cases had a recurrent para-hisian AP. Therefore 98 patients were classified into success group while 15 patients were classified into recurrence group. Demographic and ablation characteristics were analyzed. Results Gender difference was similar in two groups. The median age was 36.2 years old and was younger in recurrence group. Maximum ablation power was significantly higher in success group (29 ± 7.5 vs 22.9 ± 7.8, p &amp;lt; 0.01). Ablation time of final target sites was found to be markedly higher in success group (123.4 ± 53.1 vs 86.7 ± 58.3, p &amp;lt; 0.05). Ablation time less than 60 seconds was detected in 12 (12.2%) cases in success group and 7 (46.7%) cases in recurrence group (p &amp;lt; 0.01). Occurrence of junctional rhythm was significantly higher in recurrence group (25.5% vs 53.3%, p &amp;lt; 0.05). No severe conduction block, no pacemaker implantation and no stroke were reported. Junctional rhythm during ablation (OR = 3.833, 95%CI 1.083-13.572, p = 0.037) and ablation time &amp;lt;60s (OR = 5.487, 95%CI 1.411-21.340, p = 0.014) were independent risk factors for the recurrence of para-hisian AP. Conclusions Considering the long-term safety of ablation of para-hisian AP, proper extension of ablation time and increase of ablation power could be applied during operation.

Catheter ablation of difficult accessory pathways guided by three-dimensional electroanatomic mapping: first experience

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation of paraseptal accessory pathways (PAP) is associated with longer fluoroscopy and procedure times, more radiofrequency lesions, as well as a higher rate of recurrence and complications. In anteroseptal or midseptal PAP, recurrence and risk of AV block is even higher. Guided ablations with a three-dimensional electroanatomic mapping system (3D) report greater efficacy and safety. Purpose To assess the acute success rate and complications of PAP 3D catheter ablation. Report the recurrence rate at one year of follow-up. Methods Descriptive analysis that included patients with difficult PAP 3D catheter ablation between 2017 and 2019. Acute success was defined as the disappearance of ventricular pre-excitation 15 seconds after starting the application and the absence of retrograde conduction (Figure). In all cases, a one-year follow-up was performed with ECG and 24-hour Holter. Results 25 patients were included during the mentioned period. The average age was 23 years, 60% (15 p) were men and 56% (14 p) were symptomatic due to palpitations. 1 patient had previous heart disease (ebstein"s anomaly). 36% (9 p) had a previous procedure: 5 patients with previous failed radiofrequency ablation, 1 patient with failed anteroseptal cryoablation and 3 patients with suspended ablation due to risk of AV block. The most frequent location was the posteroseptal. (Table) The primary success rate was 92% (23 of 25 p). Ablation was unsuccessful in two patients, one with Ebstein"s disease and the other with a left posteroseptal PAP. None of the patients presented complications associated with the procedure. During the one-year follow-up, one patient was registered with asymptomatic recurrence (1 of 23; 4.35%: right posteroseptal location), demonstrated by manifest preexcitation on the control ECG. Conclusion In our first experience, catheter ablation of difficult accessory pathways guided by three-dimensional electroanatomic mapping showed a high primary success rate without associated complications. Recurrence during follow-up was similar to that reported in the literature. Accessory Pathway locationPatientsRight Posteroseptal11 (44%)Left Posteroseptal5 (20%)Anteroseptal5 (20%)Midseptal4 (16%)Abstract Figure

A new electrocardiographic marker with higher sensitivity and specificity for epicardial location of posteroseptal accessory pathway

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation of accessory pathways (AP) located in the posterior pyramidal space are often challenging due to its anatomical complexity. Scarce of data are available about the ECG features that might indicate when an epicardial approach is required in the ablation of the posteroseptal AP. Objective The purpose of this retrospective study was to describe the electrocardiographic features of posteroseptal AP which have been successfully ablated with epicardial approach and identify electrocardiographic predictors for epicardial AP location. Methods The 12 leads ECG of 75 patients with posteroseptal accessory pathways who were successfully ablated were retrospectively analyzed. ECG features for epicardial location described already in published studies have been considered (negative delta wave in DII, positive delta wave in aVR, high amplitude S wave in V6). Additionally the characteristics of the initial 40 ms of the delta wave in lead V1 (measured from the earliest QRS deflection in 12 leads) during full pre-excitation have been investigated. Results Of 75 patients with posteroseptal AP that undergone catheter ablation, 40 (53.3%) had successful epicardial ablation. An initial isoelectric or biphasic delta wave in lead V1 proved the highest sensitivity (82.5 %) respectively positive predictive value (97 %) and specificity (97 %) for an epicardial location of the AP. Deep S wave in V6 proved lower sensitivity (37.5%) and positive predictive value (68%) but higher specificity (80%) for epicardial location of AP. The specificity and sensitivity for epicardial location of AP of negative delta wave in DII were lower, however it failed to reach statistical significance. Conclusion This study shows that an initially isoelectric or biphasic delta wave aspect in lead V1 has a higher specificity, sensitivity and positive predictive value than previously described ECG markers for epicardial location of posteroseptal accessory pathways.

Non-algorithmic approach to accessory pathway localization based on a mobile app

Abstract Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): Polish Cardiac Society - Section of Non-invasive Electrocardiology and Telemonitoring (PTK SENIT) Background. Electrocardiographical localization of accessory pathways (AP) in WPW syndrome remains an elusive goal. Despite several, often very complex algorithms that were developed over the last three decades, none of them is very accurate - as demonstrated by several independent validation studies. Moreover, algorithms are difficult to remember, which further limits their usefulness. The accessory pathway regions are arbitrary and transitions between them are smooth, not binary. The same applies to ECG features such as QRS polarity – they are not binary. Moreover, even the most careful ECG lead placement cannot compensate for the variability in heart position within the chest. Therefore, it is unrealistic to expect that any ECG feature or feature set will precisely identify a particular location in a 0 vs. 1 fashion. Aim We intend to create a mobile app / web based localizing application, that would support a novel method for AP localization: a colour density map generator - based on actual distribution of a sizable number of accessory pathway with a particular QRS features. Methods A total of 881 consecutive AP ablation procedures were reviewed and patients with successful ablation of an overt accessory pathway were included. ECG with baseline and full preexcitation obtained during incremental atrial pacing were obtained. AP localization was based on stored fluoroscopic images in several projections and procedure description. Each AP localization, as well as QRS polarity in all 12 leads, separately for full and baseline preexcitation patterns, were coded and introduced into the application database. An application web-based, optimized for mobile devices was developed. This application enabled to graphically show changing localization of AP with regard to the introduced, at each step, QRS polarity in a particular ECG lead. User can choose his/her own steps or criteria; there is no need to adhere to the proposed steps. Results A total of 604 patients/ ECGs were available for density map generation. With each additional lead QRS information introduced into the application the user can appreciate more and more precise localization of the AP. This quickly enables to pinpoint the area of maximum probability, i.e. the most likely/frequent location, followed by the immediate adjacent locations. Representative screen shots of to typical inital steps for left- and right-sided APs are provided below (Figure 1 and Figure 2). Limited prospective assessment was very favourable. Conclusions A novel method, easy to use, not requiring to remember any algorithmic steps, and based on an analysis of by far the largest cohort of over accessory pathways (in comparison with published algorithms) was developed. Prospective validation of the localization application seems warranted. Abstract Figure.

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

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). 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. 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. 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.

Accessory pathway recording and ablation

Beginning in the mid-1970s, surgical ablation of accessory atrioventricular (AV) pathways (APs) was performed at a limited number of centers. The potential to target APs by catheter ablation became apparent in 1982, when Scheinman and coworkers introduced catheter ablation of the AV junction using high-energy direct current (DC) shocks from a defibrillator to produce AV block as palliative therapy for drug-resistant supraventricular tachyarrhythmias. Early attempts at DC shock ablation of APs were associated with some success,1 but the large area of barotrauma limited focused ablation and was associated with risk of cardiac perforation, AV block, and coronary artery injury.

Utility of Intracardiac Echocardiography to Guide Transseptal Catheterization for Different Electrophysiology Procedures.

"Intracardiac echocardiography (ICE) has evolved into an indispensable tool in the armamentarium of cardiac electrophysiologists not only for understanding the internal cardiac anatomy but also for establishing transseptal access and for monitoring electrophysiology procedures. ICE aids in live monitoring of every step of the procedure including early detection of complications. Access to the left atrium through transseptal catheterization is a vital step to perform atrial fibrillation and accessory pathway ablations, ablation of left ventricular tachycardias, left atrial appendage closures, left ventricular endocardial electrode implantations for cardiac resynchronization therapies, and for selectively sampling the regions of interest during endomyocardial biopsies."

Conduction Properties and Ablation of Adenosine Sensitive Accessory Pathways in Children.

Block in accessory pathway (AP) conduction with adenosine has been previously described. However, conduction characteristics of these APs has not been well defined to date. All patients with APs </ = 21years old who underwent an EP study from 2014 to 2017 were included in our study. Patients with adenosine sensitive APs were identified (group 1). Demographic and AP conduction characteristics were compared between group 1 and the entire cohort of patients. Local atrioventricular (AV) or ventriculoatrial (VA) time, cycle length and need for isoproterenol were compared to a control group matched by age and AP location (group 2). Student's t test, Wilcoxon rank sum, χ2 and Fisher's exact were used for analysis. Fourteen (7%) out of 207 patients had an adenosine sensitive AP. The median age of patients with adenosine sensitive APs was 11.8 (IQR 8.5-13.5) years vs. 14 (IQR 10.6-16.7) for the rest of the cohort (p = 0.04). Three of the 134 patients with preexcitation had adenosine sensitive APs (2%) vs. 11 of the 73 patients with concealed APs (15%) (p = 0.001). The median local AV/VA time at the site of successful ablation was longer in group 1 vs group 2 [78ms, IQR 62-116 vs. 31ms, IQR 30-38; p < 0.001]. Antegrade AP effective refractory period and total procedure time were longer in patients with adenosine sensitive APs (p = 0.03 & p = 0.04, respectively). Adenosine sensitive APs which occur in children are more often concealed. These APs have a longer conduction time at the site of successful ablation.

Effectiveness of radiofrequency ablation of various localization atrioventricular accessory pathways in adults

Effectiveness of radiofrequency ablation of various localization atrioventricular accessory pathways in adults

Transseptal Access for Catheter Ablation of Left-Sided Atrioventricular Accessory Pathways in Children

Introduction. Puncture of the atrial septum for access to the left atrium is often used for cardiac interventions in adults. In children, transseptal puncture is a less common, technically more difficult procedure, and the frequency of its complications is not well described in the literature.&#x0D; Objective. Our aim was to study the feasibility and safety of transseptal puncture in children through retrospective analysis of 208 consecutive radiofrequency catheter ablations (RFCA) for left-sided atrioventricular accessory pathways (AP).&#x0D; Results and discussion. Successful transseptal puncture was possible in 100% of cases, ablation in 97%. The mean time, including mapping and radiofrequency ablation, was 40 ± 22 minutes, and the mean fluoroscopy time was 3.8 ± 1.9 minutes. There were no complications associated with transseptal puncture. Recurrence of AP was reported in 6 (2.9%) children. Residual atrial septal defects 1 year after the procedure were detected by echocardiography in 5 (2.4%) children.&#x0D; The transseptal access ensures successful and effective ablation of the left-sided accessory pathways in the vast majority of children. RCA with transseptal access has a total operative time and fluoroscopy time comparable to those described in the literature for RCA with retrograde access. The reduced duration of the procedure and the fluoroscopy time are of great importance in the pediatric age group, which is most vulnerable to drug and radiation exposure. However, transseptal puncture in children remains a technically complex intervention with the possibility of corresponding complications. It should be performed by an experienced electrophysiologist who has experience in pediatric catheter ablation.&#x0D; Conclusions. Transseptal puncture is a feasible and reasonably safe procedure for children. It can be considered as the first choice approach in children with left-sided accessory pathways.

Delayed radiofrequency ablation efficacy in slow pathway ablation: a case report.

BackgroundThe delayed effect of radiofrequency (RF) ablation was described in cases of accessory pathway and premature ventricular contraction ablation, as well as delayed atrioventricular (AV) block after slow pathway ablation.Case summaryWe report a case of a female patient with AV nodal re-entry tachycardia (AVNRT), in whom the first electrophysiology study ended with acute failure of slow pathway ablation, despite using long steerable sheath, both right and left-sided ablation with >15 min of RF energy application and repeatedly achieving junctional rhythm. Six weeks afterwards, during scheduled three-dimensional electroanatomical mapping procedure, there was no proof of dual AV nodal conduction nor could the tachycardia be induced. Also, the patient did not have palpitations between the two procedures nor during the 12-month follow-up period.DiscussionThis case illustrates that watchful waiting for delayed RF ablation efficacy in some cases of AVNRT ablation could be reasonable, in order to reduce the risk of complications associated with slow pathway ablation.