Accessory Pathway Ablation Research Articles

CT-scan-guided-irrigated trans-catheter ablation of epicardial accessory pathways in the coronary sinus: safety and feasibility in pediatric patients.

The most common site of epicardial APs is posterior-septal, and ablation from the coronary sinus (CS) or its main tributaries is needed. However, particularly in children, it can carry a considerable risk of complications, such as coronary artery (CA) injury, CS damage, and perforation. This study aims to assess the efficacy and safety of computed tomography (CT)-scan-guided-irrigated trans-catheter (TC) ablation of epicardial APs through the CS in children. Twenty-four children (19 males; mean age 13.8 ± 2.6) with posterior-septal and left posterior epicardial APs who underwent an endocavitary electrophysiological study (EPS) and TC ablation from the CS were enrolled in this study. All patients underwent a CT scan to visualize the CS and its branches and their proximity to the CAs before the ablation. Clinical, electrophysiological and follow-up data were collected. Acute success rate was 87.5% (21 out of 24 procedures). No complications occurred. In 16 (66.7%) patients, the ablation site was detected at the proximal CS, in two (8.3%) patients in the mid-proximal CS and in six (25%) in the middle cardiac vein (MCV). Ablation was achieved using an irrigated radiofrequency (RF) catheter in all patients and without the use of fluoroscopy in 20 patients (83.3%). Over a median follow-up of 15.1months (IQR 2.5-32.3), no recurrences or complications occurred. Epicardial posterior-septal and left posterior APs, in the area of CS or MCV, can be definitively eliminated in most children using CT-scan-guided electro-anatomical mapping and transvenous irrigated RF ablation.

Wolff Parkinson White Syndrome with Rheumatic Mitral Stenosis: Double Trouble – Single Solution

WPW syndrome with rheumatic mitral stenosis is a rare and deadly combination. We report a patient with the above combination, presenting with drug-refractory antidromic tachycardia due to left atrial flutter and marked dyspnea. She underwent successful radiofrequency ablation of left-sided accessory pathway, left atrial flutter, and percutaneous mitral commissurotomy in a single sitting.

Comparison between Remotely Supported Nurse-led Electro-Anatomic Mapping and Standard Onsite Engineer Support for Electrophysiological Procedures.

Catheter ablations of complex cardiac arrhythmias are currently guided by electro-anatomic mapping systems. The aim of this study was to compare two different approaches: remotely supported nurse-led electro-anatomic mapping with standard onsite engineer support. In this retrospective observational study, 166 patients with complex and non-complex procedures were included. 82 patients benefited from electro-anatomic mapping with remotely supported nurse-led mapping (mean age: 62±16years), while the approach for 84 patients was with standard onsite engineer support (mean age: 56±19 years). Procedural characteristics, acute results and complication rates were compared between both groups and showed similar results.Complex and non-complex procedures were conducted in both groups, including left atrial and ventricular procedures. As ventricular tachycardia and accessory pathway ablations were more frequently conducted with standard onsite engineer support, we separately analyzed the largest subgroup, 105 patients with atrial fibrillation, left atrial flutter and left atrial tachycardia. Patients in this subgroup had comparable baseline characteristics, procedure times and procedural success. Nevertheless, there were longer ablation times and more utilization of fluoroscopy in the onsite group, most likely due to more complex procedures. Our results underline the practicality of remotely supported nurse-led electro-anatomic mapping. The latter approach proved to be a safe alternative to onsite engineer support. Due to its advantages, particularly for insular settings, it will likely play a greater role in the future.

Accuracy of Different Surface Electrocardiogram Algorithms for Localization of Accessory Pathway in Comparison to Invasive Electrophysiological Localization: An Observational Study

Introduction: Detection of accessory pathway (AP) on surface ECG in sinus rhythm helps in the diagnosis of Wolff-Parkinson-White Syndrome (WPW Syndrome), Catheter ablation of AP was indicated in symptomatic patients with preexcitation. Pre-ablation AP localization inferred from the 12-lead surface electrocardiogram (ECG) facilitates a tailored ablation strategy; there by specific risk can be properly assessed. As they are based on pre-excitation in the basal state, available algorithms can lead to complex and ambiguous analysis, mostly due to the variable influence of the AP over QRS morphology. Though various algorithms on surface ECG are available to predict the site of AP on surface ECG, but none of them are accurate. So, we have compared the accuracy of different algorithms in predicting the AP localization in comparison to electrophysiological study (EPS) diagnosis. Methodology: This retrospective observational study cohort consisted of 100 consecutive patients above 15 years of age presented to the tertiary care center with the history of palpitations or for assessment of a manifest AP. Accessory pathways were identified according to the site where successful radiofrequency energy was applied. Arruda algorithm, Milstein algorithm, Fitzpatrick algorithm and Pambrun algorithm were applied on a sinus rhythm manifest preexcited ECG to predict the AP localization by two independent investigators who are unaware of site of successful catheter ablation. Then those were compared with the EPS localization to test the accuracy of individual algorithm. Then Cohen’s Kappa was run to determine if there was agreement between any of the four different algorithms with EPS using SPSS version 20.0. Results: In the study population of 100 patients, male to female ratio of study population was 1.6:1, with a mean age of presentation 43.86 ± 11.4 years with the most common age group of 31 to 45 year. when the AP locations were categorized based on EP Study 56 percent of the AP were found on the left side while 43 percent of the AP were found on right side, 77 percent of the AP were septal pathways. Among the leftsided pathways, left anteroseptal constitutes majority followed by left posteroseptal pathway. On right side majority were in right posteroseptal location in our study. Based on 4 surface ECG algorithms AP was localized and each algorithm was compared with invasive EPS localization for accuracy using Cohen’s Kappa agreement analysis. As per agreement analysis the kappa value for Milstein, Pambrun algorithm, Fitzpatrik and Arruda were 0.188, 0.343, 0.441, and 0.645 respectively. It was found that Arruda algorithm had moderate strength of agreement with the findings of EPS (κ = 0.645). This is the proportion of agreement over and above chance agreement and which was statistically significant and the strongest among all the four algorithms. Conclusion: Our study has compared the accuracy of 4 surface ECG algorithms in predicting the accessory pathway localization with the EPS; it has demonstrated that the Arruda algorithm is more precise and accurate among the available algorithms followed by Fitzpatrik, Pambrun algorithm and Milstein algorithm, Knowing the pathway prior to ablation allows for optimal procedure preparation, mapping pathways that are difficult to find and finally may lessen the catheter-related injury and shortens the procedural time.

Comparison between cryotherapy and radiofrequency energy sources for parahisian accessory pathway percutaneous ablation.

Catheter ablation of parahisian accessory pathways (PHAP) are challenging due to their proximity to the normal conduction system. Retrospective studies suggest that cryoablation has a better safety profile but a higher recurrence rate when compared to radiofrequency ablation (RFCA). The objective of this study was to compare the results of parahisian AP ablation performed by electrophysiologists with experience in both technologies. Prospective single-center, non-blinded and 1:1 model was used. Patients included had parahisian AP confirmed by an electrophysiological study and referred for radiofrequency or cryotherapy ablation according to current guidelines, under fluoroscopic guidance. No electroanatomic mapping was used. A total of 30 patients (mean age of 25±9.4 years; 90% male) were enrolled between Oct/2018 to Feb/2020. Acute success rate between RFCA and CRYO were similar (93% vs. 87%, p = 0.54). A nonsignificant reduction in short-term recurrence rate for RFCA (14% vs. 30%, p = 0.3) and mechanical trauma (6% vs. 20%; p = 0.28) was observed. Long-term recurrence rate and event-free survival time were similar in both groups after 1-year follow-up (p = 0.286). No persistent complete AV block or conduction disturbance was also observed. Considering the limitation of a small sample size and the lack of use of electroanatomic mapping for RFCA, the efficacy and safety profile of parahisian AP ablation with RFCA was not different from CRYO, when performed by experienced electrophysiologists. No cases of permanent complete AV block were reported with either energy modalities.

Effects of accessory pathway catheter ablation on left ventricular function in patients with dyssynchrony-induced cardiomyopathy associated with pre-excitation syndrome

Aim. To evaluate the effect of radiofrequency ablation (RFA) of accessory pathways on left ventricle (LV) function in patients with Wolff-Parkinson-White (WPW) syndrome and preexitation-induced dyssynchrony cardiomyopathy.Methods. The study included 22 patients with registered preexitation on the ECG and signs of dyssynchronous cardiomyopathy according to echocardiography (Echo): asynchronous movement of interventricular septum, ejection fraction (EF) decrease and/or global longitudinal strain of the left ventricle (GLS LV), heart chamber increase. The average age of patients at the time of RFA of the accessory pathways - 11 years [8;14].Results. A regular normalization of the QRS complex width was observed after RFA (p = 0.0002). To assess reverse LV remodeling, all patients underwent Echo on day 3 after RFA. In patients with an initially reduced LVEF, its increase was noted. In patients with initial dilatation and an increase in LV volume, normalization of these indicators was noted. However, dynamics of LVEF and its volume was not statistically significant in the early postoperative period. According to Speckle-tracking Echo during medical check-up, complete normalization of longitudinal deformation was observed in 13 patients (59%), this indicator improvement - in 7 patients (31.8%). The average GLS LV before RFA was -17.25 [-16.4; -19], after RFA - -21.5 [-19; -24] (p = 0.0001).Conclusion. Reverse remodeling and restoration of LV function after RFA of accessory pathways indicates a cause- and-effect relationship between the accessory pathways functioning and dyssynchronous cardiomyopathy development. Therefore, patients with signs of preexitation-induced dyssynchronous cardiomyopathy are indicated for RFA of accessory pathways, regardless of age and tachycardia paroxysms.

Efficacy and safety of pulsed field ablation for accessory pathways: a pilot study.

Radiofrequency ablation is used as a first-line therapy for accessory pathways (APs). However, data regarding the effects of pulsed field ablation (PFA) on APs are limited. We sought to evaluate the acute procedural and 6-month success and safety of PFA in a cohort of patients with APs. A focal contact force-sensing PFA catheter was used for patients with APs. Pulsed field ablation generator generated a bipolar and biphasic waveform (±1000 V) with a duration of 100 ms from the tip of the PFA catheter. A 100% acute procedural success was achieved in 10 conscious patients with APs (7 left anterolateral, 2 left inferolateral, and 1 right posteroseptal APs) including 6 (60%) patients after an initial application. The average total ablation time was 6.3 ± 4.9 s for 4.7 ± 1.8 ablation sites (ASs), including 3.1 ± 2.4 s at targets and 3.2 ± 2.9 s at 3.2 ± 2 bolus ASs. The mean skin-to-skin time was 59.3 ± 15.5 min, and PFA catheter dwell time was 29.4 ± 7.8 min. One patient encountered transient sinus arrest during PFA due to parasympathetic overexcitation. Sinus rhythm was restored in all patients without any significant adverse events during the short-term follow-up. Pulsed field ablation of APs was feasible, effective, and safe. Its efficiency was remarkable for its ultrarapid termination of AP conduction. Further studies are warranted to prove whether utilization of PFA with current parameters can extend to manifold AP ablation.

Differential right apical and left basal pacing: a new maneuver that rules out the presence of a left accessory pathway with retrograde conduction

Abstract Background Differential apex-base pacing or entrainment is a very useful maneuver in patients with concealed septal accessory pathways. This study evaluates for the first time the diagnostic value of differential right apical pacing (aRV) and basal left ventricular pacing (bLV) in patients with left accessory pathways before and after ablation. Purpose To determine the value of differential aRV and bLV pacing as a simple maneuver to assess the successful ablation of left accessory pathways. Methods Successive patients with preexcitation or concealed left accessory pathways were prospectively included. Baseline pre-ablation (PRE) 1:1 retrograde conduction was evaluated by the S-A interval during pacing at the aRV (PREaRV) and at the bLV (PREbLV) measured to the earliest atrial electrogram detected by a decapolar catheter placed in the coronary sinus. The S-A interval resulting from direct atrial capture during high outputpacing at the bLV at (PREdir) was also measured. The same S-A intervals, pacing at the same locations and measured to the same dipole in the coronary sinus were reassessed after ablation (POSaRV, POSbLV, POSdir) in order to compare the total values and their differences. Results 47 patients were included (age 31 yo [range 4 – 76 yo], 70% male sex, transeptal approach used in 62%). Ablation of the accessory pathway was successful in all patients. 5 patients could not be analyzed due to absence of 1:1 retrograde conduction before ablation, 27/43 (63%) patients had 1:1 retrograde nodal conduction after ablation. A significant prolongation of the S-A intervals were observed after ablation during pacing at the aRV (POSaRV – PREaRV = 43±38 ms, IC95% 27-59 ms, p<0,001) and from the bLV (POSbVI – PREbVI = 126±53 ms, IC95% 105-147 ms, p<0,001). As expected, the S-A interval during direct atrial capture from the bLV did not prolong (POSdir – PREdir = 2±10 ms, IC95% -2 – 6 ms, p=0,41). The difference PREaRV – PREbLV before ablation (difPRE) was 80±26 ms (IC95% 72-88 ms) and never overlapped with the difference POSaRV – POSbLV after ablation (-6 ±33 ms, IC95% -19 – 8 ms) (difPOS) except in one case of left posteroseptal accessory pathway. The δ value (difPRE – difPOS) was 83±40 ms (IC95% 67-100 ms, p<0,001). A difPOS value <20 ms discriminated all successful ablations of non posteroseptal accesory pathways. Conclusion The S-A values obtained during differential RV apical and LV basal pacing before and after ablation are valid to discriminate the efficacy of the procedure. The POSaVD – POSbVI value is always <20 ms after successful ablation and excludes retrograde conduction over any left non-posteroseptal accesory pathway. This same value is ≤0 ms in 72% of cases of successful ablation.Figure.

Tackling of challenging accessory pathways utilizing open window mapping, does it add benefit?

Abstract Introduction 3D electroanatomical mapping is beneficial in accessory pathway ablation for better delineation of the anatomy, less procedure and fluro time, it depends on point-by-point mapping to identify the connection sites of the accessory pathway (AP) to the atria or ventricle, or the site of the AP potential. However, this approach requires an accurate interpretation of the local electrograms. In contrast, open window mapping (OWM) doesn’t need to differentiate the signals site of origin, it is based on an automatic annotation process in which the signals with the highest -dV/dt are annotated at each obtained point irrespective of the cardiac chamber. (1) Few reports describe the additional benefit of such technique in patients with complex congenital heart diseases. (2) Purpose To present our centre experience in using OWM technique in addition to early meets late (EML) algorism in accessory pathway ablation especially in patients with complex congenital heart disease or previous failed ablation trials. Methods We reviewed patients who underwent AVRT ablation at our centre from August 2022 to August 2023 with emphasis on cases mapped using OWM & EML techniques using high density mapping catheters. Demographic data, clinical presentation, resting & tachycardia ECGs, and Echo reports were examined thoroughly, additionally, we revised the 3D maps, ablation details, fluro dose, and outcomes of the procedures. Results Over one year, among 74 patients underwent AVRT ablation, open window mapping was used in 4 patients with manifest preexcitation (Rt posteroseptal in 3 of them & Rt free wall in one patient). Among the four patients: 3 were pediatrics, youngest was 5 years old, 19 Kg, 2 patients had previous failed ablation trials, their Echo reports revealed severe form of Ebstein anomaly with large ASD in the first patient, case 2 had single ventricle physiology with bidirectional Glenn while the two other patients had structurally normal heart (Table). The mapping using the OW & EML techniques confirmed the site of AP breakthrough conduction at Rt posteroseptal area in 3 of them and Rt posterolateral area in the remaining one, ablation resulted in immediate loss of preexcitation with no recurrence in all patients. Average fluro dose was 0.1 Gy which is significantly lower than the average dose in the remaining AVRT cases. Over median follow up period of 9 months, there were no recurrence of the accessory pathways & no complications. Conclusion Open window mapping technique is highly beneficial for accurate & fast mapping of accessory pathways especially in those with complex congenital heart where AP ablation remains considerably more challenging. OWM also added benefit in redo cases as the previous ablation trials hampered manual EGM interpretation. Finally, most of our cases were pediatrics where using high density mapping catheters and contact force ablation catheters appears to be safe and effective.Demographic, ECG, Echo & procedure data3D map & Echo in patient 2

Ablation of anomalous mitral annular pathways via transradial access: early hospital discharge due to the covid-19 pandemic

Abstract Introduction Wolff-Parkinson-White (WPW) syndrome arises from the conduction through accessory pathways (AP) connecting the atria and ventricles, bypassing the atrioventricular node. Radiofrequency catheter ablation of AP is the recommended treatment, often performed via transradial access. This approach is widely utilized in percutaneous coronary intervention due to its safety, effectiveness, patient preference, cost-effectiveness, and simplicity. Our study aims to present the results of AP ablation in the mitral annulus through transradial access amid the Covid-19 pandemic, marked by hospital bed scarcity and the need for early discharge. Materials and Methods Between May 2020 and December 2021, eight cases of transradial AP ablation in the mitral annulus were conducted. The service had previously achieved success in 16 transradial ablation cases. Among the eight cases during the pandemic, 62.5% were male, aged 24 to 56 years, all experiencing tachycardic palpitations and pre-syncope with a history of hospitalization. In 25% of cases, syncope episodes occurred. Patients were on propafenone, with no structural heart disease. Covid-19 tests were negative. Radial and ulnar artery perfusion integrity was assessed using the Allen maneuver and arterial Doppler. The right radial artery was used in 100% of cases. Sixty-two point five percent of accessory pathways were in anterolateral positions, and 37.5% were left posteroseptal. The approach was through the right radial artery, under local anesthesia, with venous sedation, using a 7Fr introducer sheath and positioning of the explorer catheter. Mapping was conducted during sinus rhythm, and adenosine IV tests followed ablation. The catheter was removed, and a pneumatic local dressing was applied for 2 hours, followed by a conventional dressing change for 24 hours. Results Ablation was successful in all eight patients. The procedure time ranged from 40 to 80 minutes, with an average of 55 minutes. Two to four radiofrequency applications were applied for a total of 2 minutes, using 55 W energy and a temperature of 55 to 60°C. No complications occurred during or after the procedure. Patients were discharged three hours post-intervention. Follow-up included reviews every four months, ECGs without ventricular pre-excitation, asymptomatic patients without antiarrhythmic medication, and no complications at the puncture site one year post-procedure. Conclusion Although based on a small sample of eight cases, and acknowledging the need for a larger sample to establish the procedure as an alternative, considering possible operator experience influence, we conclude that radial access proved effective and safe in this patient group. Its usage was exceptional, specifically in the context of a pandemic with crowded hospitals. Selection criteria and comparisons with other alternatives should be adopted for analyzing its potential future use.Transradial approachAblation catheter in the mitral plane

Trans-catheter cryoablation of parahisian accessory pathways: a single centre experience

Abstract Introduction Transcatheter radiofrequency (RF) ablation of perinodal accessory pathways (parahisian/midseptal APs) is still challenging especially in young patients due to a high risk for inadvertent atrioventricular block (AVB) requiring permanent pacing. Recently, cryo-ablation (CA) has evolved as an RF alternative, thanks to a safer profile and a better catheter stability. Purpose To evaluate the safety, efficacy and outcomes of CA in patients with parahisian/midseptal APs. Methods 73 pts undergoing a first ablation of septal APs at our institution were retrospectively analyzed. Among these, we selected 20 patients with a diagnosis of para-hisian/midseptal AP confirmed by EP study (EPS) and 3D-electro-anatomic mapping (EAM), ablated using cryoenergy. Before delivering CA, a cryomapping (CM) at the target AP site was performed at −30°C using a 6- mm-tip catheter. Successful CM was defined as: (1) loss of delta wave in case of manifest pre-excitation, (2) termination of a sustained AVRT, (3) retrograde conduction block through the AP during ventricular pacing in case of concealed AP. CA was initiated following successful CM, at a temperature of −75°C for 300 s with an additional "bonus" CA application (300s). Acute procedural endpoint was permanent complete abolition of AP conduction; long-term clinical endpoint was defined as no recurrence of delta wave or AVRT on serial ECG monitoring at follow-up (1, 6, 12 months). RESULTS Baseline characteristics are summarized in Fig. 1. Fifty-five % were pediatric patients, only 3/20 presented a structural HD. Up to 90% of the patients experienced a symptomatic AVRT, while delta-wave was present at baseline ECG in 19/20 patients. EPS combined with 3D-EAM showed a para-hisian AP in 80% and a mid-septal AP in 20%. Mean distance between His bundle electrogram and AP site was 5.72 mm (4-6.8 mm, Fig. 2). Orthodromic AVRT was induced in all the 20 pts. Maen procedural and fluoroscopy times were, respectively, 103.4 ± 26.4 and 3.15± 1.76 min . Acute success was achieved in 20/20 patients (100%) with AP block of conduction obtained within few seconds (<10s) after a mean CM number of 3.3 ± 1.2 (Fig. 2). Two patients developed transient 2:1 AV block and 1 patient transient RBBB during CM, with immediate recovery within 20s from CM termination. No peri-procedural complications or permanent AV block were observed. One patient had an early AP re-conduction (6 hours later) and was successfully re-ablated the following day. During a mean FU of 361 ± 34 days, only two patients (10%) experienced an AVRT recurrence and underwent a second successful CA. Conclusions Cryoablation of parahisian and midseptal APs is a safe and effective alternative to RF, resulting in a low risk of recurrence over 12-months-follow-up with no incidence of permanent AV block. A near-zero fluoroscopy approach combining CA and 3D-EAM is feasible and should be considered especially in very young patients with parahisian APs.Fig. 1Fig. 2

Ablation of persistent atrial fibrillation based on atrial electrogram duration map: methodology and clinical outcomes from the AEDUM pilot study

Abstract Background Catheter ablation of persistent atrial fibrillation (PsAF) represents a challenge for the electrophysiologist and there are still divergences regarding the best ablative approach to adopt. Objectives Create a new map of the duration of atrial bipolar electrograms (Atrial Electrogram DUration Map, AEDUM) to recognize a functional substrate during sinus rhythm and guide a patient-tailored ablative strategy for PsAF. Methods 40 PsAF subjects were assigned in a 1:1 ratio to either for PVI alone (Group B1) or PVI+AEDUM areas ablation (Group B2). A cohort of 15 patients without AF history undergoing left-sided accessory pathway ablation was used as a control group (Group A). In all patients, voltage and AEDUM maps were created during sinus rhythm. The minimum follow-up was 12-months, with rhythm monitoring via 48-h ECG Holter or by implantable cardiac device. Results Electrogram (EGM) duration was higher in Group B than in Group A (49±16.2ms vs 34.2±3.8ms; p-value<0.001). In Group B the mean cumulative AEDUM area was 21.8±8.2cm2; no difference between the two subgroups was observed (22.3±9.1cm2 vs 21.2±7.2cm2; p-value=0.45). The overall bipolar voltage recorded inside the AEDUM areas was lower than in the remaining atrial areas [median:1.30mV (IQR:0.71–2.38mV) vs 1.54mV (IQR:0.79–2.97mV); p-value:<0.001)]. Low voltage areas (<0.5mV) were recorded in three (7.5%) patients in Group B. During the follow-up [median 511 days(376-845days)] patients who underwent PVI-only experienced more AF recurrence than those receiving a tailored approach (65% vs 35%; p-value=0.04). Conclusions All PsAF patients exhibited AEDUM areas. An ablation approach targeting these areas resulted in a more effective strategy compared with PVI only.AEDUM mapAEDUM map and lesion set

Evaluation of T-wave memory after accessory pathway ablation in pediatric patients with Wolff-Parkinson-White syndrome.

T-wave memory (TWM) is a rare cause of T-wave inversion (TWI). Alterations in ventricular activation due to abnormal depolarization may cause repolarization abnormalities on the ECG, even if myocardial conduction returns to normal. These repolarization changes are defined as TWM. In our study, we aimed to determine the frequency of TWM development and the predictors affecting it in the pediatric population who underwent accessory pathway (AP) ablation due to Wolff-Parkinson-White (WPW) syndrome. The data of patients with manifest AP who underwent electrophysiological studies and ablation between 2015 and 2021 were retrospectively analyzed. The study included 180 patients who were under 21 years of age and had at least one year of follow-up after ablation. Patients with structural heart disease, intermittent WPWs, recurrent ablation, other arrhythmia substrates, and those with less than one-year follow-up were excluded from the study. The ECG data of the patients before the procedure, in the first 24h after the procedure, three months, and in the first year were recorded. The standard ablation technique was used in all patients. Postprocedure TWM was observed in 116 (64.4%) patients. Ninety-three patients (51.7%) had a right-sided AP, and 87 patients (48.3%) had a left-sided AP. The presence of posteroseptal AP was found to be significantly higher in the group that developed TWM. Of these patients, 107 (93.1%) patients showed improvement at the end of the first year. Preprocedural absolute QRS-T angle, postprocedural PR interval, and right posteroseptal pathway location were identified as predictors of TWM. The development of TWM is particularly associated with the right-sided pathway location, especially the right posteroseptal pathway location. The predictors of TWM are the preprocedural QRS-T angle, the postprocedural PR interval, and the presence of the right posteroseptal AP.

Delineation of intracavitary electrograms for the automatic quantification of decrement-evoked potentials in the coronary sinus with deep-learning techniques.

Cardiac arrhythmias cause depolarization waves to conduct unevenly on the myocardial surface, potentially delaying local components with respect to a previous beat when stimulated at faster frequencies. Despite the diagnostic value of localizing the distinct local electrocardiogram (EGM) components for identifying regions with decrement-evoked potentials (DEEPs), current software solutions do not perform automatic signal quantification. Electrophysiologists must manually measure distances on the EGM signals to assess the existence of DEEPs during pacing or extra-stimuli protocols. In this work, we present a deep learning (DL)-based algorithm to identify decrement in atrial components (measured in the coronary sinus) with respect to their ventricular counterparts from EGM signals, for disambiguating between accessory pathways (APs) and atrioventricular re-entrant tachycardias (AVRTs). Several U-Net and W-Net neural networks with different configurations were trained on a private dataset of signals from the coronary sinus (312 EGM recordings from 77 patients who underwent AP or AVRT ablation). A second, separate dataset was annotated for clinical validation, with clinical labels associated to EGM fragments in which decremental conduction was elucidated. To alleviate data scarcity, a synthetic data augmentation method was developed for generating EGM recordings. Moreover, two novel loss functions were developed to minimize false negatives and delineation errors. Finally, the addition of self-attention mechanisms and their effect on model performance was explored. The best performing model was a W-Net model with 6 levels, optimized solely with the Dice loss. The model obtained precisions of 91.28%, 77.78% and of 100.0%, and recalls of 94.86%, 95.25% and 100.0% for localizing local field, far field activations, and extra-stimuli, respectively. The clinical validation model demonstrated good overall agreement with respect to the evaluation of decremental properties. When compared to the criteria of electrophysiologists, the automatic exclusion step reached a sensitivity of 87.06% and a specificity of 97.03%. Out of the non-excluded signals, a sensitivity of 96.77% and a specificity of 95.24% was obtained for classifying them into decremental and non-decremental potentials. Current results show great promise while being, to the best of our knowledge, the first tool in the literature allowing the delineation of all local components present in an EGM recording. This is of capital importance at advancing processing for cardiac electrophysiological procedures and reducing intervention times, as many diagnosis procedures are performed by comparing segments or late potentials in subsequent cardiac cycles.

Frequency and Clinical Implications of Atrial Fibrillation in Patients with Accessory Pathways

Abstract:
 Atrial fibrillation (AF) is a common arrhythmia associated with various cardiac conditions. This study investigates the frequency of AF in patients with accessory pathways, anomalous electrical connections that can lead to supraventricular tachycardia.
 Objective:
 The primary objectives are to determine the prevalence of AF in patients with accessory pathways, identify associated factors, and assess the impact on clinical outcomes. A comprehensive dataset of 400 patients undergoing supraventricular tachycardia ablation at Hayatabad Medical Complex from 2020 to 2022 was analyzed.
 Method:
 A retrospective study design was employed, utilizing patient records with documented accessory pathway(s) and complete clinical-electrophysiological data. Demographic information, clinical presentation, electrocardiographic and electrophysiological data, ablation procedures, and clinical outcomes were systematically collected. Analytical approaches included frequency calculation, comparative analysis, regression analysis, and outcome assessment.
 Result:
 Out of 400 patients, 3.5% presented with AF at the time of accessory pathway ablation. Age was identified as a significant predictor of AF occurrence, with a mean age of 63.2 years in AF cases compared to 55.8 years in non-AF cases. Recurrence of arrhythmias was observed in 57.1% of patients with AF, emphasizing the need for ongoing monitoring and management.
 Conclusion:
 This study contributes valuable insights into the relatively low prevalence of AF in patients with accessory pathways. While certain factors, including age, may be associated with AF, they do not serve as definitive predictors. Tailored management and adherence to guidelines are crucial for optimizing outcomes in this unique patient population. Future research may explore genetic factors and refine risk stratification models for a deeper understanding of AF in patients with accessory pathways.

Ablation of accessory pathways in different anatomic locations using focal pulsed field ablation

BackgroundAblation of accessory pathways (APs) is the cornerstone for treatment of patients with Wolff-Parkinson-White syndrome and manifestation of atrioventricular reentrant tachycardia. Pulsed field ablation (PFA) is a new type of nonthermal energy source delivered to the underlying tissue via the ablation catheter and used for ablation of arrhythmic substrates. ObjectiveThe purpose of this study was to determine the efficiency and long-term outcome of ablation of APs of different localizations using a focal pulsed electrical field. MethodsElectrophysiological study was performed in patients with indication for AP ablation. An ablation catheter was used to map the position of AP insertion. Pulsed electric field was delivered through a standard ablation catheter. In left-sided APs, the first ablation attempt was within the coronary sinus (CS). Patient follow-up was scheduled 1–3 months after the ablation. Additional check-up was performed after 6 and 12 months. ResultsFourteen 14 patients (3 pediatric) were treated. Termination of AP conduction was achieved in all procedures. The cohort consisted of 3 right free wall, 3 posteroseptal, and 8 left-sided APs. Ablation through CS was successfully used in 7 of 8 patients with left-sided APs. No complications were reported. Median follow-up was 5.5 months. Conduction recurrence through AP was documented in 1 patient. ConclusionFocal PFA for AP shows promising results in terms of efficacy and safety. A high rate of successful termination of left-sided APs by ablation within CS may represent a new standard approach. The safety and efficacy profile of PFA seems to be transferable to the pediatric population.

Historical developments in the diagnosis and treatment of pre-excitation syndromes (WPW)

In 1930, Wolff, Parkinson and White described the syndrome that bears their names. The mechanisms of supraventricular tachycardias were analyzed by brilliant electrocardiography interpretation by Pick and Langendorf. Wellens and Durrer using electrophysiologic studies analyzed the tachycardia mechanism invasively. In Germany the group by Seipel and Breithardt as well as Neuss and Schlepper studied the tachycardia mechanisms and response to antiarrhythmic drugs invasively by electrophysiological studies. Following the first successful interruption of an accessory pathway by Sealy in 1967, surgeons and electrophysiologists cooperated in Germany. Two centers, Hannover and Düsseldorf were established. Direct current (DC) ablation of accessory pathways was introduced by Morady and Scheinman. Because of side effects induced by barotrauma of DC, alternative strategies were studied. In 1987, radiofrequency ablation was introduced and thereafter established as curative therapy of accessory pathways in all locations.

Ablation of persistent atrial fibrillation based on atrial electrogram duration map: methodology and clinical outcomes from the AEDUM pilot study

BackgroundCatheter ablation of persistent atrial fibrillation (PsAF) represents a challenge for the electrophysiologist and there are still divergences regarding the best ablative approach to adopt. Create a new map of the duration of atrial bipolar electrograms (Atrial Electrogram DUration Map, AEDUM) to recognize a functional substrate during sinus rhythm and guide a patient-tailored ablative strategy for PsAF.MethodsForty PsAF subjects were assigned in a 1:1 ratio to either for PVI alone (Group B1) or PVI+AEDUM areas ablation (Group B2). A cohort of 15 patients without AF history undergoing left-sided accessory pathway ablation was used as a control group (Group A). In all patients, voltage and AEDUM maps were created during sinus rhythm. The minimum follow-up was 12 months, with rhythm monitoring via 48-h ECG Holter or by implantable cardiac device.ResultsElectrogram (EGM) duration was higher in Group B than in Group A (49±16.2ms vs 34.2±3.8ms; p-value<0.001). In Group B the mean cumulative AEDUM area was 21.8±8.2cm2; no difference between the two subgroups was observed (22.3±9.1cm2 vs 21.2±7.2cm2; p-value=0.45). The overall bipolar voltage recorded inside the AEDUM areas was lower than in the remaining atrial areas [median: 1.30mV (IQR: 0.71–2.38mV) vs 1.54mV (IQR: 0.79–2.97mV); p-value: <0.001)]. Low voltage areas (<0.5mV) were recorded in three (7.5%) patients in Group B. During the follow-up [median 511 days (376–845days)] patients who underwent PVI-only experienced more AF recurrence than those receiving a tailored approach (65% vs 35%; p-value= 0.04).ConclusionsAll PsAF patients exhibited AEDUM areas. An ablation approach targeting these areas resulted in a more effective strategy compared with PVI only.Graphical

Successful high-resolution three-dimensional electroanatomical mapping and radiofrequency catheter ablation of a posteroseptal accessory pathway in a dog using CARTO 3

A one-year-and-seven-month-old, 28 kg, male castrated crossbreed dog was presented for supraventricular tachycardia causing recurrent episodes of anorexia and lethargy. Sotalol (2.2 mg/kg q12 h) reduced the frequency of symptomatic episodes but did not provide full relief. Three-dimensional electroanatomical mapping was performed at the Ghent University Small Animal Teaching hospital using the CARTO 3. Right atrial activation mapping identified the earliest atrial activation right posteroseptal, near the tricuspid annulus. Fast retrograde ventriculoatrial conduction during tachycardia and extrastimulus testing confirmed the presence of a concealed right posteroseptal accessory pathway. Six radiofrequency catheter ablation applications were delivered, and tachycardia remained uninducible. The dog recovered well from the procedure. Sotalol was stopped three weeks later, and no more clinical signs were noted by the owner. Repeated 24-hour electrocardiography monitoring on day one and at one, three, and 12 months after the procedure showed no recurrence of tachycardia.

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.

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. 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. The utilization of 3D mapping led to reduced fluoroscopy time, shorter procedure duration, enhanced acute success rates, and decreased incidence of complications.