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A 1.5-year-old, female-spayed mix breed dog was presented with recurrent episodes of shaking and excessive panting attributed to drug-refractory ventricular arrhythmia (VA) characterized predominantly by incessant periods of ventricular bigeminy. The VA had a narrow QRS morphology, suggestive of an origin near the His-bundle or fascicular system. Diagnostic evaluation found no structural heart disease or underlying etiology. Three-dimensional electroanatomic mapping and radiofrequency catheter ablation were pursued. Voltage mapping demonstrated normal bi-ventricular voltage (≥1.5 mV) without any fractionated or multi-component electrograms, indicating absence of ventricular myocardial scar. Pace mapping identified an endocardial origin of the VA at the basal anterior-septum of the left ventricle, distal to the His-bundle and near the left bundle branch. Two ablation lesions were delivered to this site, and a left bundle branch block was temporarily induced. The dog recovered uneventfully. One month later, the owners reported a remarkable improvement in clinical signs and follow up 48-hour Holter monitor found complete resolution of VA.

Introduction: For those cardiac resynchronization therapy (CRT) candidates who experience left-ventricular (LV) lead placement failure or underwent concomitant cardiac surgeries, surgical placement of epicardial LV lead guided by electroanatomic mapping may be a promising alternative. Methods: Electroanatomic mapping was used to guide positioning of the LV lead through a surgical approach. The LV lead was placed at the region with the latest local LV activation and normal voltage, away from the scar. Results: From April 2010 to September 2018, 10 consecutive patients (3 female) underwent surgical epicardial LV lead implantation. Among them, 3 had other surgical indications simultaneously (including 1 CRT non-responder), and 7 had failed transvenous LV lead placement. After CRT, the QRS duration was shortened from 149.3 ± 20.4 ms to 125.1 ± 15.2 ms (p = 0.01). At 6 months, the LV ejection fraction was significantly improved and remained stable in the follow-up (FU) period thereafter (baseline vs. 6 months, 31.0 ± 8.3% vs. 42.2 ± 13.4%, p = 0.006). Other parameters, including the threshold and impedance of the LV lead, were also stable at a mean FU of 755 ± 406 days, and the NYHA functional classification decreased from 2.9 ± 0.7 to 1.8 ± 0.8 (p = 0.002). Conclusions: Placement of an epicardial LV lead guided by electroanatomic mapping could be used as an adjunctive strategy in patients who were unable or refractory to conventional CRT therapy. This approach could also be applied in patients who had other surgical indications at the same time.

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

INTRODUCTION His bundle pacing (HBP) and left bundle branch area pacing (LBBAP) have emerged as attractive alternatives to traditional biventricular pacing to achieve cardiac resynchronization therapy. Early reported results have been inconsistent, particularly amongst patients in whom initial placement with traditional approaches has been unsuccessful or those with complex anatomy or congenital abnormalities. In this report, we describe the use of three-dimensional electroanatomic mapping (EAM) in five selected cases. METHODS Five patients from multiple clinical sites underwent EAM-guided HBP or LBBAP by highly trained electrophysiologists with significant experience with conduction system pacing. Each patient in this series underwent EAM-guided conduction system pacing due to complex anatomy and/or prior failed lead implantation. RESULTS EAM-guided lead implantation was successful in all five cases. Capture thresholds were relatively low and patients continued to have evidence of successful lead implantation with minimum 1-month follow-up. The fluoroscopy time varied, likely owing to the variable complexity of the cases. CONCLUSIONS The use of EAM, in combination with traditional intracardiac electrograms with or without fluoroscopy, allows more targeted and precise placement of leads for HBP and LBBAP pacing. Further investigation is needed to determine this strategy's long-term performance and to optimize patient selection.

Background Fast anatomical mapping (FAM) of the left atrium and pulmonary veins (PV) during PV isolation (PVI) generates anatomical information about the carina region additionally. We aimed to investigate the utility of these data in relation to conduction abilities of the intervenous carina. Methods We investigated 71 patients with drug‐refractory atrial fibrillation (AF) who underwent first‐time circumferential PVI using an electroanatomical mapping system. Carina width between ipsilateral PV was measured using FAM and an integrated distance measurement tool. Encirclings were divided into carina ablation and noncarina ablation groups based on the necessity of carina ablation to achieve PVI. Results In total, 142 encirclings were analyzed and first‐pass isolation was observed in 102 (72%) encirclings. Nonfirst‐pass PVI solely due to a gap on the line or persistent carina conduction was observed in 10 (7%) and 30 (21%) encirclings, respectively. Encirclings were classified into a carina ablation group (n = 30, 21%) and noncarina ablation group (n = 112, 79%). Carina width was significantly larger in the carina ablation vs nonarina ablation group (right: 11.9 ± 1.5 mm vs 8 ± 1.4 mm, P, Carina conduction after pulmonary vein isolation was studied. Especially, the relation between carina width and the necessity for carina ablation was observed using routine data from an electroanatomical mapping system.

Background Previous studies have demonstrated that some patients have spontaneous right atrium (RA)‐superior vena cava (SVC) conduction block, which could be utilized to isolate the SVC effectively by using the Rhythmia mapping system (Boston Scientific). However, employing this approach for SVC isolation using the CARTO electroanatomical mapping system (Biosense Webster) has not yet been clarified. This study aimed to evaluate the safety and efficacy of SVC isolation using the extended early meets late (EEML) tool with the CARTO system. Methods The patients who underwent SVC isolation using the CARTO system were enrolled in this study. The RA‐SVC conduction block was visualized with an EEML tool. We prospectively assessed the safety and efficacy of SVC isolation using this system. Results We analyzed 54 patients, and all SVCs were successfully isolated with no complications. Altogether, 44 patients (81.5%) had spontaneous RA‐SVC conduction block, and the remaining 10 patients (18.5%) did not. The block group required fewer radiofrequency deliveries for the SVC isolation than the nonblock group (10.7 ± 5.0 vs 15.5 ± 4.8, P = .009). The size of the isolated area in the block group was larger than that in the nonblock group (15.2 ± 5.1 cm2 vs 12.4 ± 2.5 cm2, P = .017). Conclusions Approximately 80% of the patients in this study developed a spontaneous RA‐SVC conduction block, which might contribute to shortening the time of ablation and avoiding complications., In our study, spontaneous RA‐SVC conduction block was observed in approximately 80% of the patients. The block group required fewer RF deliveries for SVC isolation than the non‐block group and the procedural time to SVC isolation in the block group was significantly less than in the non‐block group. The size of the isolated area in the block group was larger than that in the non‐block group.

Настоящата статия представя данни от националния електронен регистър BG-EPHY за електрофизиологичните катетърни аблации през 2019 и 2020 г. Материал и методи. Извършено е ретроспективно проучване на пълна двугодишна извадка от регистъра BG-EPHY. Представени са разпределение на пациентите по пол и възраст, брой процедури, честота на използване на електроанатомичен мепинг (ЕАМ) и на иригирана аблация, честота на електрофизиологичните диагнози, брой и относителен дял на успешните процедури, интрапроцедурни усложнения. Резултати: През 2019 г. в 4 електрофизиологични центъра са извършени 1033 аблации при 652-ма мъже (63.1%) и 381 жени, вкл. 12 пациенти на възраст ‹ 18 год. (1.2%). ЕАМ е използван при 46.7% от аблациите, иригиран катетър – в 52.2%, а криокатетър – в 0.5%. Най-често е правена изолация на белодробни вени, следвана от аблация на АV нодална риентри тахикардия и типично предсърдно трептене. През 2020 г. в 5 електрофизиологични центъра са извършени 835 аблации при 508 мъже (60.8%) и 327 жени, вкл. 8 пациенти на възраст ‹ 18 год. (1%). ЕАМ е прилаган в 50.9%, иригиран катетър – в 54.5%, криокатетър – в 3.8%. Най-честата аблация отново е изолацията на белодробни вени, но аблацията при типично предсърдно трептене изпреварва АV нодалната риентри тахикардия. През 2020 г. отчетливо намаляват и аблациите на допълнителни проводни връзки с 37%. И през двете години непосредственият успех е над 98%, а усложненията – под 2%. Заключение. Националният регистър по електрофизиология включва системно и непрекъснато основни данни за сърдечните аблации, извършвани в страната. Структурата на дейността е много сходна с тази в други европейски страни. Непосредственият процедурен успех е много висок, а интрапроцедурните усложнения – много редки. През 2020 година се отчита спад в броя на извършените аблации с 19% спрямо предходната година в резултат на пандемията от COVID-19. This study presents data from the national electronic registry BG-EPHY on electrophysiologic (EP) cardiac ablations in 2019 and 2020. Material and methods. This is a retrospective study of a full two-year sample of the BG-EPHY registry. Sex and age distribution of the patients, number of ablations, electroanatomic mapping (EAM), irrigated ablations, distribution of different types of arrhythmia, intraprocedural success and complications are presented. Results. In 2019 four EP laboratories performed 1033 ablations in 652 men (63.1%) and 381 women, incl. 12 pediatric ablations (1.2%). EAM was used in 46.7% of the procedures, irrigation catheter was used in 52.2%, and cryocatheter – in 0.5%. The most common procedure was pulmonary vein isolation, followed by ablation for AV nodal reentrant tachycardia and typical atrial flutter. In 2020 five EP laboratories performed 835 ablations in 508 men (60.8%) and 327 women, incl. 8 pediatric ablations (1%). EAM was used in 50.9% of the ablations, irrigation catheter – in 54.5%, and cryocatheter – in 3.8%. The most common procedure was again pulmonary vein isolation. Ablation of typical atrial flutter was the second most frequently performed procedure, ahead of AV nodal reentrant tachycardia. In 2020 the number of ablations of accessory pathways also distinctly dropped by 37%. In both years the acute success was over 98%, and the complications were less than 2%. Conclusion. The national registry of electrophysiology collects systematically and continuously basic data on all cardiac ablations performed in the country. The structure of the EP service is remarkably similar to other European countries. Acute success is very high, while intraprocedural complications are rare. In 2020 the number of the ablations dropped by 19% as a consequence of the COVID-19 pandemic.

Mapping and localizing presystolic Purkinje potentials are crucial for determining the optimal ablation site for fascicular premature ventricular contractions (PVCs). Here we present a case of PVCs originating from the distal left anterior fascicle (LAF). Activation mapping using a multipolar catheter with small electrodes demonstrated early presystolic Purkinje potentials during the PVCs. A moderately good pace-map match was also obtained near the successful ablation site. This case demonstrates the activation pattern of PVCs originating from the distal LAF and the usefulness of multipolar catheters with small electrodes for the mapping of fascicular PVCs.

The Rhythmia™ system (Boston Scientific, Natick, MA, USA) facilitates the rapid acquisition of high-resolution electroanatomical and activation maps. However, there are limited data on its efficacy and safety in pediatric and adult congenital heart disease (CHD) patients. In a retrospective, observational cohort study, adult CHD and pediatric patients followed by pediatric cardiology underwent electrophysiologic study using the Rhythmia™ electroanatomic mapping system. Variables examined included the number of electroanatomical maps required, acquisition time, procedure time, fluoroscopy time, radiation dosage, and rate of recurrent arrhythmia. Twelve consecutive patients, including six male patients (50%), were included with an average age of 27.7 years (range: 11-64 years). Seven (58%) of these patients had a diagnosis of CHD [moderate complexity in two (17%) and great complexity in five patients (42%)] and 10 (83%) patients underwent ablation. A total of 37 high-density maps were created in 12 procedures, with a median of 8,140 mapping points, taking a median of 631 seconds. The median procedure time was 189.5 minutes. The median fluoroscopy time was 0.9 minutes, with eight (67%) patients receiving no fluoroscopy at all. Recurrence occurred in one patient (8%) over a median follow-up duration of 16 months (interquartile range: 12.8-17.3 months). No adverse periprocedural events were recorded. This study suggests the use of high-density electroanatomic mapping in adult CHD patients showed potential for rapid acquisition of highly detailed maps with minimal fluoroscopy time or risk of periprocedural events in the studied population.

Right ventricular (RV) resynchronization therapy (CRT) with stimulation electrode implantation in the latest activation area guided by a high-density electroanatomic activation map was successfully performed in a patient with repaired tetralogy of Fallot (rToF), severe pulmonary regurgitation (PR), and severe dysfunction and dilatation of the right ventricle. An improvement in his clinical condition and intraventricular synchrony was achieved. There is a mechanical-electrical interaction in the right ventricle of patients with rToF; therefore, RV CRT in selected cases may be beneficial. Electroanatomic activation mapping can help achieve maximum clinical benefit by identifying the optimal stimulation site.

BACKGROUND Left atrial scar is an important entity in the atrial fibrillation substrate. P wave dispersion (PWD) is an indicator of slow and inhomogeneous conduction in the atria. In this study, we aim to investigate the relation between PWD and left atrial scars identified by electroanatomical mapping. METHODS Patients who had an electroanatomical map obtained during sinus rhythm as well as at least one electrocardiogram in sinus rhythm prior to the procedure were included in the study. Left atrial scar (defined as

Mechanisms sustaining atrial fibrillation are yet to be clarified. This article focuses on milestones in the theory of atrial fibrillation and addresses the different leading hypotheses concerning atrial fibrillation mechanisms. We start off with electric potential originating from the pulmonary vein, which triggers atrial fibrillation, discuss classic activation mapping and phase mapping as well as computer models, which have contributed to the our understanding of atrial fibrillation, and end with new mapping methods and studies highlighting the advantages and disadvantages of current mechanistic hypotheses. The technical evolution of mapping atrial fibrillation has led to new insights into the potential mechanisms underlying atrial fibrillation. A comparison between methods is essential for understanding the advantages and disadvantages of each method when mapping atrial fibrillation. Ultimately, the combination of several methods might shed light on the underlying mechanisms of atrial fibrillation and lead to a better understanding of atrial fibrillation and subsequently improve treatment of this condition.

The effective diagnosis and management of procedural complications remains an important challenge for electrophysiology operators. Intracardiac echocardiography provides a real-time imaging modality with spectral and color Doppler capabilities that integrates directly with electroanatomic mapping systems. It provides detailed characterization of anatomic variants, which allows the operator to optimize the ablation strategy to the individual thereby avoiding the inherent risk of excessive or ineffective lesions. Complications, such as intracardiac thrombus or pericardial effusion, can be detected and managed before the onset of clinical symptoms. Intracardiac echocardiography facilitates the diagnosis and management of intraoperative hypotension.

Background The purpose of this meta‐analysis was to evaluate the impact of image integration technique on clinical and procedural outcomes in patients undergoing radiofrequency catheter ablation of atrial fibrillation with a three‐dimensional electroanatomic mapping system. Methods Randomized controlled trials were identified through a systematic literature search of PubMed and CENTRAL databases from inception to April 2020. The primary outcome was arrhythmia recurrence during the follow‐up period. The secondary outcomes were the difference in total procedural time and fluoroscopy time. Results Four studies with a total of 749 patients were included. The pooled result showed no statistically significant difference between the groups with respect to arrhythmia recurrence (RR, 0.75; 95% CI, 0.47‐1.21), fluoroscopy time (MD, −6 minutes; 95% CI, −23.4 to 11.3), and total procedural time (MD, 1.1 minutes; 95% CI, −31.8 to 34.1). Conclusion Image integration to guide radiofrequency catheter ablation for patients with atrial fibrillation does not improve clinical and procedural outcomes., Meta‐analysis of four randomized controlled trials showed that integration of preprocedural CT or MRI images with real‐time electroanatomic maps to guide pulmonary vein isolation does not improve clinical and procedural outcomes.

Interest in endomyocardial biopsy (EMB) has progressively grown during the past decade. Still, its use remains limited to highly specialized centers, mostly because it is considered an invasive procedure with poor diagnostic yield and inherent complications. Indeed, the diagnostic performance of EMB is strictly linked to the sample of myocardium we can obtain. If we can precisely localize areas of diseased myocardium, sampling error or inadequate withdrawals are minimized. In this state-of-the-art review, we provide guidance on how to technically and practically perform EMB guided by electroanatomic voltage mapping and intracardiac echocardiography, and review the evidence supporting this combined approach.

Aims. 3D electroanatomical mapping combined with intracardiac echocardiography- (EAM-ICE-) guided transseptal puncture has been proven safe and effective during the radiofrequency catheter ablation (RFCA) procedure used to treat paroxysmal atrial fibrillation (PAF). In this study, we aimed to compare the curative effect and safety of RFCA via F (fluoroscopy) and zero-fluoroscopy transseptal puncture guided by EAM-ICE in patients with PAF. Methods and Results. A prospective study in which 110 patients with PAF were included and assigned to two groups was conducted. Fifty-five (50%) patients were enrolled in the EAM-ICE group, whereas the other 55 (50%) patients were enrolled in the F group. There were no significant differences in baseline characteristics between the two groups. The transseptal duration time was longer in the EAM-ICE group (19.8 ± 3.0 min vs. 8.6 ± 1.2 min, p ≤ 0.01 ); however, fluoroscopy was not used in the EAM-ICE group compared with the F group (0 mGy vs. 109.1 ± 57.9 mGy). Similarly, there was also no significant difference in the recurrence rate of atrial fibrillation between the EAM-ICE and F groups (25.5% vs. 18.2%, p = 0.356 ). Conclusion. RFCA via EAM-ICE-guided zero-fluoroscopy transseptal puncture in patients with PAF is safe and effective for long-term follow-up.

Objectives The authors reviewed 3-dimensional electroanatomic maps of perimitral flutter to identify scar-related isthmuses and determine their effectiveness as ablation sites. Background Perimitral flutter is usually treated by linear ablation between the left lower pulmonary vein and mitral annulus. Conduction block can be difficult to achieve, and recurrences are common. Methods Patients undergoing atrial tachycardia ablation using CARTO3 (Biosense Webster Inc., Irvine, California) were screened from 4 centers. Patients with confirmed perimitral flutter were reviewed for the presence of scar-related isthmuses by using CARTO3 with the ConfiDense and Ripple Mapping modules. Results Confirmed perimitral flutter was identified in 28 patients (age 65.2 ± 8.1 years), of whom 26 patients had prior atrial fibrillation ablation. Scar-related isthmus ablation was performed in 12 of 28 patients. Perimitral flutter was terminated in all following correct identification of a scar-related isthmus using ripple mapping. The mean scar voltage threshold was 0.11 ± 0.05 mV. The mean width of scar-related isthmuses was 8.9 ± 3.5 mm with a conduction speed of 31.8 ± 5.5 cm/s compared to that of normal left atrium of 71.2 ± 21.5 cm/s (p < 0.0001). Empirical, anatomic ablation was performed in 16 of 28, with termination in 10 of 16 (63%; p = 0.027). Significantly less ablation was required for critical isthmus ablation compared to empirical linear lesions (11.4 ± 5.3 min vs. 26.2 ± 17.1 min; p = 0.0004). All 16 cases of anatomic ablation were reviewed with ripple mapping, and 63% had scar-related isthmus. Conclusions Perimitral flutter is usually easy to diagnose but can be difficult to ablate. Ripple mapping is highly effective at locating the critical isthmus maintaining the tachycardia and avoiding anatomic ablation lines. This approach has a higher termination rate with less radiofrequency ablation required.

Aims. To determine the role of the prevalence of low-voltage areas in the occurrence of arrhythmia recurrence after interventional treatment of atrial fibrillation (AF).Methods. The study included 38 patients with paroxysmal (52.6%) and persistent (47.4%) forms of AF who underwent interventional treatment of AF using high-density electroanatomical mapping (at least 10,000 EGM points). Analysis of electroanatomical maps was performed after the completion of the ablation procedure. The area of the low-voltage zones was measured manually. Then, the areas of all regions of low-voltage activity were summed up; the resulting value was expressed as a percentage of the total surface area of the left atrium (LA).Results. The observation period was 12.8±3.2 months. Based on the results of endocardial mapping, all patients were divided into 2 groups according to the prevalence of low-voltage areas in the LA. The first group included patients with an area of low-voltage zones less than 5% of the total surface of the left atrium, and the second with an area of low-voltage areas of more than 5% of the total surface of the left atrium. The patients of the first group had a lower LA volume compared to patients from the second group, with mean values of 119.87±16.35 ml and 154.57±33.23 ml, respectively (p=0.007). In the first group, AF recurrence was recorded in one patient after catheter treatment, in the second group in 5 patients.Conclusion. Common areas of low-voltage activity in the left atrium, detected by high-density mapping before the procedure for catheter treatment of AF, are a predictor of arrhythmia recurrence after interventional treatment.

Ablation treatment for persistent atrial fibrillation (persAF) remains challenging due to the absence of a 'ground truth' for atrial substrate characterization and the presence of multiple mechanisms driving the arrhythmia. We implemented an unsupervised classification to identify clusters of atrial electrograms (AEGs) with similar patterns, which were then validated by AEG-derived markers.956 bipolar AEGs were collected from 11 persAF patients. CARTO variables (Biosense Webster; ICL, ACI and SCI) were used to create a 3D space, and subsequently used to perform an unsupervised classification with k-means. The characteristics of the identified groups were investigated using nine AEG-derived markers: sample entropy (SampEn), dominant frequency, organization index (OI), determinism, laminarity, recurrence rate (RR), peak-to-peak (PP) amplitude, cycle length (CL), and wave similarity (WS).Five AEG classes with distinct characteristics were identified (F = 582, P0.0001). The presence of fractionation increased from class 1 to 5, as reflected by the nine markers. Class 1 (25%) included organized AEGs with high WS, determinism, laminarity, and RR, and low SampEn. Class 5 (20%) comprised fractionated AEGs with in low WS, OI, determinism, laminarity, and RR, and in high SampEn. Classes 2 (12%), 3 (13%) and 4 (30%) suggested different degrees of AEG organization.Our results expand and reinterpret the criteria used for automated AEG classification. The nine markers highlighted electrophysiological differences among the five classes found by the k-means, which could provide a more complete characterization of persAF substrate during ablation target identification in future clinical studies.

Because of the high prevalence of different types of arrhythmias in population, new strategies and treatment methods are being developed by medical communities. The most perspective strategy for treating refractory arrhythmias is stereotactic radioablation. This article presents the review of experimental and clinical researches of radioablation of different heart zones and describes the first experimental study of stereotactic heart radioablation in Russian Federation.

Background In idiopathic outflow tract ventricular arrhythmias (OT‐VAs), identifying the site with the earliest activation time (EAT) using activation mapping is critical to eliminating the arrhythmogenic focus. However, the optimal EAT for predicting successful radiofrequency catheter ablation (RFCA) has not been established. Hypothesis To evaluate the association between EAT and successful RFCA in idiopathic OT‐VAs and to determine the optimal cut‐off value of EAT for successful ablation. Methods We retrospectively analyzed patients undergoing RFCA for idiopathic OT‐VAs at a single center from January 2015 to December 2019. Results Acute procedural success was achieved in 168 patients (87.0%). Among these patients, 158 patients (81.9%) were classified in the clinical success group according to the recurrence of clinical VAs during median (Q1, Q3) follow‐up (330 days [182, 808]). EAT was significantly earlier in the clinical success group compared with the recurrence (p = .006) and initial failure (p

Glomus tumors are rare benign soft tissue lesions, most commonly found on the skin. They are an extremely rare cause of the cardiac tumor. We report a case of right atrial glomus tumor excised using a novel technique utilizing cardiac electroanatomical mapping techniques ordinarily used for arrhythmia surgery.

A 66-year-old male had an atrial tachycardia (AT) during a first extensive pulmonary vein (PV) isolation (PVI) of persistent atrial fibrillation. Activation mapping during the AT using Rhythmia (Boston Scientific, Marlborough, MA, USA) exhibited a centrifugal pattern with the earliest activation at the left-sided carina, and conduction towards the inferior left atrium (LA) over the left PVI line. The post-pacing interval was similar to the tachycardia cycle length (TCL) upon entrainment from the LA roof, left-sided carina, and anterior, inferior, and septal LA, but was longer than the TCL upon entrainment from the left superior PV and lateral and posterior LA. These findings suggested the presence of a macroreentrant AT circuit with epicardial conduction from the roof toward the inferior LA via the left-sided carina over the PVI line and propagation to the anterior LA through the septum. A radiofrequency application at the left-sided carina terminated the AT. This case suggested a rare type of PV-gap reentrant AT with multiple epicardial conduction gaps by high-resolution activation mapping and entrainment pacing, which may have been associated with non-transmural radiofrequency lesions along the PVI line. Further, the origin of the residual epicardial gaps may have been subepicardial myocardial strands or the Marshall ligament.

Aims Conventional His bundle pacing (HBP) can be technically challenging and fluoroscopy-intense, particularly in patients with His-Purkinje conduction disease (HPCD). Three-dimensional electroanatomical mapping (EAM) facilitates non-fluoroscopic lead navigation and HB electrogram mapping. We sought to assess the procedural outcome of routine EAM-guided HBP compared with conventional HBP in a real-world population and evaluate the feasibility and safety of EAM-guided HBP in patients with HPCD. Methods and results We included 58 consecutive patients (72 ± 13 years; 71% male) who underwent an attempt to conventional (EAM− group; n = 29) or EAM-guided (EAM+ group; n = 29) HBP between June 2019 and April 2020. The centre’s learning curve was initially determined (n = 40 cases) to define the conventional control group and minimize outcome bias favouring EAM-guided HBP. His bundle pacing was successful in 26 patients (90%) in the EAM+ and 27 patients (93%) in the EAM− group (P = 0.64). The procedure time was 90 (73–135) and 110 (70–130) min, respectively (P = 0.89). The total fluoroscopy time [0.7 (0.5–1.4) vs. 3.3 (1.4–6.5) min; P Conclusion Implementation of routine EAM-guided HBP lead implantation is feasible and safe in a real-world cohort of patients with and without HPCD and results in a tremendous reduction in radiation exposure without prolonging procedure time or increasing procedure-related complications.

Introduction Defining atrial fibrillation (AF) wave propagation is challenging unless local signal features are discrete or periodic. Periodic focal or rotational activity may identify AF drivers. Our objective was to characterize AF propagation at sites with periodic activation to evaluate the prevalence and relationship between focal and rotational activation. Methods We included 80 patients (61 ± 10 years, persistent AF 49%) from the FaST randomized trial that compared the efficacy of adjunctive focal site ablation versus pulmonary vein isolation. Patients underwent left atrial (LA) activation mapping with a 20-pole circular catheter during spontaneous or induced AF. Five-second bipolar and unipolar electrograms in AF were analyzed. Periodic sites were identified by spectral analysis of the bipolar electrogram. Activation maps of periodic sites were constructed using an automated, validated tracking algorithm, and classified into three patterns: focal sites (FS), rotation (RO), or pseudo-rotation (pRO). Results The most common propagation pattern at periodic sites was FS for 5-s in all patients (4.9 ± 1.9 per patient). RO and pRO were observed in two and seven patients, respectively, but were all transient (3-5 cycles). Activation from a FS evolved into transient RO/pRO in five patients. No patient had autonomous RO/pRO activations. Patients with RO/pRO had greater LA surface area with periodicity (78 ± 7 vs. 63 ± 16%, p = .0002) and shorter LA periodicity CL (166 ± 10 vs. 190±28 ms, p = .0001) than the rest. Conclusion Using automated, regional AF periodicity mapping, FS is more prevalent and temporally stable than RO/pRO. Most RO/pRO evolve from neighboring FS. These findings and their implications for AF maintenance require verification with global, panoramic mapping.

Pediatric patients with complete congenital atrio-ventricular (AV) block are generally exposed to life-long dyssynchronous right ventricular (RV) pacing. His bundle pacing (HBP) is an alternative method of pacing that better restores physiological ventricular activation which could prevent pacing-induced cardiomyopathy. We present a case of a 5-year-old child with complete AV block who underwent successful permanent HBP implantation. Three-dimensional electro-anatomical mapping system was used to facilitate the procedure and reduce the fluoroscopy time. There were no acute procedure-related complications, and electrical parameters were stable at short-term follow-up.

Background/Purpose Left atrial appendage closure (LAAC) is conventionally guided by fluoroscopy and transesophageal echocardiography. We introduce an LAAC technique without fluoroscopy exposure using intracardiac echocardiography (ICE) and electroanatomic mapping system (EAMS) under local anesthesia. Methods Seven non-valvular atrial fibrillation patients who underwent LAAC with the LAmbre devices under the ICE and EAMS guidance were compared to 7 patients following the conventional approach by propensity score matching. ICE probe was advanced into the left atrium (LA) to guide sizing and device implantation following the orthogonal tri-axial technique (Axis-X: from left pulmonary veins [PVs] to LAA; Axis-Y: from right PV ostium to LAA; Axis-Z: from lower LA to LAA). Results The mean diameters of ostia and landing zone were 21.4 ± 3.9 mm and 20.4 ± 4.2 mm, respectively. LAmbre devices with a mean umbrella diameter of 23.7 ± 4.2 mm and cover disc diameter of 29.4 ± 3.6 mm were successfully implanted and acute complete LAA sealing without peri-device leak (PDL) were achieved in all cases. Neither fluoroscopy exposure nor contrast consumption was recorded. No procedure related complications were documented. The mean procedural time and PDLs at follow-ups were comparable to those in the conventional group. No stroke or thromboembolic events were documented. Conclusion The fluoroscopy exposure could be minimized, even to zero, in the ICEguided LAAC procedures feasibly and safely using LAmbre devices. The orthogonal triaxial technique is considered efficacious and safe for the procedures.

Background Ventricular tachycardia (VT) is a major cause of morbidity in patients with cardiomyopathy. Radiofrequency ablation has emerged as the mainstay of the management of recurrent sustained VT in these patients. We describe the clinical characteristics, procedural and medium term outcomes of patients undergoing ablation of scar VT in a tertiary care center in India. Methods This was a single-center descriptive cohort study. All patients who underwent ablation for scar related VT were included. Endpoints were immediate procedural success, procedural complications and recurrence during follow up. Results A total of 72 patients with scar VT underwent ablation with electroanatomic mapping. Previous myocardial infarction (MI) was the commonest etiology (69.4%) with arrhythmogenic right ventricular cardiomyopathy (ARVC) being the next common (19.4%). Acute procedural success was achieved in 69.4% patients, partial success in 9.7% and failure in 1 patient (1.4%). Outcome was labeled indeterminate in 19.4% who did not undergo post ablation VT induction. Procedural complications were seen in 4%. Follow up data was available in 95% of the patients with a mean follow up of 28.9 ± 22.8 months. At one year, freedom from VT was 83.8% and mortality was 13.2%. Overall mortality during follow up was 22.1% while VT recurrence was seen in 35.3%. Recurrence rate was higher in ARVC as compared to previous MI. Conclusions Ablation of scar VT has high acute success rates. Ablation is safe with low risk of major complications. Rates of recurrence are higher in patients with ARVC as compared to post MI VT.

Ventricular tachycardia arising from the papillary muscles and other endocavitary structures are preferably ablated under intracardiac echocardiographic (ICE) guidance whenever feasible. However, the availability, need of trained operators, and the expenses involved restrict the routine use of ICE in many cath labs. Point density exclusion (PDX) mapping is a simple technique that doesn't demand any additional expense or tool apart from the routine electroanatomical mapping and thus can be widely applied in mapping of arrhythmias arising from endocavitary structures. The following report describes such a case and explains the method of performing PDX mapping.

Percutaneous epicardial access continues to have a growing role within cardiac electrophysiology. The classic approach has typically been with a Tuohy needle via a subxiphoid approach guided by fluoroscopic landmarks and tactile feedback. Recent developments have highlighted the role of the micropuncture needle, electroanatomic mapping, and real-time pressure sensors to reduce complications. Further, different access sites, such as the right atrial appendage, have been described and may offer a novel approach to percutaneous epicardial access. In addition, future directions of percutaneous access may involve direct visualization, near-field impedance monitoring, and real-time virtual imaging.

Ablation of premature ventricular contractions (PVCs), relies mostly on a detailed activation mapping. This can be impossible to achieve in case of paucity or even absence of PVCs during the procedure. Pacemapping as an alternative has many limitations. We present a case of a patient with very frequent symptomatic PVCs, that on the day of the procedure had total absence of PVCs. We performed successful ablation based exclusively on electrocardiographic imaging confirmed by substrate mapping.

We present the long-term follow-up of a 31-year-old woman who underwent cardioneuroablation (for atrioventricular (AV) block. Slow pathway ablation was performed in September 2017 with normal follow-up until April 2018, when the patient started noticing symptoms of palpitations at rest, and the electrocardiogram showed a Mobitz I AV block. A cardiac stress test and 24-h Holter monitoring demonstrated first- and second-degree block and normal AV conduction during times of higher heart rate. (Level of Difficulty: Advanced.), Graphical abstract, We present the long-term follow-up of a 31-year-old woman who underwent cardioneuroablation (for atrioventricular (AV) block. Slow pathway…

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.

Use of the 12-lead electrocardiogram (ECG) is fundamental for the assessment of heart disease, including arrhythmias, but cannot always reveal the underlying mechanism or the location of the arrhythmia origin. Electrocardiographic imaging (ECGi) is a non-invasive multi-lead ECG-type imaging tool that enhances conventional 12-lead ECG. Although it is an established technology, its continuous development has been shown to assist in arrhythmic activation mapping and provide insights into the mechanism of cardiac resynchronization therapy (CRT). This review addresses the validity, reliability, and overall feasibility of ECGi for use in a diverse range of arrhythmias. A systematic search limited to full-text human studies published in peer-reviewed journals was performed through Medline via PubMed, using various combinations of three key concepts: ECGi, arrhythmia, and CRT. A total of 456 studies were screened through titles and abstracts. Ultimately, 42 studies were included for literature review. Evidence to date suggests that ECGi can be used to provide diagnostic insights regarding the mechanistic basis of arrhythmias and the location of arrhythmia origin. Furthermore, ECGi can yield valuable information to guide therapeutic decision-making, including during CRT. Several studies have used ECGi as a diagnostic tool for atrial and ventricular arrhythmias. More recently, studies have tested the value of this technique in predicting outcomes of CRT. As a non-invasive method for assessing cardiovascular disease, particularly arrhythmias, ECGi represents a significant advancement over standard procedures in contemporary cardiology. Its full potential has yet to be fully explored.

Since the introduction of atrial fibrillation (AF) ablation in the 1990s, the procedure has continuously evolved, with gradual improvements in outcomes and safety. Recent technological advancements include the introduction of contact force catheters and high-resolution electroanatomical mapping systems, while imaging modalities including transesophageal echocardiography and fluoroscopy have become integral parts of AF ablation procedures. Further, intraprocedural intracardiac echocardiography and the integration of cardiac magnetic resonance and computed tomography images with electroanatomical mapping have shown promise to improve procedural outcomes by reducing radiation exposure and procedural times. However, available data on procedural utility and the reduction in AF recurrence rates associated with these modalities are mixed. This review therefore aims to discuss the current common imaging modalities used in AF ablation and their potential impact on outcomes. In particular, imaging is discussed with respect to the important information it offers before, during, and after the procedure. Perspectives on the future of imaging in AF ablation are also shared.

Background: Voltage mapping is critical to define substrate during ablation. In ventricular tachycardia, abnormal potentials may be targets. However, wavefront of activation could impact local signal characteristics. This may be particularly true when comparing sinus rhythm versus paced rhythms. We sought to determine how activation wavefront impacts electrogram characteristics. Methods: Patients with ischemic cardiomyopathy, ventricular tachycardia, and without fascicular or bundle branch block were included. Point by point mapping was done and at each point, one was obtained during an atrial paced rhythm and one during a right ventricular paced rhythm. Signals were adjudicated after ablation to define late potentials, fractionated potentials, and quantify local voltage. Areas of abnormal voltage (defined as

Introduction. Transseptal puncture (TSP) is a routine access route in patients with left-sided ablation substrates and is performed safely on fluoroscopy (+/− echocardiographic guidance). We report on our experience using a radiofrequency (RF) needle in an unselected group of patients to demonstrate safety and usefulness of direct tip visualization on the 3D electroanatomical mapping (EAM) system with specific emphasis on total radiation exposure. Methods and Results. We retrospectively reviewed 42 consecutive left-sided ablation procedures with TSP performed using an RF needle guided by fluoroscopy and/or EAM visualization by a single operator. The procedures included atrial fibrillation (n = 33), atrial tachycardia (n = 8), and ventricular tachycardia (n = 1) ablations. Fourteen of 41 patients had congenital heart disease, including 9 patients with previous septal closure. Twenty-two patients had at least one previous TSP. All TSPs were performed successfully and without complications. The overall median fluoroscopy time amounted to 3.2 min and median exposure of 199.5 µGy∗m2. In a subgroup of patients (n = 27), the RF needle was visualized on the EAM system: median radiation time was 0.88 (interquartile range: 0–3.4) min and median exposure 33.5 [0–324.8] µGy∗m2. Conclusions. TSP using an RF needle is an effective technique, also in congenital patients with artificial patch material and in normal patients with multiple previous TSPs. Moreover, the RF needle tip visualization on EAM allows a low (or even zero) fluoroscopy approach.

Background Right atrial electroanatomical mapping may be combined with SoundStar 3D diagnostic ultrasound catheter (EAM‐ICE) as a zero‐fluoroscopy procedure for radiofrequency catheter ablation (RFCA). We aimed to evaluate the efficiency and safety of zero‐fluoroscopy transseptal puncture guided by EAM‐ICE and fluoroscopy combined with intracardiac echocardiography (F‐ICE) in patients with paroxysmal atrial fibrillation (PAF). Hypothesis Zero‐fluoroscopy transseptal puncture is an effective and safe procedure. Methods This study had a prospective design. A total of 57 patients with PAF were enrolled and assigned to two groups. Twenty‐seven patients were enrolled in the EAM‐ICE group, and 30 patients were enrolled in the F‐ICE group. Results There were no statistically significant differences in baseline patient characteristics between groups. Transseptal puncture was successful in all patients (57/57, 100%). Total procedure time and duration of transseptal puncture were lower in the F‐ICE group (199.4 ± 26.0 minutes vs 150.7 ± 22.1 minutes, P = 0.000; 118.4 ± 19.7 vs 70.5 ± 13.5 minutes, P = 0.000). There was no use of fluoroscopy in the EAM‐ICE group (0 mGy vs 70.5 ± 13.5 mGy); the duration of fluoroscopy in the EAM‐ICE group was negligible (0 minutes vs 5.4 ± 1.9 minutes). No procedural complication occurred in either group. Conclusions EAM‐ICE guided zero‐fluoroscopy transseptal puncture is an effective and safe procedure.