Search

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 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.

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 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.

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

Background The pathophysiological mechanism of focal atrial tachycardias (AT) remains obscure. Methods Fifteen patients (6 males, age 45 ± 18) with focal AT underwent high‐density activation mapping using a new software called extended early‐meets‐late (EEML). Results Irrespective of the arrhythmia mechanism, low bipolar voltage fractionated signals (0.14 ± 0.10 mV) were seen at the earliest activation site. The mean low‐voltage area (LVA) at the earliest activation site was 3.2 ± 1.0 cm2. EEML mapping revealed zones of conduction delay at the borders of LVAs. Conclusions LVAs protected by zones of slow conduction appears to play an important role in the initiation and maintenance of focal ATs., Low‐voltage areas protected by zones of slow conduction appear to play an important role in the pathophysiology of focal ATs.

Multi-electrode mapping (MEM) is increasingly applied in ablation of complex atrial arrhythmias. This study aimed to evaluate MEM for analysis and treatment of complex macroreentry atrial tachycardia (MAT).Patients with MAT related to scarring, history of heart surgery or atrial linear ablation were studied. Patients were mapped with conventional activation mapping (CAM) or MEM. After characterizing the mechanism of atrial tachycardia (AT), the ablation was performed.The study consisted of 114 eligible patients, 74 in the CAM and 40 in MEM. Compared with CAM, MEM had a shorter procedure duration (156.7 ± 59.1 ms vs. 127.3 ± 59.3 ms, P = 0.003) and mapping duration (62.6 ± 35.7 ms vs. 30.5 ± 15.3 ms, P 0.001) and more mapping points (1364.9 ± 828.7 points vs. 148.3 ± 79.6 points, P 0.001). There were no significant differences between CAM and MEM in acute ablation success rate, complication, postoperative AADs, and ablation duration. The mean disease-free survival time in CAM versus MEM was 20.8 (95% CI: 17.6-24.1) months versus 26.6 (95% CI: 22.7-30.4) months. The median disease-free survival time in the CAM versus MEM was 20.0 (95% CI: 13.9-26.1) months versus 30.0 (95% CI: 26.7-36.3) months. The AT recurrence risk of MEM was 0.522 times that of CAM (HR 95% CI: 0.282-0.968; P = 0.039).MEM is strongly recommended in ablation of complex MAT.

INTRODUCTION Accurate identification of slow conducting regions in patients with scar-related atrial tachycardia (AT) is difficult using conventional electrogram annotation for cardiac electroanatomic mapping (EAM). Estimating delays between neighboring mapping sites is a potential option for activation map computation. We describe our initial experience with CARTO 3 Coherent Mapping (Biosense Webster Inc,) in the ablation of complex ATs. METHODS Twenty patients (58 ± 10 y/o, 15 males) with complex ATs were included. We created three-dimensional EAMs using CARTO 3 system with CONFIDENSE and a high-resolution mapping catheter (Biosense Webster Inc). Local activation time and coherent maps were used to aid in the identification of conduction isthmus (CI) and focal origin sites. System-defined slow or nonconducting zones and CI, defined by concealed entrainment (postpacing interval

Increasing awareness of the health risks associated with the exposure of patients and staff in the catheterization laboratory to radiation has encouraged the pursuit of efforts to reduce the use of fluoroscopy during catheter ablation procedures. Although nonfluoroscopic guidance of ablation catheters has been previously described, transseptal access is still perceived as the last remaining barrier to completely fluoroless ablations. This study examined the safety and effectiveness of transseptal puncture and radiofrequency (RF) catheter ablation using a completely fluoroless approach. Three hundred eighty-two consecutive cases that had undergone completely nonfluoroscopic RF catheter ablation were evaluated. Ablation procedures were performed for atrial fibrillation, atrial flutter, atrioventricular reentry tachycardia, and pulmonary vein complex/ventricular tachycardia. Transseptal puncture and RF ablation were conducted under three-dimensional electroanatomic mapping and intracardiac echocardiography image guidance. Fluoroless transseptal puncture and catheter ablation were completed successfully in all cases, with no intraoperative complications. One patient required minimal use of fluoroscopy to visualize sheath advancement through an existing inferior vena cava filter. Procedural time was approximately 2.2 hours from transvenous access until case conclusion; transseptal access was obtained within 28 minutes of procedure initiation. Arrhythmia was found to recur in 27% of cases on average three months after the procedure. We demonstrate the safety and effectiveness of a completely fluoroless transseptal puncture and RF ablation technique that eliminates radiation exposure and enables complex electrophysiology procedures to be performed in a lead-free environment.

Background Ventricular arrhythmias (VAs) have never been systematically investigated in patients with myocarditis at different stages. Objectives The purpose of this study was to compare baseline and follow-up characteristics of VAs in patients with active myocarditis (AM) versus previous myocarditis (PM). Methods A total of 185 consecutive patients (69% males, age 44 ± 15 years, left ventricular ejection fraction 49 ± 14%) with myocarditis and VA at index hospitalization, including ventricular fibrillation, ventricular tachycardia (VT), nonsustained ventricular tachycardia (NSVT), and Lown’s grade ≥2 premature ventricular complexes, were enrolled. AM and PM groups were defined based on endomyocardial biopsy and cardiac magnetic resonance findings. A subset of patients (n = 46, 25%) also underwent electroanatomic mapping and VA transcatheter ablation. Results At presentation, AM patients (n = 123, 66%) more commonly had ventricular fibrillation (8 cases vs. 0 cases; p = 0.053), and both irregular (61% vs. 11%; p Conclusions In myocarditis patients, polymorphic and irregular VA are more common during the active inflammatory phase, whereas monomorphic and regular VA are associated with healed myocarditis.

Ventricular bipolar voltage values0.5 and1.0/1.5 mV (epi- and endocardium) correlating with dense scar and border zone, respectively, were established using a 3.5-mm tip catheter. Novel microelectrode catheters promise improved mapping resolution; however, whether standard voltage criteria apply to catheters with smaller electrode size and interelectrode distance remains unclear.The purpose of this study was to determine whether traditional bipolar voltage criteria for scar apply during substrate mapping with a microelectrode catheter.Paired bipolar and microbipolar voltage values were acquired from control swine (n = 2) using the microelectrode catheter and assessed for systemic differences. In a postinfarction swine model (n = 6), scar characteristics were compared between the bipolar maps and microbipolar maps using both standard and adjusted voltage criteria derived from the control animals.In control swine, although 5th percentile values for bipolar and microbipolar voltage were similar (1.12 vs 1.22 mV [left ventricular (LV) endo]; 0.88 mV vs 0.98 mV [epi]), median values were significantly greater when acquired by microbipolar electrodes (3.60 vs 6.76 mV, P = .002 [LV endo]; 2.61 vs 2.72 mV, P = .02 [epi]). Microbipolar values were systematically larger by 2.0× and 1.4× in the LV endocardium and epicardium, respectively. Application of standard voltage values to microbipolar maps in postinfarct swine underestimated scar area by approximately 41% in the LV endocardium (13.7 vs 33.4 cmBipolar voltage values acquired from microelectrodes are systemically larger than those acquired from standard catheters. New reference values should be established for these novel catheters.

We highlight a diagnostic challenge in a patient with dyspnea on exertion due to radiation therapy–induced severe first-degree atrioventricular block and how permanent His bundle pacing was helpful in overcoming these symptoms. (Level of Difficulty: Intermediate.), Graphical abstract, This case highlights a diagnostic challenge in a patient with dyspnea on exertion due to radiation therapy–induced severe first-degree…

Ventricular tachycardias originating from the Purkinje system are the most common type of idiopathic left ventricular tachycardia. The majority if not all of the reentrant circuit involved in this type of tachycardia is formed by the Purkinje fibres of the left bundle branch, particularly the left posterior fascicle. In general, slowly conducting Purkinje fibres (P1) form the antegrade limb, and normally conducting Purkinje fibres (P2) form the retrograde limb of the reentrant circuit of the ventricular tachycardia originating from the left posterior fascicle. Elimination of the critical Purkinje elements in the reentrant circuit is the route to successful ablation. While the reentrant circuit identified by activation mapping provides the roadmap to ablation targets, comparing the difference in the His-ventricular interval during sinus rhythm and tachycardia also helps to identify the critical site in the reentrant circuit.

Background Ventricular arrhythmias (VAs) represent a critical issue with regard to sports eligibility assessment in athletes. The ideal diagnostic evaluation of competitive and leisure-time athletes with complex VAs has not been clearly defined. Objective The purpose of this study was to assess the clinical implications of invasive electrophysiological assessments and endomyocardial biopsy (EMB) among athletes with VAs. Methods We evaluated 227 consecutive athletes who presented to our institutions after being disqualified from participating in sports because of VAs. After noninvasive tests, electrophysiological study (EPS), electroanatomic mapping (EAM), and EAM- or cardiac magnetic resonance imaging–guided EMB was performed, following a prespecified protocol. Sports eligibility status was redefined at 6-month follow-up. Results From our sample, 188 athletes (82.8%) underwent EAM and EPS, and 42 (15.2%) underwent EMB. A diagnosis of heart disease could be formulated in 30% of the study population (67/227; 95% confidence interval [CI] 0.24–0.36) after noninvasive tests; in 37% (83/227; 95% CI 31%–43%) after EPS and EAM; and in 45% (102/227; 95% CI 39%–51%) after EMB. In the subset of athletes undergoing EMB, invasive diagnostic workup allowed diagnostic reclassification of half of the athletes (n = 21 [50%]). Reclassification was particularly common among subjects without definitive findings after noninvasive evaluation (n = 23; 87% reclassified). History of syncope, abnormal echocardiogram, presence of late gadolinium enhancement, and abnormal EAM were linked to sports ineligibility at 6-month follow-up. Conclusion A comprehensive invasive workup provided additional diagnostic elements and could improve the sports eligibility assessment of athletes presenting with VAs. The extensive invasive evaluation presented could be especially helpful when noninvasive tests show unclear findings.