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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. [ABSTRACT FROM AUTHOR]

Background: While advances in the characterization of the structural substrate in arrhythmogenic right ventricular cardiomyopathy (ARVC) have been made, the ventricular tachycardia (VT) circuit remains incompletely described.Objective: The purpose of this study was to delineate the reentrant VT circuit with simultaneous epicardial and endocardial mapping (SEEM) in ARVC.Methods: Twenty-three consecutive patients with ARVC and VT underwent SEEM at 4 centers between 2014 and 2020. Retrospective analysis was performed on combined isochronal activation maps.Results: Of the 30 VT circuits, 24 were delineated with SEEM (956 [341-1843] endocardial points and 1763 [882-3054] epicardial points). The apex and outflow tract rarely harbored VT circuits, with 50% distributed in the inferior wall and 43% in the free wall. The entire tachycardia cycle length was recorded from the epicardium in 71% of circuits. In all circuits, a large proportion of the tachycardia cycle length was recorded from the epicardium relative to the endocardium. Localized epicardial reentry was observed in 35% of patients (14 mm × 15 mm), which was associated with smaller endocardial low voltage area (39 cm2 vs 104 cm2; P = .002) and preserved right ventricular ejection fraction (35% vs 25%; P = .046) compared with those with larger circuit dimensions. Seventy percent of termination sites were achieved from the epicardium.Conclusion: High-resolution recordings from both myocardial surfaces confirm a consistent predominance of epicardial participation during reentry in ARVC. Only the perivalvular inflow region of the "triangle of dysplasia" had a strong propensity to harbor VT circuits, with the greatest proportion located in the inferior wall. Localized epicardial reentry may be a manifestation of earlier stage disease with a relative paucity of endocardial substrate. [ABSTRACT FROM AUTHOR]

Intracardiac echocardiography (ICE) is the most practical method for online imaging during electrophysiological procedures. It allows guiding of complex catheter ablation procedures together with electroanatomical mapping systems, either with minimal or with zero fluoroscopy exposure. Besides safe and reproducible transseptal puncture, ICE helps to assess location and contact of the tip of the ablation catheter relative to specific anatomical structures. Another option is visualization of the arrhythmogenic substrate in patients with ventricular arrhythmias. This article describes the clinical utility of ICE in non-fluoroscopic electrophysiology procedures more in detail. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the learning curve for atrial fibrillation (AF), supraventricular tachycardia (SVT), and premature ventricular contraction (PVC) radiofrequency ablation (RFA) using zero fluoroscopy.Methods: This is a retrospective, single-center study of 167 patients undergoing ablation between 2016 and 2019. Minimal fluoroscopy approach was initiated after the first 20 cases of PVI and SVT RFA. Procedures were divided consecutively into increments of 10 cases to determine operator learning curve.Results: A total of 64 (38%) had SVT ablations, 26 (16%) had PVC ablations, and 77 (46%) had AF and underwent PVI. For SVT RFA, fluoroscopy time improved from 4.1 ± 3.5 min during the first 10 cases to 0.8 ± 1.2 min after 50 cases (p = 0.0001). Sixty-two out of 64 (97%) of cases were successful. In PVC RFA, fluoroscopy time was 7.7 ± 5.5 min for the first 5, 2.3 ± 3.4 min after 15, and 0 min after 20 cases (p = 0.0008). Twenty-four out of 26 (92%) of cases were acutely successful with recurrence in 2/26 (8%) of patients over 9 ± 9 months. In PVI, fluoroscopy time was 9.9 ± 3.3 min over the first 20 cases, 2.6 ± 2.3 min after 40 cases, and 0.1 min after 50 cases (p < 0.0001). PVI procedure time was 170 ± 34 min after 60 cases from 235 ± 41 min initially (p 0.001). Six out of 77 (8%) had AF recurrence at 12 months.Conclusions: Zero fluoroscopy ablation for AF, SVT, and PVC can be safely achieved without increasing procedure time. The steepest learning curve occurs over the first 20, 15, and 40 cases for SVT, PVC, and PVI ablation respectively. [ABSTRACT FROM AUTHOR]

BACKGROUND: Late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) of ventricular scar has been shown to be accurate for detection and characterization of arrhythmia substrates. However, the majority of patients referred for ventricular tachycardia (VT) ablation have an implantable cardioverter-defibrillator (ICD), which obscures image integrity and the clinical utility of MRI. OBJECTIVE: The purpose of this study was to develop and validate a wideband LGE MRI technique for device artifact removal. METHODS: A novel wideband LGE MRI technique was developed to allow for improved scar evaluation on patients with ICDs. The wideband technique and the standard LGE MRI were tested on 18 patients with ICDs. VT ablation was performed in 13 of 18 patients with either endocardial and/or epicardial approach and the correlation between the scar identified on MRI and electroanatomic mapping (EAM) was analyzed. RESULTS: Hyperintensity artifact was present in 16 of 18 of patients using standard MRI, which was eliminated using the wideband LGE and allowed for MRI interpretation in 15 of 16 patients. All patients had ICD lead characteristics confirmed as unchanged post-MRI and had no adverse events. LGE scar was seen in 11 of 18 patients. Among the 15 patients in whom wideband LGE allowed visualization of myocardium, 10 had LGE scar and 5 had normal myocardium in the regions with image artifacts when using the standard LGE. The left ventricular scar size measurements using wideband MRI and EAM were correlated with R(2) = 0.83 and P = .00003. CONCLUSION: Wideband LGE MRI improves the ability to visualize myocardium for clinical interpretation, which correlated well with EAM findings during VT ablation.

A 37-year-old man with Brugada syndrome and frequent appropriate implantable cardioverter-defibrillator shocks received an epicardial substrate ablation. During the procedure to eliminate delayed potentials, transient, marked ST-segment elevation in lead V2 was observed, particularly in the anterior right ventricle with a borderline between normal and low-voltage areas. (Level of Difficulty: Intermediate.)

Key Clinical Message The presence of a Gore‐Tex patch can create difficulty in performing transeptal puncture for atrial septal defect patients underwent atrial fibrillation ablation. The maneuverability and stability of using manually operated catheters via retrograde aortic approach could be overcome by a large‐curved catheter to form a loop facilitating approachability to all parts of left atrium.

Localized changes in myocardial conduction velocity (CV) are pro-arrhythmic, but high-resolution mapping of local CV is not yet possible during clinical electrophysiology procedures. This is in part because measurement of local CV at small spatial scales (1 mm) requires accurate annotation of local activation time (LAT) differences with very high temporal resolution (≤1 ms), beyond that of standard clinical methods. We sought to develop a method for high-resolution measurement of LAT differences and validate against existing techniques. First, we use a simplified theoretical model to identify a quantitative relationship between the LAT difference of a pair of electrodes and the peak amplitude of the bipolar EGM measured between them. This allows LAT differences to be calculated from bipolar EGM peak amplitude, by a novel “Determination of EGM Latencies by Transformation of Amplitude” (DELTA) method. Next, we use simulated EGMs from a computational model to validate this method. With 1 kHz sampling, LAT differences less than 4 ms were more accurately measured with DELTA than by standard LAT annotation (mean error 3.8% vs. 22.9%). In a 1-dimensional and a 2-dimension model, CV calculations were more accurate using LAT differences found by the DELTA method than by standard LAT annotation (by unipolar dV/dt timing). DELTA-derived LAT differences were more accurate than standard LAT annotation in simulated complex fractionated EGMs from a model incorporating fibrosis. Finally, we validated the DELTA method in vivo using 18,740 bipolar EGMs recorded from the left atrium of 10 atrial fibrillation patients undergoing catheter ablation. Using clinical EGMs, there was agreement in LAT differences found by DELTA, standard LAT annotation, and unipolar waveform cross-correlation. These results demonstrate an underlying relationship between a bipolar EGM’s peak amplitude and the activation time difference between its two electrodes. Our computational modeling and clinical results suggest this relationship can be leveraged clinically to improve measurement accuracy for small LAT differences, which may improve CV measurement at small spatial scales.

BackgroundElectroanatomic mapping systems are used to support electrophysiology research. Data exported from these systems is stored in proprietary formats which are challenging to access and storage-space inefficient. No previous work has made available an open-source platform for parsing and interrogating this data in a standardized format. We therefore sought to develop a standardized, open-source data structure and associated computer code to store electroanatomic mapping data in a space-efficient and easily accessible manner.MethodsA data structure was defined capturing the available anatomic and electrical data. OpenEP, implemented in MATLAB, was developed to parse and interrogate this data. Functions are provided for analysis of chamber geometry, activation mapping, conduction velocity mapping, voltage mapping, ablation sites, and electrograms as well as visualization and input/output functions. Performance benchmarking for data import and storage was performed. Data import and analysis validation was performed for chamber geometry, activation mapping, voltage mapping and ablation representation. Finally, systematic analysis of electrophysiology literature was performed to determine the suitability of OpenEP for contemporary electrophysiology research.ResultsThe average time to parse clinical datasets was 400 ± 162 s per patient. OpenEP data was two orders of magnitude smaller than compressed clinical data (OpenEP: 20.5 ± 8.7 Mb, vs clinical: 1.46 ± 0.77 Gb). OpenEP-derived geometry metrics were correlated with the same clinical metrics (Area: R2 = 0.7726, P < 0.0001; Volume: R2 = 0.5179, P < 0.0001). Investigating the cause of systematic bias in these correlations revealed OpenEP to outperform the clinical platform in recovering accurate values. Both activation and voltage mapping data created with OpenEP were correlated with clinical values (mean voltage R2 = 0.8708, P < 0.001; local activation time R2 = 0.8892, P < 0.0001). OpenEP provides the processing necessary for 87 of 92 qualitatively assessed analysis techniques (95%) and 119 of 136 quantitatively assessed analysis techniques (88%) in a contemporary cohort of mapping studies.ConclusionsWe present the OpenEP framework for evaluating electroanatomic mapping data. OpenEP provides the core functionality necessary to conduct electroanatomic mapping research. We demonstrate that OpenEP is both space-efficient and accurately representative of the original data. We show that OpenEP captures the majority of data required for contemporary electroanatomic mapping-based electrophysiology research and propose a roadmap for future development.

Localized changes in myocardial conduction velocity (CV) are pro-arrhythmic, but high-resolution mapping of local CV is not yet possible during clinical electrophysiology procedures. This is in part because measurement of local CV at small spatial scales (1 mm) requires accurate annotation of local activation time (LAT) differences with very high temporal resolution (≤1 ms), beyond that of standard clinical methods. We sought to develop a method for high-resolution measurement of LAT differences and validate against existing techniques. First, we use a simplified theoretical model to identify a quantitative relationship between the LAT difference of a pair of electrodes and the peak amplitude of the bipolar EGM measured between them. This allows LAT differences to be calculated from bipolar EGM peak amplitude, by a novel "Determination of EGM Latencies by Transformation of Amplitude" (DELTA) method. Next, we use simulated EGMs from a computational model to validate this method. With 1 kHz sampling, LAT differences less than 4 ms were more accurately measured with DELTA than by standard LAT annotation (mean error 3.8% vs. 22.9%). In a 1-dimensional and a 2-dimension model, CV calculations were more accurate using LAT differences found by the DELTA method than by standard LAT annotation (by unipolar dV/dt timing). DELTA-derived LAT differences were more accurate than standard LAT annotation in simulated complex fractionated EGMs from a model incorporating fibrosis. Finally, we validated the DELTA method in vivo using 18,740 bipolar EGMs recorded from the left atrium of 10 atrial fibrillation patients undergoing catheter ablation. Using clinical EGMs, there was agreement in LAT differences found by DELTA, standard LAT annotation, and unipolar waveform cross-correlation. These results demonstrate an underlying relationship between a bipolar EGM's peak amplitude and the activation time difference between its two electrodes. Our computational modeling and clinical results suggest this relationship can be leveraged clinically to improve measurement accuracy for small LAT differences, which may improve CV measurement at small spatial scales. [ABSTRACT FROM AUTHOR]

Electroanatomic mapping systems have become an essential tool to guide the identification and ablation of arrhythmic substrate. Recently, a novel guiding system for electrophysiology procedures was introduced that uses dielectric sensing to perform high resolution anatomical imaging. Dielectric imaging systems use electrical fields to differentiate anatomic structures based on their conductivity and permittivity. This technique enables non‐fluoroscopic, noncontact mapping of anatomic structures, assessment of pulmonary vein occlusion state during cryoballoon ablation, and has the potential to assess for additional tissue characterization including tissue thickness and tissue type. This article elaborates on the functioning and potential of dielectric imaging systems and provides two cases to illustrate the clinical impact for electrophysiology procedures. [ABSTRACT FROM AUTHOR]

Purpose: Sinus node inability or conduction disorders of its surrounding atrial myocardium cause sinus node dysfunction (SND). This study aimed to characterize right atrium (RA) substrates and long-term atrial lead performance after pacemaker implantation in non-senile SND patients.Methods: Eighteen SND patients (53.3 ± 9.6 years) controlled by 18 age-matched supraventricular tachycardia patients were consecutively enrolled. The P-wave amplitude (PWA) and P-wave duration (PWD) were measured on surface electrocardiography. Electroanatomic mapping was conducted to assess the bipolar voltage, complex signals, volume, and activation time of RA. Pacemaker implantation was performed in SND patients after mapping.Results: Compared with controls, SND patients showed significant PWA reduction (0.13 ± 0.02 vs. 0.16 ± 0.04 mV, p = 0.017) and PWD prolongation (120.8 ± 15.2 vs. 105.2 ± 8.6 ms, p = 0.001). The RA endocardial voltage was lower (1.56 ± 0.78 vs. 2.57 ± 0.55 mV, p < 0.001) and activation time was longer (112.1 ± 14.9 vs. 90.8 ± 12.4 ms, p < 0.001) in the study group. Atrial lead was anchored at the lower atrial septum in one patient and failed in another due to extensive atrial scarring. During a median follow-up of 86 (57-88) months, one patient lost atrial capturing, and overall atrial sensing was significantly decreased (2.44 ± 1.16 vs. 1.87 ± 1.01 mV, p = 0.003).Conclusions: Atrial involvement was proved and the process was progressive in non-senile SND patients, as demonstrated by diffused RA lower voltage, slower conduction, and the decrease of the atrial lead sensing. [ABSTRACT FROM AUTHOR]

Purpose of Review: There are risks to both patients and electrophysiology providers from radiation exposure from fluoroscopic imaging, and there is increased interest in fluoroscopic reduction. We review the imaging tools, their applications, and current uses to eliminate fluoroscopy. Recent Findings: Multiple recent studies provide supporting evidence for the transition to fluoroscopy-free techniques for both ablations and device implantation. The most frequently used alternative imaging approaches include intracardiac echocardiography, cardiac MRI guidance, and 3D electroanatomic mapping systems. Electroanatomic mapping and intracardiac echocardiography originally used to augment fluoroscopy imaging are now replacing the older imaging technique. The data supports that the future of electrophysiology can be fluoroscopy-free or very low fluoroscopy for the vast majority of cases. Summary: As provider and institution experience grows with these techniques, many EP labs may choose to completely forego the use of fluoroscopy. Trainees will benefit from early experience with these techniques. [ABSTRACT FROM AUTHOR]

Background: Electroanatomic mapping systems are used to support electrophysiology research. Data exported from these systems is stored in proprietary formats which are challenging to access and storage-space inefficient. No previous work has made available an open-source platform for parsing and interrogating this data in a standardized format. We therefore sought to develop a standardized, open-source data structure and associated computer code to store electroanatomic mapping data in a space-efficient and easily accessible manner. Methods: A data structure was defined capturing the available anatomic and electrical data. OpenEP, implemented in MATLAB, was developed to parse and interrogate this data. Functions are provided for analysis of chamber geometry, activation mapping, conduction velocity mapping, voltage mapping, ablation sites, and electrograms as well as visualization and input/output functions. Performance benchmarking for data import and storage was performed. Data import and analysis validation was performed for chamber geometry, activation mapping, voltage mapping and ablation representation. Finally, systematic analysis of electrophysiology literature was performed to determine the suitability of OpenEP for contemporary electrophysiology research. Results: The average time to parse clinical datasets was 400 ± 162 s per patient. OpenEP data was two orders of magnitude smaller than compressed clinical data (OpenEP: 20.5 ± 8.7 Mb, vs clinical: 1.46 ± 0.77 Gb). OpenEP-derived geometry metrics were correlated with the same clinical metrics (Area: R 2 = 0.7726, P < 0.0001; Volume: R 2 = 0.5179, P < 0.0001). Investigating the cause of systematic bias in these correlations revealed OpenEP to outperform the clinical platform in recovering accurate values. Both activation and voltage mapping data created with OpenEP were correlated with clinical values (mean voltage R 2 = 0.8708, P < 0.001; local activation time R 2 = 0.8892, P < 0.0001). OpenEP provides the processing necessary for 87 of 92 qualitatively assessed analysis techniques (95%) and 119 of 136 quantitatively assessed analysis techniques (88%) in a contemporary cohort of mapping studies. Conclusions: We present the OpenEP framework for evaluating electroanatomic mapping data. OpenEP provides the core functionality necessary to conduct electroanatomic mapping research. We demonstrate that OpenEP is both space-efficient and accurately representative of the original data. We show that OpenEP captures the majority of data required for contemporary electroanatomic mapping-based electrophysiology research and propose a roadmap for future development. [ABSTRACT FROM AUTHOR]

Background: Post‐ablation atrial tachycardias (ATs) are characterized by low‐voltage signals that challenge current mapping methods. In this study, we analyzed common mistakes during activation mapping and delineated a mapping strategy for correct interpretation of tachycardia mechanisms in patients with challenging underlying substrate. Methods and results: Thirty‐one patients referred for AT ablation were selected for the study. Three types of incorrect activation patterns were identified, which were referred to as unrecognized block line (pseudo‐macroreentry and pseudo‐fig‐8 reentry), incorrect activation timing window of interest (WOI) (chaotic activation), and mis‐annotation of complex signals (multiple sites of "early meets late"). Pseudo‐macroreentry and chaotic activation occur in focal or localized reentry AT with the error related to the WOI selection (four cases), incorrect annotation of local activation time (six cases), or a previous line of atrial block in (seven cases). Pseudo‐fig‐8 reentry (five cases) and multiple sites of "early meets late" (nine cases) occur in macroreentrant AT with blocked areas and low‐voltage atrial substrate. All ATs were successfully eliminated at the origin site. Conclusions: We delineated a series of ATs in the setting of a disordered pattern of activation mapping encountered in patients after previous extensive ablation or atriotomy. The algorithm proposed rapidly corrects the activation map and identifies the mechanism of the AT. [ABSTRACT FROM AUTHOR]

Introduction: We report a case of a fetus with complex congenital heart disease and supraventricular tachycardia in the setting of maternal high grade atrioventricular block at 26 weeks' gestation. Methods and results: Electroanatomic mapping allowed successful implantation of a permanent pacemaker to provide adequate back‐up pacing in the mother with zero radiation exposure, thus allowing safe delivery of transplacental anti‐arrhythmic medications to reduce the fetal arrhythmia burden and optimize the fetal ventricular rate. Conclusion: This is the first reported case of using electroanatomic mapping, with zero fluoroscopy use, for pacemaker lead placement and for a novel indication. [ABSTRACT FROM AUTHOR]

Purpose of Review: Ventricular tachycardia (VT) is a significant cause of cardiac sudden death (SCD) in various cardiomyopathy diseases. The following review will focus on the role of cardiac imaging in risk assessment for VT induction and novel technique and evidence regarding VT therapy including VT ablation and implantable cardiac defibrillator (ICD) therapy. Recent Findings: In regard to VT risk stratification, characterizing VT substrate by cardiac imaging including cardiac magnetic resonance (CMR), multidetector computed tomography (MDCT), and positron-emission tomography (PET) has a significant role in predicting mortality and ventricular arrhythmic events. Integrating cardiac imaging with electroanatomic mapping can act synergistically on improving VT ablation. Moreover, recently developed novel ablation technologies such as bipolar ablation (BPA) and stereotactic body radiotherapy (SBRT) can be potentially beneficial to patients with VTs that are not responding to conventional treatment strategies. Besides, the effectiveness of novel concept of antitachycardia pacing (ATP), automated ATP, has been reported by using virtual patient modeling recently. Summary: Risk stratification for future VT episodes is significantly important to timely select ICD candidates for patients with cardiomyopathy, and cardiac imaging can play a distinct role in this process. Novel and less invasive VT mapping, ablation techniques, and newly developed adaptive pacing techniques can help us overcome challenging VT cases and further improve the treatment for these life-threatening arrhythmias including prevention of sudden death. [ABSTRACT FROM AUTHOR]

Background: Catheter ablation (CA) is a safe and efficient treatment in patients with an atrioventricular accessory pathway (AP). Electroanatomical mapping (EAM) systems are useful during CA of AP, especially for reducing fluoroscopy. There are limited data about the feasibility of CA procedures performed with the use of the EAM system entirely without fluoroscopy in adults with AP. The aim of the study is to assess the feasibility, efficacy and safety of CA with the use of EAM without fluoroscopy, compared to CA with EAM and fluoroscopy in patients with AP. Methods: The study included 83 consecutive patients (age 38.25 ± 15.8 years), who were subjected to CA for AP. In 40 patients CA was performed with the use of EAM without fluoroscopy (EAM group), and in 43 patients CA was performed with EAM and fluoroscopy (control group). Baseline characteristics, procedure parameters and complications were obtained from the medical records. Data on permanent success rate was obtained after the mean follow-up time of 1 year. Primary outcomes were acute procedural success rate, long term success rate at 1-year follow-up and complications. Secondary outcomes were the procedure time and number of applications. Results: There were no statistically significant differences in baseline characteristics between the groups, except for the AP locations. Right-sided AP was more common in the EAM group, while left-sided AP was more common in the control group (p = 0.007 and p = 0.004, respectively). Acute procedural success was achieved in 38 patients (95.0%) in the EAM group and in 39 patients (90.7%) in the control group (p = 0.449). Long term success rate was achieved in 36 patients (90.0%) in the EAM group and in 36 (83.7%) patients in the control group (p = 0.399). There was one minor complication in the form of RBBB in the EAM group (p = 0.138). The mean procedure time was shorter in the EAM group compared to the control group (93.0 ± 58.3 min vs. 127.6 ± 57.5 min; p = 0.009). Conclusions: CA of both right-sided and left-sided AP completely guided by EAM without the use of fluoroscopy is feasible, safe and effective.

Recent publications have reported the feasibility of atrioventricular node ablation (AVNA) and concomitant His-bundle pacing guided by an electroanatomic tridimensional mapping system (ETMS). We report the case of a 65-year-old female patient in which zero fluoroscopy left bundle branch pacing and AVNA were performed guided just by ETMS. Optimal device functioning, electrical parameters stability, and correct lead location were observed 24 h and 30 days after the procedure. In selected cases, in which ionizing radiation is not recommended, this technique may represent an alternative for performing both interventions in the same procedure. < Learning objective: Left bundle branch pacing is a physiological form of ventricular pacing achievable with zero fluoroscopy, being a feasible alternative technique when fluoroscopy is not recommended.> [ABSTRACT FROM AUTHOR]

Purpose: In radiofrequency ablation near coronary arteries (CA), coronary angiography is traditionally recommended to estimate distance between catheter and CA. This study aimed to investigate the feasibility of an alternative approach for intuitively demonstrating spatial location of catheter and CA during ablation of ventricular arrhythmias (VAs) originating from aortic root (AR) and great cardiac vein (GCV). Methods: During mapping and ablation, 3D-reconstructed cardiac CT and electroanatomic mapping were merged, and distance between CA and catheter was monitored. Coronary angiography, for distance verification, was used when the distance was less than 5 mm in image integration model (IIM). Results: Twenty-three patients (52.26 ± 17.89 years, 12 men) with ablation originating in left cusp (LCC, n = 8), right cusp (n = 2), and left-right cusp junction (LCC-RCC, n = 12) and GCV (n = 1) were enrolled. In IIM, the distance between origin and CA was less than 5 mm in 2 VAs originating in LCC and one in GCV (3/23), whereas distance for ablation was always safe (12.3–22.3 mm) for VAs of LCC-RCC origin. IIM avoided angiography use in 20 patients, reducing radiation exposure by 80.6% (650.18 ± 624.31 vs 3356.97 ± 1529.46uGycm2, P = 0.088). VA termination failed in two cases of LCC origin due to proximity to CA, and was achieved in all other patients (91.3%). No CA damage occurred during the procedures. Conclusion: Mapping and ablation under IIM guidance of VAs of AR and GCV origin appears feasible and safe, while avoiding angiography use particularly in VAs of LCC-RCC origin. [ABSTRACT FROM AUTHOR]

Aims: Prior studies have described a variety of mechanisms for atrial fibrillation (AF) originating in the right atrium (RA). In this study, we report a series of patients in whom an extensive right atrial free wall low-voltage zone (LVZ) served as the AF substrate.Methods and Results: Five patients with a clinical syndrome of paroxysmal AF and atrial tachycardia (AT) underwent electrophysiologic evaluation. Five patients (3 M; age 52 ± 7 years) had symptomatic paroxysmal AF for (28 ± 17 months) not responsive to medical therapy. At the initial EP study, AT was inducible in four patients and was spontaneous in one patient. In all patients, tachycardia instability precluded detailed AT mapping. Sinus or pace maps indicated an extensive LVZ in the lateral RA trabeculated free wall which consisted of regions of low amplitude complex signals interspersed between electrically silent areas. Radiofrequency ablation aimed at rendering the LVZ electrical inert was successful in eliminating AF in four of five patients. At a follow-up of 28 ± 15 months, one patient had an isolated recurrence of AF. However, two patients required repeat ablation for recurrent AT.Conclusion: An extensive LVZ in the trabeculated RA free wall constitutes an unusual substrate for AF. These patients also demonstrate unstable ATs originating from the same zone. Radiofrequency ablation to render the low-voltage zone electrically inert is an effective strategy to manage AF and AT. [ABSTRACT FROM AUTHOR]

Background: Catheter-based slow pathway modification (SPM) for atrioventricular nodal reentrant tachycardia (AVNRT) is traditionally performed at empiric sites using anatomical landmarks and test ablation feedback within the triangle of Koch (TK). While studies have described more tailored techniques such as bipolar low voltage bridge (LVB) and wavefront collision identification, few have systematically compared the diagnostic yields of each and none have investigated whether omnipolar mapping technology provides incremental benefit. The objective of this study was to compare the utility of omnipolar and bipolar-derived qualitative and quantitative measurements in identifying and localizing dual AVN substrate in patients with versus without AVNRT., Methods: A retrospective case-control study of consecutive patients with paroxysmal supraventricular tachycardia undergoing electrophysiology study with both omnipolar and bipolar mapping from 2022-2023., Results: Thirteen AVNRT cases (median age 16.1 years, 512 TK points) were compared to nine non-AVNRT controls (median age 15.7 years, 332 TK points). Among qualitative variables, an omnipolar activation vector pivot, defined as a ≥45 degree change in activation direction within the TK, had the highest positive (81%) and negative predictive values (100%) for identifying AVNRT cases and had a median distance of 1 mm from SPM sites. Among quantitative variables, the optimal discriminatory performance for successful SPM sites was observed using bipolar voltage restricted to a peak frequency >340 Hz (c statistic 0.75)., Conclusions: Omnipolar vector pivot analysis represents an automated, annotation-independent qualitative technique that is sensitive and specific for AVNRT substrate and co-localizes with successful SPM sites. Bipolar voltage quantitatively describes SP anisotropy better than omnipolar voltage, and the addition of peak frequency signal analysis further optimizes the selection of SPM sites., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Endocardial electrogram (EGM) characteristics in nonischemic cardiomyopathy (NICM) have not been explored adequately for prognostication., Objective: We aimed to study correlation of bipolar and unipolar EGM characteristics with left ventricular ejection fraction (LVEF) and ventricular tachycardia (VT) in NICM., Methods: Electroanatomic mapping of the left ventricle was performed. EGM characteristics were correlated with LVEF. Differences between groups with and without VT and predictors of VT were studied., Results: In 43 patients, unipolar EGM variables had better correlation with baseline LVEF than bipolar EGM variables: unipolar voltage (r = +0.36), peak negative unipolar voltage (r = -0.42), peak positive unipolar voltage (r = +0.38), and percentage area of unipolar low-voltage zone (LVZ; r = -0.41). Global mean unipolar voltage (hazard ratio [HR], 0.4; 95% confidence interval [CI], 0.2-0.8), extent of unipolar LVZ (HR, 1.6; 95% CI, 1.1-2.3), and percentage area of unipolar LVZ (HR, 1.6; 95% CI, 1.1-2.3) were significant predictors of VT. For classification of patients with VT, extent of unipolar LVZ had an area under the curve of 0.82 (95% CI, 0.69-0.95; P < .001), and percentage area of unipolar LVZ had an area under the curve of 0.83 (95% CI, 0.71-0.96; P = .01). Cutoff of >3 segments for extent of unipolar LVZ had the best diagnostic accuracy (sensitivity, 90%; specificity, 67%) and cutoff of 33% for percentage area of unipolar LVZ had the best diagnostic accuracy (sensitivity, 95%; specificity, 60%) for VT., Conclusion: In NICM, extent and percentage area of unipolar LVZs are significant predictors of VT. Cutoffs of >3 segments of unipolar LVZ and >33% area of unipolar LVZ have good diagnostic accuracies for association with VT., Competing Interests: Disclosures Dr Sanders reports having served on the advisory boards of Medtronic, Abbott Medical, Boston Scientific, CathRx, and PaceMate and that the University of Adelaide has received on his behalf research funding and/or lecture and/or consulting fees from Medtronic, Abbott Medical, and Boston Scientific. Dr Pathak reports having served on the advisory boards of Medtronic, Abbott Medical, and Boston Scientific and that Canberra Heart Rhythm Foundation has received on his behalf research funding and/or lecture and/or consulting fees from Medtronic, Abbott Medical, Boston Scientific, and Biotronik. All other authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Therapies for substrate‐related arrhythmias include ablation or drugs targeted at altering conductive properties or disruption of slow zones in heterogeneous myocardium. Conductive compounds such as carbon nanotubes may provide a novel personalizable therapy for arrhythmia treatment by allowing tissue homogenization. Methods: A nanocellulose carbon nanotube‐conductive hydrogel was developed to have conduction properties similar to normal myocardium. Ex vivo perfused canine hearts were studied. Electroanatomic activation mapping of the epicardial surface was performed at baseline, after radiofrequency ablation, and after uniform needle injections of the conductive hydrogel through the injured tissue. Gross histology was used to assess distribution of conductive hydrogel in the tissue. Results: The conductive hydrogel viscosity was optimized to decrease with increasing shear rate to allow expression through a syringe. The direct current conductivity under aqueous conduction was 4.3 × 10−1 S/cm. In four canine hearts, when compared with the homogeneous baseline conduction, isochronal maps demonstrated sequential myocardial activation with a shift in direction of activation to surround the edges of the ablated region. After injection of the conductive hydrogel, isochrones demonstrated conduction through the ablated tissue with activation restored through the ablated tissue. Gross specimen examination demonstrated retention of the hydrogel within the tissue. Conclusions: This proof‐of‐concept study demonstrates that conductive hydrogel can be injected into acutely disrupted myocardium to restore conduction. Future experiments should focus on evaluating long‐term retention and biocompatibility of the hydrogel through in vivo experimentation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract Background Left atrial (LA) enlargement has been identified as a predictor of worse clinical outcome after catheter ablation for atrial fibrillation (AF). We investigated the correspondence of LA size parameters assessed by echocardiography, CT and 3D electroanatomical mapping in patients with AF treated by catheter ablation. Methods We analyzed echocardiographic LA volume measurements by disc summation method (LAVDISC), computed tomography (LAVCT) and 3D electroanatomical mapping (LAVCARTO) in 100 pts. (71% males; aged 63 ± 8 years; paroxysmal AF in 55% of patients). Results Mean LAVDISC was 83 ± 25 ml (median: 115; IQR: 98–140 ml), mean LAVCT was 120 ± 34 ml (median: 115; IQR: 98–140 ml) and mean LAVCARTO was 123 ± 36 ml (median: 118; IQR: 99–132 ml). Pearson’s correlation coefficient between LAVDISC a LAVCT was 0.6 (p

Background: Atrial tissue fibrosis can cause electrical or structural remodeling in patients with atrial fibrillation. Transforming growth factor beta 1(TGF-β1) signaling acts as a central role in fibroblast activation. In this report, we aimed to investigate the relationship between serum level of TGF-β1 and mean left atrial voltage in patients with chronic atrial fibrillation (CAF). Methods: A total of 16 consecutive adult patients with CAF who underwent catheter ablation were enrolled. Blood samples for measurement of TGF-β1 were collected from periphery veins and coronary sinus before pulmonary vein isolation. The measurement was performed with a commercially available ELISA kit. Cardiac indices were measured using echocardiography. The left atrial electroanatomic mapping was performed after pulmonary vein isolation. Results: Serum level of TGF-β1 in peripheral blood was higher than that in coronary sinus (p

Introduction: Technological advancement in the setting of atrial fibrillation (AF) ablation has decreased radiation exposure and complications associated with the procedure. Yet, transseptal puncture (TSP) remains a challenging step that necessitates accurate guidance. We describe our experience performing TSP under electroanatomic (EA) guidance. Methods and results: The analysis included 145 consecutive EA‐guided ablation procedures performed between June 2018 and April 2019 and 145 consecutive standard ablations performed before June 2018. EA guidance utilized the CARTO 3 three‐dimensional mapping system to reconstruct anatomic and electrical characteristics of the right atrium and fossa ovalis. Patients with a history of previous cardiac surgery were excluded. For EA‐guided procedures, the mean patient age was 60 ± 10 years, 75.2% were male, and 69.0% had paroxysmal AF. Similarly, the mean age for conventional procedures was 60 ± 11 years, 71.0% were male, and 71.7% had paroxysmal AF. The fossa ovalis was detected as a region of low voltage, <0.75 mV. EA guidance yielded shorter fluoroscopy times (EA vs. conventional, 3.6 ± 2.5 vs. 13.5 ± 10.5 min; p <.001) and a lower dose area product than conventional guidance (13 ± 11 Gy* cm2 vs. 28 ± 27 Gy* cm2; p <.001). The total procedure duration was similar between groups (146 ± 48 vs. 148 ± 54 min). There were no significant complications related to TSP. Conclusion: During AF ablation, TSP with EA guidance facilitated safe access to the left atrium while reducing radiation risk to both patients and operators. [ABSTRACT FROM AUTHOR]

Objective: Unipolar intracardiac electrograms (uEGMs) measured inside the atria during electro-anatomic mapping contain diagnostic information about cardiac excitation and tissue properties. The ventricular far field (VFF) caused by ventricular depolarization compromises these signals. Current signal processing techniques require several seconds of local uEGMs to remove the VFF component and thus prolong the clinical mapping procedure. We developed an approach to remove the VFF component using data obtained during initial anatomy acquisition. Methods: We developed two models which can approximate the spatio-temporal distribution of the VFF component based on acquired EGM data: Polynomial fit, and dipole fit. Both were benchmarked based on simulated cardiac excitation in two models of the human heart and applied to clinical data. Results: VFF data acquired in one atrium were used to estimate model parameters. Under realistic noise conditions, a dipole model approximated the VFF with a median deviation of 0.029 mV, yielding a median VFF attenuation of 142. In a different setup, only VFF data acquired at distances of more than 5 mm to the atrial endocardium were used to estimate the model parameters. The VFF component was then extrapolated for a layer of 5 mm thickness lining the endocardial tissue. A median deviation of 0.082 mV (median VFF attenuation of 49x) was achieved under realistic noise conditions. Conclusion: It is feasible to model the VFF component in a personalized way and effectively remove it from uEGMs. Significance: Application of our novel, simple and computationally inexpensive methods allows immediate diagnostic assessment of uEGM data without prolonging data acquisition. [ABSTRACT FROM AUTHOR]

The management of ventricular arrhythmias (VA) in the presence of an apparently normal heart represents a major clinical challenge and a main field of clinical research. In the past years, new imaging techniques and the spreading of new generation genetic testing have improved our knowledge of the pathogenesis of apparently idiopathic VA. However, in the absence of specific recommendations, the type and the number of noninvasive and invasive studies necessary to rule out a possible underlying cause of VA or sudden cardiac death remain extremely variable. Therefore, in many patients the underlying cardiac disease is not recognized, and a possible specific therapeutic approach cannot be initiated. Endomyocardial biopsy (EMB) can provide a significant contribution to the identification of myocardial disorders causing VA but has never been definitively included in the routine diagnostic work‐up of these patients due to the possible sampling error particularly in disorders with a focal or patchy distribution. Three‐dimensional electroanatomic mapping (EAM) may guide EMB allowing to draw myocardial samples from abnormal voltage, areas of the ventricular wall, thus reducing sampling error and increasing the sensitivity of EMB. The systematic association of EAM with EMB represents a crucial approach to characterize the pathological substrate of electroanatomic abnormalities and VA and to further clarify the arrhythmogenic mechanisms of acquired and also inherited arrhythmic disorders. [ABSTRACT FROM AUTHOR]

Background: The combination of contact force (CF) and local impedance (LI) may improve tissue characterization and lesion prediction during radiofrequency (RF) ablation.Objective: The purpose of this study was to evaluate the utility of LI combined with CF in assessing RF ablation efficacy.Methods: An LI catheter with CF sensing was evaluated in swine (n = 11) and in vitro (n = 14). The relationship between LI and CF in different tissue types was evaluated in vivo. Discrete lesions were created in vitro and in vivo at a range of forces, powers, and durations. Finally, an intercaval line was created in 3 groups at 30 W: 30s, Δ20Ω, and Δ30Ω. In the Δ20Ω and Δ30Ω groups, the user ablated until a 20 or 30 Ω LI drop. In the 30s group, the user was blinded to LI.Results: In vivo, distinction in LI was found between the blood pool and the myocardium (blood pool: 122 ± 7.02 Ω; perpendicular contact: 220 ± 29 Ω; parallel contact: 207 ± 31 Ω). LI drop correlated with lesion depth both in vitro (R = 0.84) and in vivo (R = 0.79), informing sufficient lesion creation (LI drop >20 Ω) and warning of excessive heating (LI drop >65 Ω). When creating an intercaval line, the total RF time was significantly reduced when using LI guidance (6.4 ± 2 minutes in Δ20Ω and 8.1 ± 1 minutes in Δ30Ω) compared with a standard 30-second workflow (18 ± 7 minutes). Acute conduction block was achieved in all Δ30Ω and 30s lines.Conclusion: The addition of LI to CF provides feedback on both electrical and mechanical loads. This provides information on tissue type and catheter-tissue coupling; provides feedback on whether volumetric tissue heating is inadequate, sufficient, or excessive; and reduces ablation time. [ABSTRACT FROM AUTHOR]

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Background: Increased peak luminal esophageal temperature (LET) is associated with increased risk of esophageal injury after left atrial posterior wall (LAPW) ablation. The magnitude, distribution, and risk factors of LET increase with high-power short-duration (HPSD) LAPW ablation are not well understood.Objective: The purpose of this study was to describe the spatial and temporal characteristics of LET changes associated with HPSD LAPW radiofrequency (RF) ablation.Methods: LET was sampled at 20 Hz using a 12-point esophageal temperature monitor (CIRCA S-CATH; Circa Scientific, Inc) in 16 patients undergoing LAPW ablation. Esophageal temperature sensor position and lesion locations were recorded using an electroanatomic mapping system with fluoroscopic integration (CARTO 3, CARTOUNIVU; Biosense Webster, Inc). Point-by-point LAPW ablation was performed at 50 W for 6 seconds. The first 20 LAPW lesions were individually analyzed in each patient.Results: LET increase ≥4°C (8 lesions: max LET 5.8°C), 2°-4°C (34 lesions), and 1°-2°C (58 lesions) occurred at 9 ± 2 mm, 8 ± 2 mm, and 13 ± 2 mm from sensors, respectively. Lesions placed >20 mm from a temperature sensor did not result in an LET increase ≥2°C. Temperature resolution to within 1°C of baseline occurred ∼60 seconds after cessation of RF application. Consecutive lesions resulting in additive heating of at least 1°C occurred in 17 lesion pairs with an interlesion distance of 9 ± 4 mm and interlesion time of 21 ± 4 seconds.Conclusion: HPSD LAPW ablation can result in severe esophageal temperature increases. Significant LET increase will be undetected when lesions are >20 mm away from a temperature sensor. Additive LET increase was observed with consecutive lesions placed <20 mm apart within 60 seconds. [ABSTRACT FROM AUTHOR]

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 < 0.001) and polymorphic VA (NSVT and VT: 19% vs. 2%; p = 0.002; premature ventricular complexes: 63% vs. 16%; p < 0.001). Only in PM patients with NSVT or VT, the dominant morphology (right-bundle branch block with superior axis) was 100% predictive of abnormal LV inferoposterior substrate at both cardiac magnetic resonance and electroanatomic mapping. At 27 ± 7 months prospective follow-up, 55 patients (30%) experienced malignant VA (AM vs. PM, p = 0.385). Although a prevalence of polymorphic and irregular VA was confirmed in AM patients with persistent inflammation in follow-up (58%), a predominance of monomorphic and regular VA was found in AM patients after myocarditis healing (42%), as well as in PM patients (all p < 0.001).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. [ABSTRACT FROM AUTHOR]

Background: Ventricular bipolar voltage values <0.5 and <1.0/1.5 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.Objective: The purpose of this study was to determine whether traditional bipolar voltage criteria for scar apply during substrate mapping with a microelectrode catheter.Methods: 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.Results: 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 cm2, P = .004).Conclusion: Bipolar voltage values acquired from microelectrodes are systemically larger than those acquired from standard catheters. New reference values should be established for these novel catheters. [ABSTRACT FROM AUTHOR]

Introduction: Minimal data exist on the Advisor HD Grid (HDG) catheter and the Precision electroanatomic mapping (EAM) system for ventricular arrhythmia (VA) procedures. Using the HDG catheter, the EAM uses the high‐density (HD) wave mapping and best duplicate software to compare the maximum peak‐to‐peak bipolar voltages within a small zone independent of wavefront direction and catheter orientation. This study aimed to summarize the procedural experience for VAs using the HDG catheter. Methods: Clinical and procedural characteristics of VA ablation procedures were retrospectively reviewed that used the HDG catheter and the Precision EAM over a 12‐month period. Results: A total of 22 patients, 18 with sustained ventricular tachycardia and 4 with premature ventricular contractions were included. Clinically indicated left and/or right ventricular (LV, RV, respectively), and aortic maps were created. LV substrate maps (n = 13) used a median 1700 points (interquartile range [IQR]25%‐75%, 1427‐2412) out of a median 18 573 (IQR25%‐75%, 15 713‐41 067) total points collected. RV substrate maps (n = 11) used a median 1435 points (IQR25%‐75%, 1114‐1871) out of a median 16 005 (IQR25%‐75%, 11 063‐21 405) total points collected. Total point utilization, used vs collected, was 9%. Mean mapping time was 43 ± 17 minutes (substrate, 34 ± 18 minutes; activation/pace mapping, 9 ± 13 minutes). Acute success was achieved in 56 (86%) and short‐term success achieved in 16 patients (73%) at a median follow‐up of 145 days (IQR25%‐75%, 62‐273 days). There were no procedural complications. Conclusion: HD wave mapping using the novel HDG catheter integrated with the Precision EAM is safe and feasible in VA procedures in the LV, RV, and aorta. Mapping times are consistent with other multielectrode mapping catheters. [ABSTRACT FROM AUTHOR]

Background: Conventional fluoroscopy guidance, permanent His-bundle pacing (HBP) usually involves high fluoroscopy exposure. This study aims to explore the feasibility of Ensite NavX system and compare its pacing parameters and fluoroscopy doses (FD) with that of conventional fluoroscopy guiding HBP.Methods and Results: A total of 30 patients receiving HBP from June to January 2019 were prospectively enrolled into this study (15 patients guided by conventional fluoroscopy and 15 patients by NavX system). Procedure time, FD, and pacing parameters were recorded at implant and 3-month follow-up. Fourteen patients (93.3%) underwent successful HBP using Ensite NavX system. The total FD was 1.4 ± 0.5 mGy in NavX group and 16.1 ± 2.2 mGy in conventional group (P < 0.001). The His lead FD was 0.4 ± 0.3 mGy in NavX group and 12.5 ± 2.2 mGy in conventional group (P < 0.001). There was no significant difference in pacing parameters at implant and follow-up between the two groups.Conclusion: Guided by Ensite NavX system, HBP is efficient with a significant reduction in fluoroscopy exposure. [ABSTRACT FROM AUTHOR]

Ventricular tachycardia is typically hemodynamically unstable. Strategies to target the arrhythmogenic substrate during sinus rhythm are essential for therapeutic ablation. Electroanatomic mapping is the cornerstone of substrate-based strategies; ablation can be directed within a delineated scar region defined by low voltage. Bipolar voltage mapping has inherent limitations. Specific electrogram characteristics may improve the specificity of localizing the most arrhythmogenic regions within the substrate. Deceleration zones during sinus rhythm are niduses for reentry and can be identified by isochronal late activation mapping, which is a functional analysis of substrate propagation with local annotation to electrogram offset. [ABSTRACT FROM AUTHOR]

In stable ventricular tachycardia (VT), activation mapping and entrainment mapping are the most important strategies to describe the reentrant circuit and its critical components. In many patients, however, VT is noninducible or hemodynamically unstable and unmappable. Several technological advances have broadened ablation options in unmappable VTs. Preprocedural imaging and intraprocedural imaging play an important role in location and extent of the substrate. Electroanatomic mapping with several technological improvements allows more precise electrical assessment of the substrate. A combination of imaging and electroanatomic mapping allows substantial modification of arrhythmogenic substrate in sinus rhythm or during device pacing without hemodynamic compromise. [ABSTRACT FROM AUTHOR]

Introduction: Point‐by‐point 3‐dimensional (3D) electroanatomic mapping (EAM) is used to guide catheter ablation of premature ventricular complexes (PVCs). Due to the differences in the spatial excursion of the cardiac chambers during cardiac cycles in PVCs vs sinus rhythm, the 3D location registration during PVCs is shifted relative to sinus rhythm. In this study, we describe our strategy to adjust for this displacement in real‐time during PVC mapping. Methods and Results: We report 21 patients who underwent catheter ablation of 23 unique PVCs using Carto 3. After mapping the earliest site for each PVC, we reregistered its 3D location to a sinus rhythm beat in real‐time, and used this to guide ablation lesion delivery. The PVC earliest location was spatially displaced from the successful ablation lesion in sinus rhythm by average 6.7 (range 3.3–13.0) mm. Offline, we subsequently analyzed 25 unique chamber maps and 606 PVC points. For each point, we reregistered the 3D location to a preceding sinus beat. The PVC points were displaced from sinus rhythm location by average 4.4 (0.3–13.7) mm. The maximally displaced point for each chamber was 7.7 (4.7–13.7) mm. The general direction of shift during PVC was leftward and inferior relative to sinus rhythm. Conclusions: During electroanatomic mapping of PVCs using the Carto 3 system, points mapped during PVCs are spatially displaced relative to their location in sinus rhythm. Electrophysiologists should recognize this phenomenon and account for the shift to guide accurate delivery of ablation lesions. [ABSTRACT FROM AUTHOR]

Multielectrode epicardial mapping during robotic implantation of cardiac resynchronization‐defibrillator system. Robotically assisted endoscopic implantation of cardiac implantable devices is well documented to be both feasible and safe, and this technique provides particular benefit in patients with limited vascular access. In a patient meeting Class I indication for cardiac resynchronization therapy with defibrillator and inaccessible vascular access, we describe in this case an optimization strategy for intraoperative left ventricular lead placement utilizing robotic epicardial electroanatomic mapping as well as the feasibility of implanting a totally epicardial biventricular cardioverter‐defibrillator system. [ABSTRACT FROM AUTHOR]

The management of atrial fibrillation (AF) is not only a clinical challenge but also an imaging challenge. The role of different imaging modalities to estimate the thromboembolic risk in AF is a key clinical question. The present review summarizes the advances of myocardial imaging in the stratification of thromboembolic risk, diagnosis, and management of left atrial thrombosis in patients with AF. These imaging techniques are also important for understanding arrhythmias and their consequences. It is becoming fundamental for guiding therapy. Still, large studies are required, but be sure that left atrial imaging will become more and more clinically fundamental. • Atrial anatomy and functions are key and should not be forgotten by imagers. There are key pathophysiological, prognostic, and therapeutic values in analyzing the left, and probably also the right, atria. • Atrial volumes are important; atrial deformation during the reservoir and probably also during the active booster pump function have to be considered. • Cardiac computed tomography as well as cardiac magnetic resonance imaging have important roles, also for assessing atrial anatomy, characterizing tissue, and guiding for treatment strategies. • Data from many proof-of-concept and large, prospective, interventional studies have been missing until now in the field of imaging the atria. [ABSTRACT FROM AUTHOR]

Aims: To examine the feasibility and safety of a novel protocol for low fluoroscopy, electroanatomic mapping (EAM)-guided Cardiac resynchronization therapy with a defibrillator (CRT-D) implantation and using both EnSite NavX (St. Jude Medical, St. Paul, MN, USA) and Carto 3 (Biosense Webster, Irvine, CA, USA) mapping systems.Methods and Results: Twenty consecutive patients underwent CRT implantation using either a conventional fluoroscopic approach (CFA) or EAM-guided lead placement with Carto 3 and EnSite NavX mapping systems. We compared fluoroscopy and procedural times, radiopaque contrast dose, change in QRS duration pre- and post-procedure, and complications in all patients. Fluoroscopy time was 86% lower in the EAM group compared to the conventional group [mean 37.2 min (CFA) vs. 5.5 min (EAM), P = 0.00003]. There was no significant difference in total procedural time [mean 183 min (CFA) vs. 161 min (EAM), P = 0.33] but radiopaque contrast usage was lower in the EAM group [mean 16 mL (CFA) vs. 4 mL (EAM), P = 0.006]. Likewise, there was no significant change in QRS duration with BiV pacing between the groups [mean -13 (CFA) vs. -25 ms (EAM), P = 0.09].Conclusion: Electroanatomic mapping-guided lead placement using either Carto or ESI NavX mapping systems is a feasible alternative to conventional fluoroscopic methods for CRT-D implantation utilizing the protocol described in this study. [ABSTRACT FROM AUTHOR]