Bipolar Mapping Research Articles

Conduction gap mapping of linear ablation lesions with high-density mapping.

When performing linear ablation, creating contiguous and transmural lesions are technically challenging due to the difficulty in finding electrical conduction gaps. We hypothesized that high-density mapping could identify the gaps. This study included consecutive patients who underwent conduction gap mapping of de novo lesions (41 patients, 55 lines) and previous lesions (25 patients, 34 lines). We analyzed the utility of bipolar and unipolar conduction gap mapping and retrospectively assessed the voltage and morphology of the bipolar electrograms at the gap sites. Bipolar and unipolar propagation maps were classified into three types: the propagation wavefront traveled through the linear ablation lesions (direct leak), the wavefront jumped to an opposite site across the line and returned to the line (jump and return leak), and others (indefinite leak). In the jump and return leak maps, the site where it returned suggested a conduction gap site. Bipolar propagation maps identified 30 (54.5%) conduction gaps and unipolar maps identified 40 (72.7%) gaps at de novo linear ablation lesions (P = .01), and 32 (94.1%) gaps and 33 (97.1%) gaps, respectively, at previous lesions (P = .56). Bipolar voltage mapping did not add any further efficacy in detecting conduction gaps, and the morphology of the electrograms recorded at the gap sites was not related to the types of propagation maps. Conduction gaps of linear ablation lesions can be visualized by high-density mapping with a high probability. Unipolar propagation, when used with bipolar mapping, may help detect conduction gap sites.

A Correspondence Analysis of Fifty-Five Japanese Historical First-to Fifth-Year English-as-a-Foreign-Language Textbooks

The present paper aims to quantitatively analyze the features of fifty-five Japanese historical English-as-a-Foreign-Language textbooks, Books 1-5, by using a correspondence analysis, focusing on their homogeneities / differences, and to compare the results with those of the correspondence analyses of the Book-1, Book-3 and Book-5 textbooks. The following were the obtained results. First, the correspondence analysis results proved capable of differentiating the features of the fifty-five historical textbooks. In particular, the bipolar map indicated that the two dimensions, difficult (+) vs. easy (-) (Dim 1) axis and artificial- (+) vs. natural-sounding (-) (Dim 2) axis contributed to differentiating their inter-relationships. Second, their inter-relationship was explained 80.4 percent by the seven dimensions, i.e., (1) difficult/easy texts (Dim 1), (2) artificial-/natural-sounding discourse (Dim 2), (3) dialogue-/passage-based textbooks (Dim 3), (4) t eacher-/non teacher-dominance (Dim 4), (5) strictly / loosely controlled (Dim 5), (6) redundant/concise (Dim 6) and (7) connected/disconnected (Dim-7). Third, the differences of the fifty-five Books-1-5 textbooks were explained by the same dimensions as those of the Book-3 and Book-1 results up to the seventh dimension. The results of the present correspondence analysis were graphically represented by two methods, coordinate (bipolar) representation and dendrogram. Concerning the theoretical implications and practical use of the present study, it was proved that CA is a powerful tool for the quantitative analysis and evaluation of EFL textbooks and that difficulty vs. easiness and artificial-sounding vs. natural-sounding are useful viewpoints for EFL teachers and educators in describing and grasping EFL textbooks. https://doi.org/10.26803/ijlter.19.4.14

MP07-16 MAPPING PELVIC FLOOR HYPERTONICITY IN WOMEN WITH IC/BPS USING HIGH-DENSITY SURFACE EMG

INTRODUCTION AND OBJECTIVE: Pelvic floor hypertonicity (PFH) is a debilitating symptom of interstitial cystitis/bladder pain syndrome (IC/BPS). The diagnosis and assessment of PFH are based on subjective pelvic examinations, and results between examiners may vary. Precise assessment is critical to the clinical diagnosis and management of PFH. The objective of this study is to provide innovative techniques to objectively assess neurogenic PFH in women with IC/BPS using an intra-vaginal high-density surface electromyography (HD-sEMG) probe. METHODS: Seven female subjects (44±13 yr.) with IC/BPS were recruited. A full pelvic exam was administered to identify hypertonic muscles. Intra-vaginal HD-sEMG was then acquired at rest from a novel 64-channel HD-sEMG probe, as shown in Figure 1(a). Z-scores were calculated using the subjects without hypertonicity as a reference population, as shown in Figure 1(b). Root-mean-squared (RMS) amplitude during resting state was calculated from differential signals for each channel to define a hypertonicity index. Innervation zones (IZs) were identified from the bipolar mapping of decomposed signals, and summarized into an IZ distribution mapping. RESULTS: Of the 7 subjects recruited, 5 had normal pelvic floor muscle tone and 2 exhibited hypertonicity upon muscle palpation. Women with PFH demonstrated a much higher hypertonicity index (12.6±3.5 vs. 4.5±1.2). The hypertonic zone defined by the RMS mapping coincided with the digital hypertonic muscle assessment, as shown in Figures 1(c) and 1(d) for two subjects without hypertonicity, and Figures 1(e) and 1(f) for the two subjects with hypertonicity. Motor units were decomposed, and the corresponding IZs were localized, as shown in Figures 1(g) and (h) for two women without hypertonicity, and Figures 1(i) and (j) for the women with hypertonicity. CONCLUSIONS: This study represents the first effort to employ intra-vaginal HD-sEMG to assess PFH in women with IC/BPS. Our results demonstrate the feasibility of HD-sEMG to provide a quantitative analysis of PFH and provide a precise localization of hypertonic muscles and IZs. The proposed HD-sEMG based techniques provide promising tools for clinical diagnosis and treatment of PFH, such as the personalized guidance of BoNT injections.Source of Funding: This study received funding support from the SUFU Foundation and NIH DK113525.

Electroanatomic bipolar mapping for detection of arrhythmogenic substrate in catheter ablation of atrial fibrillation

The article presents data comparing the results of late gadolinium-enhanced magnetic-resonance imaging and bipolar mapping. The results of studies on the use of bipolar mapping data for substrate modification in catheter ablation of atrial fibrillation are presented, and perspectives for the development of the method are indicated.

Understanding unipolar electrograms and global activation from noninvasive mapping for diagnosing arrhythmias

In the past several decades Electrocardiographic Imaging has been developed, validated, and recently commercialized for clinical use (Medtronic CardioInsight™). The technology noninvasively maps cardiac electrical potentials by combining multi-channel body surface electrocardiograms and patient specific heart-torso geometry. Unlike contact catheter mapping where bipolar electrograms are commonly used, noninvasive mapping is unipolar in nature. While bipolar electrograms reflect local activation time, noninvasive mapping reflects both local and global information. Characterizing arrhythmias using noninvasive mapping requires a different approach than what is used with bipolar mapping during electrophysiological studies. With multiple example cases, this article aims to demonstrate how in-depth analysis of noninvasive electrogram features and global activation patterns can reveal clinically important characteristics of arrhythmias, which may not be evident on the automatically generated maps. These characteristics include transmural location of the ectopic focus, differential locations within structural proximity, engagement of bundle or specific tissue, and substrate properties. The analysis approach involves applying unipolar potential fundamentals and relating electrogram features, global activation with underlying electrophysiology and cardiac anatomy to explain specific mapping phenomenon. If validated, easy-to-use diagnostic criteria or algorithms can be built and automated as product features in the commercial system to facilitate future noninvasive mapping in patients.

Standard peak-to-peak bipolar voltage amplitude criteria underestimate myocardial scar during substrate mapping with a novel microelectrode catheter

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. 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 [leftventricular (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). 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.

P981Predictor factors and the prognostic role of persistent pulmonary veins isolation in patients with arrhythmia recurrence necessitating a second ablation procedure

Abstract Aims Pulmonary vein isolation (PVI) is the treatment of choice in patients (pts) with symptomatic atrial fibrillation. Durable pulmonary veins isolation (PVI) seems to be associated with a lower risk of AF recurrence, but the predictor factors of persistent PVI are still uncertain. We aimed to determinate the predictor factors and the prognostic role of persistent pulmonary veins isolation in pts with arrhythmia recurrence necessitating a second ablation procedure. Methods and results Our Study included 102 pts (65.7% male, 65±8 years old, 75.5% persistent AF) with arrhythmia recurrence, whom underwent a Redo-PVI between October 2016 and Mars 2018. Patients were divided into two groups regarding the persistence of PVI. Group 1 included 20 pts with persistent PVI and Group 2 included 82 pts with reconnection of at least one PV. The clinical profile, ablation data and three months arrhythmia recurrence were analyzed. There were no statistical differences in terms of clinical profile between the two groups of pts (age; p=0.513, gender; p=0.299, BMI; p=0.077, diabetes mellitus; p=0.621, coronary artery disease; p=0.787; arterial hypertension; p=0.732; left ventricle ejection fraction; p=0.323 and left atrial diameter; p=0.5). Patients in group 1 presented more often with atrial tachycardia compared to group 2 Patients (30% versus 7.3%; p=0.014). Regarding the ablation data, there were no differences between the two groups in terms of procedure time (p=0.710) but the ablation time was longer in group 2 patients (29.1±13.7 versus 20.8±10.5 min. p=0.031). Low voltage areas (LVA) acquired by bipolar electroanatomical mapping were more often and diffuse in group 1 patients (70% versus 40.3%; p=0.050). The three months arrhythmia recurrence after Redo-Ablation was the same between the two groups (p=1.000). Conclusion The type of arrhythmia recurrence and low voltage areas are predictor factors of persistent pulmonary veins isolation in patients with arrhythmia recurrence necessitating a second ablation procedure. This fact can help in planning the second ablation procedure. Persistent PVI seems to have no prognostic role regarding the three months arrhythmia recurrence after Redo-Ablation.

Global Innervation Zone Identification With High-Density Surface Electromyography.

The aim of this study is to compare the performance of three strategies in determining the global innervation zone (IZ) distribution. High-density surface electromyography was recorded from the biceps brachii muscle of seven healthy subjects under isometric voluntary contractions at 20%, 50%, and 100% of the maximal voluntary contraction and supramaximal musculocutaneous nerve stimulations. IZs were detected: first, by visual identification in a column-specific manner (IZ-1D); second, based on decomposed bipolar mapping of motor unit action potentials (IZ-2D); and third, by source imaging in the three-dimensional muscle space (IZ-3D). All three IZ detection approaches have exhibited excellent trial-to-trial repeatability. Consistent IZ results were found in the axial direction of the arm across all three approaches, yet a difference was observed in the mediolateral direction. Among all three approaches, IZ-3D is capable of providing the most comprehensive information regarding the global IZ distribution, while maintaining high consistency with IZ-1D and IZ-2D results. IZ-3D approach can be a potential tool for global IZ imaging, which is critical to the clinical diagnosis and treatment of neuromuscular disorders.

Electroanatomic and Pathologic Right Ventricular Outflow Tract Abnormalities in Patients With Brugada Syndrome

BackgroundThe prevalence and significance of structural abnormalities in Brugada syndrome (BrS) are still largely debated. ObjectivesThe authors investigated the relationship between genetic background, electroanatomic abnormalities, and pathologic substrate in BrS. MethodsThey performed 3-dimensional electroanatomic unipolar and bipolar mapping in 30 patients with BrS. Twenty patients underwent 3-dimensional electroanatomic unipolar and bipolar mapping–guided right ventricular outflow tract (RVOT) endomyocardial biopsy. Programmed ventricular stimulation and genetic analysis were performed in all patients. ResultsLow-voltage areas (LVAs) were observed at unipolar map in 93% of patients and at bipolar map in 50% of cases. Unipolar LVAs were always larger than bipolar LVAs, were always colocalized, and in all cases included RVOT. Disease-causing mutations were detected in 10 (33%) patients. Programmed ventricular stimulation was positive in 16 cases (53%). In 75% of patients, RVOT histology showed pathologic findings with myocardial inflammation in 80% of them. Among patients with abnormal bipolar map submitted to endomyocardial biopsy, 9 (81%) showed evidence of myocardial inflammation. Conversely, bipolar map was abnormal in 83% of patients with myocardial inflammation. Myocardial inflammation was also more prevalent among inducible patients (83% vs. 25% in noninducible; p = 0.032). ConclusionsBrS is characterized by electroanatomical and structural abnormalities localized to RVOT with a gradient of the pathologic substrate from epicardium to endocardium possibly driven by myocardial inflammation. These findings reclassify BrS as a combination of structural and electrical defects opening the way to new risk stratification and therapeutic strategies.

Evaluation of the Mandibular Incisive Canal by Panoramic Radiography and Cone-Beam Computed Tomography

Background: Radiofrequency ablation (RFA) in Brugada syndrome (BrS) has been performed both endocardially and epicardially. The substrate in BrS is thus unclear. Objectives: To investigate the functional endocardial substrate and its correlation with clinical, electrophysiological and ECG findings in order to guide an endocardial ablation. Methods: Thirteen patients (38.7±12.3 years old) with spontaneous type 1 ECG BrS pattern, inducible VF with programmed ventricular stimulation (PVS) and syncope without prodromes were enrolled. Before to endocardial mapping the patients underwent flecainide testing with the purpose of measuring the greatest ST-segment elevation for to be correlated with the size and location of substrate in the electro-anatomic map. Patients underwent endocardial bipolar and electro-anatomic mapping with the purpose of identify areas of abnormal electrograms (EGMs) as target for RFA and determine the location and size of the substrate. Results: When the greatest ST-segment elevation was in the 3rd intercostal space (ICS), the substrate was located upper in the longitudinal plane of the right ventricular outflow tract (RVOT) and a greatest ST-segment elevation in 4th ICS correspond with a location of substrate in lower region of longitudinal plane of RVOT. A QRS complex widening on its initial and final part, with prolonged transmural and regional depolarization time of RVOT corresponded to the substrate locateded in the anterior-lateral region of RVOT. A QRS complex widening rightwards and only prolonged transmural depolarization time corresponded with a substrate located in the anterior, anterior-septal or septal region of RVOT. RFA of endocardial substrate suppressed the inducibility and ECG BrS pattern during 34.7±15.5 months. After RFA, flecainide testing confirmed elimination of the ECG BrS pattern. Endocardial biopsy showed a correlation between functional and ultrastructural alterations in two patients.

Epicardial-endocardial breakthrough during stable atrial macroreentry: Evidence from ultra–high-resolution 3-dimensional mapping

Evidence for epicardial-endocardial breakthrough (EEB) is derived from mapping inferences in patients with atrial fibrillation who may also have focal activations. The purpose of this study was to investigate whether EEB could be discerned during stable right atrial (RA) macroreentry using high-density high-spatial resolution 3-dimensional mapping. Macroreentry was diagnosed using 3-dimensional mapping and entrainment. Bipolar maps were reviewed for EEB defined as (1) presence of focal endocardial activation with radial spread unaccounted for by an endocardial wavefront and (2) present with the same timing on every tachycardia cycle. The EEB site was always in proximity to a line of endocardial conduction slowing or block. Distance and conduction velocity from the line of block to the EEB site was calculated. Electrograms at EEB sites were individually analyzed for morphology and to confirm direction of activation. Entrainment was performed at EEB sites. Twenty-six patients were studied. Fourteen examples of EEB were seen: 11 at the posterior RA (4 at the superior portion of the posterior wall and 7 at the inferior section) and 1 each at the cavotricuspid isthmus postablation, RA septum, and inferolateral RA. The mean area of the EEB site was 0.6 ± 0.2 cm2. A mean of 79.5% ± 18.6% of unipolar electrograms at the EEB site demonstrated an rS morphology. The mean distance and conduction velocity from the line of endocardial block to the EEB site at the posterior RA was 13.6 ± 2.3 mm and 59.3 ± 12.3 cm/s, respectively. In 4 patients, entrainment demonstrated that EEB sites were within the circuit and in 1 of these patients critical to arrhythmia maintenance. Activation maps during tachycardia and coronary sinus pacing demonstrated EEB at the same anatomic site. EEB sites were demonstrated in stable atrial macroreentry supported by systematic entrainment confirmation and demonstration of the same phenomenon during pacing.

LEFT ATRIAL ELECTROANATOMIC SUBSTRATE AS A PREDICTOR OF ATRIAL FIBRILLATION RECURRENCE AFTER CIRCULAR RADIOFREQUENCY PULMONARY VEINS ISOLATION. OBSERVATIONAL PROSPECTIVE STUDY RESULTS

Aim . To evaluate an extent of left arrial (LA) electroanatomical substrate (EAS) by the method of high density contact mapping in patients with atrial fibrillation (AF) and estimate its impact on recurrence rate following circular radiofrequency pulmonary veins (PV) isolation in prospective observational study. Material and methods. Totally 181 high symptomatic subjects with paroxysmal (142 pts) and persistent (39 pts) AF, who underwent circular RF PVI were enrolled. We created and prospectively analyzed LA electroanatomical high density bipolar maps. Bipolar signals ≤0.75mV, associated with local conduction velocity delay &lt;1 m/s were tagged on LA maps and considered as EAS. Relative EAS areas outside PV ostia were consistently measured. All of the patients were followed up at least for 3 years and AF recurrence rate and redo procedures were recorded. Results . A mean relative EAS area was 13.8±10.3% and 32.6±18.5% in patients with paroxysmal and persistent AF, respectively (P=0,02). During a mean follow-up of 32±7 months, AF recurrence was diagnosed in 69 (38%) of patients. Following a redo ablation in 51 (28%) of patients, subsequent AF recurrence developed in 31 pts (19%). Multivariate analysis showed that only relative EAS areas was independently associated with AF recurrence (HR 1.05, CI 95% 1.02-1.09, P=0.002) and ach 10% increase in the extent of relative EAS area was associated with a 1.6-fold elevation of AF recurrence rate after the index ablation. But the impact of the EAS on clinical outcome after redo ablation was even higher (HR =1,09, p=0,0018) and each 10% increase in the extent of relative EAS area was associated with a 2.4-fold elevation of AF recurrence rate after a redo ablation. Conclusion. The present study suggests that an extent of LA EAS in patients undergoing PVI — is a significant and independent predictor of AF recurrence. This data can have important role for further development and personalization of strategy of interventional treatment in patients with AF.

Cardiac CT With Delayed Enhancement in the Characterization of Ventricular Tachycardia Structural Substrate: Relationship Between CT-Segmented Scar and Electro-Anatomic Mapping

ObjectivesThis study sought to compare myocardial scars depicted by computed tomography (CT) with electrical features from electro-anatomic mapping (EAM), assessing the potential role of CT integration in ventricular tachycardia (VT) and radiofrequency catheter ablation (RFCA) procedures. BackgroundImaging-based characterization of VT myocardial substrate is required to plan EAM and, potentially, to guide RFCA. MethodsForty-two consecutive patients, 35 of whom had implantable cardioverter-defibrillator, all referred for VT RFCA, underwent pre-procedural CT including an angiographic and a 10-min delayed-enhancement scan. Segmental comparison between scars segmented from CT and low voltages (bipolar voltages <1.5 mV; unipolar voltages <8 mV), late potentials, and RF ablation points on EAM, was carried out. In a subset of 16 consecutive patients, a further point-by-point analysis was performed: a CT-derived 3-dimensional structure including heart anatomy and myocardial scars was integrated with EAM for quantitative comparison. ResultsCT scans identified scars in 39 patients and defined left ventricular wall involvement and mural distribution. Overall segmental concordance between CT and EAM was good (κ = 0.536) despite the presence of implantable cardioverter-defibrillator, scar etiologies, and mural distribution. CT identified segments characterized by low voltages with good sensitivity (76%), good specificity (86%), and very high negative predictive value (95%). Late potentials and RF ablation points fell on scarred segments identified from CT in 79% and 81% of cases, respectively. Point-by-point quantitative comparison revealed good correlation between the average area of scar detected at CT and at bipolar mapping (CT = 4,901 mm2, bipolar voltages-EAM = 4,070 mm2; R = 0.78; p < 0.0001). In this study, 70% and 84% of low-amplitude bipolar points were mapped at a maximum distance of 5 mm and 10 mm from CT-segmented scar, respectively. ConclusionsCT with delayed-enhancement provides a 3-dimensional characterization of VT scar substrate together with a detailed anatomic model of the heart. This information may offer assistance to plan EAM and RFCA procedures and is potentially suitable for EAM-imaging integration.

Abstract 18572: Limitations of Endocardial Unipolar Voltage Mapping in Predicting the Epicardial Substrate

Introduction: Bipolar voltage mapping detects areas of scar and guides ablation of VT. The role of endocardial unipolar voltage mapping is not well defined. We examined the endo-epicardial substrate in a mixed cohort of patients with structural heard disease (SHD) to determine whether an endocardial unipolar low voltage area predicts the presence and location of an epicardial scar. Results: Data from 24 consecutive patients with SHD (11 ICM, 6 NICM, 3 HCM, 2 ARVC, 1 myocarditis, 1 Brugada) with a detailed (mean points per map 200) combined endocardial-epicardial substrate mapping were retrospectively reviewed. Maps were obtained using a 3D mapping system (CARTO 3) and normal thresholds used were ≤1.5 mV for bipolar voltage, and ≤5.5 (RV) or ≤8.3 mV (LV) for unipolar voltage. Mapping was performed in the LV in 17 patients, in the RV in 6 patients, in both in 1 patient. An endocardial unipolar low voltage area was found in 21/25 maps. In 12/21 maps there was no corresponding epicardial scar, while in 3/4 cases an epicardial scar was detected despite a negative unipolar map (PPV=43%, NPV=25%, P=NS; Fig. 1). In the 9 cases with both positive endocardial unipolar and epicardial bipolar maps, the epicardial scar was found in the corresponding ventricular region of the endocardial low-voltage area, although unipolar area had a tendency to overestimate the area of the scar (115 vs 95 cm 2 ). Conclusion: In this series of patients with SHD, analysis of unipolar voltage maps could not reliably predict the epicardial arrhythmogenic substrate. There is a modest correlation between areas of endocardial unipolar low voltage and epicardial scars (57% of patients with an abnormal unipolar map had a normal epicardial substrate). Moreover, an epicardial substrate cannot be safely excluded based on a normal unipolar endocardial map. Fig. 1 Abnormal bipolar epicardial map (left) with corresponding normal unipolar endocardial map (right) in a patient with ARVC. Pink dots represent area of defragmentation.

PO57SAFETY AND EFFICACY OF PREOPERATIVE CORTICAL MAPPING USING A NAVIGATED TRANSCRANIAL MAGNETIC STIMULATION (NTMS) TECHNOLOGY IN PATIENTS HARBORING BRAIN TUMOURS IN ELOQUENT AREAS

INTRODUCTION: Maximum safe resection of tumours located in eloquent areas is hampered by risk of motor, language and visual deficits. nTMS is a rapidly emerging, non-invasive brain stimulation technique generating pre-operative cortical function maps critical for surgical guidance around eloquent cortex. We report our early experience on efficacy, safety and physiological intraoperative correlation. METHOD: Six patients underwent cortical mapping (1 language, 5 motor) using Nexstim Navigated Brain Stimulation (NBS). Single TMS pulses delivered at intensities evoking responses in abductor pollicis brevis. Patients were co-registered to volumetric T1 or T2-weighted MRI. Surgical corridors and anatomically determined functional regions were identified by applying TMS in a topographically systematic manner. Presence/absence of responses were noted in target muscles (arm/leg). For language mapping, without TMS, baseline responses to line drawings were recorded via built-in video. Five-pulse trains of TMS were applied to language areas. Speech arrest and response errors were compared to baseline. During awake surgery, functional ‘on/off' maps were utilised with intraoperative imaging, fMRI, diffusion tensor imaging, and direct cortical stimulation (DCS). RESULTS: The were no technique-related adverse effects. Patients tolerated the technique well. Comparison of TMS and bipolar DCS maps confirmed a high degree of overlap (<2 mm). CONCLUSION: NBS-TMS is safe and can be used to accurately identify pre-operatively eloquent cortical function, and is comparable to DCS; it may be useful for functional mapping in patients not suitable for awake surgery. More data is required to validate this technique in a larger cohort of patients.

Three-Dimensional Innervation Zone Imaging from Multi-Channel Surface EMG Recordings.

There is an unmet need to accurately identify the locations of innervation zones (IZs) of spastic muscles, so as to guide botulinum toxin (BTX) injections for the best clinical outcome. A novel 3D IZ imaging (3DIZI) approach was developed by combining the bioelectrical source imaging and surface electromyogram (EMG) decomposition methods to image the 3D distribution of IZs in the target muscles. Surface IZ locations of motor units (MUs), identified from the bipolar map of their MU action potentials (MUAPs) were employed as a prior knowledge in the 3DIZI approach to improve its imaging accuracy. The performance of the 3DIZI approach was first optimized and evaluated via a series of designed computer simulations, and then validated with the intramuscular EMG data, together with simultaneously recorded 128-channel surface EMG data from the biceps of two subjects. Both simulation and experimental validation results demonstrate the high performance of the 3DIZI approach in accurately reconstructing the distributions of IZs and the dynamic propagation of internal muscle activities in the biceps from high-density surface EMG recordings.

Imaging and epicardial substrate ablation of ventricular tachycardia in patients late after myocarditis

We present clinical, electroanatomical mapping (EAM), imaging, and catheter ablation (CA) strategies in patients with myocarditis-related ventricular tachycardia (VT). Between January 2010 and July 2012, 26 consecutive patients underwent imaging-guided CA of myocarditis-related ventricular arrhythmias, 23 of 26 using a combined endo-epicardial approach. Segment per segment correspondence of late enhanced (LE) scar localization with EAM scar was assessed in all patients with available uni/bipolar maps (n = 19). Induced VTs were targeted prior to substrate modification. Late potentials (LPs) abolition constituted a procedural endpoint independently from VT inducibility. Clinical monomorphic VT was induced in 15 of 26 patients (57.7%) and was associated with epicardial LPs in 10 of 15, completely abolished in 7 of 10 patients. Of the 10 patients rendered non-inducible VTs were ablated epicardially in 7. Late potentials were also detected in 7 of 11 initially non-inducible patients and completely abolished in 4. After a median follow-up of 23 (15-31) months, 20 of 26 patients (76.9%) remained free from VT recurrence. Bipolar mapping revealed low-voltage scar (<1.5 mV) in 1 patient endocardially and in 14 of 19 epicardially. Unipolar mapping revealed low-voltage scar (<8 mV) in 12 of 19 patients endocardially and in 18 of 19 epicardially. Correspondence of LE scar localization with endocardial bipolar scar was 1%, with endocardial unipolar scar 23.7%, with epicardial bipolar scar 39.8%, and with epicardial unipolar scar 66.2%. Pre-procedural scar imaging and EAM findings support the necessity of an epicardial approach in patients with prior myocarditis. Epicardial unipolar mapping (<8 mV) is superior in scar identification and CA based on substrate modification is safe and effective in this setting.

Outflow Tract Ventricular Tachycardia Mapped to the Coronary Arteries: Anatomical Correlates and Management Strategies

The coronary cusps have been well described as a successful site for ablation in patients with symptomatic outflow tract ventricular tachycardia. The earliest site of activation is rarely found at the ostia or into the main coronary arteries. The exact anatomic substrate, diagnostic characteristics, and therapeutic approaches for such instances are poorly understood. We retrospectively reviewed outflow tract ventricular arrhythmia (OTVA) ablations done at Mayo Clinic Rochester from 2003 to 2011 (total VT: 414; outflow tract VT: 106). Three cases were identified where the earliest site of activation was not within the cusp but rather at or within the coronary ostia (3/414 for all VT: 0.7%; 3/106 for all OTVT: 2.8%). In 1 patient, the left main coronary artery (LMCA) was found to have electrograms (EGMs) recorded with bipolar mapping that preceded activation in the cusps or the left ventricular outflow tract. In 2 cases, the right coronary ostium and proximal right coronary artery recorded the earliest signals. Intracardiac echocardiographic guidance was used to successfully ablate these arrhythmias targeting the aortic route (1 patient) or the right coronary cusp (2 patients), and essentially isolated the focus of origin from the ventricular outflow tracts. Detailed mapping of surrounding structures, including the atrial appendages, the contralateral outflow tract, and the coronary venous system excluded far-field mapping in the artery as a cause for early activation at the ostial location. Local EGM characteristics suggested an unusually lengthy supravalvar myocardial extension as the likely arrhythmogenic substrate. Ablation was successful without coronary arterial or valvular injury and without valvular or root stenosis. Endocardial ablation isolating foci of origin in the vicinity of the coronary ostia is a challenging procedure but can be performed safely with appropriate visualization and is effective in the treatment of OTVA.

Bipolar Mapping, Revisited Or: These Aren't the Electrograms You're Looking For

Journal of Cardiovascular ElectrophysiologyVolume 24, Issue 6 p. 655-657 EDITORIAL COMMENT Bipolar Mapping, Revisited Or: These Aren't the Electrograms You're Looking For SURAJ KAPA M.D., SURAJ KAPA M.D. Division of Cardiology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USASearch for more papers by this authorMATHEW D. HUTCHINSON M.D., Corresponding Author MATHEW D. HUTCHINSON M.D. Division of Cardiology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USAAddress for correspondence: Mathew D. Hutchinson, M.D., Hospital of the University of Pennsylvania, 3400 Spruce Street, 9 Founders Pavilion, Philadelphia, PA 19104, USA. Fax: 215-615-5235; E-mail: mathew.hutchinson@uphs.upenn.eduSearch for more papers by this author SURAJ KAPA M.D., SURAJ KAPA M.D. Division of Cardiology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USASearch for more papers by this authorMATHEW D. HUTCHINSON M.D., Corresponding Author MATHEW D. HUTCHINSON M.D. Division of Cardiology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USAAddress for correspondence: Mathew D. Hutchinson, M.D., Hospital of the University of Pennsylvania, 3400 Spruce Street, 9 Founders Pavilion, Philadelphia, PA 19104, USA. Fax: 215-615-5235; E-mail: mathew.hutchinson@uphs.upenn.eduSearch for more papers by this author First published: 20 February 2013 https://doi.org/10.1111/jce.12118 No disclosures. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume24, Issue6June 2013Pages 655-657 RelatedInformation

Anatomical and electrophysiological variations of Koch’s triangle and the impact on the slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia: a study using 3D mapping

This study aimed to reveal individual variations in Koch's triangle using NavX and to evaluate the efficacy of the NavX-guided slow pathway ablation. A regional geometry around Koch's triangle was constructed in 42 consecutive patients with atrioventricular nodal reentrant tachycardia (AVNRT), and a bipolar electrogram map was created with 72 ± 30 sampling points during sinus rhythm to identify sites with Haissaguerre's slow potentials (SPs) and His bundle electrograms (HBEs) to examine the anatomical and electrical variations. Radiofrequency ablation was performed at the most prominent SP recording site. The acute results and long-term outcome were examined in comparison to another 42 consecutive patients who underwent a conventional fluoroscopy-guided slow pathway ablation in the previous months. The size of Koch's triangle and the coronary sinus ostium varied over a wide range of 132 to 490 and 69 to 346mm(2), respectively. HBEs were recorded linearly along the antero-septal right atrium (n = 29) or deviated downward toward the midseptum (n = 13, 31%). The SPs were always distributed below the lowest HBE recording site. The NavX-guided ablation eliminated AVNRT with a median of 1 radiofrequency pulse, 9.1 ± 4.6min of fluoroscopy, and 49 ± 14min of procedure time, all of which were significantly smaller than those in fluoroscopy-guided ablation. No procedure-related complications or long-term recurrence was noted in either group. Koch's triangle varies in terms of the size and electrogram distribution, and the NavX-guided slow pathway ablation overcomes the diversity and seems more effective than fluoroscopy-guided ablation.