Low-voltage bridge strategy to guide cryoablation of typical and atypical atrioventricular nodal re-entry tachycardia in children: mid-term outcomes in a large cohort of patients

EP Europace ◽  
2020 ◽  
Author(s):  
Fabrizio Drago ◽  
Camilla Calvieri ◽  
Mario Salvatore Russo ◽  
Romolo Remoli ◽  
Vincenzo Pazzano ◽  
...  
Keyword(s):  
Recurrence Rate ◽  
Low Voltage ◽  
Electrophysiological Study ◽  
Large Cohort ◽  
Definitive Treatment ◽  
Lesion Length ◽  
Voltage Mapping ◽  
Arrhythmogenic Substrate ◽  
Catheter Tip ◽  
Procedural Success

Abstract Aims In the current literature, results of the low-voltage bridge (LVB) ablation strategy for the definitive treatment of atrioventricular nodal re-entry tachycardia (AVNRT) seem to be encouraging also in children. The aims of this study were (i) to prospectively evaluate the mid-term efficacy of LVB ablation in a very large cohort of children with AVNRT, and (ii) to identify electrophysiological factors associated with recurrence. Methods and results One hundred and eighty-four children (42% male, mean age 13 ± 4 years) with AVNRT underwent transcatheter cryoablation guided by voltage mapping of the Koch’s triangle. Acute procedural success was 99.2% in children showing AVNRT inducibility at the electrophysiological study. The overall recurrence rate was 2.7%. The presence of two LVBs, a longer fluoroscopy time and the presence of both typical and atypical AVNRT, were found to be significantly associated with an increased recurrence rate during mid-term follow-up. Conversely, there was no significant association between recurrences and patient’s age, type of LVB, lesion length, number of cryolesions or catheter tip size. Conclusion The LVB ablation strategy is very effective in AVNRT treatment in children. Recurrences are related to the complexity of the arrhythmogenic substrate.

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

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Yalçin Gökoglan ◽  
Mahmut F Günes ◽  
Luigi Di Biase ◽  
Carola Gianni ◽  
Sanghamitra Mohanty ◽  
...  
Keyword(s):  
Low Voltage ◽  
3D Mapping ◽  
Bipolar Voltage ◽  
Voltage Mapping ◽  
Arrhythmogenic Substrate ◽  
Mapping System ◽  
3D Mapping System ◽  
Modest Correlation

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.

scholarly journals Comparison of Unipolar and Bipolar Voltage Mapping for Localization of Left Atrial Arrhythmogenic Substrate in Patients With Atrial Fibrillation

2020 ◽  
Vol 11 ◽  
Author(s):  
Deborah Nairn ◽  
Heiko Lehrmann ◽  
Björn Müller-Edenborn ◽  
Steffen Schuler ◽  
Thomas Arentz ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Left Atrial ◽  
Low Voltage ◽  
High Density ◽  
Border Zone ◽  
Electrode Spacing ◽  
Bipolar Voltage ◽  
Voltage Mapping ◽  
Arrhythmogenic Substrate ◽  
The Impact

Background: Presence of left atrial low voltage substrate in bipolar voltage mapping is associated with increased arrhythmia recurrences following pulmonary vein isolation for atrial fibrillation (AF). Besides local myocardial fibrosis, bipolar voltage amplitudes may be influenced by inter-electrode spacing and bipole-to-wavefront-angle. It is unclear to what extent these impact low voltage areas (LVA) in the clinical setting. Alternatively, unipolar electrogram voltage is not affected by these factors but requires advanced filtering.Objectives: To assess the relationship between bipolar and unipolar voltage mapping in sinus rhythm (SR) and AF and identify if the electrogram recording mode affects the quantification and localization of LVA.Methods: Patients (n = 28, 66±7 years, 46% male, 82% persistent AF, 32% redo-procedures) underwent high-density (>1,200 sites, 20 ± 10 sites/cm2, using a 20-pole 2-6-2 mm-spaced Lasso) voltage mapping in SR and AF. Bipolar LVA were defined using four different thresholds described in literature: <0.5 and <1 mV in SR, <0.35 and <0.5 mV in AF. The optimal unipolar voltage threshold resulting in the highest agreement in both unipolar and bipolar mapping modes was determined. The impact of the inter-electrode distance (2 vs. 6 mm) on the correlation was assessed. Regional analysis was performed using an 11-segment left atrial model.Results: Patients had relevant bipolar LVA (23 ± 23 cm2 at <0.5 mV in SR and 42 ± 26 cm2 at <0.5 mV in AF). 90 ± 5% (in SR) and 85 ± 5% (AF) of mapped sites were concordantly classified as high or low voltage in both mapping modes. Discordant mapping sites located to the border zone of LVA. Bipolar voltage mapping using 2 vs. 6 mm inter-electrode distances increased the portion of matched mapping points by 4%. The unipolar thresholds (y) which resulted in a high spatial concordance can be calculated from the bipolar threshold (x) using following linear equations: y = 1.06x + 0.26mV (r = 0.994) for SR and y = 1.22x + 0.12mV (r = 0.998) for AF.Conclusion: Bipolar and unipolar voltage maps are highly correlated, in SR and AF. While bipole orientation and inter-electrode spacing are theoretical confounders, their impact is unlikely to be of clinical importance for localization of LVA, when mapping is performed at high density with a 20-polar Lasso catheter.

scholarly journals Epicardial voltage mapping in patients with postinfarction ventricular tachycardia: a pilot study

2020 ◽  
Vol 27 ◽  
pp. 22-27
Author(s):  
K. A. Simonova ◽  
E. N. Mikhaylov ◽  
R. B. Tatarskiy ◽  
A. V. Kamenev ◽  
D. V. Panin ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Ventricular Tachycardia ◽  
Low Voltage ◽  
Epicardial Mapping ◽  
Voltage Mapping ◽  
Arrhythmogenic Substrate ◽  
Ablation Success ◽  
History Of ◽  
Ventricular Activity ◽  
Epicardial Access

Introduction. Radiofrequency ablation (RFA) is an established treatment of post-myocardial infarction ventricular tachycardia (VT). Endocardial VT ablation can be insufficient for VT termination when the scar is intramural/epicardial.Purpose: to assess the extent of epicardial electrophysiological VT substrate in patients with remote myocardial infarction.Materials and methods. Thirteen patients with sustained postinfarction VT, who signed an informed consent, were included into the study. All patients underwent full clinical evaluation. Electroanatomical voltage bi- and unipolar mapping of endocardial and epicardial surfaces was performed. Maps were evaluated for the presence of low-voltage areas and local abnormal ventricular activity (LAVA). RFA was performed at LAVA sites. The end-point of the procedure was scar LAVA abolition and VT noninducibility (procedure success). VT recurrence was detected using an implantable cardioverter-defibrillator and/or ECG monitoring.Results. Epicardial access was successful in 12 patients. Epicardial access was performed at a first procedure in 7 patients, 4 patients had a history of previous endocardial ablation. Epicardial LAVA sites were detected in 9 patients. Endocardial and epicardial arrhythmogenic substrate localization coincided in 8 patients. One patient had only epicardial scar, 1 patient had only septal endocardial scar. In one patient LAVA sites had different localizations on epicardial and endocardial maps. Acute ablation success was noted in 12 patients.Conclusion. In our patient group transmural scar and epicardial electrophysiological arrhythmogenic substrate was detected in 82% of cases. Isolated endocardial ablation may be unsuccessful, in such cases epicardial mapping and ablation might be useful.

scholarly journals Identification of Low-voltage Areas: A Unipolar, Bipolar and Omnipolar Perspective

2021 ◽  
Author(s):  
Mathijs S. van Schie ◽  
Rohit K. Kharbanda ◽  
Charlotte A. Houck ◽  
Eva A.H. Lanters ◽  
Yannick J.H.J. Taverne ◽  
...  
Keyword(s):  
Low Voltage ◽  
Volume Overload ◽  
Surrogate Markers ◽  
Epicardial Mapping ◽  
Atrial Volume ◽  
Bipolar Voltage ◽  
Voltage Mapping ◽  
Arrhythmogenic Substrate ◽  
Different Types ◽  
Mapping Techniques

Background - Low-voltage areas (LVA) are commonly considered surrogate markers for an arrhythmogenic substrate underlying tachyarrhythmias. It remains challenging to define a proper threshold to classify LVA and it is unknown whether unipolar, bipolar and the recently introduced omnipolar voltage mapping techniques are complementary or contradictory in classifying LVAs. Therefore, this study examined similarities and dissimilarities in unipolar, bipolar and omnipolar voltage mapping and explored the relation between various types of voltages and conduction velocity (CV). Methods - Intra-operative epicardial mapping (interelectrode distance 2mm, ±1900 sites) was performed during sinus rhythm in 21 patients (48±13 years, 9 male) with atrial volume overload. Cliques of 4 electrodes (2x2 mm) were used to calculate the maximal unipolar (V uni,max ), bipolar (V bi,max ) and omnipolar (V omni,max ) voltages and mean CV. Areas with V bi,max or V omni,max ≤0.5 mV were defined as LVA. Results - V uni,max was not only larger than V bi,max but also larger than V omni,max (7.08 [4.22-10.59] mV vs. 5.27 [2.39-9.56] mV and 5.77 [2.58-10.52] mV respectively, P<0.001). In addition, the largest bipolar clique voltage was on average 1.66 (range: 1.0 - 59.0) times larger to the corresponding perpendicular bipolar voltage pair. LVAs identified by a bipolar or omnipolar threshold corresponded to a broad spectrum of unipolar voltages and, even though CV was generally decreased, still high CVs and large unipolar voltages were found in these LVAs. Conclusions - In patients with atrial volume overload, there were considerable discrepancies in the different types of LVAs. Additionally, identification of LVAs was hampered by considerable directional differences in bipolar voltages. Even using directional independent omnipolar voltage to identify LVAs, high CVs and large unipolar voltages are present within these areas. Therefore, a combination of low unipolar and low omnipolar voltage may be more indicative of 'true' LVAs.

scholarly journals Diagnostic Yield of Electroanatomic Voltage Mapping in Guiding Endomyocardial Biopsies

Circulation ◽  
2020 ◽  
Vol 142 (13) ◽  
pp. 1249-1260 ◽  
Author(s):  
Michela Casella ◽  
Antonio Dello Russo ◽  
Marco Bergonti ◽  
Valentina Catto ◽  
Edoardo Conte ◽  
...  
Keyword(s):  
Cardiac Magnetic Resonance ◽  
Sensitivity And Specificity ◽  
Low Voltage ◽  
Diagnostic Yield ◽  
Gadolinium Enhancement ◽  
Promising Tool ◽  
Voltage Mapping ◽  
Few Data ◽  
New Diagnosis ◽  
Complications Rate

Background: Electroanatomic voltage mapping (EVM) is a promising modality for guiding endomyocardial biopsies (EMBs). However, few data support its feasibility and safety. We now report the largest cohort of patients undergoing EVM-guided EMBs to show its diagnostic yield and to compare it with a cardiac magnetic resonance (CMR)–guided approach. Methods: We included 162 consecutive patients undergoing EMB at our institution from 2010 to 2019. EMB was performed in pathological areas identified at EVM and CMR. CMR and EVM sensitivity and specificity regarding the identification of pathological substrates of myocardium were evaluated according to EMB results. Results: Preoperative CMR showed late gadolinium enhancement in 70% of the patients, whereas EVM identified areas of low voltage in 61%. Right (73%), left (19%), or both ventricles (8%) underwent sampling. EVM proved to have sensitivity similar to CMR (74% versus 77%), with specificity being 70% and 47%, respectively. In 12 patients with EMB-proven cardiomyopathy, EVM identified pathological areas that had been undetected at CMR evaluation. Sensitivity of pooled EVM and CMR was as high as 95%. EMB analysis allowed us to reach a new diagnosis, different from the suspected clinical diagnosis, in 39% of patients. The complications rate was low, mostly related to vascular access, with no patients requiring urgent management. Conclusions: EVM proved to be a promising tool for targeted EMB because of its sensitivity and specificity for identification of myocardial pathological substrates. EVM was demonstrated to have accuracy similar to CMR. EVM and CMR together conferred a positive predictive value of 89% on EMB.

scholarly journals Endocardial vs endo-epicardial ablation of ventricular arrhythmia in arrhythmogenic right ventricular cardiomyopathy: a single center experience

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
K.A Simonova ◽  
A.V Kamenev ◽  
R.B Tatarskiy ◽  
M.A Naymushin ◽  
V.S Orshanskaya ◽  
...  
Keyword(s):  
Ventricular Arrhythmia ◽  
Low Voltage ◽  
Arrhythmogenic Right Ventricular Cardiomyopathy ◽  
Control Group ◽  
Definite Diagnosis ◽  
Premature Ventricular Contractions ◽  
Single Center Experience ◽  
Voltage Mapping ◽  
Epicardial Access

Abstract Background The majority of patients have a sub-epicardial scar as a substrate for VT episodes. Purpose We sought to compare the efficacy of endocardial (ENDO) and epicardial (EPI) substrate modification in patients with ARVC. Methods 20 consecutive ARVC patients (mean age 41,4±13,8, 70% males; ICD previously implanted in 10 patients) with indications to ventricular arrhythmia ablation (RFA) were included into a prospective observational study. The EPI group consisted of 10 patients with sustained ventricular tachycardia (VT) (definite diagnosis ARVC – 8 patients; borderline – 1, possible – 1) who signed an informed consent to epicardial access. The ENDO group included 10 patients (definite diagnosis ARVC – 9 patients), five of them demonstrated sustained VT and 5 patients had frequent symptomatic premature ventricular contractions (PVC). Epicardial access in the EPI group was obtained through subxyphoid puncture. Bi- and unipolar voltage mapping of endocardial and epicardial surfaces was performed. Maps were evaluated for the presence of local abnormal ventricular electrical activity (LAVA, low-voltage areas and sites with highly fractionated or late activity). Ablation was performed at sites of LAVA on either side of the ventricular wall. In the ENDO group endocardial only ablation at LAVA sites was performed. RF energy ablation was 40W at the epicardial surface and 40–50W at the endocardial surface. Results In the EPI group endocardially mapped area of unipolar endocardial low voltage zone (LVZ) significantly prevailed over bipolar endocardial area of LVZ: 75.4 cm2 [IQR: 23.2; 211.9] vs 6.7 cm2 [IQR: 4.4; 35.5](P=0.009). Epicardial bipolar LVZ area prevailed over unipolar epicardial LVZ area: 65.3 cm2 [IQR: 55.6; 91.3] vs 6.7 cm2 [IQR: 4.4; 35.3] (P=0.005). Endocardial unipolar LVZ area in the EPI group was larger than in the ENDO group (P&gt;0,05). After ablation non-inducibility of any ventricular arrhythmia was achieved in 90% of patients in the EPI group and in 80% of cases in the ENDO group. During a mean follow-up period of 22.3±10.5 months freedom of ventricular arrhythmia recurrence was 70% in the EPI group and 100% in the control group. Conclusions Although epicardial area of abnormal potentials significantly prevails over endocardial area, endocardial unipolar mapping and higher RF ablation power allow performing successful ventricular arrhythmia treatment in the majority of ARVC patients. Funding Acknowledgement Type of funding source: None

Abstract 20107: Randomized Comparison of Personalized versus Standardized Substrate Modification During Catheter Ablation for Symptomatic Atrial Fibrillation

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Simon Kircher ◽  
Arash Arya ◽  
David Altmann ◽  
Sascha Rolf ◽  
Andreas Bollmann ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Low Voltage ◽  
Randomized Study ◽  
Standard Group ◽  
Linear Lesions ◽  
Substrate Modification ◽  
Arrhythmogenic Substrate ◽  
Group 2 ◽  
Group 1

Introduction: Pulmonary vein (PV) isolation forms the cornerstone of any ablation procedure for atrial fibrillation (AF). There is, however, no uniform strategy how to detect and target left atrial (LA) arrhythmogenic substrate outside the PV antra. Fibrosis that corresponds well to LA low-voltage areas (LVAs) seems to play a key role in AF arrhythmogenesis and might therefore be a suitable target for additional substrate modification (SM). Objective: The purpose of this prospective randomized study was to compare a novel technique for SM based on ablation of potentially arrhythmogenic LA LVAs with a standard approach consisting of empiric LA linear ablation. Methods: Patients (pts) with symptomatic paroxysmal or persistent AF were randomized to standard (group 1) or personalized (group 2) SM. Circumferential PV isolation was the primary step in both groups. In group 1, pre-defined linear lesions were applied at the LA roof and bottom, respectively, and at the mitral isthmus only in pts with persistent AF. In group 2, targets for SM (i.e. LVAs) were identified by detailed bipolar voltage mapping (BVM) during sinus rhythm irrespective of AF type. Peak-to-peak electrogram amplitudes were defined as “normal” (> 0.5 mV), as “low voltages” (0.2 to 0.5 mV), or as “scar” (< 0.2 mV). LVAs were targeted by tissue homogenization and / or strategic linear lesions. The primary endpoint was freedom from any atrial arrhythmia (i.e. AF, atrial flutter, or atrial tachycardia) > 30 seconds off antiarrhythmic drugs on serial 7-d-Holter ECG recordings after a follow-up period of 12 months. Results: In total, 124 ablation-naïve pts (mean age 63 ± 9 years, 62 % male, 49 % with persistent AF) were enrolled in this study. LVAs were present in 18 % of pts with paroxysmal and in 41 % of pts with persistent AF (p<0.05). At the end of the follow-up period, 25 out of 59 pts (42 %) in the conventional group were free from arrhythmia recurrence as compared to 40 out of 59 pts (68 %) in the BVM-guided group (unadjusted log rank p = 0.003). Conclusion: Personalized SM guided by endocardial BVM is associated with a higher success rate compared to a conventional approach applying empirical SM based on AF phenotype.

Abstract 15692: Voltage Mapping in Atrial Fibrillation vs Sinus Rhythm: Results From the Mavs Study

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Carola Gianni ◽  
Jerri A Cunningham ◽  
Sanghamitra Mohanty ◽  
CHINTAN TRIVEDI ◽  
Domenico G Della Rocca ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Sinus Rhythm ◽  
Low Voltage ◽  
Lateral Wall ◽  
Posterior Wall ◽  
Anterior Wall ◽  
Inferior Wall ◽  
Voltage Mapping ◽  
First Time ◽  
Mapping Catheter

Background: Left atrial (LA) scar can be identified with bipolar voltage mapping during sinus rhythm (SR). It is not clear whether the same voltage criteria can be applied during atrial fibrillation (AF). Objective: Aim of this study was to compare voltage maps performed in the same patient both in AF and SR. Methods: Voltage mapping was performed using a 10-pole circular mapping catheter in patients with non-paroxysmal AF undergoing first time RF ablation. For descriptive purposes, the LA was divided in 6 regions: septum, posterior wall (PW), inferior wall (IW), lateral wall, anterior wall, and roof. The threshold for low voltage was <0.5 mV (with a color range setting 0.2-0.5 mV). Mild “scar” was defined as an area low voltage 5-20%, moderate 20-35% and severe as >35%. Results: 16 patients (62% persistent AF, 38% longstanding persistent AF) were included in the study. The map density was comparable during AF and SR (mean points per map 551 vs 547, paired t test P = NS). 2 patients displayed normal voltage during both AF and SR. 14 patients showed areas of low voltage during AF, which were still present during SR in 8. All patients with mild “scarring” during AF (n = 4), showed normal voltage during SR. Of the 7 patients with moderate “scarring”, 2 patients showed normal voltage during SR, while in the remaining 5 “scarring” was only mild during SR. 3 patients showed extensive “scarring” during AF, which was only moderate during SR. During AF, areas of low voltage were more commonly observed in the PW (12/14) followed by the IW (6/14) and antero-septum (4/14); while in SR, in the antero-septum (4/8), PW (3/8) and IW (3/8). Interestingly, in all patients both the PW/IW and (less dramatically) the antero-septum showed more “scarring” during AF as compared to SR. Conclusion: Areas of low voltage are more severe and diffuse during AF when compared to SR. When areas of low voltage are detected during AF, they are more commonly seen in the PW, IW and antero-septal areas.

3255Characterization of the arrhythmogenic substrate with multimodality imaging in ischemic patients undergoing VT ablation: relationship between cardiac computed tomography and magnetic resonance

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
G Zucchelli ◽  
D Soto Iglesias ◽  
B Jauregui ◽  
C Teres ◽  
D Penela ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Magnetic Resonance ◽  
Cardiac Ct ◽  
Low Voltage ◽  
Multimodality Imaging ◽  
Cardiac Computed Tomography ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Ventricular Ejection Fraction ◽  
Arrhythmogenic Substrate

Abstract Background Cardiac magnetic resonance (CMR)-aided ventricular tachycardia (VT) substrate ablation has shown to improve VT recurrence-free survival, through a better identification of the arrhythmogenic substrate. However, the access to CMR may be limited in certain centers or sometimes Its use can be contraindicated in patients with cardiac implantable electronic device. Cardiac computed tomography (CT) has shown to improve the results of substrate ablation, correlating with low-voltage areas and local abnormal ventricular activity, and identifying ridges of myocardial tissue (CT-channels) that may be appropriate target sites for ablation. Purpose To evaluate the correlation between CT and CMR imaging in identifying anatomical heterogeneous tissue channels (CMR-channels) or CT-channels in ischemic patients undergoing VT substrate ablation. Methods The study included 30 post-myocardial infarction (MI) patients (mean age 69±10; 94% male, left ventricular ejection fraction 35±10%), who underwent both CMR and cardiac CT before VT substrate ablation. Using a dedicated post-processing software, the myocardium was segmented in 10 layers from endocardium to epicardium both for the CMR and CT, characterizing the presence of CMR-channels and CT-channels, respectively, by two blinded operators, assigned either to CMR or CT analysis. CMR-channels were classified as endocardial (CMR-channels in layer <50%), epicardial (CMR-channels in layers ≥50%) or transmural (in both endo and epicardial layers). Presence and location of CT and CMR-channels were compared. Results In 26/30 patients (86.7%) 91 CT-channels (mean 3.0±1.9 per patient) were identified while 30/30 (100%) showed CMR-channels (n=76; mean 2.4±1.2 per patient). We found 190 CT-channel entrances (mean 6.3±4.1 per patient), and 275 CMR-channel entrances (mean 8.9±4.9 per patient) on cardiac CT and CMR, respectively. There were 47/91 (51.6%) true positive CT-channels. On the contrary, 44/91 (48.4%) CT-channels were considered false positives [19/91 (20.9%) identified out of CMR scar], and 29/76 (38.2%) CMR-channels could not be identified on CT. Thirty-six out of 76 (47.4%) CMR-channels were considered as non-endocardial (epi- or transmural). Twenty-nine out of 36 (80.5%) non-endocardial CMR-channels were coincident with CT-channels. CT and CMR Channels Conclusion CT shows a modest sensitivity in identifying CMR-channels and fails in ascertain their complexity, underestimating the number of entrances; however, channels location at CT fit well with CMR for those classified as transmural or epicardial.

Axonal conduction in multiple sclerosis: A combined magnetic resonance imaging and electrophysiological study of the medial longitudinal fasciculus

2014 ◽  
Vol 21 (7) ◽  
pp. 905-915 ◽  
Author(s):  
Chenyu Wang ◽  
David Paling ◽  
Luke Chen ◽  
Sean N Hatton ◽  
Jim Lagopoulos ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Conduction Velocity ◽  
Electrophysiological Study ◽  
Vestibular Stimulation ◽  
Medial Longitudinal Fasciculus ◽  
Lesion Length ◽  
Onset Latency ◽  
Axonal Conduction ◽  
Axonal Dysfunction

Objective: The objective of this paper is to inform the pathophysiology of medial longitudinal fasciculus (MLF) axonal dysfunction in patients with internuclear ophthalmoplegia (INO) due to multiple sclerosis (MS), and develop a composite structural-functional biomarker of axonal and myelin integrity in this tract. Methods: Eighteen patients with definite MS and clinically suspected INO underwent electrical vestibular stimulation and search-coil eye movement recording. Components of the electrically evoked vestibulo-ocular reflex (eVOR) were analyzed to probe the latency and fidelity of MLF axonal conduction. The MLF and T2-visible brainstem lesions were defined by high-resolution MRI. White matter integrity was determined by diffusion-weighted imaging metrics. Results: eVOR onset latency was positively correlated with MLF lesion length (left: r = 0.66, p = 0.004; right: r = 0.75, p = 0.001). The mean conduction velocity (±SD) within MLF lesions was estimated at 2.72 (±0.87) m/s. eVOR onset latency correlated with normalized axial diffusivity ( r = 0.66, p < 0.001) and fractional anisotropy ( r = 0.44, p = 0.02) after exclusion of cases with ipsilateral vestibular root entry zone lesions. Conclusions: Axonal conduction velocity through lesions involving the MLF was reduced below levels predicted for natively myelinated and remyelinated axons. Composite in vivo biomarkers enable delineation of axonal from myelin processes and may provide a crucial role in assessing efficacy of novel reparative therapies in MS.

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