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

Author(s):  
Mathijs S. van Schie ◽  
Rohit K. Kharbanda ◽  
Charlotte A. Houck ◽  
Eva A.H. Lanters ◽  
Yannick J.H.J. Taverne ◽  
...  

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.

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Yalçin Gökoglan ◽  
Mahmut F Günes ◽  
Luigi Di Biase ◽  
Carola Gianni ◽  
Sanghamitra Mohanty ◽  
...  

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.


2020 ◽  
Vol 11 ◽  
Author(s):  
Deborah Nairn ◽  
Heiko Lehrmann ◽  
Björn Müller-Edenborn ◽  
Steffen Schuler ◽  
Thomas Arentz ◽  
...  

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 (&gt;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: &lt;0.5 and &lt;1 mV in SR, &lt;0.35 and &lt;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 &lt;0.5 mV in SR and 42 ± 26 cm2 at &lt;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.


2020 ◽  
Vol 27 ◽  
pp. 22-27
Author(s):  
K. A. Simonova ◽  
E. N. Mikhaylov ◽  
R. B. Tatarskiy ◽  
A. V. Kamenev ◽  
D. V. Panin ◽  
...  

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.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
C Houck ◽  
E A H Lanters ◽  
P Knops ◽  
P C Van De Woestijne ◽  
J W Roos-Hesselink ◽  
...  

Abstract Background Various atrial regions may contribute to the arrhythmogenic substrate for atrial tachyarrhythmias, including atrial fibrillation (AF), in patients with right atrial (RA) volume overload in congenital heart disease (CHD). It is widely recognized that structural and electrical remodelling of the RA occurs, but a previous endovascular mapping study showed that the left atrium (LA) was also affected in patients with atrial septal defect (ASD). The role of Bachmann's bundle (BB) and posterior left atrium (PLA) is yet unknown. Purpose To quantify and compare prevalence and severity of conduction disorders during sinus rhythm between atrial regions in patients with CHD and RA volume overload, using intraoperative high-resolution epicardial mapping. Methods Thirty-one patients (female: n=18, age: 48.5±13.8 years, history of AF: n=5) undergoing cardiac surgery for secundum ASD (n=18), sinus venosus defect (n=11) or isolated partial abnormal pulmonary venous return (n=2) were included. Intra-operative epicardial mapping (N=128/192 electrodes, interelectrode distance: 2mm) of the RA, BB, LA and PLA was performed during sinus rhythm. Conduction delay (CD) and block (CB) were quantified per region as proportion (%), length of lines (mm) and maximum conduction time (Δ local activation time between two adjacent electrodes). Results Proportion of CD on BB was 3.9% (2.3–4.9), RA 3.1% (1.9–3.8), PLA 2.4% (1.2–3.6) and LA 2.3% (1–3) and was higher on BB compared to PLA (p=0.002) and LA (p<0.001) but not RA (p=0.063). Proportion of CB on BB was 2.1% (1.2–5.4), RA 2.2% (1.1–3.4), PLA 0.8% (0.1–2.4) and LA 0.8% (0.3–1.6) and was smaller on LA compared to BB (p=0.001) and RA (p=0.004). There were no significant differences in length of CD/CB lines between regions, except that length of the longest CB line per patient was longer in the RA compared to LA (p=0.008). Maximum conduction time was highest in the RA (median 40ms) as opposed to BB (31ms), LA (21ms) and PLA (18ms; all p<0.0083 with Bonferroni correction), suggesting conduction disorders were more severe in the RA. For sub analysis, the RA surface was divided into 1) the crista terminalis region and 2) the lateral RA wall. In the crista terminalis region, proportions of CD and CB were higher, CD/CB lines were longer and maximum conduction times were higher (all p<0.05). Differences between patients with and without AF were solely observed on BB: patients with AF had a higher proportion and longer lines of CB (p<0.05), though outcomes should be interpreted with caution due to the small number of patients with AF. Conclusions In adult patients with CHD and RA volume overload, both RA and BB were affected by conduction disorders. More specifically, conduction disorders in the RA were mainly concentrated in the crista terminalis region. These findings suggest that not only the RA but also BB may be involved in the arrhythmogenic substrate for atrial tachyarrhythmias in these patients. Acknowledgement/Funding Dutch Heart Foundation [no 2012T0046]; LSH-Impulse [no 40-43100-98-008]; CVON [no 914728] and VIDI [no 91717339] to N.M.S. de Groot.


EP Europace ◽  
2020 ◽  
Author(s):  
Fabrizio Drago ◽  
Camilla Calvieri ◽  
Mario Salvatore Russo ◽  
Romolo Remoli ◽  
Vincenzo Pazzano ◽  
...  

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.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
R Schoenbauer ◽  
J Tomala ◽  
B Kirstein ◽  
Y Huo ◽  
T Gaspar ◽  
...  

Abstract Background Bipolar voltage mapping is a widely accepted approach to identify areas of arrhythmogenic substrate in patients presenting for atrial fibrillation (AF) ablation. However, until now little is known about the correlation of left atrial (LA) bipolar voltage distribution and LA transport function. Purpose To study the impact of LA low voltage zones (LVZ) on LA transport function. Methods 107 consecutive patients presenting for ablation of symptomatic AF (34 paroxysmal AF, 73 persistent AF) were prospectively enrolled. Each patient underwent cardiac magnetic resonance imaging (CMR) within 24 hours prior to the ablation procedure. 59 patients were in sinus rhythm (SR) and 48 in AF. LA phasic indexed volumes (LAVi) and ejection fractions were calculated using biplane area length formula. In addition LA phasic strains and strain rates were analyzed using dedicated software (Figure 1A & B). LA bipolar voltage mapping was performed prior to beginning of ablation in sinus rhythm using a 3-dimensional mapping system and LVZ were defined as areas of bipolar voltage <0.5mV. Results LVZ were present in 47 patients (23 in SR). The area of LVZ was 14.6cm2 (5.3–34.0). For patients in AF at the time of CMR only elevated minimal and maximal LAVi (p=0.001 and p=0.002 respectively) but no LA functional parameter was predictive for the occurrence of LVZ. In contrast for patients in SR all LA phasic volumes (endsystolic, pre atrial contraction and enddiastolic LAVi) and LA function parameters (passive, active and total ejection fraction (EF), reservoir, conduit and booster pump strains and strain rates) were predictive for the occurrence of LVZ. After clustered and pooled multivariate logistic regression only impaired booster pump strain rate was still predictive for occurrence of LVZ (OR 0.974, 95% CI 0.950–0.998, p=0.036). In addition Pearson correlation analysis revealed a strong link between LA booster pump functional parameters and cm2 expansion of LVZ areas: LA active EF, LA booster pump strain and SR (r=−0.42, p=0.044; r=−0.47, p=0.024; r=−0.65, p=0.001 [Figure 1C] respectively). Conclusion For patients in SR LA transport function is closely linked to the occurrence of LA LVZ and outperforms LA volumetric measurements for the prediction of LA LVZ. Furthermore LA booster pump function parameters show robust correlation to the extension of LA LVZ.


2021 ◽  
Vol 23 (Supplement_G) ◽  
Author(s):  
Nicolò Sisti ◽  
Amato Santoro ◽  
Claudia Baiocchi ◽  
Antonio Biancofiore ◽  
Simone Pistoresi ◽  
...  

Abstract A 38 years-old man was admitted to our hospital after ventricular tachycardia with left-bundle-branch block and inferior axis morphology. After undergoing different examinations the criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC) were met. An electrophysiological study was then performed together with endocardial bipolar and unipolar voltage map. Unipolar and bipolar voltage mapping of the right ventricle showed low voltage areas and corresponding fragmented potentials from the tricuspid annulus to the inferior apex. On the right ventricular outer tract (RVOT), the bipolar voltage mapping was normal while the unipolar mapping showed low-voltage areas in the antero-septal outer tract. An off-line map was used to perform speckle tracking analysis on intracardiac echocardiography (ICE) clips of right ventricle and standard echocardiography. A reduction of the strain analysis was stored in correspondence of the fragmented electrograms area, in particular, speckle tracking analysis on ICE views showed a reduction of the RV LS in the segments below tricuspid valve, in the three different myocardial layers. The endocardial longitudinal strain was reduced from sub-tricuspidalic segments to the RV apex in accordance with the fragmentated potentials stored during voltage mapping. On the contrary, at anterior RVOT wall, the unipolar voltage mapping showed fragmented potentials and the STE analysis revealed a reduced epicardial LS. This case report lays emphasis on the importance of the integration of ICE-derived right ventricular strain and voltage mapping in the improvement of the sensibility of an early diagnosis of the ARVC.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Tilko Reents ◽  
Johann Cristoph Geller ◽  
Jörg Mittag ◽  
Ralf Schneider ◽  
Isabell Deisenhofer ◽  
...  

Background: Different substrate based ablation strategies have been developed for ablation of ventricular tachycardia (VT) after myocardial infarction (MI). We investigated the “Dynamic Substrate Mapping (DSM)”, a tool integrated into the noncontact mapping (NCM) system. Methods: An electrophysiologic study (EPS) was performed 96 ± 10 days after experimental anteroseptal MI in 19 female sheep. Scar was defined by NCM during sinus rhythm. The area of scar was determined using the DSM tool with a cut-off of 50 %, 40%, 30% and 20% of the largest deflection of the unipolar electrogram. The scar was determined by either magnetic resonance imaging (MRI, n=9) or pathology (n=10). Areas determined by MRI or pathology and by DSM were compared. In 11 patients referred for ablation of VT simultaneous electroanatomical mapping and NCM was performed. The location of the low voltage area in the bipolar voltage map and the DSM were compared. Results: For all 19 animals a low voltage area was delineated with a cut off of 50% of the largest unipolar deflection. The low voltage area determined with DSM was greater then the scar determined by pathology or MRI (29,32 ± 28,83 cm 2 vs 8,52 ± 3,48 cm 2 . p < 0,05). Infarct scar determined by MRI or pathology was always located within the low voltage area determined by DSM. There was no correlation between the sizes of the low voltage area determined by pathology/MRI and DSM. Delineation of a low voltage area was not possible in all animals with a cut off of 40%, 30%, and 20%. In 11 patients, locations of the low voltage areas determined by bipolar voltage maps and DSM corresponded well. The area defined by DSM was larger then the area defined by bipolar voltage map. there was a good correlation between the size of the low voltage areas determined by bipolar voltage map and DSM for cut off values of 50% and 40% (r 2 = 0,66 and r 2 = 0,61; p<0,05). With a cut off of 30% and 20% of the largest unipolar deflection a low voltage area could not be defined for all patients. Conclusion: Sizes of abnormal myocardium defined by DSM do not correlate with scar areas determined by pathology or MRI. Areas of abnormal myocardium delineated by DSM are greater then areas defined with bipolar voltage map. A detailed description of the scar border zone with DSM during sinus rhythm alone is not feasible.


Circulation ◽  
2020 ◽  
Vol 142 (13) ◽  
pp. 1249-1260 ◽  
Author(s):  
Michela Casella ◽  
Antonio Dello Russo ◽  
Marco Bergonti ◽  
Valentina Catto ◽  
Edoardo Conte ◽  
...  

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.


Medicina ◽  
2021 ◽  
Vol 57 (7) ◽  
pp. 660
Author(s):  
Csilla-Andrea Eötvös ◽  
Roxana-Daiana Lazar ◽  
Iulia-Georgiana Zehan ◽  
Erna-Brigitta Lévay-Hail ◽  
Giorgia Pastiu ◽  
...  

Among the different types, immunoglobulin light chain (AL) cardiac amyloidosis is associated with the highest morbidity and mortality. The outcome, however, is significantly better when an early diagnosis is made and treatment initiated promptly. We present a case of cardiac amyloidosis with left ventricular hypertrophy criteria on the electrocardiogram. After 9 months of follow-up, the patient developed low voltage in the limb leads, while still maintaining the Cornell criteria for left ventricular hypertrophy as well. The relative apical sparing by the disease process, as well as decreased cancellation of the opposing left ventricular walls could be responsible for this phenomenon. The discordance between the voltage in the frontal leads and precordial leads, when present in conjunction with other findings, may be helpful in raising the clinical suspicion of cardiac amyloidosis.


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