A new approach to atrial flutter ablation using functional substrate mapping with wavefront discontinuity during sinus rhythm

Abstract Funding Acknowledgements Type of funding sources: None. Background Ultra high-density (UHD) mapping allows accurate identification of local abnormal electrograms and low voltage within a small area range, allowing precise identification of reentry circuits. Areas with high isochronal density in a small area known as deceleration zones (DZ) are responsible for reentry. Purpose Identify the DZ and areas of low voltage in sinus rhythm (SR) and evaluate the feasibility of performing atrial flutter (AFL) ablation by targeting those zones. Methods We prospectively enrolled patients in SR referred for AFL ablation (either typical or atypical). An isochronal late activation mapping (ILAM) during SR with UHD catheter was performed, annotating latest deflection of local electrograms. DZ were defined as areas with >3 isochrones within 1cm radius, prioritizing zones with maximal density. Atrial flutter was then induced and ILAM during flutter was performed for comparison. Voltage mapping was also assessed (0.1-0.5mV). Ablation targeted DZ in SR that displayed the higher voltage. DZ in SR were compared to DZ in AFL. Number of radiofrequency (RF) applications needed to terminate AFL were assessed. After AFL termination, complete line of the slow conduction zone was completed, and pulmonary vein isolation (PVI) was done in case of left AFL. Categorical variables are presented in absolute and relative values and median and interquartile range were used for numerical variables, as well t-student test for correlation of numerical variables. Results We studied 6 AFL (4 atypical, 66.7%) in 5 patients, 2 male (40%), median age 70 (64- 72). UHD ILAM in SR with 2195 points (1212-2865) and 2197 points (1356-3102) in AFL (p = 0.62). The UHD ILAM identified a median of (QR) DZ in SR, that colocalized with AFL isthmus and DZ in AFL in 100%. DZ were not always located in low voltage areas. Aiming at the higher voltage in the DZ terminated the AFL in all cases, with a median RF time of 38 (25-58) seconds and AFL was no longer inducible. However, according to protocol, the complete line of slow conduction zone was done, with a median RF time of 1049.5 (274-1194) seconds (p = 0,009). Conclusions Isochronal mapping in sinus rhythm with UHD catheters can display the functional substrate for reentry in AFL, allowing a substrate guided ablation in case of non-inducible AFL. Targeting the areas of high isochronal density, is effective in terminating AFL, obviating the need for extensive ablation. Abstract Figure.

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Characterization of Low Right Atrial Isthmus as the Slow Conduction Zone and Pharmacological Target in Typical Atrial Flutter

Circulation ◽

10.1161/01.cir.96.8.2601 ◽

1997 ◽

Vol 96 (8) ◽

pp. 2601-2611 ◽

Cited By ~ 54

Author(s):

Ching-Tai Tai ◽

Shih-Ann Chen ◽

Chern-En Chiang ◽

Shih-Huang Lee ◽

Kwo-Chang Ueng ◽

...

Keyword(s):

Atrial Flutter ◽

Right Atrial ◽

Slow Conduction ◽

Typical Atrial Flutter ◽

Pharmacological Target ◽

Conduction Zone

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

Circulation ◽

10.1161/circ.142.suppl_3.15692 ◽

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.

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Slow conduction zone as an early electrical remodeling change in patients with atrial fibrillation

European Heart Journal ◽

10.1093/ehjci/ehaa946.0539 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

H Kishima ◽

T Mine ◽

E Fukuhara ◽

M Ishihara

Keyword(s):

Atrial Fibrillation ◽

Low Voltage ◽

Ascending Aorta ◽

Right Atrial ◽

Electrical Remodeling ◽

Atrial Pacing ◽

Descending Aorta ◽

Contact Areas ◽

Slow Conduction ◽

Conduction Zone

Abstract Background The slow conduction zone (SCZ) in the left atrium (LA) detected using 3-D mapping and high-resolution imaging system has attracted attention as an arrhythmia substrate of atrial fibrillation (AF). However, the occurrence mechanism of SCZ remains unclear. Purpose This aim of this study is to clarify whether SCZ is related to the low voltage zone (LVZ) or the LA anatomical contact areas with other organs such as aorta or thoracic spine in patients with AF. Methods We studied 36 patients (21 males, 68±10 years, 14 paroxysmal AF; PAF, 17 persistent AF; PeAF, 5 long-standing persistent AF; LS-PeAF) who received catheter ablation for AF. High-density LA mapping during sinus rhythm or right atrial pacing after pulmonary vein isolation were constructed by acquiring more than 2000 endocardial points in each patient. Isochronal activation maps were created at 5-ms interval setting, and the SCZ was identified on the activation map by finding a site with isochronal crowding of ≥3 isochrones, which are calculated as ≤27 cm/s (figure). The LVZ was defined as the following; mild (<1.5 mV), moderate (<1.0 mV), and severe LA-LVZ (<0.5 mV). The LA contact areas (CoAs; ascending aorta-anterior LA, descending aorta-posterior LA, and vertebrae-posterior LA) were assessed using computed tomography. Results The SCZ was distributed linearly (figure), and observed in 35 of 36 patients (97.2%). The SCZ was often found in the anterior (89%), roof (64%), and septal wall (47%) of LA, and longest in patients with LS-PeAF (PAF: 56±34 mm, PeAF; 79±41 mm, LS-PeAF; 107±34mm, P=0.0351). The prevalence rate of SCZ (97.2%) was higher than LVZ (figure, mild LA-LVZ; 91.7%, moderate LA-LVZ: 66.7%, severe LA-LVZ; 25%). The 55.8% of SCZ overlapped with mild LA-LVZ, 37.6% of SCZ with moderate LA-LVZ, and 19.1% of SCZ with severe LA-LVZ. The LA CoAs were found in all patients. A total of 72 CoAs (average surface area, 7.0±4.0 cm2) were identified. A CoA was found in each of the three representative regions, ascending aorta-anterior LA (4.1±2.0 cm2, 36 of 36 patients, 100%), descending aorta-posterior LA (2.3±1.2 cm2, 12 of 36 patients, 33%), and vertebrae-posterior LA (3.4±2.1 cm2, 24 of 36 patients, 67%). However, only 22% of SCZ matched with the LA anatomical contact areas. Conclusion The slow conduction zone reflects LA electrical remodeling and may be a precursor finding of the low voltage zone, not LA contact areas in patients with atrial fibrillation. Funding Acknowledgement Type of funding source: None

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Clinical Outcomes of low-voltage area-guided left atrial linear ablation for non-paroxysmal atrial fibrillation patients

PLoS ONE ◽

10.1371/journal.pone.0260834 ◽

2021 ◽

Vol 16 (12) ◽

pp. e0260834

Author(s):

Hao-Tien Liu ◽

Chia-Hung Yang ◽

Hui-Ling Lee ◽

Po-Cheng Chang ◽

Hung-Ta Wo ◽

...

Keyword(s):

Atrial Fibrillation ◽

Sinus Rhythm ◽

Paroxysmal Atrial Fibrillation ◽

Left Atrial ◽

Low Voltage ◽

Reverse Remodeling ◽

Voltage Mapping ◽

Linear Ablation

Background The therapeutic effect of low-voltage area (LVA)-guided left atrial (LA) linear ablation for non-paroxysmal atrial fibrillation (non-PAF) is uncertain. We aimed to investigate the efficacy of LA linear ablation based on the preexisting LVA and its effects on LA reverse remodeling in non-PAF patients. Methods We retrospectively evaluated 145 consecutive patients who underwent radiofrequency catheter ablation for drug-refractory non-PAF. CARTO-guided bipolar voltage mapping was performed in atrial fibrillation (AF). LVA was defined as sites with voltage ≤ 0.5 mV. If circumferential pulmonary vein isolation couldn’t convert AF into sinus rhythm, additional LA linear ablation was performed preferentially at sites within LVA. Results After a mean follow-up duration of 48 ± 33 months, 29 of 145 patients had drugs-refractory AF/LA tachycardia recurrence. Low LA emptying fraction, large LA size and high extent of LVA were associated with AF recurrence. There were 136 patients undergoing LA linear ablation. The rate of linear block at the mitral isthmus was significantly higher via LVA-guided than non-LVA-guided linear ablation. Patients undergoing LVA-guided linear ablation had larger LA size and higher extent of LVA, but the long-term AF/LA tachycardia-free survival rate was higher than the non-LVA-guided group. The LA reverse remodeling effects by resuming sinus rhythm were noted even in patients with a diseased left atrium undergoing extensive LA linear ablation. Conclusions LVA-guided linear ablation through targeting the arrhythmogenic LVA and reducing LA mass provides a better clinical outcome than non-LVA guided linear ablation, and outweighs the harmful effects of iatrogenic scaring in non-PAF patients.

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A new electrophysiological triad for atrial flutter critical isthmus identification and localization

EP Europace ◽

10.1093/europace/euab116.101 ◽

2021 ◽

Vol 23 (Supplement_3) ◽

Author(s):

P Adragao ◽

D Nascimento Matos ◽

P Galvao Santos ◽

F Moscoso Costa ◽

G Rodrigues ◽

...

Keyword(s):

Atrial Fibrillation ◽

Atrial Flutter ◽

Cycle Length ◽

Low Voltage ◽

Prospective Analysis ◽

Electroanatomical Mapping ◽

Funding Sources ◽

Activation Times ◽

Density Zone ◽

Funding Acknowledgements

Abstract Funding Acknowledgements Type of funding sources: None. Introduction In a previous retrospective study it was demonstrated that an electrophysiological triad was able to identify critical isthmus in atrial flutter (AFL) patients. This triad is based in the Carto® electroanatomical mapping (EAM) version 7, which displays a histogram of the local activation times (LAT) of the tachycardia cycle length (TCL), in addition to the activation and voltage maps. This study aimed to prospectively assess the ability of an electrophysiological triad to identify and localize the AFL’s critical isthmus. Methods Prospective analysis of a unicentric registry of individuals who underwent left AFL ablation with Carto® EAM. All patients with non-left AFL, lack of high-density EAM, less than 2000 collected points or lack of mapping in any of the left atrium walls or structures were excluded. Ablation sites of arrhythmia termination were compared to an electrophysiological triad constituted by: areas of low-voltage (0.05 to 0.3mV), sites of deep histogram valleys (LAT-Valleys) with less than 20% density points relative to the highest density zone and a prolonged LAT-Valley duration that included 10% or more of the TCL. The longest LAT-Valley was designated as the primary valley, while additional valleys were named as secondary. Results A total of 12 patients (9 men, median age 72 IQR 67-75 years) were included. All patients presented with left AFL and 67% had a previous atrial fibrillation and/or flutter ablation. The median TCL and number collected points were 250 (230─290) milliseconds and 3150 (IQR 2340─3870) points, respectively. All AFL presented with at least 1 LAT-Valley in the analysed histograms, which corresponded to heterogeneous low-voltage areas (0.05 to 0.3mV) and encompassed more than 10% of TCL. Eleven of the 12 patients presented with at least 1 secondary LAT-Valley. All arrhythmias were effectively terminated after undergoing radiofrequency ablation in the primary or the secondary LAT-Valley location. Conclusion In a prospective analysis, an electrophysiological triad was able to identify the AFL critical isthmus in all patients. Further studies are needed to assess the usefulness of this algorithm to improve catheter ablation outcomes.

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Abstract 13669: Slow Conduction Zone of Left Atrium is a Precursor to Low Voltage Area in Patients With Atrial Fibrillation

Circulation ◽

10.1161/circ.142.suppl_3.13669 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Hideyuki Kishima ◽

Takanao Mine ◽

Ryo Kitagaki ◽

Eiji Fukuhara ◽

Masaharu Ishihara

Keyword(s):

Atrial Fibrillation ◽

Left Atrium ◽

Low Voltage ◽

Anterior Wall ◽

Right Atrial ◽

Wall Region ◽

Contact Areas ◽

Slow Conduction ◽

Conduction Zone ◽

Right Atrial Appendage

Introduction: The slow conduction zone (SCZ) in the left atrium (LA) has attracted attention as an arrhythmia substrate of atrial fibrillation (AF). However, the occurrence mechanism of SCZ remains unclear. Hypothesis: The SCZ is related to the low voltage area (LVA) or the LA anatomical contact areas (CoAs) with other organs in patients with AF. Methods: We studied 100 patients (49 non-paroxysmal AF, 66 males, 67.9 ± 9.9 years) who received catheter ablation for AF. High-density LA mapping during right atrial appendage pacing at a rate of 100 bpm after pulmonary vein isolation were constructed. Isochronal activation maps were created at 5-ms interval setting, and the SCZ was identified on the activation map by finding a site with isochronal crowding of ≥3 isochrones, which are calculated as ≤27 cm/s (Figure). The LVA was defined as the following; mild (<1.3 mV), moderate (<1.0 mV), and severe LVA (<0.5 mV). The CoAs (ascending aorta-anterior LA, descending aorta-posterior LA, and vertebrae-posterior LA) were assessed using computed tomography. Results: The SCZ was distributed linearly (Figure), and observed in 95 of 100 patients (95%). The SCZ was most frequently observed in the anterior wall region (77%). A longer SCZ was significantly associated with a larger LA size and a prevalence of non-PAF. The 51.2±36.2% of SCZ overlapped with mild LVA, 32.9±32.8% of SCZ with moderate LVA, and 14.6±22.0% of SCZ with severe LVA. In contrast, only 25.6±28.0 % of SCZ matched with the CoAs. Conclusion: The slow conduction zone reflects LA electrical remodeling and may be a precursor finding of the low voltage zone, not LA contact areas in patients with atrial fibrillation.

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10 Automated high density left atrial voltage mapping of low voltage areas in atrial fibrillation differs from sinus rhythm

10.1136/heartjnl-2021-ics.10 ◽

2021 ◽

Author(s):

J Mannion ◽

SJ Lennon ◽

J Keaney ◽

J Galvin ◽

J O’Brien ◽

...

Keyword(s):

Atrial Fibrillation ◽

Sinus Rhythm ◽

Left Atrial ◽

Low Voltage ◽

High Density ◽

Voltage Mapping

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Sinus rhythm electrocardiogram depolarization abnormalities in patients with non-ischemic cardiomyopathy as predictors of myocardial scar

EP Europace ◽

10.1093/europace/euab116.338 ◽

2021 ◽

Vol 23 (Supplement_3) ◽

Author(s):

MR Arceluz ◽

I Luiba ◽

C Tschabrunn ◽

G Supple ◽

D Frankel ◽

...

Keyword(s):

Sinus Rhythm ◽

Phase I ◽

Phase Ii ◽

Low Voltage ◽

P Value ◽

Funding Sources ◽

Arrhythmogenic Substrate ◽

High Prevalence ◽

Qrs Fragmentation ◽

Reference Cohort

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Winkelman family research fund. Background. The arrhythmogenic substrate in nonischemic cardiomyopathy (NICM) characteristically consists of fibrosis with surviving myocytes. We hypothesized that the substrate may be reflected on the 12-lead ECG as depolarization abnormalities (QRS fragmentation [QRSf] and J waves) during sinus rhythm in patients with VT. Methods. Phase I subjects included a retrospective cohort with NICM and VT referred for VT ablation between 2007 and 2020 who had detailed substrate mapping. Phase II subjects included a prospective reference cohort with NICM and No VT referred for primary prevention ICD between 2017 and 2019. All patients had supraventricular rhythm. 12-lead ECGs voltage and presence of QRSf/J waves were compared between phase I and phase II patients. Results. Forty-five (59.2%) patients had epicardial (EPI) VT circuits and EPI LV low voltage. Thirty-one (40.8%) had endocardial (ENDO) VT circuits and Endo LV low voltage. All 38 Phase II subjects had cardiac magnetic resonance imaging (cMRI) with 26 (68.4%) patients demonstrating late gadolinium enhancement (LGE). Lower voltage in the limb leads was present in Phase I (NICM/VT) [DI (0.63 ± 0.33 vs 0.87 ± 0.4, p = 0.002), DII (0.6 ± 0.27 vs 0.85 ± 0.36, p < 0.001), DIII (0.59 ± 0.35 vs 0.74 ± 0.33, p = 0.03), AVR (0.53 ± 0.24 vs 0.75 ± 0.32, p < 0.001) and AVF (0.50 ± 0.26 vs 0.70 ± 0.28, p < 0.001)] than phase II (NICM/No VT) patients. A high prevalence of QRSf was observed in patients who had indices of LV scar with abnormal bipolar map or LGE on cMRI (ENDO 74.1% vs EPI 77.7%, p = 0.71 and LGE 73% vs No LGE 41.7%, p = 0.06). QRSf were noted in order of prevalence, in the inferior leads (ENDO 67.7% vs EPI 66.6%, p = 0.92), lateral leads (ENDO 35.5% vs EPI 48.9%, p = 0.24) and anterior leads (ENDO 22.6% vs EPI 22.2%, p = 0.97). The positive predictive value of inferior, lateral or anterior ≥2 QRSf leads as a predictor of regional scar among sustained VT patients was 92%, 97% and 88%, respectively. The presence of J waves was more frequently in patients with EPI substrate vs ENDO substrate (57.7% vs 9.6%, p < 0.001), and mainly noted in lateral and inferior leads. Conclusions. In patients with NICM and VT the presence and location of LV scarring can be predicted by depolarization abnormalities on 12-lead ECG. ECG characteristics NICM VT and EPI substrate(n = 45) NICM VT and ENDO substrate(n = 31) p value NICM No VT and LGE(n = 26) NICM No VT and No LGE(n = 12) p value QRSf in 2 contiguous leads 35 (77.7%) 23 (74.1%) p = 0.71 19 (73%) 5 (41.7%) p = 0.06 QRSf in lead DII, DIII, AVF 30 (66.6%) 21 (67.7%) p = 0.92 17 (65.4%) 5 (41.7%) p = 0.16 QRSf in lead DI, AVL, V5, V6 22 (48.9%) 11 (35.5%) p = 0.24 10 (38.5%) 3 (25%) p = 0.41 QRSf in lead V1, V2, V3, V4 10 (22.2%) 7 (22.6%) p = 0.97 9 (34.6%) 2 (16.7%) p = 0.25

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