scholarly journals Low-Voltage Zones as the Atrial Fibrillation Substrates: Relationship With Initiation, Perpetuation, and Termination

2021 ◽  
Vol 8 ◽  
Author(s):  
Zheng Liu ◽  
Yu Xia ◽  
Changyan Guo ◽  
Xiaofeng Li ◽  
Pihua Fang ◽  
...  

Background: Low-voltage zones (LVZs) were usually targeted for ablation in atrial fibrillation (AF). However, its relationship with AF initiation, perpetuation, and termination remains to be studied. This study aimed to explore such relationships.Methods: A total of 126 consecutive AF patients were enrolled, including 71 patients for AF induction protocol and 55 patients for AF termination protocol. Inducible and sustainable AF were defined as induced AF lasting over 30 and 300 s, respectively. Terminable AF was defined as those that could be terminated into sinus rhythm within 1 h after ibutilide administration. Voltage mapping was performed in sinus rhythm for all patients. LVZ was quantified as the percentage of the LVZ area (LVZ%) to the left atrium surface area.Results: The rates of inducible, sustainable, and terminable AF were 29.6, 18.3, and 38.2%, respectively. Inducible AF patients had no significant difference in overall LVZ% compared with uninducible AF patients (10.2 ± 11.8 vs. 8.5 ± 12.6, p = 0.606), while sustainable and interminable AF patients had larger overall LVZ% than unsustainable (16.2 ± 11.5 vs. 0.5 ± 0.7, p < 0.001) and terminable AF patients (44.6 ± 26.4 vs. 26.3 ± 22.3, p < 0.05), respectively. The segmental LVZ distribution pattern was diverse in the different stages of AF. Segmental LVZ% difference was initially observed in the anterior wall for patients with inducible AF, and the septum was further affected in those with sustainable AF, and the roof, posterior wall, and floor were finally affected in those with interminable AF.Conclusions: The associations between LVZ with AF initiation, perpetuation, and termination were different depending on its size and distribution.

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Carola Gianni ◽  
Jerri A Cunningham ◽  
Sanghamitra Mohanty ◽  
CHINTAN TRIVEDI ◽  
Domenico G Della Rocca ◽  
...  

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.


EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
D Nairn ◽  
C Nagel ◽  
B Mueller-Edenborn ◽  
H Lehrmann ◽  
A Jadidi ◽  
...  

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG) through DO637/22-3 Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg through the Research Seed Capital (RiSC) program. Introduction Presence of left atrial (LA) fibrotic low voltage substrate (LVS) is associated with high risk for arrhythmia recurrences in patients undergoing pulmonary vein isolation (PVI) for atrial fibrillation (AF). PVI and additional ablation of LVS - as identified by mapping in sinus rhythm (SR) or AF - has been reported to improve SR maintenance rates, despite differences of the extent and distribution of LA-LVS in SR versus AF.  Aims To study the relationship between SR and AF voltage maps, we sought to identify the optimal AF voltage threshold providing the highest concordance in the extent and distribution of LVS when comparing voltage maps in SR vs. AF. Methods Using the statistical shape modelling software Scalismo, the voltage information from the SR and AF maps (acquired prior to PVI) from 28 patients (66 ± 7 years, 46% male, 82% persistent AF) was projected onto a representative LA-geometry. Sensitivity and specificity of LVS identification were calculated for varying thresholds during AF and the correlation between the SR (threshold 0.5mV) and AF maps was assessed and areas of agreeing LVS classification (SR & AF) were identified for each patient. The data of all 28 patients were combined to a spatial histogram of agreement between SR and AF low voltage maps. Results  The correlation between SR and AF maps was high across all patients, with agreement at 60-95% of all mapped sites (Figure A: each red triangle represents one patient and the respective agreement of LVS classification and substrate extent).  The optimal AF threshold - to identify LA-LVS &lt;0.5 mV in SR - was 0.29 mV (Q1-3: 0.20-0.37 mV) and was independent of the underlying extent of LVS during SR (Figure A: each blue asterisk represents one patient and the corresponding AF threshold and substrate extent). Agreement between LVS in AF vs. SR was high across most (&gt;90) patients on the anterior LA, lateral LA and the left atrial appendage. Lower agreement (60% of patients) was observed in the posterior wall (Figure B). Conclusions SR and AF voltage maps reveal high spatial concordance in low voltage substrate at the anterior LA, lateral LA and LA appendage, however significant discordances in LVS are found in 40% of patients at the posterior LA. Further studies on an extended patient cohort should assess if regional voltage-thresholds would result in an improved substrate concordance between AF and SR substrate maps. Abstract Figure.


2011 ◽  
Vol 27 (Supplement) ◽  
pp. PE4_040
Author(s):  
Higashi Yukei ◽  
Hisa Shimojima ◽  
Daisuke Wakatsuki ◽  
Sayaka Yamaya ◽  
Tokutada Sato ◽  
...  

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260834
Author(s):  
Hao-Tien Liu ◽  
Chia-Hung Yang ◽  
Hui-Ling Lee ◽  
Po-Cheng Chang ◽  
Hung-Ta Wo ◽  
...  

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.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Hideyuki Kishima ◽  
Takanao Mine ◽  
Ryo Kitagaki ◽  
Eiji Fukuhara ◽  
Masaharu Ishihara

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.


EP Europace ◽  
2020 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
A Lepillier ◽  
X Copie ◽  
W Escande ◽  
M Niro ◽  
O Paziaud ◽  
...  

Abstract .  Background: Dedicated ablation strategies for persistent atrial fibrillation (AF) have shown a limited success rate with frequent atrial tachycardia (AT) occurrence. Recent studies suggest that atrial arrhythmogenic sites are related to tissular heterogeneities and increased fibrosis can be identified as reduced bipolar voltage areas. . Purpose: Targeting low voltage areas (LVA) in addition to PVI may represent an efficient strategy for the ablation of persistent AF, and may limit the risk of AT recurrence. . Methods: We prospectively included consecutive patients with symptomatic persistent AF. The ablation strategy consisted of the following steps: circumferential pulmonary vein isolation (CPVI), Sinus rhythm restoration by electrical cardioversion, voltage map performed in sinus rhythm. Complementary RFA was guided by low voltage areas (0.2-0.4 mV). Success was defined as freedom from AF/ atrial flutter or atrial arrhythmia at 12 months or more. . Results:  101 patients (mean age: 62.5 +/- 10.4 years, men 73%) were included with persistent AF or long standing AF (7%). Procedure time was: 154 ± 25 min and fluoroscopy time: 184 ± 90 sec. Time of RFA was 44.7 +/- 12 min. Mean LA volume was 182 +/- 38 mL. LVA were found in 50 patients (49.5%). The distribution of these areas was:  30 anterior wall 29.7%), 21 septum (20.7%), 19 roof (18.8%), 5 inferior (4.9%), 11 left appendage (10.8%), 6 posterior (5.9%), 3 mitral isthmus (3%). RF ablation was realized for all LVA and homogenisation was attempt. After a single procedure at a mean FU of 12 months, 72.3% of patients were free of symptomatic AF. 27 patients had recurrence of atrial AF: 7 permanent, 15 persistent and 5 paroxysmal AF. Predictive factors of recurrence of AF were: long standing persistent AF, large left atrial volume (&gt; 205 mL), shorts AF cycle length (&lt; 168 ms) and reduce LEVF (&lt; 45%). Atrial tachycardia occurred in 5 patients (4,9%). Mechanisms of AT were: typical cavo-tricuspid flutter in one patient, peri-mitral flutter in 2 patients, and atrial focal tachycardia (close to pulmonary veins) in 2 patients. . Conclusion: These results suggest that PVI with complementary RF ablation guided on low voltage areas is an efficient strategy for symptomatic persistent AF, and reduce the recurrence of AT following this ablation strategy.


2002 ◽  
Vol 283 (3) ◽  
pp. H1244-H1252 ◽  
Author(s):  
Shengmei Zhou ◽  
Che-Ming Chang ◽  
Tsu-Juey Wu ◽  
Yasushi Miyauchi ◽  
Yuji Okuyama ◽  
...  

Repetitive rapid activities are present in the pulmonary veins (PVs) in dogs with pacing-induced sustained atrial fibrillation (AF). The mechanisms are unclear. We induced sustained (>48 h) AF by rapidly pacing the left atrium (LA) in six dogs. High-density computerized mapping was done in the PVs and atria. Results show repetitive focal activations in all dogs and in 12 of 18 mapped PVs. Activation originated from the middle of the PV and then propagated to the LA and distal PV with conduction blocks. The right atrium (RA) was usually activated by a single large wavefront. Mean AF cycle length in the PVs (left superior, 82 ± 6 ms; left inferior, 83 ± 6 ms; right inferior, 83 ± 4 ms) and LA posterior wall (87 ± 5 ms) were significantly ( P < 0.05) shorter than those in the LA anterior wall (92 ± 4 ms) and RA (107 ± 5 ms). PVs in normal dogs did not have focal activations during induced AF. No reentrant wavefronts were demonstrated in the PVs. We conclude that nonreentrant focal activations are present in the PVs in a canine model of pacing-induced sustained AF.


Author(s):  
B Radha ◽  
S A Sayganov ◽  
T Y Gromiko

Objective: To elucidate the mechanism of atrial fibrillation and evaluate left atrium function after restoration of sinus rhythm in patients with acute posterior wall myocardial infarction ( MI). Materials and Methods: The study included 53 patients with posterior wall MI.All patients were divided into 2 groups. The first group consisted of 33 a people with paroxysms of atrial fibrillation (AF), and the second included 20 control subjects without arrhythmia. All percutaneous intervention was performed within the first 24 hours. Patients were evaluated for time and duration of paroxysms, the size of the heart chambers and the recovery time of the left atrium (LA)function. Results: Patients with posterior wall myocardial infarction developed AF in the early stages of the disease (in 91% on the first day), with short duration of paroxysms, stopped spontaneously and often within 1 hour (in 11 people). There were no significant differences in the size of the heart chambers, left ventricular contractility and hemodynamic disturbances in patients of both groups. AF in most cases developed in patients without left ventricular failure (in 27 people; 82%). Wherein the proximal right coronary artery occlusion was observed more frequently in patients with atrial fibrillation, than in the control group (17 vs 2; p <0,001). Approximately half patients(16 ) with AF before the appearance of atrial fibrillation bradysystolya of atria (less than 50 in 1 min) was recorded, due to acute sinus node dysfunction. After the reversion of sinus rhythm mechanical function of the LA was absent in only 4 people with left ventricular failure. Effective systole of LA was restored only 7 days after reversion to sinus rhythm. The rare occurrence of mechanical dysfunction after discontinuation of arrhythmia indicates a low probability of thrombosis and embolism in the systemic circulation. Conclusion: In cases of patients with posterior wall localization of MI main causes of AF include acute ischemia of atria due to occlusion of the right coronary artery above the branches supplying atrium. Atrial bradysystolya due to acute sinus node dysfunction often contributes to the development of AF as a substitute atrial rate (acute syndrome of tachy-bradycardia). In case of patients with posterior wall MI AF episodes were rarely accompanied by hemodynamic disturbances and the risk of systemic thromboembolism after reversion to sinus rhythm was low.


2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
P Adragao ◽  
D Nascimento Matos ◽  
F Costa ◽  
P Galvao Santos ◽  
G Rodrigues ◽  
...  

Abstract Introduction Twenty years ago, pulmonary veins (PV) ostia were identified as the left atrium (LA) areas with the shortest refractory period during sinus rhythm. Pulmonary veins isolation (PVI) became standard of care, but clinical results are still suboptimal. Today, a special tool using the Carto® electroanatomical mapping (EAM) allows for AF cycle length mapping (CLM), to identify the areas in the left atria with shortest refractory period, during atrial fibrillation. Using this EAM tool, our study aimed to find the LA areas with the shortest refractory period to better recognize electrical targets for catheter ablation. Methods Retrospective analysis of an unicentric registry of individuals with symptomatic drug-refractory AF who underwent PVI with Carto® EAM. CLM was performed with a high-density mapping Pentaray® catheter before and after PVI and in 4 redo procedures. We assessed areas of short cycle length (SCL) (defined as 120 to 250ms), and their relationships with complex fractionated atrial electrograms (CFAE), and low-voltage zones (from 0.1 to 0.3mV). Results A total of 18 patients (8 men, median age 63 IQR 58–71 years) were included. Most patients presented with persistent AF (n=12, 67%), and 4 patients (22%) had a previous PVI. The mean shortest measured cycle length in AF was 140ms (SD ±27ms). All patients presented areas of SCL located in the PVs or their insertion, 70% in the posterior/roof region adjacent to the left superior pulmonary vein (LSPV) (figure 1) and 60% in the anterior region of the right superior pulmonary vein (RSPV). These two areas remained the fastest even after PVI. The anterior mitral region rarely presented SCL (17%). SCL were related to low-voltage areas in 94% and were adjacent to CFAE. Low-voltage areas and CFAE were more frequent and had a larger LA dispersion than SCL. Conclusion We confirmed in 3D mapping that PVs are the LA zones with shortest refractory period, not only in sinus rhythm but also during AF. The persistence of SCL areas in the border zones of the PVI lines suggest the benefit of a more extensive CLM guided ablation. Larger studies are needed. FUNDunding Acknowledgement Type of funding sources: None. Short cycle length mapping


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