Scar identification, quantification, and characterization in complex atrial tachycardia: a path to targeted ablation?

Laţcu, Decebal Gabriel; Bun, Sok Sithikun; Casado-Arroyo, Rubén; Wedn, Ahmed Mostfa; Benaich, Fatima Azzahrae; Hasni, Karim; Enache, Bogdan; Saoudi, Nadir

doi:10.1093/europace/euy182

Cited by 14 publications

(26 citation statements)

References 55 publications

(59 reference statements)

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“…In low‐noise condition (<0.02 mV baseline noise), small local potentials (<0.05 mV) can well be identified in both unipolar and bipolar electrograms . Mapping systems and special electrodes that are available today allow acquisition of bipolar recordings with a noise level of 0.01 mV (peak‐to‐peak) …”

Section: Unipolar Recording Modementioning

confidence: 99%

Electrogram recording and analyzing techniques to optimize selection of target sites for ablation of cardiac arrhythmias

Bakker

2019

Pacing Clinical Electrophis

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The extracellular electrogram is caused by transmembrane currents that flow into extracellular space during propagation of the electrical impulse. Electrograms are usually recorded in unipolar or bipolar mode that have different characteristics, but provide complementary information. Both recording modes have specific advantages, but also suffer from disadvantages. Techniques to circumvent some of the weaknesses are reviewed. The origin of remote and fractionated deflections and their relation with electrode characteristics are discussed. Epicardial and endocardial sites of origin and breakthrough sites as well as the effect of fatty tissue on extracellular electrograms are presented. Induction of tachycardia to assess the arrhythmogenic area is not always possible because of hemodynamic instability of the patient. Techniques to assess sites with high reentry vulnerability without induction of arrhythmias are outlined such as activation‐repolarization mapping and decremental stimulation. Pitfalls of substrate mapping and techniques to avoid them as omnipolar mapping and characterization of complex electrograms by entropy are presented. Technical aspects that influence electrogram morphology as electrode size, filtering, contact force, and catheter position are delineated. Data from the various publications suggest that a combination of unipolar and bipolar electrogram analysis techniques is helpful to optimize determination of target sites for ablation.

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Section: Unipolar Recording Modementioning

confidence: 99%

Electrogram recording and analyzing techniques to optimize selection of target sites for ablation of cardiac arrhythmias

Bakker

2019

Pacing Clinical Electrophis

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“…Iatrogenic scars and lesions on LAAW provide a potential substrate for atrial tachycardia (AT). The mechanism of scar-related ATs is usually complicated due to the non-uniformity of scars and the versatility of activation [ 6 , 7 ]. With the guidance of a high-density mapping system, we investigated the electrophysiological characteristics and ablation strategy of scar-related LAAW reentrant AT in patients after LAAW.…”

Section: Introductionmentioning

confidence: 99%

Left Atrial Anterior Wall Scar-Related Atrial Tachycardia in Patients after Catheter Ablation or Cardiac Surgery: Electrophysiological Characteristics and Ablation Strategy

Wang

Chen

et al. 2022

JCDD

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Background: The mechanisms of atrial tachycardia (AT) related to the left atrial anterior wall (LAAW) are complex and can be challenging to map in patients after catheter ablation for atrial fibrillation (AF) or cardiac surgery. We aimed to investigate the electrophysiological characteristics AT and to devise an ablation strategy. Methods and Results: We identified 31 scar-related LAAW reentrant ATs in 22 patients after catheter ablation for AF or cardiac surgery. Activation maps of the left atrium (LA) or both atria were obtained using a high-density mapping system, and the precise mechanism and critical area for each AT were analyzed. Patients were followed up regularly in a clinic. After analyzing the activation and propagation of each AT, the scar-related LAAW ATs were classified into three types, based on mechanisms related to: (1) LAAW conduction gap(s) in 19 LA macro-reentrant ATs; (2) LAAW epicardial connection(s) in 11 LA or bi-atrial ATs; and (3) LAAW local micro-reentry in 1 LAAW AT. Multiple ATs were identified in seven patients. Effective ablation (termination or circuit change of AT) was obtained in 30 ATs by targeting the critical area identified by the mapping system. During 16.0 ± 7.6 months follow-up, recurrent AT occurred in two patients. Conclusions: Three mechanisms of scar-related AT of LAAW were identified, most of which were related to LAAW conduction gaps. Notably, epicardial AT or bi-atrial AT comprised a nonnegligible proportion. A high-density mapping system could make it possible to determine the accurate mechanism of AT and serve as a guide following ablation.

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“…6 While characterization of a heterogeneous ventricular scar is easier compared to an atrial scar, modification of the scar is easier in atrium in AT with single circuit. 9 The group proposed a patient-specific scarthresholding process to better understand substrate for scar-related AT. Where, after map completion, dense scar thresholding was performed in each case wherever necessary.…”

Section: Discussionmentioning

confidence: 99%

“…A recent review article discussed scar‐related AT and incorporated atrial substrate data from HD voltage map into the activation map, in AT with single circuit 9 . The group proposed a patient‐specific scar‐thresholding process to better understand substrate for scar‐related AT.…”

Section: Discussionmentioning

confidence: 99%

“…This has previously been a barrier toward delineation of scars versus low voltage but healthy areas. The advancement of high‐density (HD) mapping catheters and multipolar catheters has essentially overcome this barrier, allowing for creation of very detailed substrate maps 6–9 . In addition, the spatial resolution of these multipolar catheters is also significantly improved, allowing for identification of channels within the scars that could be potential substrate for reentry circuits 6 …”

Section: Introductionmentioning

confidence: 99%

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Dynamic voltage threshold adjusted substrate modification technique for complex atypical atrial flutters with varying circuits

Methachittiphan

Akoum

Gopinathannair

et al. 2020

Pacing Clinical Electrophis

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Background: Atypical atrial flutter (AFL) is common in patients with postsurgical atrial scar, with macro-or microscopic channels in the scar acting as substrate for reentry. Heterogeneous atrial scarring can cause varying flutter circuits, which makes mapping and ablation challenging, and recurrences common. Aim: We hypothesize that dynamically adjusting voltage thresholds can identify heterogeneous atrial scarring, which can then be effectively homogenized to eliminate atypical AFLs. Methods: We studied consecutive patients who presented to Electrophysiology laboratory for atypical AFL ablation with history of atriotomy and included the patients with multiple, varying flutter circuits during mapping in our study. We excluded patients with stable flutter circuit that was sustained and could be localized using traditional entrainment and activation mapping strategy. In the included patients, we performed detailed high-density voltage map of the atrium of interest. We adjusted voltage thresholds as needed to identify heterogeneity and channels in the scarred regions. A thorough scar homogenization was performed with irrigated smart-touch ablation catheter. Re-inducibility of tachycardia, and immediate and long-term outcomes were studied. Results: Of five studied cases, one was female; age 66 ± 10 years. All five had prior surgical substrate. All the patients had multiple flutter morphologies, which varied as we mapped the AFL. After scar homogenization, tachycardia was not inducible in any patient. No recurrence of flutter was noted during a mean follow-up duration of 450 ± 27 days. Conclusion: High-density voltage mapping and homogenization of the scar can be an effective strategy in eliminating complex scar-mediated atypical AFL with multiple circuits.

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Scar identification, quantification, and characterization in complex atrial tachycardia: a path to targeted ablation?

Cited by 14 publications

References 55 publications

Electrogram recording and analyzing techniques to optimize selection of target sites for ablation of cardiac arrhythmias

Electrogram recording and analyzing techniques to optimize selection of target sites for ablation of cardiac arrhythmias

Left Atrial Anterior Wall Scar-Related Atrial Tachycardia in Patients after Catheter Ablation or Cardiac Surgery: Electrophysiological Characteristics and Ablation Strategy

Dynamic voltage threshold adjusted substrate modification technique for complex atypical atrial flutters with varying circuits

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