Directional Influences of Ventricular Activation on Myocardial Scar Characterization

Tung, Roderick; Josephson, Mark E.; Bradfield, Jason S.; Shivkumar, Kalyanam

doi:10.1161/circep.116.004155

Cited by 94 publications

(17 citation statements)

References 20 publications

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“…Such regional dispersion of LA voltage could be explained by preferential fibrosis of LA regions consequent on the occurrence of AF. However, although histological and imaging studies have identified regional variation in fibrotic remodeling in the left atrium — for example, showing greatest fibrosis in the posterior wall (27) — bipole voltage is also affected by a number of other factors including orientation of the recording bipolar to the activation wave, rhythm during mapping, and activation direction–dependent wave collision 28 , 29 . Overall, these observations suggest that bipolar voltage mapping alone may be insufficient to define the electrical substrate for AF and may therefore be an imperfect target for ablation strategies beyond pulmonary vein isolation alone.…”

Section: Discussionmentioning

confidence: 99%

Intra-Atrial Conduction Delay Revealed by Multisite Incremental Atrial Pacing is an Independent Marker of Remodeling in Human Atrial Fibrillation

Williams

Linton

Harrison

et al. 2017

JACC: Clinical Electrophysiology

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ObjectivesThis study sought to characterize direction-dependent and coupling interval–dependent changes in left atrial conduction and electrogram morphology in uniformly classified patients with paroxysmal atrial fibrillation (AF) and normal bipolar voltage mapping.BackgroundAlthough AF classifications are based on arrhythmia duration, the clinical course, and treatment response vary between patients within these groups. Electrophysiological mechanisms responsible for this variability are incompletely described.MethodsIntracardiac contact mapping during incremental atrial pacing was used to characterize atrial conduction, activation dispersion, and electrogram morphology in 15 consecutive paroxysmal AF patients undergoing first-time pulmonary vein isolation. Outcome measures were vulnerability to AF induction at electrophysiology study and 2-year follow-up for arrhythmia recurrence.ResultsConduction delay showed a bimodal distribution, occurring at either long (high right atrium pacing: 326 ± 13 ms; coronary sinus pacing: 319 ± 16 ms) or short (high right atrium pacing: 275 ± 11 ms; coronary sinus pacing: 271 ± 11 ms) extrastimulus coupling intervals. Arrhythmia recurrence was found only in patients with conduction delay at long extrastimulus coupling intervals, and patients with inducible AF were characterized by increased activation dispersion (activation dispersion time: 168 ± 29 ms vs. 136 ± 11 ms). Electrogram voltage and duration varied throughout the left atrium, between patients, and with pacing site but were not correlated with AF vulnerability or arrhythmia recurrence.ConclusionsWithin the single clinical entity of paroxysmal AF, incremental atrial pacing identified a spectrum of activation patterns correlating with AF vulnerability and arrhythmia recurrence. In contrast, electrogram morphology (characterized by electrogram voltage and duration) was highly variable and not associated with AF vulnerability or recurrence. An improved understanding of the electrical phenotype in AF could lead to improved mechanistic classifications.

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Section: Discussionmentioning

confidence: 99%

Intra-Atrial Conduction Delay Revealed by Multisite Incremental Atrial Pacing is an Independent Marker of Remodeling in Human Atrial Fibrillation

Williams

Linton

Harrison

et al. 2017

JACC: Clinical Electrophysiology

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“…12 Depending on the spline orientation or different conduction (sinus rhythm or pacing manoeuvres), different BVs (variation around 30%) are measured, and a significant percentage of around 30% of LAVA are recorded or masked. 7,[21][22][23] These variations are most often present in the scar border zone (mixed scar tissue) and with orthogonal bipole activation. This limitation may theoretically be overcome using omnipole mapping or maximal bipolar amplitude mapping (HD wave) with the HD Grid catheter, or by concomitant use of imaging-derived substrate information.…”

Section: Bipole Orientationmentioning

confidence: 99%

“…Fractal surface modification of the electrodes is sometimes used to obtain a small geometric footprint to minimise artefact interaction with multiple wavefronts. However, these fractals have 7 Examples of differences in field of view are given in Figure 5.…”

Section: Difference In Signal-to-noise Ratiomentioning

confidence: 99%

Impact of Micro-, Mini- and Multi-Electrode Mapping on Ventricular Substrate Characterisation

Berte

Zeppenfeld

Tung

2020

Arrhythm Electrophysiol Rev

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Accurate substrate characterisation may improve the evolving understanding and treatment of cardiac arrhythmias. During substrate-based ablation techniques, wide practice variations exist with mapping via dedicated multi-electrode catheter or conventional ablation catheters. Recently, newer ablation catheter technology with embedded mapping electrodes have been introduced. This article focuses on the general misconceptions of voltage mapping and more specific differences in unipolar and bipolar signal morphology, field of view, signal-to-noise ratio, mapping capabilities (density and resolution), catheter-specific voltage thresholds and impact of micro-, mini- and multi-electrodes for substrate mapping. Efficiency and cost-effectiveness of different catheter types are discussed. Increasing sampling density with smaller electrodes allows for higher resolution with a greater likelihood to record near-field electrical information. These advances may help to further improve our mechanistic understanding of the correlation between substrate and ventricular tachycardia, as well as macro-reentry arrhythmia in humans.

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“…[21] Mapping in a rhythm with a cycle length and activation wavefront orientations which differ to the clinical VTs may not identify regions of functional block that are critical to the VT isthmus. [26,27] Furthermore, not all LAVA and late potentials lie in critical parts of the VT circuit. Complete substrate elimination, while currently the strategy with the best supporting evidence, may not be entirely necessary for the elimination of all VTs.…”

Section: Implications For Substrate Mappingmentioning

confidence: 99%

“…Strategies to demarcate such zones are needed, but approaches which use pacing from multiple sites and/or different cycle lengths have been shown to improve detection of poorly coupled fibres and are likely to be useful. [27] Evidence to support ablation of a targeted subset of LAVA with dynamic poor coupling comes from studies using close-coupled extra-stimuli to identify dynamic increases in EGM duration and latency. Although small, these studies have demonstrated a high rate of non-inducibility and low rate of VT recurrence with a targeted approach.…”

Section: Implications For Substrate Mappingmentioning

confidence: 99%

Ventricular Tachycardia Isthmus Characteristics: Insights from High-density Mapping

Martin

Hocini

Haïsaguerre

et al. 2019

Arrhythm Electrophysiol Rev

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In the context of structural heart disease, ventricular tachycardia (VT) is related to surviving fibres in incomplete scar. New technologies which allow electroanatomic mapping at higher density and with smaller, more closely spaced electrodes have allowed new insights into the characteristics of VT circuits. VT isthmuses are complex structures, with multiple entrances, exits and dead ends of activation. The isthmus is frequently defined by regions of functional block and several VT circuits can be possible in a VT “critical zone”. In this review, we discuss these new insights and how they may improve VT ablation strategies, as well as discussing emerging technologies which may further develop our understanding.

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Directional Influences of Ventricular Activation on Myocardial Scar Characterization

Cited by 94 publications

References 20 publications

Intra-Atrial Conduction Delay Revealed by Multisite Incremental Atrial Pacing is an Independent Marker of Remodeling in Human Atrial Fibrillation

Intra-Atrial Conduction Delay Revealed by Multisite Incremental Atrial Pacing is an Independent Marker of Remodeling in Human Atrial Fibrillation

Impact of Micro-, Mini- and Multi-Electrode Mapping on Ventricular Substrate Characterisation

Ventricular Tachycardia Isthmus Characteristics: Insights from High-density Mapping

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