High-Density Mapping and Ablation of Primary Nonfocal Left Atrial Tachycardia

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Introduction:The aim of this study was to investigate electrophysiological findings in patients with arrhythmia recurrence undergoing a repeat ablation procedure using ultra-high-density (UHDx) mapping following an index procedure using either contact-force (CF)-guided radiofrequency current (RFC) pulmonary vein isolation (PVI) or second-generation cryoballoon (CB) PVI for treatment of atrial fibrillation (AF). Methods and Results: Fifty consecutive patients with recurrence of AF and/or atrial tachycardia (AT) following index CF-RFC PVI (n = 21) or CB PVI (n = 29) were included. A 64-pole mini-basket mapping catheter in combination with an UHDxmapping system-guided ablation was used. RFC was applied using a catheter tip with three incorporated mini-electrodes. PV reconnection rates were higher after CF-RFC PVI (CF-RFC: 2.5 ± 1.3 PVs vs CB: 1.4 ± 0.9 PVs; P = .0025) and left PVs were more frequently reconnected (CF-RFC: 64% PVs vs CB: 35% PVs; P = .0077).Fractionated signals along the antral index ablation line (FS) were found in 30% of CB-PVI patients (CF-RFC: 9.5% vs CB:30%; P = .098) targeted for ablation. In five cases, FS were a critical part of maintaining consecutive AT. The main AT mechanism found during reablation (n = 45 ATs) was macroreentry (80% [36/45], CF-RFC: 78.9% vs CB: 80.8%; P = 1.0) with a variety of circuits throughout both atria.Conclusion: UHDx mapping is sensitive in detecting conduction gaps along the index ablation line. Left PVs are more frequently reconnected after initial CF-RFC PVI. FS are a common finding after CB PVI and can maintain certain forms of ATs. ATs after index PVI are mostly macroreentries with a broad spectrum of entities. K E Y W O R D Satrial fibrillation, contact-force radiofrequency catheter ablation, cryoballoon ablation, pulmonary vein isolation, ultra-high-density mapping

Section: Discussionmentioning

confidence: 99%

Ultra–high‐density mapping of conduction gaps and atrial tachycardias: Distinctive patterns following pulmonary vein isolation with cryoballoon or contact–force‐guided radiofrequency current

Gunawardene

Akbulak

Jularic

et al. 2020

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“…Mapping and catheter ablation was performed as described previously using conscious sedation 14,15,18 . In brief, a steerable 6‐F decapolar diagnostic catheter (Inquiry™, 2–5–2 mm spacing, St. Jude Medical, St. Paul, MN, USA; or Dynamic DECA, Bard Electrophysiology; Boston Scientific, Marlborough, MA, USA) was placed in the coronary sinus as a reference.…”

Section: Methodsmentioning

confidence: 99%

“…A learning curve and accumulating evidence regarding AT mechanisms within the last 4 years might have impacted procedural outcomes over time. 14,18 Outcome might also be improved by a new analysis algorithm (e.g., Lumipoint), which has been used since October 2018. This software tool helps to identify areas of interest, for example, by visualizing how much tissue is activated at a certain time point, which has been found to additionally facilitate the critical isthmus detection.…”

Section: Limitationsmentioning

confidence: 99%

Outcome after tailored catheter ablation of atrial tachycardia using ultra‐high‐density mapping

Jungen

Akbulak

Kahle³

et al. 2020

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Introduction: Tailored catheter ablation of atrial tachycardias (ATs) is increasingly recommended as a potentially easy treatment strategy in the era of high-density mapping (HDM). As follow-up data are sparse, we here report outcomes after HDMguided ablation of ATs in patients with prior catheter ablation or cardiac surgery. Methods and Results: In 250 consecutive patients (age 66.5 ± 0.7 years, 58% male) with ATs (98% prior catheter ablation, 13% prior cardiac surgery) an HDM-guided catheter ablation was performed with the support of a 64-electrode mini-basket catheter. A total of 354 ATs (1.4 ± 0.1 ATs per patient; mean cycle length 304 ± 4.3 ms; 64% macroreentry, 27% localized reentry, and 9% focal) with acute termination of 95% were targeted in the index procedure. A similar AT as in the index procedure recurred in five patients (2%) after a median follow-up time of 535 days (interquartile range (IQR) 25th-75th percentile: 217-841). Tailored ablation of reentry ATs with freedom from any arrhythmia was obtained in 53% after a single procedure and in 73% after 1.4 ± 0.4 ablation procedures (range: 1-4). A total of 228 patients (91%) were free from any arrhythmia recurrence after 210 days (IQR: 152-494) when including optimal usual care. Conclusions: Tailored catheter ablation of ATs guided by HDM has a high acute success rate. The recurrence rate of the index AT is low. In patients with extensive atrial scaring further ablation procedures need to be considered to achieve freedom from any arrhythmia.

“…In this cohort, there was a tendency for focal ATs to arise from areas of low voltage. In contrast, another recent report presented high‐density mapping of 15 ATs from the LA in patients who had no prior interventions . Most of these primary ATs were macroreentry, and many were located in the anterior LA.…”

Section: Underlying Substrate For Left Atrial Tachycardiasmentioning

confidence: 98%

“…In contrast, another recent report presented high-density mapping of 15 ATs from the LA in patients who had no prior interventions. 20 Most of these primary ATs were macroreentry, and many were located in the anterior LA. There was a high proportion of low voltage areas in the anterior LA, which formed a corridor of slow conduction between the scar and the mitral annulus.…”

Section: Localized Reentry Can Occur In Various Regions In the La Butmentioning

confidence: 99%

Approach to catheter ablation of left atrial flutters

Markowitz

Thomas

Liu

et al. 2019

Left atrial tachycardias (ATs) most commonly occur after catheter or surgical ablation of atrial fibrillation and in patients with atrial myopathies. Pre‐existing scar in the left atrium (LA) can result in complex circuits, sometimes with narrow channels that can be detected with high‐resolution mapping. The most common forms of macroreentrant AT from the LA are variants of peri‐mitral and roof‐dependent reentry. Localized reentrant rhythms occur in the setting of fibrosis that gives rise to slow conduction and may occur adjacent to areas of prior ablation. The approach to treating these ATs involves first identifying the left atrial origin, defining the tachycardia circuit – which can be facilitated by ultrahigh density mapping and entrainment – and selecting a suitable isthmus to target for ablation. An important endpoint in ablating left atrial flutters is to establish and confirm bidirectional line of the block. Challenges in ablating these ATs include the presence of multiple tachycardias, defining circuits with complex activation patterns and achieving durable lines of block, particularly in the lateral mitral isthmus. Progress in treating these arrhythmias has come from new mapping technologies and the recognition of epicardial connections that allow for persistent conduction across ablation lesions. Also, advances in delivering energy to obtain complete transmural lesions promise to improve the long‐term success of ablating ATs from the LA.