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

Abstract

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

Noninvasive assessment of durability of ablation lesions with magnetic resonance imaging: Are we there yet?

“…Finally, the definition of the visual gap on MRI used in this study, a non‐LGE site larger than 4 mm, almost certainly overestimated the number of true gaps. For instance, the authors observed at least one visual gap in each of the 16 segments around the PVs in more than 10% CB patients; this is at odds with data obtained with ultrahigh‐density mapping, 9 and also with the good clinical outcomes reported here. Future research should look at correlating these MRI‐visualized gaps with actual gaps seen on repeat electrophysiological study so that the clinical significance of these can be better defined.…”

“…RFCA and cryoballoon ablation (CBA) are by far the most common modalities used for PVI, and there is remarkable equivalence in their clinical results 8 . However, the handling of the two technologies in the catheter laboratory is very different, and ultrahigh‐density mapping has shown important differences in the number and location of chronic gaps between the two 9 . The use of MRI in characterizing these differences has not been well‐described so far.…”

Pulsed‐field ablation combined with ultrahigh‐density mapping in patients undergoing catheter ablation for atrial fibrillation: Practical and electrophysiological considerations

“…5,17,18 However, the inferior aspect of the right inferior PV seems a sweet spot for reconnection after cryoballoon PVI 5 and left-sided PVs were more frequently reconnected after contact-force RF during UHDx mapping. 5 Up to now, the current findings suggest that rare conduction gaps after PFA have only been reported on superior PVs.…”

Left Atrial Fibrosis after Single Shot Guided Pulmonary Vein Isolation

“…The clinical impact of these observations of collaterally ablated parts of the LA needs to be analyzed in a larger patient population, especially the question of whether these lesions lead to iatrogenic atrial tachycardias. It has been recently reported by Gunarwardene et al that patients may present with atrial tachycardias after CB ablation due to residual fractionated signals along the previous cryothermal lesions [ 20 ].…”

“…that patients may present with atrial tachycardias after CB ablation due to residual fractionated signals along the previous cryothermal lesions [20].…”