Termination of the left atrial tachycardia by the ablation of epicardial critical isthmus visualized with a novel high-resolution mapping system

Aims The circuit of pulmonary vein-gap re-entrant atrial tachycardia (PV-gap RAT) after atrial fibrillation ablation is sometimes difficult to identify by conventional mapping. We analysed the detailed circuit and electrophysiological features of PV-gap RATs using a novel high-resolution mapping system. Methods and results This multicentre study investigated 27 (7%) PV-gap RATs in 26 patients among 378 atrial tachycardias (ATs) mapped with Rhythmia™ system in 281 patients. The tachycardia cycle length (TCL) was 258 ± 52 ms with P-wave duration of 116 ± 28 ms. Three types of PV-gap RAT circuits were identified: (A) two gaps in one pulmonary vein (PV) (unilateral circuit) (n = 17); (B) two gaps in the ipsilateral superior and inferior PVs (unilateral circuit) (n = 6); and (C) two gaps in one PV with a large circuit around contralateral PVs (bilateral circuit) (n = 4). Rhythmia™ mapping demonstrated two distinctive entrance and exit gaps of 7.6 ± 2.5 and 7.9 ± 4.1 mm in width, respectively, the local signals of which showed slow conduction (0.14 ± 0.18 and 0.11 ± 0.10m/s) with fragmentation (duration 86 ± 27 and 78 ± 23 ms) and low-voltage (0.17 ± 0.13 and 0.17 ± 0.21 mV). Twenty-two ATs were terminated (mechanical bump in one) and five were changed by the first radiofrequency application at the entrance or exit gap. Moreover, the conduction time inside the PVs (entrance-to-exit) was 138 ± 60 ms (54 ± 22% of TCL); in all cases, this resulted in demonstrating P-wave with an isoelectric line in all leads. Conclusion This is the first report to demonstrate the detailed mechanisms of PV-gap re-entry that showed evident entrance and exit gaps using a high-resolution mapping system. The circuits were variable and Rhythmia™-guided ablation targeting the PV-gap can be curative.

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P6565The relation between the variation of CL and atrial tachycardia

European Heart Journal ◽

10.1093/eurheartj/ehz746.1155 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

M T Takigawa ◽

C A Andre ◽

A L Lam ◽

W E Escande ◽

Y N Nakatani ◽

...

Keyword(s):

High Resolution ◽

Coronary Sinus ◽

Cycle Length ◽

Atrial Tachycardia ◽

Correct Diagnosis ◽

High Resolution Mapping ◽

Mapping System ◽

Resolution Mapping ◽

The Right ◽

The Relationship

Abstract Background Complex ATs with a complicated circuit have been increasing because of the native or iatrogenic scars in atrium. However, development of resolution in the EAM allows us to reach the correct diagnosis. The purpose of this study was to reassess the relationship between characteristics of ATs and cycle length based on the correct diagnosis with high-resolution mapping system. Method Among 85 consecutive AT patients treated with with high-resolution mapping system “Rhythmia”, patients with at least one mappable AT during procedure were prospectively included in this study. Maximal, minimal, and variation of ATCL was calculated from the decapolar in the coronary sinus (CS) during 2minutes, and the relation between CL and respiration was measured on the Rhythmia (Figure 1). These values were compared to AT types. Results 90 ATs in 65 patients (mean 59±13 yrs, 16 females, 55 post-AF ATs) including 4 focal-ATs, 23 localized-AT, and 63 macroreentrant ATs were analyzed. As shown in the table 1, the maximum and minimum CL was similar between focal-AT, localized-AT, and, macroreentrant-AT. However, both absolute CL-variation and ratio of CL-variation were significantly smaller in macroreentrant ATs (P=0.009 and P=0.0012, respectively). Table 2 described the comparison between 66 left-ATs and 24 right-ATs. Although the maximum and minimum CL were similar, both absolute CL-variation and ratio of CL-variation were significantly larger in right ATs (P=0.001 and P=0.007, respectively). Additionally, the correlation of CL to the respiration was significantly more frequently seen in the right-ATs (3.0% in left-ATs and 62.5% in right-ATs, P<0.0001). Table 1, 2 and Figure 1 Conclusions CL-variation of ATs may be significantly smaller in macroreentrant ATs and significantly larger in right ATs. CL-variation correlated to the respiration may suggest right-ATs. These information may be helpful to diagnose ATs before mapping.

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