ClinicalImaging/MappingInsights from atrial surface activation throughout atrial tachycardia cycle length: A new mapping tool
Graphical abstract
Introduction
Atrial tachycardia (AT) is frequently observed in the context of atrial fibrillation (AF) ablation, due to both substrate and ablation scars.1, 2, 3 Demonstrating the entire AT circuit with entrainment mapping alone may be challenging4 Improvement in mapping systems and catheters now allows mapping with sufficient resolution to demonstrate the precise activation sequence of these complex ATs,5, 6, 7, 8 However, mapping systems still struggle with complex electrograms (EGMs), and this may impact activation maps.9 LUMIPOINT is a novel set of software features in the Rhythmia mapping system (Boston Scientific, Marlborough, MA) centered around an algorithm that detects all activations present in every EGM irrespective of local activation time.10 The activated atrial surface area in a given time-of-interest period through the entire cycle length (CL) may be shown. In addition, SKYLINE is a tool that displays a full chamber activation in an intuitive 2-dimensional trace with the histogram of the atrial surface activation throughout the AT CL. Peaks in the histogram are seen when a large part of the atrium is activated, whereas valleys correspond to a smaller surface of activation. Theoretically, this valley in the histogram may correspond to the isthmus of the tachycardia circuit.
We studied whether histograms of focal ATs differ from those of reentrant ATs, and whether valleys in the histogram indicate practical ablation sites. We also systematically investigated the mechanisms corresponding to these valleys.
Section snippets
Study population
We prospectively examined 85 consecutive AT patients undergoing ablation guided by high-density mapping with the Rhythmia system in our center between November 2014 and December 2015. Of these patients, 67 who had at least 1 complete activation map during the procedure were included in the study. All patients gave written informed consent according to the institutional guidelines of the University of Bordeaux Health System with ethical approval for the study.
Electrophysiological study and mapping with Rhythmia
Antiarrhythmic medications were
Patient and AT characteristics and outcomes
The baseline characteristics of the 67 patients are listed in Table 1 and AT characteristics in Table 2. Fifty patients (74.6%) had ATs after AF ablation, with a mean of 1.6 ± 1.3 procedures. Among them, 108 ATs were mapped with the Rhythmia mapping system and diagnosed as focal AT (n = 17), macroreentrant AT (n = 57), localized reentry (n = 21), or multiple-loop reentry (n = 13). The multiple-loop reentries in this study were all dual-loop reentries. Activation maps of 14,307 ± 6917 points
Major findings
In the present study, we demonstrated the following. (1) The GAH pattern of focal ATs is typical, with a plateau (no activation) >30% of the CL with GAH-Score <0.1, allowing for instant diagnosis. (2) GAH-Valleys are due to activation of a limited surface area and mostly correspond to slow conduction. However, lines of block and wavefront collision may also be seen. (3) Approximately 80% of slow conduction areas highlighted based on GAH-Valleys occur within the AT circuits, thereby identifying
Conclusion
The LUMIPOINT GAH shows focal vs reentrant mechanisms at first glance. Decrease in atrial activation area is mostly due to slow conduction and highlights areas of special interest, with sensitivity of 100% for practical ablation sites.
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Cited by (29)
The Use of Local Activation Timing Histogram in Ablation of Focal and Re-Entrant Atrial Tachycardias
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2023, JACC: Clinical ElectrophysiologyDifferentiating atrial tachycardias with centrifugal activation: Lessons from high-resolution mapping
2021, Heart RhythmCitation Excerpt :This, however, would be different from a value of zero, which would indicate the absence of any activity between 2 consecutive activations, as expected in a focal source. We originally defined this value as “GAH score” in this study following the previous article.19 Based on the LUMIPOINT-SKYLINE as shown in Figure 2, the lowest GAH score (Figure 2A), duration of GAH score < 0.1 (Figure 2B), duration of the plateau in GAH score < 0.1 (Figure 2C) were measured and the duration of GAH score < 0.1/TCL ratio and the duration of the plateau in GAH score < 0.1/TCL ratio were calculated.
A new electrophysiologic triad for identification and localization of the critical isthmus in atrial flutter
2020, Revista Portuguesa de CardiologiaCitation Excerpt :The amount of points per bar represents the segmental activated area of the left atrium with the same LAT (1/20 TCL). We classified a valley in the LAT histogram (LAT-valley) as a section of the plot with 20% or less recorded points than the maximum LAT value (highest bar).9 To accept this section as a zone of slow conduction, it should contain at least 10% of the TCL.10
High-resolution/Density Mapping in Patients with Atrial and Ventricular Arrhythmias
2019, Cardiac Electrophysiology ClinicsCitation Excerpt :Beyond voltage mapping (discussed previously), UHD activation mapping (in AT or sinus rhythm [SR]) provides considerable help in identifying the substrate of AT (ie, incision lines [Fig. 3]) as well as for validating block across previously created ablation lines.25 Automatic detection of double potential EGM and diatolic potentials are near-future software improvements that will be available (Lumipoint embedded in Rhythmia [Fig. 4]).26,27 The Carto 3 system (v6) with the HD coloring feature provides improved visualization of propagation.
This research was partly funded by a grant from Investments of the Future: IHU LIRYC ANR-10-IAHU-04. Drs Haïssaguerre, Hocini, Jaïs, and Sacher have received lecture fees from Biosense Webster and Abbott. Drs Denis, Derval, Jaïs, and Sacher received speaking honoraria and consulting fees from Boston Scientific. Mr Jean-Rodolphe Roux is an employee of Boston Scientific. All other authors have reported that they have no conflicts relevant to the contents of this paper to disclose.