PMC9880887_01
A: A high-density activation map within the LAA. Blue tag indicated the first ablation site, at which AT was terminated. Red tags show the additional ablation sites. The lower electrogram shows the local electrogram and the upper electrogram shows the reference electrogram of the coronary sinus catheter 2-3. The number showed in the box indicated the local activation time. Window of interest was set from -100 msec to 130 msec. Auto scar setting was 0.01 mV. Scar (grey dot) point was  0.01 mV. B-C: Voltage map during AT. Color threshold was 0.05-0.50 mV. D: Voltage map during AT. Color threshold was 0.05-0.10mV.AT = atrial tachycardia; LAA = left atrial appendage; LIPV = left inferior pulmonary vein; LSPV = left superior pulmonary vein.
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PMC9880887_01_gr1.jpg
fig1
High-density mapping using a CARTO system and PentaRay  NAV catheter (Biosense Webster, Diamond Bar, CA) revealed a localized reentrant activation pattern within the LAA (Fig. 1, supplemental Movie1, 2), accounting for 99% of the tachycardia cycle length. The voltage map during AT showed severe low voltage area around the LAA (Fig. 1B, C and 1D). An activation map around LAA showed a possibility of (1) figure-of-eight atrial tachycardia, (2) localized reentrant tachycardia of LAA ridge related (Fig. 1A white arrow), (3) localized reentrant tachycardia around LAA body (Fig. 1A pink arrow), and (4) focal tachycardia from LAA with conduction block. AT (Fig. 1A, blue tag), terminated the AT in 26s using an open irrigation contact force sensing catheter (Thermocool Smart-Touch SF, Biosense Webster, Diamond Bar, CA). After a bonus application to connect two scars around the successful site, the AT could no longer be induced.
Intracardiac electrograms before AT induction and after AT termination by radiofrequency ablation. Left panel: Intracardiac electrograms before AT induction. Right panel: Intracardiac electrograms after AT termination by radiofrequency ablation. LAA activation was not delayed by ablation. AT = atrial tachycardia; CS d = distal coronary sinus; CS p = proximal coronary sinus; HLRA = high lateral right atrium; HRA = high right atrium; LAA = left atrial appendage; LLRA = low lateral right atrium.
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PMC9880887_01_gr2.jpg
fig2
High-density mapping using a CARTO system and PentaRay  NAV catheter (Biosense Webster, Diamond Bar, CA) revealed a localized reentrant activation pattern within the LAA (Fig. 1, supplemental Movie1, 2), accounting for 99% of the tachycardia cycle length. An activation map around LAA showed a possibility of (1) figure-of-eight atrial tachycardia, (2) localized reentrant tachycardia of LAA ridge related (Fig. 1A white arrow), (3) localized reentrant tachycardia around LAA body (Fig. 1A pink arrow), and (4) focal tachycardia from LAA with conduction block. LAA activation was not delayed after ablation compared with before ablation (Fig. 2).