Atrial Tachycardias Arising from Ablation of Atrial Fibrillation: A Proarrhythmic Bump or an Antiarrhythmic Turn?
Top: The electrogram recordings from four sites (red, blue, yellow, and maroon stars) on anterior and posterior left atriums are timed with coronary sinus dipole (CS 9-10) as reference. Local electrograms recorded from high (red star) and low (blue star) anterior sites are 126 ms and 172 ms, respectively from the reference suggestive of high to low anterior left atrial activation pattern. Local electrograms recorded from the high (maroon star) and low (yellow star) posterior sites are 146 ms and 178 ms, respectively from the reference suggestive of high to low posterior left atrial activation pattern. This pattern which rules out macroreentry is consistent with focal tachycardia arising from a focus. Bottom: Focus is shown in the roof shown as “”. The arrows display centrifugal activation of the atria. Ablation catheter (RF) records continuous low voltage (0.176 mV) electrical activity spanning 166ms during atrial tachycardia (cycle length 234 ms). Recording 71% of tachycardia cycle length at a single spot suggests localized reentry as the mechanism of tachycardia.
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