Background: Centrifugal activation displayed by an ultra-high resolution mapping system, ‘Rhythmia
TM‘ may indicate a focal AT or passive activation from the other chamber or epicardial structures. However, the differentiation is not always easy without creating an entire map.
Objective: We aimed to discriminate these mechanisms using the activation map created by the Rhythmia and the LUMIPOINT feature displaying the atrial global activation histogram (GAH).
Methods: Forty-nine centrifugal activations in 48 ATs diagnosed with the Rhythmia
TM-system were analyzed; 13 were focal ATs and 36 were passive activations at the septum or CS ostium (CSOS, n=30) and the other sites in atrium (n=19).
Results: Results are summarized in the Figure. Most passive activations originated from the septum or CSOS were from the opposite chamber. Split origins strongly suggested the passive activation from the other chamber with a positive predictive value of 100%. A larger area activating within the initial 20ms strongly suggested the passive activation (P=0.05) than the focal AT. All passive activations originated from the other sites in atrium were from the epicardial structure. The endocardial entrance region was included in the AT circuit. Deepest GAH-score (P=0.001), duration of GAH-score<0.1(P=0.0006), duration of GAH-score<0.1/TCL (P=0.00003) were significantly associated with a passive activation. Unipolar QS pattern at the origin was more suggestive of focal AT in any origin (P<0.01).
Conclusion: A location of the centrifugal activation and high-resolution activation map with the GAH data may allow us to differentiate focal AT vs passive activation at one glance. <!--EndFragment-->