Atrial Tachycardias Arising from Ablation of Atrial Fibrillation: A Proarrhythmic Bump or an Antiarrhythmic Turn?

Figure 3

Atrial activation around the mitral annulus is shown during atrial tachycardia. Septal (green marker) to lateral (black marker) atrial activation pattern on decapolar coronary sinus (CS) catheter is demonstrated. Electrical activity recorded on mapping catheter (RF) in reference to proximal CS dipole 9-10 is demonstrated from two different sites (red and blue markers). Mapping catheter positioned at anterolateral mitral annulus (red marker) is activated 92 ms after proximal CS. Mapping catheter positioned at anteroseptal mitral annulus (blue marker) is activated 154 ms after proximal CS. Thus, during tachycardia, atrial activation proceeds laterally from the septum in the posterior left atrium and septally from the lateral aspect of anterior left atrium. This pattern conforms to that of perimitral flutter. Activation pattern around the mitral annulus comprises of the entire cycle length of this flutter (orange pillars march through yellow background which represents one cycle length).