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A Wide Complex Tachycardia with Changing Atrial Activation Sequence


Address for reprints: Romeo Ayou, M.D., Department of Electrophysiology, Royal Jubilee Hospital, 1952 Bat Street, Victoria, British Columbia, V8R 1J8, Canada. Fax: 1250 595 0425; e-mail:


Change of the retrograde atrial activation sequence during radiofrequency (RF) ablation of left-side accessory pathway can be due to another accessory pathway, another mechanism for the tachycardia, or due to intraatrial conduction block, partial or complete, caused by RF delivery to a site proximal to the site of insertion of the accessory pathway. In this case report, a temporary complete intraatrial conduction block was created by RF delivery proximal to the site of accessory pathway insertion, causing a change in the retrograde atrial activation sequence during ongoing tachycardia that was terminated by ablation at the insertion site of accessory pathway.

(PACE 2013; 36:e23–e26)