Adenosine sensitive focal atrial tachycardia originating from the non-coronary aortic cusp.

We report on the characteristics and the ablation procedure of a focal atrial tachycardia originating from the non-coronary aortic cusp. The electrophysiological features of the tachycardia included: (i) incessant pattern; (ii) easy induction and termination by atrial stimulation; (iii) earliest right atrial activation at the para-hisian area; and (iv) termination by adenosine. Left-sided mapping revealed the earliest atrial activation during the tachycardia at the non-coronary aortic cusp. Radiofrequency energy application at this site successfully terminated the tachycardia. Mapping of the non-coronary aortic cusp should always be considered when the earliest right atrial activation is recorded at the para-hisian area in order to avoid the risk of atrioventricular block by inappropriate ablation near the His-bundle region.