Abstract: Abstract Objective: To investigate electrophysiological characteristics and radiofrequency catheter ablation in patients with atrial tachycardia(AT) originating from the non-coronary aortic sinus(NAS) or its adjacent tissue.Methods: Ten patients[6 female,4 males,the age from 50 to 71,mean age(58.1±6.1)years]with paroxysmal AT for (4.7±2.6)years were included. After ATs were induced by atrial or ventricular stimulation,the activation mapping was performed during AT to identify the earliest activation in the right atria and the NAS,meanwhile to analyzed the surface electrocardiogram features of the AT and the sinus rhythm,finally radiofrequency ablation application was delivered in NAS.Results:ATs with mean cycle length of (318.3±50.1)ms were easily reproducibly induced and terminated by atrial pacing in all 10 patients.Regular activation mapping in atria showed that a relative earlier atrial activation was located at the top of the His bundle of the anteroseptal region in the right atria,and failed to terminated AT.Through puncture femoral artery,mapping in the NAS demonstrated that an earlier atrial activation preceded the atrial activation at the surface electrocardiogram by(55.8±5.6)ms.ATs were terminated less than 10 seconds during the first or second radiofrequency ablation.All 10 patients were free of AT without antiarrhymic drugs during a follow-up of(12.5±5.3)months.No complications occurred in anyone of the 10 patients.The P′ wave duration(73.1±3.8)ms during AT was significantly shorter than the P wave duration(92.3±5.1)ms during sinus rhythm(P<0.05).Conclusion:Mapping and ablation from the NAS can be used as a new approach when failed to radiofrequency ablation at the His bundle of the anteroseptal region. The P′ wave duration during AT originating from the NAS or its adjacent tissue was significantly shorter than the P wave duration during sinus rhythm.By this characteristic can we select NAS as a reference when the AT was failed to ablate.

Key words: aortic, atrial tachycardia, non-coronary sinus, His bundle