Distribution of the Origin of Adenosine Triphosphatesensitive Atrial Tachycardias with the Earliest Activation Recorded in the His Bundle Catheter: Are They Limited to the Immediate Vicinity of the His Bundle?

Background: The aim of this study was to assess the spatial distribution of the origins of adenosine triphosphate (ATP) sensitive focal atrial tachycardias (AT) that have their earliest activation recorded in the His bundle (HB) catheter.

Methods And Results: Catheters were placed according to the standard fashion for an electrophysiologic study of supraventricular arrhythmia, namely, high right atrium, HB, coronary sinus, and right ventricle. The ATs with their earliest activation recorded in the HB catheter and that were terminated by rapid injection of ATP (4.3 ± 2.5mg), formed the study group (n=12). After catheter ablation of these ATs, the distances between the successful ablation site and the HB area were measured. Only one successful site was near the HB and the other sites were at the noncoronary sinus of Valsalva (n=6), tricuspid annulus (n=3), right atrial septum (n=1), and left atrial septum (n=1). The average distance between the HB catheter and successful site was 10.4 ± 8.8mm. In 5 of the 12 cases (the 3 tricuspid and 2 septal foci), the distances were greater than 10mm.

Conclusions: When ablating ATP-sensitive AT with the earliest activation recorded in the HB catheter, it is important to perform detailed mapping not only around the HB.