Successful catheter ablation of atrial tachycardia initiated with orthodromic capture of superior vena cava potentials.

A case of successful catheter ablation of paroxysmal atrial fibrillation and atrial tachycardia is reported. After pulmonary vein isolation, atrial tachycardia was induced by the use of isoproterenol and burst pacing from the catheter in the right atrium. An attempt was made to create a three-dimensional (3D) map of the atrial tachycardia, but the atrial tachycardia was terminated in the middle of the mapping. The 3D map was insufficient but indicated that the superior vena cava was involved in the circuit. When the intracardiac electrograms were reviewed, it was found that the atrial tachycardia was initiated with orthodromic capture of superior vena cava potentials and it was considered that the atrial tachycardia involved the superior vena cava-right atrium junction. Accordingly, superior vena cava isolation was performed. After that, atrial fibrillation and atrial tachycardias were not induced by the use of isoproterenol and burst pacing. In this case, an intracardiac electrogram at the time of induction of the tachycardia was helpful for understanding the circuit of the tachycardia.