Clinical and electrophysiological features of respiratory cycle–dependent atrial tachycardia: An analysis of three cases

Introduction Focal atrial tachycardia (AT) accounts for 5%–15% of arrhythmias in adults who undergo electrophysiological study (EPS) for paroxysmal supraventricular tachycardia, and it can be generated by enhanced automaticity, triggered activity, and microreentry. Radiofrequency catheter ablation (RFCA) has been reported as a curative therapy for AT with a high success rate. While almost all instances of AT can be induced by atrial programmed or constant pacing with or without isoproterenol infusion, some ATs with distinct inducibility features have been reported. Swallowing-induced AT is one of the most well-known ATs of unusual presentation. Activation mapping of swallowing-induced AT requires patients to swallow during mapping because it typically cannot be induced by any pacing methods or isoproterenol, and can only be induced by deglutition. RFCA is also effective in eliminating swallowing-induced AT, similar to typical AT. Therefore, understanding how to induce targeted AT is important to the success of RFCA. Another atypical form of AT, respiratory cycle–dependent AT (RCAT), is a rare clinical condition, the mechanism of which has not been clarified. This report describes successful induction and elimination of RCAT in 3 patients in whom different mechanisms underlying the appearance of RCAT were confirmed.