Unintentional Resetting Phenomenon Caused by Catheter-induced Mechanical Stimulation of the Left Anterolateral Accessory Pathway during Orthodromic Atrioventricular Reciprocating Tachycardia

Abstract

<span style=font-size:11.0pt;font-family: times= new= roman,serif;mso-fareast-font-family:times= roman=>1. Abstract An 80-year-old woman was admitted to our hospital for treatment of paroxysmal supraventricular tachycardia which had been increased sharply after the antiarrhythmic drug was decreased. Electrophysiological study demonstrated orthodromic atrioventricular reciprocating tachycardia via the left anterolateral accessory pathway with relatively slow concealed conduction, which we supposed to be a target for catheter ablation. Interestingly, only while the ablation catheter tip was being placed just on the accessory pathway, the tachycardia cycle length was occasionally altered with the atrial sequence advancing forward a little, and the culprit pathway was successfully ablated at this point. We concluded, based on some electrophysiological findings, that this phenomenon was caused by electrophysiological mechanism of resetting, certainly induced by direct mechanical stimulation onto the accessory pathway. <span style=font-size:11.0pt;font-family: times= new= roman,serif;mso-fareast-font-family:times= roman=>2. Keywords: <span style=font-size:10.0pt;font-family: times= new= roman,serif=> Accessory Pathway; Atrioventricular Reciprocating Tachycardia; Mechanical Stimulation; Resetting Phenomenon; Slow Concealed Conduction