Successful Cryoablation of an Anteroseptal Accessory Pathway Guided by Electroanatomical Activation Mapping

Abstract: The use of electroanatomical mapping can facilitate the identification of the ideal cryoablation site by providing a three-dimensional map of the earliest activation site. Combined use of the cryoablation technology with electroanatomical mapping can further increase the precision and safety of the procedure by applying test applications at a lower energy level.

J INVASIVE CARDIOL 2016;28(12):E227.

Key words: cryoablation, Carto, electroanatomical activation mapping

Case Presentation

A 39-year-old male patient was referred to our electrophysiology lab with a previously diagnosed anteroseptal accessory pathway with an antegradely conducting effective refractory period of 240 ms. Following diagnostic electrophysiological evaluation, precise Carto electroanatomical activation mapping was performed using a 8 Fr, 4 mm Navistar catheter (Biosense-Webster) from both sides of the interatrial septum, which showed the earliest ventricular activation close to the His position at the right anteroseptal region (Figure 1A). In an attempt to reduce the risk of atrioventricular (AV) block, further mapping was performed using test applications (-30 °C) with a cryoablation catheter (7 Fr, 6 mm Freezor Xtra; Medtronic). As the cryoenergy was applied just slightly anterior to the His position, the accessory pathway disappeared within 2 seconds (Figure 1B), followed by full cryoablation (at -75 °C) for a total period of 4 minutes. The accessory pathway did not appear during a waiting period of 45 minutes and during the clinical follow-up thereafter.

Rapidly conducting accessory pathways at the right anteroseptal position pose a clinical challenge given the associated risk for permanent AV block and the resultant need for lifetime pacemaker therapy. Mapping for the appropriate ablation position is usually performed by conventional means searching for the earliest ventricular activation along the tricuspid annulus and avoiding the regions with the His-potential. Electroanatomical mapping can facilitate the identification of the ideal ablation site by providing a three-dimensional map of the earliest activation site. Combined use of the cryoablation technology with electroanatomical mapping can further increase the precision and safety of the procedure by applying test applications at a lower energy level, which are thought to exert a reversible effect on AV conduction.

From the Arrhythmia and Electrophysiology Division, University Heart Center, Zurich, Switzerland.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Yalcinkaya is supported by the European Society of Cardiology Training Grant. The remaining authors report no conflicts of interest regarding the content herein.

Manuscript submitted June 10, 2016, final acceptance given June 15, 2016.

Address for correspondence: Emre Yalcinkaya, MD, FESC, Arrhythmia and Electrophysiology Division, University Heart Center, 8091, Zurich, Switzerland. Email: emre.yalcinkaya@usz.ch