Successful elimination of a Mahaim pathway using an 8 mm tip cryoablation catheter in a child

Mahaim fibers typically demonstrate decremental conduction properties and constitute approximately 3% of preexcitation syndromes (1). Mahaim pathways are usually right-sided, however several leftsided cases have been reported (2). Conventionally Mahaim pathway ablation is performed with radiofrequency ablation (RFA). We report a patient who presented with a wide QRS tachycardia with left bundle branch block (LBBB) pattern. The electrophysiology study demonstrated Mahaim tachycardia and the patient was successfully treated with cryoablation following a failed attempt with RFA

Assessment of atrioventricular conduction following cryoablation of atrioventricular nodal reentrant tachycardia in children

WOS: 000337733100008PubMed ID: 24472089Background Early-onset transient atrioventricular block (AVB) is a rare occurrence following cryoablation of atrioventricular nodal reentrant tachycardia (AVNRT), despite lack of any AVB at the end of the procedure. The purpose of this prospective study was to assess AVB shortly after successful cryoablation of AVNRT in children. Methods A 6-mm-tip cryocatheter was used in 39 procedures. An 8-mm-tip catheter was used in 11 procedures. Twelve-lead electrocardiograms (ECGs) and 24-hour ambulatory ECGs were performed 24 hours prior to the procedure and immediately following the procedure. All procedures were done using the EnSite system (St. Jude Medical, St. Paul, MN, USA) without fluoroscopy. Results Although nine (18%) patients developed variable degrees of transient AVB during the procedure, all of them had normal atrioventricular (AV) conduction at the end of the procedure and did not require any intervention. Four of these patients had variable degrees of transient AVB following the procedure despite having normal AV conduction at the end of the procedure. One developed Mobitz type I AVB, which lasted for 11.5 hours, and the other three experienced 2:1 AVB, which lasted for 2, 8, and 24 hours, respectively. All patients had complete resolution of the AVB, which was also documented with the 24-hour ambulatory ECGs after the procedure. Conclusion Early transient AVB can develop following AVNRT cryoablation even if AV conduction is normal at the end of the procedure. Despite the transient AVB in the initial 24 hours after the procedure in some cases, there is no evidence for ongoing AV nodal dysfunction

Cryoablation with an 8-mm-Tip -catheter for right-sided accessory pathways in children

WOS: 000380902800003PubMed ID: 27197083BackgroundCryoablation is increasingly utilized in children because of its safety profile. Recently, larger catheter tips have been more widely used to improve long-term success rates. The aim of this study was to assess the safety and efficacy of 8-mm-tip catheters for cryoablation of right-sided accessory pathways (APs) in children. MethodsElectrophysiological procedures were performed using the EnSite system (St. Jude Medical Inc., St. Paul, MN, USA). ResultsBetween July 2010 and July 2014, 54 patients (mean age: 13.1 3.7 years) underwent cryoablation using an 8-mm-tip catheter. In 18 of 54 (33%) patients where an 8-mm-tip catheter was the first-choice catheter, the success rate was 18 of 18 (100%). There was a history of previous failed attempts or recurrence with radiofrequency ablation and/or 6-mm-tip cryoablation in 36 of 54 (67%) patients. The success rate in these patients was 24 of 36 (67%). No fluoroscopy was used in 34 of 54 procedures. The recurrence rate was six of 42 (14%) during a mean follow-up period of 32 +/- 15 months. In one patient, transient atrioventricular block occurred. ConclusionsCryoablation with an 8-mm-tip catheter for right-sided APs in children who weigh over 40 kg appears to be safe and acutely effective in cases where conventional ablation methods fail and also as a first choice for ablation procedure. However, the recurrence rate still seems to be high