Catheter technique for ablation of accessory atrioventricular pathway: long-term results

Catheter ablation of an accessory atrioventricular pathway wasattempted in six patients with recurrent tachy arrhythmias resistantto medication (four to five trials). Localization of the accessorypathway was performed by potential recordings with an electrodecatheter from the region of the tricuspid and mitral valve ringsduring orthodromic supraventricular tachycardia (n = 4), duringsinus rhythm (n = l), and during ventricular pacing (n = 1).Using this mapping technique, the site of earliest atrial orventricular activation through the accessory pathway was localizedin the anterior septal (n = 2), right free wall (n = 2), posteriorseptal (n = 2), or left free wall (n= 1) region of the atrioventricularvalve rings. The shortest ventriculo–atrial (VA) and atrio–ventricular(AV) intervals measured in the local electrograms ranged fromVA = 45–70 ms, and AV = 45–65 ms, respectively.The accessory pathway responsible for the arrhythmia demonstratedexclusive retrograde (n = 4) or bidirectional (n = 2) conductionproperties. A total of 13 direct current transcatheter shocks(one to three per patient) of 20–200 J each were aimedat the site of the accessory pathway. Thereby, conduction throughthe accessory pathway was abolished (n = 5) or modified (n =l) and the patients were freed from their syncope and disablingarrhythmias (follow-up: 4–6–5–9 years). Theprocedure was well tolerated without complications. Mappingguided catheter ablation of accessory pathways is an effectivetreatment of refractory supraventricular tachyarrhythmias inselected patients.