Efficacy and safety of transcatheter ablation of posteroseptal

Eight patients with a posteroseptal accessory pathway and symptomatic atrial fibrillation and/or orthodromic reciprocating tachycardia underwent attempted transcatheter ablation of the accessory pathway. A quadripolar electrode catheter was positioned within the coronary sinus such that the proximal pair of electrodes straddled the os. This proximal pair of electrodes was made electrically common and connected to the cathodal output of a defibrillator. A patch electrode placed over the midthoracic spine was connected to the anodal sink of the defibrillator. Two to three transcatheter shocks were delivered, with a cumulative energy of 600 to 900 J. Immediately after the shocks were delivered, retrograde accessory pathway conduction was absent in each patient. Anterograde conduction through the posteroseptal accessory pathway was absent in six patients and could not be assessed in two patients who each had a second right-sided accessory pathway. Long-term results were assessed in seven patients 4 to 11 months after delivery of the shocks. Anterograde and retrograde conduction through the posteroseptal accessory pathway was absent in five patients. In one patient, retrograde accessory pathway conduction was absent and anterograde conduction was present but was slower than at baseline. In this patient, orthodromic tachycardia was no longer inducible and the ventricular rate during induced atrial fibrillation was 150 beats/min, compared with 220 beats/min before the attempted ablation. He has remained asymptomatic without antiarrhythmic drug therapy for 18 months. In one patient, the transcatheter shocks had no long-term effect on accessory pathway conduction. The shocks delivered at the os of the coronary sinus were well tolerated. There was no long-term effect on anterograde conduction through the atrioventricular junction. Retrograde conduction through the atrioventricular junction was impaired in three patients. In four patients who underwent direct or angiographic visualization of the coronary sinus, no abnormalities were seen. Transcatheter ablation of posteroseptal accessory pathways has a long-term success rate of at least 75% and a low morbidity rate. Closed-chest catheter ablation of posteroseptal accessory pathways is an attractive alternative to surgical ablation of these pathways. Circulation 72, No. 1, 170-177, 1985. EXPERIENCE in more than 150 patients with supraventricular tachycardia refractory to pharmacologic treatment has indicated that catheter ablation of the atrioventricular junction results in good or excellent arrhythmia control in approximately 90% of patients. 1,2 Catheter ablation of accessory pathways has also been attempted, but with less overall success. Attempts at ablation of left-sided accessory pathways by shocks delivered within the coronary sinus have generally been unsuccessful and, moreover, have reFrom the Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, and Division of Cardiology, Department of Internal Medicine, University Hospitals, University of Michigan, Ann Arbor. Address for correspondence: Fred Morady, M.D.. Division of Cardiology, W1 151 1, Box 55, University Hospitals, University of Michigan, 1405 E. Ann St., Ann Arbor, MI 48109. Received March 5, 1985; revision accepted April 11 1985. sulted in perforation of the coronary sinus.3 Catheter ablation of right-sided accessory pathways has been limited by difficulty in precisely localizing these pathways.46 Attempts at transcatheter ablation of posteroseptal accessory pathways have met with some degree of success but, to date, the total published experience with this technique has consisted of only six patients.7-10 The posteroseptal accessory pathway was successfully ablated in four of these six patients, and no complications were reported. However, only two cases in which the procedure was successful were reported in detail.7 10 Although encouraging, the results reported to date are clearly too preliminary to allow valid conclusions regarding the efficacy or safety of the catheter ablation technique in the treatment of patients who have a posteroseptal accessory pathway. The purpose of this report is to present the results of CIRCULATION 170 by gest on N ovem er 8, 2017 http://ciajournals.org/ D ow nladed from THERAPY AND PREVENTION-ARRHYTHMIA attempted catheter ablation of a posteroseptal accessory pathway in a series of eight patients to help define the efficacy and safety of this new alternative to surgical ablation of posteroseptal accessory pathways.