CLINICAL ASPECTS DURING LONG-TERM FOLLOW-UP AFTER DC SHOCK ABLATION OF THE ATRIOVENTRICULAR JUNCTION - A BELGIAN EXPERIENCE

Ninety-three patients, who underwent DC shock ablation were reviewed o ver a mean follow-up period of 54 months (range 3 to 84 months). These patients (46 male and 47 female, mean age: 58 years) had failed an av erage of 3 drugs, and the duration of symptoms was more than 2 years. Paroxysmal atrial fibrillation or flutter was treated in 75 patients ( 80.6 %) ; the remainder had supraventricular tachycardia or reciprocat ing tachycardia using an accessory pathway. One shock of 200 J was eff ective in producing third degree AV block in 40 patients (43 %), while 2 or more shocks were used in another 53 patients (57 %). Chronic com plete heart block (CHB) was obtained in 85 patients (91 %), modificati on of conduction was seen in 2 patients (2.1 %), and failure to achiev e an improvement in 6 patients (6.4). All the patients of the last gro up had received more than 4 shocks (200 to 400 J). However no signific ant difference between the amplitude of atrial and His electrograms co uld be shown between the CHB patients and those in whom conduction per sisted. Over a mean follow-up of 54 months, 66 patients (72 %) with su ccessful ablation during the first 48 hours after the procedure remain ed in CHB. In 18 patients AV conduction resumed but they were all asym ptomatic: 10 patients (10.8 %) without antiarrhythmic therapy and 8 pa tients (8.6 %) with medication. In conclusion, ablation of the AV junc tion is effective in more than 82 % of patients. Most of the time long -term success can be predicted within 48 hours. However, due to the in vasive character of DC shocks, this technique has been supplanted by t he less aggressive radiofrequency method.