[Intravenous ablation of the atrio-ventricular junction in patients with supraventricular tachyarrhythmias].

Since the first successful therapeutic DC ablation of the AV junction in 1986, we have treated 20 symptomatic patients with drug-refractory supraventricular tachyarrhythmias (average of 6 antiarrhythmic drugs prior to the ablation attempt). The primary rhythm disturbances necessitating ablation were: AV nodal reentrant tachycardia (50% of pts), atrial flutter or fibrillation, with an uncontrolled rapid ventricular response (40%), atrioventricular reentrant tachycardia using an accessory pathway (20%), atrial tachycardia (10%), and junctional reciprocating tachycardia (5%). Percutaneous catheter ablation of the AV junction was made by Gallagher's method. The USCI 4-polar catheter (7F) was used in 40% of pts, and bipolar Cordis catheter (5F) in the remaining 60%. 70% of pts received either one or two shocks, usually of 200 or 300 J during one session. Another 25% received stored cumulative energy from 800 to 1200 J (in two sessions), and one patient--1800 J (during three sessions). In 85% of pts, the immediate post-ablation conduction was third-degree AV block with the escape pacemaker, ranging from 20 to 50 beats/min., which was infra-His in 57%, and supra-His in 43% of pts. In 15% of pts were either first-degree AV block (10%) or normal AV conduction (5%). A His bundle deflection more than 0.2 mV was predictive of successful production of third-degree AV block. Except a mild and transient increase of indicating enzymes (CPK and CPK-MB) we did not observe any other serious complications directly related to the ablalation procedure. Follow-up study included 19 pts (time range from 2 to 56 months, mean 28).(ABSTRACT TRUNCATED AT 250 WORDS)