Catheter ablation of ventricular tachycardia using defibrillator pulses: electrophysiological findings and long-term results.

Catheter ablation of ventricular tachycardia (VT) was attempted in 24 patients (mean age 49 +/- 15.1 years) with a history of recurrent sustained VT resistant to previous antiarrhythmic drug therapy. 14 patients (58.3%) had also failed to respond to long-term administration of amiodarone alone and in combination with class I antiarrhythmic drugs. Endocardial catheter mapping during induced or spontaneous VT and/or pacemapping were performed to identify the site of origin of VT. Direct-current high-energy anodal shocks were delivered from a conventional cardioverter with stored energies of 100, 200 or 400 J via the distal electrode of conventional catheters. A total of 139 shocks was delivered during the ablation procedure. One patient died from wall perforation. Within 1 week of ablation, nine patients developed spontaneous recurrences of monomorphic sustained VT, identical to the clinical VT, and one patient developed a VT with a new morphology. In addition, four patients had a recurrence of their clinical VT after several weeks. In seven of 14 patients with spontaneous recurrences after the first ablation procedure and in three patients in whom VT was again inducible at the end of the first week, a second ablation procedure was performed. One patient with inducible VT after the first and second ablation sessions was given a third ablation procedure, and was discharged from hospital on anti-arrhythmic drugs which were successful despite being previously ineffective. After a mean follow-up period of 14.1 +/- 9.1 months, there were no spontaneous recurrences of sustained VT in 17 patients (71%) (nine without antiarrhythmic drugs and eight on antiarrhythmic drugs). In the remaining patients, incessant non-sustained VT (n = 2) or recurrent sustained VT (n = 2) occurred, and two patients died suddenly (at 2 and 21 months). There was no correlation between catheter mapping data or the results of pre-discharge electrophysiological study and clinical outcome during long-term follow-up. Complications related to catheter ablation included pulmonary oedema, cardiac tamponade, femoral artery occlusion, multiple episodes of ventricular tachycardia/fibrillation and thrombus formation, each in one patient (major complications; n = 7,29.1%), as well as transient third degree AV block, transient right or left bundle branch block, transient marked ST elevation or transient atrial tachycardia (minor complications; n = 8, 33.3%). The results suggest that catheter ablation might become an effective procedure for the non-pharmacological treatment of sustained VT.(ABSTRACT TRUNCATED AT 400 WORDS)