Catheter ablation of ventricular tachycardia using radiofrequency current
Borggrefe, M.; Willems, S.; Chen, X.; Hindricks, G.; Haverkamp, W.; Martinez-Rubio, A.; Hief, C.; Shenasa, M.; Breithardt, G.
Herz 17(3): 171-178
1992
ISSN/ISBN: 0340-9937 PMID: 1639336 Document Number: 391593
Catheter ablation techniques have evolved as an alternative to map-guided surgery and proven effective in a variety of supra-ventricular tachyarrhythmias. Direct current catheter ablation has been shown to be effective in about 50 to 70% of cases. Approximately, 60% of patients with structural heart disease and monomorphic ventricular tachycardia were successfully treated using direct current ablation techniques. This overall success rate and possible risks associated with the use of direct current have stimulated the search for other energy sources appropriate for catheter ablation. Presently, only a few preliminary reports on the clinical efficacy of radiofrequency energy for the treatment of ventricular tachyarrhythmias in man exist. 23 patients with identifiable heart disease at a mean age of 52 .+-. 17 years underwent radiofrequency catheter ablation. 16 patients had coronary artery disease, one patient dilative cardiomyopathy and six patients had arrhythmogenic right ventricular disease. All patients presented with chronic current sustained ventricular tachycardia. After detailed endocardial catheter mapping radiofrequency energy was applied at the site of earliest ventricular activation during ventricular tachycardia which could be entrained during fixed rate ventricular pacing at the site of origin of ventricular tachycardia. At all ablation sites a long latency between the stimulus and QRS complex was noted. Of 23 patients 18 were treated with radiofrequency alone whereas in five patients a second ablation procedure using direct current was performed. Following the ablation procedures, 14 patients (61%) remained free of ventricular tachycardia. One patient died due to congestive heart failure 21 months following ablation. Taking these findings and reported experience of other investigators with the use of radiofrequency ablation of ventricular tachycardia in patients with structural heart disease into account, the overall success rate is approximately 55%. This relatively low success rate is in contrast to findings in patients with ventricular tachycardia and no identifiable heart disease in whom a success rate up to 94% can be obtained. Further imporvements of ablation techniques are mandatory to increase the success rate of radiofrequency ablation in patients with underlying cardiac abnormalities.