Radiofrequency catheter ablation of ventricular tachycardias in patients with postinfarction scars]

Radiofrequency catheter ablation has recently emerged as a therapeutic option for ventricular tachycardia in postinfarction patients. However, the indications for its use and the mapping procedure remain controversial. The most common arrhythmogenic circuit found fits an "8" shape model. This model incorporates a slow conducting central area, separated from the surrounding myocardium by conduction blocking areas and with entrance and exit sites. This circuit has classically been confined in the left ventricle. However, recently successful radiofrequency catheter ablation of ventricular tachycardia has been reported from the right ventricle. Several markers for adequate positioning of the ablation catheter have been reported: local presystolic activity, isolated mid diastolic potential, transient entrainment with concealed fusion, match between electrogram-QRS and stimulus-QRS intervals, match between first postpacing interval and tachycardia cycle length and tachycardia electrocardiographic reproduction by pace-mapping. Procedure related complications are rare and the success rate is around 70%. Nevertheless, currently this technique should be limited to postinfarction patients with ventricular tachycardia meeting certain requisites.