ABLATION OF VENTRICULAR-TACHYCARDIA ASSOCIATED WITH TETRALOGY OF FALLOT - DEMONSTRATION OF BIDIRECTIONAL BLOCK

Ablation of VT in Tetralogy of Fallot. Introduction: Ventricular tachy cardia is commonly seen in patients following surgical repair for tetr alogy of Fallot, The technique of ablation for this arrhythmia is not well defined. Methods and Results: In two patients with ventricular ta chycardia following surgical repair of tetralogy of Fallot, the tradit ional indicators for a site for ventricular tachycardia ablation did n ot yield cure, Based on careful mapping, the circuit was found to invo lve the isthmus between the outflow tract patch and the tricuspid annu lus; linear radiofrequency lesions across this isthmus resulted in cur e of ventricular tachycardia, Not only was the tachycardia no longer i nducible, but bidirectional block at the line of ablation confirmed in terruption of the reentrant circuit. Conclusion: A linear radiofrequen cy lesion was effective in eliminating ventricular tachycardia in both patients, The demonstration of bidirectional block confirms a cure in dependent of inducibility of ventricular tachycardia.