[The treatment of intranodal tachycardias with intracavitary fulguration].

The electrical ablation of the His bundle with proximal intracardiac shocks of low energy was performed through an electrical catheter, to 14 patients with AV nodal reentry tachycardias refractory to pharmacological therapy, to whom at least 3 antiarrhythmic drugs were previously administered. The electrical energy applied oscillated between 10 to 150 Joules (114 average). 11 patients (72%) recovered the normal atrioventricular conduction and in the electrophysiological evaluation was found: 1--Increase in the duration of the AH interval. 2--No existence of two AV nodal pathways. 3--Absence of retrograde conduction. 4--Impossibility to induce tachycardia. The PR interval was prolonged (60 ms average) after the electrical shocks. These criteria defined the total effectiveness of the procedure. In the 3 remaining patients (28%) a permanent atrioventricular complete block was induced and the implantation of the permanent pacemaker was required. It was concluded that the electrical fulguration of the atrioventricular junction with low energy is an effective technique as curative treatment for intranodal reentry tachycardias, which can be applied without induction of permanent cardiac block.