[Atrial demand pacemaker and radio-frequency system in the treatment of brady-tachy syndrome and of recurrent supraventricular tachycardia refractory to drug therapy. Methods and results in eight cases (author's transl)].

The Authors refer on the methods and the results of permanent electrical treatment with atrial demand pacemakers and radio-frequency systems in 6 cases of brady-tachy syndrome and in 2 cases of recurrent supraventricular tachycardia refractory to drug therapy. In the 6 patients with brady-tachy syndrome atrial demand pacemakers with incorporated radiofrequency receiver were employed; in the 2 patients with supraventricular tachycardia a subcutaneous receiver for radiofrequency stimulation was implanted. The catheters employed were: in 3 patients screw-in leads placed in the right atrial appendage and in 5 unipolar sinus coronary leads. The patient-activated transmitter is been realized in two models: the first one can emit short bursts of eight impulses at the rates of 150-220-260 b/m, each one is selectable by the patient; the number and the period of the beats of the second transmitter can be programmed only by one of us; the stimulator is then given to the patient with a personalized fixed program accordingly to the electrophysiological and clinical observations. During a mean follow up of 7.7 months the safety of the leads both for the stability and the electrical behaviour was noticed in all patients but one with a coronary sinus lead in which a stimulation failure was noticed after the eighth month of stimulation because of high threshold requiring the implantation of a ventricular pacemaker. In the brady-tachy syndrome cases the treatment had a considerable antiarrhythmic efficacy, each patient showing a reduction of hyperkinetic episodes and the ability to interrupt them. In the two cases of refractory supraventricular tachycardia a complete control of the episodes by overdrive stimulation was obtained.