[High-frequency stimulation in the prevention of atrioventricular tachycardias: relation to stimulation site and location of the accessory conduction pathway].

To assess the validity of train stimulation for the prevention of accessory pathway mediated atrioventricular tachycardia, thirteen patients were studied. Tachycardia was induced from high right atrium and coronary sinus by means of single extrastimuli; preventive stimulation at high right atrium and coronary sinus consisted of the delivery of a train of ten or eleven stimuli 10 ms apart, following the tachycardia initiating stimulus. Preventive train stimulation at the site of tachycardia induction was successful in all patients when the train exceeded the atrial effective refractory period of the initiating stimulus to achieve single atrial capture within the "preventive zone". In patients with a left-sided accessory pathway in whom tachycardia was induced from the coronary sinus, preventive stimulation at high right atrium failed because of interatrial conduction delay. It is concluded that train stimulation is an effective mode of prevention of atrioventricular reentrant tachycardia, yet preventive stimulation should be performed as close as possible to the reentry circuit to reduce interatrial conduction delay.