[Paroxysmal junctional tachycardia and normal ECG in sinus rhythm. Is their mechanism influenced by the age of the patient at the time of the study?].

At the time of the curative treatment of paroxysmal junctional tachycardias, to determine the mechanism of the tachycardia is important. Five-hundred forty intracardiac or esophageal electrophysiological studies were performed in patients aged from 9 to 86 years and then revieved. There was no preexcitation syndrome on surface ECG. Programmed atrial stimulation was performed in basal state and if necessary repeated after infusion of isoproterenol. Atrioventricular nodal reentrant tachycardia was the most frequent cause of junctional tachycardia (72%) since childhood and in all stages of life. Concealed accessory pathway reentrant tachycardias were identified in 22% of tachycardias with a stable incidence during the course of life. Various mechanisms of tachycardia were identified in the remaining patients. In conclusion, the mechanism of paroxysmal junctional tachycardia is not correlated with the age of the patient.