Influence of age on the electrophysiological mechanism of paroxysmal supraventricular tachycardias.

The purpose of this study was to evaluate the influence of age on the mechanism of paroxysmal supraventricular tachycardia (PSVT). Previous studies have shown age and sex differences between certain arrhythmias and especially changes in electrophysiological characteristics of Wolff-Parkinson-White syndrome. Four hundred and eighty five patients aged 9-86 years, with PSVT and without Wolff-Parkinson-White syndrome in sinus rhythm, were studied. The esophageal or intracardiac electrophysiological study used a standardized atrial pacing protocol. Paroxysmal junctional tachycardia was induced in 475 patients. The mechanism of tachycardia was not influenced by age and atrioventricular nodal reentrant tachycardia (AVNRT) was found as the main cause of PSVT in all ranges of age. Atrioventricular reentrant tachycardia (AVRT) using a concealed accessory pathway (AP) had a similar incidence from youth to elderly. The ratio male/female (M/F) and the inducibility of other arrhythmias (atrial flutter/fibrillation) (AF/AFl) were also found to be similar in all ranges of age. The age of the patients did not influence the mechanism of the tachycardia. Most of PVST were related to a AV nodal reentrant tachycardia. Concealed accessory pathway was identified with a similar incidence in young and old patients.