Sulimov VA, Papakin GM, Preobrazhenskii VIu, Kuz'menkov DV, Syrkin AL. Kardiologiia 1988;28(2):11-7. Thirty patients with frequent attacks of supraventricular tachycardia were investigated, and a reciprocal paroxysmal atrioventricular tachycardia due to additional atrioventricular junctions was diagnosed in 16 of those. Heart rhythm disorders were rooted in the apparent Wolff-Parkinson-White syndrome in 8 patients, and in its latent variety in another 8. A comparative assessment of diagnostic potentials of esophageal and intracardiac electrophysiologic investigation demonstrated the latter to be an effective method for provoking reciprocal atrioventricular tachycardias and allow a reliable assessment of basic antegrade refractory periods and intervals of the heart's conductive system, including the effective refractory period of Kent's bundle, in patients with additional atrioventricular junctions. In esophageal electrophysiologic studies, electrographic V-A interval exceeding 90 ms during an attack of tachycardia is a major sign of reciprocal atrioventricular tachycardia due to additional atrioventricular junctions.