Zhdanov AM, Gukov AO, Shanaeva NS. Ter Arkh 1989;61(4):67-74. The authors provide the results of examining the conduction system of the heart in 623 patients with different disorders of heart conduction and rhythm by means of transesophageal pacing (TEP). The non-invasive electrophysiological examination of patients with sick sinus syndrome with latent disorders of atrioventricular (AV) conduction, and with supraventricular tachyarrhythmias turned out to be of high diagnostic value, inducing no complications. Application of programmed TEP (scanning extrastimulus on basis pacemaking) employed by the authors for the first time during TEP considerably widens the diagnostic possibilities of the technique permitting the measurement of the refractory periods of the conduction system (the refractory periods of the sinus node, atria, and AV-conduction system along normal and additional pathways), the performance of the trigger and removal of supraventricular arrhythmias with diagnostic and treatment purposes in view. The use of TEP for the treatment of patients with the syndrome of the prolonged QT interval and ventricular premature heart beat accelerates the choice of adequate antiarrhythmic therapy and raises its efficacy.