Lipnitskii TN, Otkalenko IuK, Randin AG, Stepaniuk AV. Vrach Delo 1991 Oct;(10):83-6. Studied were 24 patients with the syndrome of premature excitation of the ventricles. In 18 of them transesophageal electrophysiological examination was carried out. Reciprocal paroxysmal tachycardia was revealed in 16 patients (orthodromic form--in 14, antidromic--in 2 patients). Cardiac fibrillation with a cardiac contraction rate of 320-340 per minute was noted in 2 patients. Difficulties are noted in the differential diagnosis of antidromic form with ventricular paroxysmal tachycardia and risk of development of ventricular fibrillation in auricular fibrillation. The authors propose a method of diagnosis of latent forms of the syndrome of premature excitation of the ventricles using short-term pharmacological block of atrioventricular conduction in intravenous administration of ATP.