Smetnev AS, Islam MN, Sokolov SF, Golitsyn SP, Bankuzov VA, Malakhov VI. Kardiologiia 1990 Feb;30(2):32-7. 27 patients underwent serial electrophysiological studies by using transesophageal atrial stimulation. A-V nodal reciprocal tachycardia was documented by intracardiac electrophysiological examinations. Sustained tachycardia was induced in all the patients before drug administration. On day 4 after oral verapamil, 320 mg/day, ethmosine, 800 mg/day, and ethacizine, 150 mg/day, the patients were subjected to transesophageal atrial stimulation. An antiarrhythmic effect was regarded to be reached if the authors failed to induced sustained tachycardias again. Verapamil, ethmosine, and ethacizine were found to be beneficial in 21 (78%), 13 (48%) and 21 (78%) patients, respectively. A comparative analysis demonstrated that ethacisine was not inferior to verapamil, but ethmosine produced less effects than verapamil and ethacizine. The crossover and individual efficacy shown by each drug suggests that it is necessary to use the technique of serial testing and to choose beneficial drugs from a possibly wide range of medicaments for each patient.