He F, Zhao X, Cheng X. Shanxi Medical College, Taiyuan. Chung Kuo I Hsueh Ko Hsueh Yuan Hsueh Pao 1994 Jun;16(3):239-41. The clinical acute electrophysiological effects of propafenone were evaluated using transesophageal atrial pacing (TEAP) in 65 patients with various arrhythmias. The mean age of the patients was 41 years. Incremental pacing and programmed ectopic stimulation were performed on each patient before and during drug administration. Propafenone was given as a bolus injection of 1.5mg.kg-1 body weight followed by drip infusion at a rate of 1 mg.min-1. S-R, P wave, P-R and QRS intervals were prolonged from 194.43 +/- 21.59, 97.49 +/- 10.92, 148.00 +/- 16.20 and 82.21 +/- 7.18ms 223.00 +/- 29.25, 100.22 +/- 10.60, 166.60 +/- 20.10 and 86.54 +/- 7.19ms, respectively (P < 0.005), A-V conduction system effective refractory period (AVCSERP) was prolonged from 316.35 +/- 82.97ms to 360.31 +/- 82.67ms (P < 0.0001) in the treated group. There was no change of atrial ERP and QTc interval (P > 0.05). Fast and slow pathway ERP was prolonged by 13% and 28% of the control value, respectively (P < 0.015), and accessory pathway ERP was prolonged from 278.89 +/- 27.13ms to 305.56 +/- 33.58ms (P < 0.001), in the treated group. Sinus cycle length, corrected sinus nodal recovery time and total sinus-atrial conductive time were significantly prolonged (P < 0.0001). The results can partially explain the antiarrhythmic effects and the side effects of propafenone. TEAP is dependable in evaluating the clinical electrophysiological effects of drugs.