Supraventricular bradycardia is an occasional complication after orthotopic heart transplantation. This study was undertaken to analyze the effectiveness of orciprenaline to increase heart rate and thus to avoid pacemaker implantation. Between January 1989 and December 1990, 109 patients underwent orthotopic heart transplantation at our institution, of whom 80 patients were included in the study (66 male, 14 female; age 9 to 62 years). Within the early postoperative period (< 14 days) 29 of 80 patients (36%) developed supraventricular bradycardia. Two patients underwent immediate pacemaker implantation, 27 patients were treated with oral orciprenaline (4-6 x 20 mg). 9 of the 27 patients (33%) showed an increase of the heart rate from 57 to 76/min, which remained sufficiently high after discontinuation of the drug. 18 patients (67%) did not respond to the drug (mean heart rate 45/min) and were scheduled for pacemaker implantation, which was performed in all except two. The period of orciprenaline application in both subsets of patients were comparable (postoperative day after HTX = POD 4.6-19.6 vs POD 5.9-23.2, Student's t-test: not significant). During the follow-up period of 6 months, none of the patients developed further bradycardia. However, 11 out the 18 patients with pacemaker implantation (61%) regained sufficient supraventricular rhythm (mean heart rate 96/min). In summary, orciprenaline application is able to prevent pacemaker implantation in one third of patients with sinus dysrhythmia after heart transplantation.