In a 4-year interval, 3/55 (7.8%) heart transplant recipients developed (greater than 4 weeks) severe sinus node dysfunction. An epicardial ventricular pacemaker was implanted at 90, 40, and 38 days after operation. Follow-up ranged from 7 to 20 months. In two of the three cases, failure of stimulation or sensing was detected at the 3rd and 4th month after pacemaker implantation. Sinus rhythm reappeared in two of the three patients at the 2nd and 4th months after transplantation. Severe sinus node disease requiring pacemaker implantation can improve following the first 3 months after transplantation. Failure of stimulation or sensing may not be uncommon.