Pacemaker implantation for early sinus node dysfunction after orthotopic heart transplantation.

Among 60 patients who received OHT at our institution between November 1986 and January 1990, 4 actually needed implantation of a permanent pacemaker. Three patients with symptomatic early sinus node dysfunction were identified and were satisfactorily paced on the VVIR mode. All three showed sinus recovery within three months following implantation and had their pacemaker switched from the VVIR mode to a simple ventricular demand pacing. Interestingly, administration of beta-blocking drugs quickly reinstituted pace dependence. The patients' outcome is excellent (18 to 48 months follow-up). No difference with the global cohort of our OHT recipients was noticed, apart from an apparent high incidence of infections (3/3) with (2/3) CMV and severe rejection (3/3) during the first month postoperatively. This data suggests that sinus dysfunction may be the result of a multifactorial (rejection, CMV, ...) injury to the conduction system, and is only clinically relevant beyond a threshold level. Denervation hypersensitivity, together with correction of these factors, may account for the restoration of a sufficient reserve of conduction system, and therefore appropriate sinus node function in basal conditions.