Seventy-seven nonrejecting transplant recipients were cross-sectionally studied by positron emission tomography with the catecholamine analogue C-11 hydroxyephedrine at 4.8 - 3.5 years after transplantation. Results were compared with history-derived parameters related to recipient‘s clinical course before, during and after surgery, donor characteristics and immunogenetics. Partial reinnervation was observed in 52 patients (extent 25 - 16% of left ventricle). Complete denervation was found in 25 patients at various times after transplantation. Reinnervation extent correlated with time after surgery (r=0.387; P<0.001), but also inversely with donor (r=-0.309, P=0.006) and recipient age (r=-0.243, P=0.032). Maximal hydroxyephedrine retention correlated inversely with frequency of rejection episodes (r=-0.267, P=0.019), was reduced when aortic complications occurred perioperatively (9 patients), and correlated inversely with aortic cross clamp time (r=-0.331, P=0.006). Other parameters were not associated with reinnervation. Patients were surveyed for clinical complications over >12 months after PET (until 7.3 - 4.2 years after transplantation), but significant effects of reinnervation on outcome were not observed. Conclusion – The present data suggest that sympathetic reinnervation after cardiac transplantation is not only a function of time. Reinnervation is more likely in case of young age, fast and uncomplicated surgery and low rejection frequency. Despite little effects on prognosis in otherwise healthy recipients, improved understanding of clinical determinants may contribute to enhance allograft reinnervation and thereby augment exercise capacity in the future.