Denervation of the heart involves an alteration (density, distribution of beta 1-beta 2-types) of beta-adrenoceptors in long-term follow-up. To elucidate the influence of these changes on left ventricular contractility and to provide an effective alternative treatment to re-transplantation in cases of chronic rejection (coronary vasculopathy-CVP, unspecific myocardial allograft failure-UMAF) a clinical study on 19 male transplant recipients after orthotopic heart transplantation without CVP and UMAF in the non-rejecting state was undertaken. Six male patients served as a control group to compare the systolic function at rest. Left ventricular end-systolic pressure-volume relationships (ESPVR) (k-slope) were registered and computer measured using a conductance catheter-technique under conditions of a transiently occluded vena cava and at a fixed heart rate (atrial pacing) in all patients (n = 25). In the transplanted patient group the acute response of enoximone (0.75 mg/kg) administered intravenously was recorded. The position of the ESPVR in the transplanted hearts were not different as compared to the data obtained from the non-transplanted hearts at rest. The k-slope increased from the baseline data after the acute infusion of enoximone in the transplanted hearts. The dosage of enoximone used produced a significant leftward shift in the ESPVR in most patients (89%). In addition, 42% of the patients showed an insignificant drop in left ventricular systolic pressure. Thus, the baseline contractile characteristics of the heart transplant recipients without chronic rejection and in the non-rejecting state is not obviously different from those in non-transplanted patients at rest independent of the time since operation.(ABSTRACT TRUNCATED AT 250 WORDS)