摘要
To evaluate effects of β adrenergic receptor blockade on allograft performan ce, and to correlate these effects with sympathetic reinnervation. Myocardial ca techolamine storage capacity was determined in 12 non rejecting transplant reci pients using PET and C 11 adrenaline (epinephrine). Haemodynamics and left vent ricular function were measured using radionuclide angiography at rest and during symptom limited exercise before and after non selective β blockade(proprano lol iv). Exercise time and stress induced increases of heart rate and LVEF befo re β blockade were significantly higher in reinnervated compared to denervated recipients. While resting LVEF remained unchanged, heart rate and blood pressur e were generally reduced by β blockade, which was well tolerated by all patien ts. Exercise time and increases of heart rate and LVEF were more attenuated in r einnervated recipients. Differences of chronotropic and inotropic response to ex ercise between groups were no longer present following β blockade. Correlation s between myocardial adrenaline retention, peak heart rate and increase of globa l, as well as regional ejection fraction during exercise were observed before, b ut not during β blockade. Acute, non selective β blockade is well tolerated by transplant recipients, but significantly attenuates beneficial functional ef fects of sympathetic reinnervation on exercise performance. The data suggest tha t reappearance of sympathetic nerve terminals is associated with reestablishment of intact pre/postsynaptic interaction.
To evaluate effects of β adrenergic receptor blockade on allograft performan ce, and to correlate these effects with sympathetic reinnervation. Myocardial ca techolamine storage capacity was determined in 12 non rejecting transplant reci pients using PET and C 11 adrenaline (epinephrine). Haemodynamics and left vent ricular function were measured using radionuclide angiography at rest and during symptom limited exercise before and after non selective β blockade(proprano lol iv). Exercise time and stress induced increases of heart rate and LVEF befo re β blockade were significantly higher in reinnervated compared to denervated recipients. While resting LVEF remained unchanged, heart rate and blood pressur e were generally reduced by β blockade, which was well tolerated by all patien ts. Exercise time and increases of heart rate and LVEF were more attenuated in r einnervated recipients. Differences of chronotropic and inotropic response to ex ercise between groups were no longer present following β blockade. Correlation s between myocardial adrenaline retention, peak heart rate and increase of globa l, as well as regional ejection fraction during exercise were observed before, b ut not during β blockade. Acute, non selective β blockade is well tolerated by transplant recipients, but significantly attenuates beneficial functional ef fects of sympathetic reinnervation on exercise performance. The data suggest tha t reappearance of sympathetic nerve terminals is associated with reestablishment of intact pre/postsynaptic interaction.
