Cardiovascular and Metabolic Responses to Exercise in Heart Transplanted Children

Abstract

Heart transplantation has become an accepted therapy for end-stage congestive heart failure not only in adults but also in children (P-HTR), particularly following improvements in the immunosuppressive regimens. However, little is known about the structural evolution of the allograft or its adaptive response to increased metabolic demand. Normal growth of the allograft is especially important in P-HTR, since the possibility to undergo cardiac development commensurate to the increase in body size is essential for the normal physical performance of these patients (10). In addition, adequate growth may hypothetically be associated with some form of cardiac reinnervation, which, as is well known, does not occur in adults. So far, however, experimental evidence of sinus node reinnervation is lacking even for P-HTR. In fact, a study by Hsu et al. (2) has shown that the heart rate (HR) response to graded exercise of P-HTR is similar to that of adult HTR (A-HTR).