UNIGE document Scientific Article
previous document  unige:10355  next document
add to browser collection
Title

Age-related heart rate response to exercise in heart transplant recipients. Functional significance

Authors
Marconi, Claudio
Marzorati, Mauro
Fiocchi, Roberto
Mamprin, Filippo
Ferrazzi, Paolo
Published in Pflügers Archiv. 2002, vol. 443, no. 5-6, p. 698-706
Abstract The heart rate (HR) and O(2) uptake (VO(2)) responses to cycle ergometer exercise and the role of O(2) transport in limiting submaximal and maximal aerobic performance were assessed in 33 heart transplant recipients (HTR) [14 children (P-HTR), 11 young adults (YA-HTR) and 8 middle-age adults (A-HTR)] and in 28 age-matched control subjects (CTL). In 7 P-HTR ("responders") the HR response to the onset of exercise (on-response) was as fast as that of CTL, whereas in all other patients ("non-responders") the HR on-response was typical of the denervated heart. Compared with non-responder P-HTR, responder P-HTR were also characterized by a normal peak HR (177+/- 16 vs. 151+/- 25 beats/min), an equally slow time constant for the VO(2) on-response (tau: 54 +/- 11 vs. 62+/- 13 s) and a similar low (approximately 60% of that of CTL) peak VO(2) (28 +/- 7 vs. 26 +/- 10 ml/kg per min). On the other hand non-responder YA-HTR and A-HTR were characterized by a relatively low peak HR (151 +/- 21 and 144 +/- 29 beats/min, respectively), a slow tau for the on-response (63 +/- 12 and 70 +/- 11 s) and a low peak (28 +/- 7 and 19 +/- 6 ml/kg per min). In conclusion, a sizeable number of paediatric patients (responder P-HTR) may reacquire the normal HR response to exercise, both in terms of kinetics and maximal level. Despite the almost complete recovery of cardiovascular function, and, probably, oxygen delivery, both the kinetics of the VO(2) on-response and the maximal aerobic power of the responder P-HTR were similar to those of non-responder P-HTR. The latter finding is probably attributable to peripheral limitations, due to inborn and/or pharmacological muscle deterioration.
Keywords AdolescentAdultAging/ physiologyFemaleHeart/innervation/physiologyHeart Rate/ physiologyHeart TransplantationHumansMaleMiddle AgedMuscle, Skeletal/physiologyOxygen Consumption/ physiologyPhysical Exertion/ physiologyPulmonary Gas Exchange/physiology
Stable URL http://archive-ouverte.unige.ch/unige:10355
Full text
Identifiers
PMID: 11889566
Structures
141 hits and 0 download since 2010-08-06
Update
Export document
Format :
Citation style :