title: Relation of etiology of heart failure (ischemic versus nonischemic) before transplantation to delayed pulmonary oxygen uptake kinetics after heart transplantation.
abstract: The effect that pretransplantation heart failure cause has on pulmonary oxygen uptake (VO2p) kinetics and peak aerobic power (VO2peak) in heart transplant recipients (HTRs) has not been studied. We examined VO2p kinetics and VO2peak in HTRs with previous ischemic heart failure (I-HTRs; n=16, mean age 64+/-6 years) or nonischemic heart failure (NI-HTRs; n=13, mean age 50+/-12 years). HTRs performed an incremental exercise (VO2peak) test and a constant work rate submaximal exercise (VO2p kinetics) test. A monoexponential model was used to determine the phase II VO2p time constant (tau). Phase II VO2p tau was slower in I-HTRs (49+/-10 seconds) than in NI-HTRs (34+/-10 seconds) (p<0.001). No significant difference was found between I-HTRs and NI-HTRs for VO2peak (19.0+/-6.4 vs 23.0+/-8.2 ml.kg-1.min-1, respectively), change in heart rate from rest to steady-state exercise (11+/-8 vs 9+/-9 beats.min-1, respectively), or peak exercise heart rate (140+/-22 vs 144+/-22 beats.min-1, respectively). In conclusion, the prolonged phase II VO2p tau in I-HTRs compared with NI-HTRs suggests that the magnitude of alteration in VO2p kinetics after heart transplantation may be dependent on previous heart failure cause.
authors.affiliation: Cardiovascular Therapeutic Exercise Laboratory, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Corey R
authors.initials: CR
authors.lastname: Tomczak
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Jendzjowsky
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Riess
authors.forename: Wayne
authors.initials: W
authors.lastname: Tymchak
authors.forename: Daniel
authors.initials: D
authors.lastname: Kim
authors.forename: Robert
authors.initials: R
authors.lastname: Haennel
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Haykowsky
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005080:Exercise Test; D016027:Heart Transplantation / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000503:physiopathology* / Q000601:surgery; D011659:Pulmonary Gas Exchange / Q000502:physiology*