title: Progressive improvement in hemodynamic response to muscle metaboreflex in heart transplant recipients.
abstract: Exercise capacity remains lower in heart transplant recipients (HTRs) following transplant compared with normal subjects, despite improved cardiac function. Moreover, metaboreceptor activity in the muscle has been reported to increase. The aim of the present investigation was to assess exercise capacity together with metaboreflex activity in HTR patients for 1 yr following heart transplant, to test the hypothesis that recovery in exercise capacity was paralleled by improvements in response to metaboreflex. A cardiopulmonary test for exercise capacity and Vo(2max) and hemodynamic response to metaboreflex activation obtained by postexercise ischemia were gathered in six HTRs and nine healthy controls (CTL) four times: at the beginning of the study (T0, 42 ± 6 days after transplant), at the 3rd, 6th, and 12th month after TO (T1, T2, and T3). The main results were: 1) exercise capacity and Vo(2max) were seen to progressively increase in HTRs; 2) at T0 and T1, HTRs achieved a higher blood pressure response in response to metaboreflex compared with CTL, and this difference disappeared at T2 and T3; and 3) this exaggerated blood pressure response was the result of a systemic vascular resistance increment. This study demonstrates that exercise capacity progressively improves in HTRs after transplant and that this phenomenon is accompanied by a progressive reduction of the metaboreflex-induced increase in blood pressure and systemic vascular resistance. These facts indicate that, despite improved cardiac function, resetting of cardiovascular regulation in HTRs requires months.
authors.affiliation: Department of Medical Sciences, Sport Physiology Lab., University of Cagliari, Italy. crisafulli@tiscali.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Crisafulli
authors.forename: Filippo
authors.initials: F
authors.lastname: Tocco
authors.forename: Raffaele
authors.initials: R
authors.lastname: Milia
authors.forename: Luca
authors.initials: L
authors.lastname: Angius
authors.forename: Marco
authors.initials: M
authors.lastname: Pinna
authors.forename: Sergio
authors.initials: S
authors.lastname: Olla
authors.forename: Silvana
authors.initials: S
authors.lastname: Roberto
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Marongiu
authors.forename: Maurizio
authors.initials: M
authors.lastname: Porcu
authors.forename: Alberto
authors.initials: A
authors.lastname: Concu
mesh_terms: D001794:Blood Pressure / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D016027:Heart Transplantation / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007511:Ischemia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D012018:Reflex / Q000502:physiology*