Document Detail


Left ventricular distensibility does not explain impaired exercise capacity in pediatric heart transplant recipients.
MedLine Citation:
PMID:  23260705     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
BACKGROUND: Despite improved ventricular function after heart transplantation, the aerobic capacity, as measured by peak oxygen consumption (VO(2peak)) of pediatric heart transplant recipients (HTRs), remains 30% to 50% lower than age-matched healthy individuals. Research in adult HTRs suggests that diastolic dysfunction is a major determinant of exercise intolerance; however, it is unknown whether the impaired VO(2peak) in younger HTRs is due to reduced left ventricular (LV) distensibility.
METHODS: Eight HTRs (mean age, 15 years; mean time post-transplant, 7 years) and 8 matched healthy controls were studied. To evaluate LV distensibility, echocardiographic measurements of ventricular volumes were obtained in 3 positions: supine, head-up tilt, and head-down tilt. Subsequently, participants underwent exercise stress testing to evaluate VO(2peak).
RESULTS: As expected, VO(2peak) was 26% lower in HTRs (p<0.05). Ventricular volumes in each position were small in HTRs (p = 0.01); however, the percentage change in LV end-diastolic volume indexed (EDVi) to body surface area after the transition from supine to head-up tilt and from head-up tilt to head-down tilt were similar between HTRs (p = 0.956) and controls (p = 0.801). The change in EDVi during the transition from head-up tilt to head-down tilt (LV distensibility) strongly predicted VO(2peak) in patients (R(2) = 0.614, p = 0.021) and controls (R(2) = 0.510, p = 0.047). Importantly, the slope of this relationship did not differ between HTRs (1.01) and controls (0.977; p = 0.951).
CONCLUSIONS: LV distensibility does not appear to be a major determinant of exercise intolerance in young HTR.
Authors:
Luis A Altamirano-Diaz; Michael D Nelson; Lori J West; Nee S Khoo; Ivan M Rebeyka; Mark J Haykowsky
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation     Volume:  32     ISSN:  1557-3117     ISO Abbreviation:  J. Heart Lung Transplant.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2012-12-24     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9102703     Medline TA:  J Heart Lung Transplant     Country:  United States    
Other Details:
Languages:  eng     Pagination:  63-9     Citation Subset:  IM    
Copyright Information:
Copyright © 2013 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.
Affiliation:
Stollery Children's Hospital, University of Alberta, Edmonton, Alberta, Canada; Department of Pediatrics, Children's Hospital, London Health Science Centre, University of Western Ontario, London, Ontario, Canada. Electronic address: luis.altamiranodiaz@lhsc.on.ca.
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