Document Detail

The importance of the muscle and ventilatory blood pumps during exercise in patients without a subpulmonary ventricle (Fontan operation).
MedLine Citation:
PMID:  23083785     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: The aim of this study was to determine the relative contribution of the muscle and ventilatory pumps to stroke volume in patients without a subpulmonic ventricle.
BACKGROUND: In patients with Fontan circulation, it is unclear how venous return is augmented to increase stroke volume and cardiac output during exercise.
METHODS: Cardiac output (acetylene rebreathing), heart rate (electrocardiography), oxygen uptake (Douglas bag technique), and ventilation were measured in 9 patients age 15.8 ± 6 years at 6.1 ± 1.8 years after Fontan operation and 8 matched controls. Data were obtained at rest, after 3 min of steady-state exercise (Ex) on a cycle ergometer at 50% of individual working capacity, during unloaded cycling at 0 W (muscle pump alone), during unloaded cycling with isocapnic hyperpnea (muscle and ventilatory pump), during Ex plus an inspiratory load of 12.8 ± 1.5 cm water, and during Ex plus an expiratory load of 12.8 ± 1.6 cm water.
RESULTS: In Fontan patients, the largest increases in stroke volume and stroke volume index were during zero-resistance cycling. An additional increase with submaximal exercise occurred in controls only. During Ex plus expiratory load, stroke volume indexes were reduced to baseline, non-exercise levels in Fontan patients, without significant changes in controls.
CONCLUSIONS: With Fontan circulation increases in cardiac output and stroke volume during Ex were due to the muscle pump, with a small additional contribution by the ventilatory pump. An increase in intrathoracic pressure played a deleterious role in Fontan circulation by decreasing systemic venous return and stroke volume.
Keri M Shafer; Jorge A Garcia; Tony G Babb; David E Fixler; Colby R Ayers; Benjamin D Levine
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-10-17
Journal Detail:
Title:  Journal of the American College of Cardiology     Volume:  60     ISSN:  1558-3597     ISO Abbreviation:  J. Am. Coll. Cardiol.     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-09     Completed Date:  2013-01-29     Revised Date:  2013-07-17    
Medline Journal Info:
Nlm Unique ID:  8301365     Medline TA:  J Am Coll Cardiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2115-21     Citation Subset:  AIM; IM    
Copyright Information:
Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
Department of Internal Medicine, University of Texas Southwestern, Dallas, TX, USA.
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MeSH Terms
Cardiac Output / physiology
Exercise / physiology*
Exercise Test
Exercise Tolerance / physiology*
Fontan Procedure*
Heart Rate / physiology*
Oxygen Consumption / physiology*
Stroke Volume / physiology*
Young Adult
Grant Support
Comment In:
J Am Coll Cardiol. 2013 Jun 4;61(22):2314-5   [PMID:  23524225 ]
J Am Coll Cardiol. 2013 Jun 4;61(22):2314   [PMID:  23524222 ]

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