Document Detail


Exercise induces biventricular mechanical dyssynchrony in children with repaired tetralogy of Fallot.
MedLine Citation:
PMID:  21088123     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: The mechanisms underlying adverse electro-mechanical interaction after tetralogy of Fallot (TOF) repair remain unclear. This study investigated biventricular dyssynchrony in children with TOF and its relationship to exercise, QRS duration (QRSd) and ventricular mechanics.
METHODS: 29 asymptomatic children (5-18 years) with repaired TOF were prospectively evaluated by MRI, cardiopulmonary exercise testing and echocardiography at rest and during bicycle exertion. Their dyssynchrony results were compared with those of 44 resting and 27 exercising, age- and sex-matched controls. An intraventricular dyssynchrony index was calculated from the SD of regional time intervals in 12 left ventricular (LV) 'Ts LV-12SD' and eight right ventricular (RV) 'Ts RV-8SD' segments. Ventricular size, volumes, ejection fractions, pulmonary regurgitant volumes and peak oxygen consumption and N-terminal BNP levels were quantified in the patients.
RESULTS: Despite moderate RV dilatation (median indexed RV end-diastolic volume 145.2 ml/m(2)) and right bundle branch block (median QRSd 130 ms) compared with controls, children with TOF demonstrated neither RV nor LV dyssynchrony at rest (Ts RV-8SD, 37.9±10.2 vs 44.3±10.3, 95% CI -11.8 to -0.99, p=0.02; Ts LV-12SD, 38.6±16.8 vs 34.0±10.8, 95% CI -1.8 to 11.0, p=0.16). Exercise stress induced biventricular dyssynchrony in patients with TOF but not in controls (Ts RV-8SD, 59.9±34.4 vs 28.2±10.4, p<0.0001, 95% CI 17.2 to 46.3; Ts LV-12SD, 48.0±18.6 vs 31.9±10.7, 95% CI 7.9 to 24.4, p=0.002). This was unrelated to QRSd, ventricular volumes and function, or peak oxygen consumption.
CONCLUSION: Exercise induces biventricular mechanical dyssynchrony in children with TOF.
Authors:
S Lucy Roche; Lars Grosse-Wortmann; Andrew N Redington; Cameron Slorach; Gareth Smith; Paul F Kantor; Mark K Friedberg
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Heart (British Cardiac Society)     Volume:  96     ISSN:  1468-201X     ISO Abbreviation:  Heart     Publication Date:  2010 Dec 
Date Detail:
Created Date:  2010-11-22     Completed Date:  2011-01-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9602087     Medline TA:  Heart     Country:  England    
Other Details:
Languages:  eng     Pagination:  2010-5     Citation Subset:  AIM; IM    
Affiliation:
The Labatt Family Heart Center, The Hospital for Sick Children, Toronto, Ontario, Canada.
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Arrhythmias, Cardiac / etiology*
Child
Child, Preschool
Echocardiography
Exercise / physiology*
Female
Humans
Magnetic Resonance Angiography
Male
Prospective Studies
Pulmonary Valve Insufficiency / etiology
Tetralogy of Fallot / complications*,  surgery
Ventricular Dysfunction, Left / etiology*
Ventricular Dysfunction, Right / etiology*
Grant Support
ID/Acronym/Agency:
//Canadian Institutes of Health Research

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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