Document Detail

Changes in QRS duration are associated with maximal exercise capacity in adult patients with repaired tetralogy of Fallot.
MedLine Citation:
PMID:  16137509     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: In adult patients with repaired tetralogy of Fallot (TF) QRS duration at rest seems to be a predictor of maximal exercise. We examined the relationship between QRS duration during exercise and exercise performance. DESIGN: In 57 consecutive TF patients QRS duration in V1 (ms) was measured at rest, at maximal exercise (Wmax, W), and at peak oxygen consumption (peak VO2, ml/min). Stroke volume (SV) was calculated from cardiac output, obtained by CO2 rebreathing. Spearman rank correlation was used to describe the relationship between QRS duration and exercise performance. Statistical significance was defined as P<0.05. RESULTS: Seven patients, who didn't pass the anaerobic threshold, and one outlier (Wmax=340 W) were excluded, resulting in a sample of 49 patients (75.5% male; median age=24 years, range 16-43 years). QRS duration at rest (median=160 ms, range 78-194 ms) and at maximal exercise (median=153 ms, range 80-193 ms) did not differ significantly. The median change of QRS duration during exercise was -5 ms (range -31 to +83 ms). This was negatively correlated with Peak VO2 (2081+/-577 ml/min; rho=-0.33, P=0.02) and Wmax (182+/-53 Watt; rho=-0.33, P=0.02). In patients with QRS shortening peak VO2 and the exercise induced increase in SV were significantly higher than in patients with QRS shortening. CONCLUSIONS: This study indicates that QRS shortening during exercise in TF patients is related with a better exercise performance. Lower increase in stroke volumes may be responsible for this difference. Further research is needed to elaborate these findings.
W Budts; Johan Defoor; An Stevens; M Vanden Wyngaerd; Ph Moons; L Vanhees
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  International journal of cardiology     Volume:  104     ISSN:  0167-5273     ISO Abbreviation:  Int. J. Cardiol.     Publication Date:  2005 Sep 
Date Detail:
Created Date:  2005-09-02     Completed Date:  2006-08-08     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8200291     Medline TA:  Int J Cardiol     Country:  Ireland    
Other Details:
Languages:  eng     Pagination:  46-51     Citation Subset:  IM    
Internal Medicine, Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium.
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MeSH Terms
Cardiac Surgical Procedures*
Exercise Test
Exercise Tolerance*
Heart Conduction System / physiopathology*
Oxygen Consumption
Severity of Illness Index
Stroke Volume
Tetralogy of Fallot / physiopathology*,  surgery*
Time Factors
Treatment Outcome
Ventricular Dysfunction, Right / physiopathology,  surgery

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