Document Detail

Ventilatory inefficiency reflects right ventricular dysfunction in systolic heart failure.
MedLine Citation:
PMID:  20688926     Owner:  NLM     Status:  In-Data-Review    
BACKGROUND: An increased minute ventilation ($$\dot{\hbox{ V }}$$e)/carbon dioxide production (Vco(2)) relationship, an expression of ventilatory inefficiency (VI), is associated with increased morbidity and mortality in patients with left ventricular systolic dysfunction (LVSD). A direct link between VI and a specific cardiac abnormality has not been established.
METHODS: We analyzed cardiopulmonary exercise test (CPET) data from patients (N = 83) with severe LVSD (ischemic and nonischemic; left ventricular ejection fraction [LVEF] 19% ± 7%) and at least moderate exercise intolerance. Subjects were stratified into two groups based on the ($$\dot{\hbox{ V }}$$e/Vco(2) ratio at anaerobic threshold ($$\dot{\hbox{ V }}$$e/Vco(2)@AT) (group 1 $$\dot{\hbox{ V }}$$e/Vco(2)@AT ≤ 34; group 2 $$\dot{\hbox{ V }}$$e/Vco(2)@AT > 34). Clinical, CPET, echocardiographic, and hemodynamic data were compared between groups.
RESULTS: Group 2 subjects had lower exercise capacity (peak ($$\dot{\hbox{ V }}$$o(2), 45.7% ± 11.8% vs 50.4 ± 8.9% predicted; P < .05), with a significantly lower oxygen pulse (71.6% ± 24.5% vs 85.4 ± 18.5% predicted) and maximum systolic BP (122 ± 19 mm Hg vs 138 ± 22 mm Hg; P < .001 for both), suggesting a more blunted stroke volume to exercise vs group 1. There were no differences in left ventricular (LV) size, LVEF, or mitral regurgitation between the two groups. In sharp contrast, group 2 had larger right ventricular (RV) dimensions (4.5 ± 1.1 cm vs 3.9 ± 0.8 cm) and more severe RV systolic dysfunction (RV fractional area change 26% ± 11% vs 33% ± 12%; tricuspid annular plane systolic excursion [TAPSE] 1.6 ± 0.5 cm vs 2.0 ± 0.5 cm; all P < .001) vs group 1. Multivariable analysis revealed that only TAPSE and Doppler-estimated pulmonary artery systolic pressure were independently associated with $$\dot{\hbox{ V }}$$e/Vco(2)@AT and the ($$\dot{\hbox{ V }}$$e/Vco(2)slope. The $$\dot{\hbox{ V }}$$e/Vco(2)@AT, $$\dot{\hbox{ V }}$$e/Vco(2) slope, and TAPSE had nearly identical predictive value for death or transplant.
CONCLUSIONS: The present study suggests that VI is a functional, noninvasive marker of more advanced right-sided heart dysfunction in patients with severe LVSD.
Amanda B Methvin; Anjali T Owens; Anthony G Emmi; Michael Allen; Susan E Wiegers; Daniel L Dries; Kenneth B Margulies; Paul R Forfia
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Publication Detail:
Type:  Journal Article     Date:  2010-08-05
Journal Detail:
Title:  Chest     Volume:  139     ISSN:  1931-3543     ISO Abbreviation:  Chest     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-03-02     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0231335     Medline TA:  Chest     Country:  United States    
Other Details:
Languages:  eng     Pagination:  617-25     Citation Subset:  AIM; IM    
Cardiovascular Division, Heart Failure/Transplant, and Pulmonary Hypertension Programs, Perelman Center for Advanced Medicine, Heart and Vascular Center, 2 E Pavilion, Philadelphia, PA 19104.
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