Document Detail


Left atrial mechanical adaptation to long-standing hemodynamic loads based on pressure-volume relations.
MedLine Citation:
PMID:  9605056     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Left atrial (LA) adaptation during the development of left ventricular (LV) dysfunction is not fully understood. We performed echocardiographic assessment of LA volumes simultaneously with recordings of pulmonary wedge pressures in 60 patients. Twenty patients had no structural or functional LV abnormalities, 20 had a recent myocardial infarction with LV dysfunction, and 20 suffered from congestive heart failure (CHF). Pressure-volume loops were obtained at baseline and during increases in LA pressure produced by normal saline infusion. LA afterload was estimated by the effective LV elastance (E(LV)). Atrioventricular coupling was calculated by the E(LV)/E(es) ratio (where E(es) is the end-systolic elastance). E(es) increased in patients with myocardial infarction (0.80 +/- 0.09 mm Hg/ml, p <0.001), whereas it decreased in patients with CHF (0.22 +/- 0.05 mm Hg/ml, p <0.001) compared with controls (0.61 +/- 0.07 mm Hg/ml). Similarly, stroke workload increased in patients with myocardial infarction (60.7 +/- 7.3 mm Hg x ml, p <0.001), whereas it decreased in patients with CHF (25.4 +/- 2.2 mm Hg x ml, p <0.001) compared with controls (44.8 +/- 5.5 mm Hg x ml). In all patients LA stiffness (slope of the relation of the filling portion of the pressure-volume loop) was increased compared with controls (controls: 0.13 +/- 0.04, patients with myocardial infarction: 0.22 +/- 0.05, and patients with CHF: 0.27 +/- 0.05 mm Hg/ml, p <0.001 for both comparisons). Moreover, the E(LV)/E(es) ratio increased gradually as LV function deteriorated (controls: 1.06 +/- 0.10, patients with myocardial infarction: 1.35 +/- 0.16, and patients with CHF: 6.90 +/- 0.84, p <0.001). Thus, early in heart failure, LA pump function is augmented but LA stiffness increases and work mismatch occurs. With further progression of LV dysfunction, LA pump function decreases as a result of increased afterload imposed on the LA myocardium.
Authors:
J M Dernellis; C I Stefanadis; A A Zacharoulis; P K Toutouzas
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The American journal of cardiology     Volume:  81     ISSN:  0002-9149     ISO Abbreviation:  Am. J. Cardiol.     Publication Date:  1998 May 
Date Detail:
Created Date:  1998-06-10     Completed Date:  1998-06-10     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0207277     Medline TA:  Am J Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1138-43     Citation Subset:  AIM; IM    
Affiliation:
First Cardiology Department, Amalia Fleming Hospital, University of Athens, Greece.
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological*
Atrial Function, Left / physiology*
Female
Heart Failure / physiopathology
Humans
Male
Middle Aged
Myocardial Infarction / physiopathology
Ventricular Dysfunction, Left / physiopathology*
Ventricular Function, Left / physiology*
Ventricular Pressure

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