Document Detail

Immediate functional effects of left ventricular reduction: a Doppler echocardiographic study in the rat.
MedLine Citation:
PMID:  16520267     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Immediate functional effects of left ventricle reduction (LVR) are not yet fully defined. Those effects have been studied in the experimental model of myocardial infarction scar plication (MISP) in the rat. METHODS AND RESULTS: A Doppler echocardiogram was performed immediately before and after MISP in 20 rats with infarction of the left ventricle (LV) larger than 40%. LV diastolic volume reduction (475 +/- 114 versus 185 +/- 65 muL) was accompanied by heart rate decrease (230 +/- 25 versus 166 +/- 27 beats/min) and increase of ejection fraction (37 +/- 7 versus 67 +/- 12%), fractional shortening (18 +/- 3 versus 46 +/- 8%) and posterior wall shortening velocity (1.50 +/- 0.62 versus 2.01 +/- 0.46 cm/s). LV diastolic volume/stroke volume slope was steeper after LVR, suggesting enhancement of the Frank-Starling mechanism. Restrictive pattern of left atrial emptying was alleviated after LVR (E wave: 101 +/- 15 versus 66 +/- 14 cm/s; E/A ratio: 6.8 +/- 2.9 versus 5.0 +/- 2.2; E wave deceleration time: 36 +/- 6 versus 51 +/- 10 msec) even though left atrial diameter (0.69 +/- 0.07 versus 0.66 +/- 0.06 cm) and A wave (18.0 +/- 9.4 versus 15.8 +/- 7.8 cm/s) did not vary. Additionally, a pulmonary flow profile suggesting pulmonary hypertension was observed in 12 of 17 animals before, and in only 3 after, LVR. CONCLUSION: LVR favors cardiac function not only by reducing afterload. The present data are in consonance with previous suggestions that the Frank-Starling mechanism is enhanced after MISP and, in addition to LV ejection function improvement, the unprecedented facilitation of left atrial emptying after LVR was particularly noteworthy. Even though LVR restricts ventricular distensibility, atrial emptying can be facilitated, probably on account of LV ejection improvement.
Rosemeire M Kanashiro; Roberto M Saraiva; Alexandra Alberta; Ednei L Antonio; Valdir A Moisés; Paulo J F Tucci
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of cardiac failure     Volume:  12     ISSN:  1532-8414     ISO Abbreviation:  J. Card. Fail.     Publication Date:  2006 Mar 
Date Detail:
Created Date:  2006-03-07     Completed Date:  2006-08-08     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9442138     Medline TA:  J Card Fail     Country:  United States    
Other Details:
Languages:  eng     Pagination:  163-9     Citation Subset:  IM    
Department of Physiology, Federal University of São Paulo, Rua Estado de Israel 181/94, CEP: 04022-000 São Paulo, Brazil.
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MeSH Terms
Blood Flow Velocity / physiology
Cicatrix / surgery*,  ultrasonography
Diastole / physiology
Disease Models, Animal
Echocardiography, Doppler, Pulsed*
Heart Rate / physiology
Heart Ventricles / physiopathology,  surgery*,  ultrasonography*
Hypertension, Pulmonary / physiopathology,  ultrasonography
Myocardial Infarction / physiopathology,  surgery*,  ultrasonography
Myocardium / pathology
Pulmonary Circulation / physiology
Rats, Wistar
Stroke Volume / physiology
Systole / physiology

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

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