Document Detail

Left ventricular echocardiographic and histologic changes: impact of chronic unloading by an implantable ventricular assist device.
MedLine Citation:
PMID:  8613620     Owner:  NLM     Status:  MEDLINE    
OBJECTIVES: We studied the effects of chronic left ventricular unloading by a ventricular assist device and assessed left ventricular morphologic and histologic changes. BACKGROUND: The implantable left ventricular assist device has been effective as a "bridge" to cardiac transplantation. Although there are reports documenting its circulatory support, little is known about the effects of chronic left ventricular unloading on the heart itself. METHODS: We performed intraoperative transesophageal echocardiography at the insertion and explanation of a HeartMate left ventricular assist device in 19 patients with end-stage heart failure. They were supported by the assist device for 3 to 153 days (mean [+/-SD] 68 +/- 33). Measurements were taken retrospectively to obtain left atrial and ventricular diameters and interventricular septal and posterior wall thicknesses. Histologic examinations were made from the left ventricular myocardial specimens of 15 patients at the times of insertion and explanation for heart transplantation. Insertion and explanation specimens were compared qualitatively (0 to 3 scale) for wavy fibers, contraction band necrosis and fibrosis, with quantitative measurement of minimal myocyte diameter across the nucleus. RESULTS: Left atrial and left ventricular diastolic and systolic diameters decreased immediately after insertion of the left ventricular assist device (from 46 to 35, 63 to 41 and 59 to 36 mm, respectively, all p < 0.001). Left ventricular wall thickness increased from 10 to 14 mm (p < 0.001) for the interventricular septum and from 10 to 13 mm for the posterior wall (p<0.001). No echocardiographic measurements showed significant subsequent changes at the chronic stage. Myocardial histologic findings demonstrated a reduction in myocyte damage (from 1.9 to 0.5, p<0.001, for wavy fiber and from 1.3 to 0.2, p<0.01, for contraction band necrosis) and an increase in fibrosis (from 1.3 to 1.9, p<0.05), but without significant change in myocyte diameter (from 15.6 to 16.8 micrometer, p=0.065). CONCLUSIONS: Left ventricular unloading with the implantable assist device induces an immediate increase in wall thickness, consistent with the reduction in chamber size, thereby decreasing wall stress. Chronic unloading allows myocardial healing and fibrosis without evidence for ongoing myocyte damage or atrophy. Left ventricular assist device insertion may have a role in "resting" the ventricle for selected patients with heart failure.
S Nakatani; P M McCarthy; K Kottke-Marchant; H Harasaki; K B James; R M Savage; J D Thomas
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of the American College of Cardiology     Volume:  27     ISSN:  0735-1097     ISO Abbreviation:  J. Am. Coll. Cardiol.     Publication Date:  1996 Mar 
Date Detail:
Created Date:  1996-06-03     Completed Date:  1996-06-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8301365     Medline TA:  J Am Coll Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  894-901     Citation Subset:  AIM; IM    
Department of Cardiology, The Cleveland Clinic Foundation, Ohio 44195, USA.
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MeSH Terms
Analysis of Variance
Echocardiography, Transesophageal
Endomyocardial Fibrosis / pathology
Heart Atria / pathology,  ultrasonography
Heart Ventricles / pathology,  ultrasonography*
Heart-Assist Devices*
Least-Squares Analysis
Linear Models
Middle Aged
Retrospective Studies
Ventricular Function, Left*

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

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