Regression of cellular hypertrophy after left ventricular assist device support.
BACKGROUND
Although multiple studies have shown that the left ventricular assist device (LVAD) improves distorted cardiac geometry, the pathological mechanisms of the "reverse remodeling" of the heart are unknown. Our goal was to determine the effects of LVAD support on cardiac myocyte size and shape.


RESULTS
Isolated myocytes were obtained at cardiac transplantation from 30 failing hearts (12 ischemic, 18 nonischemic) without LVAD support, 10 failing hearts that received LVAD support for 75+/-15 days, and 6 nonfailing hearts. Cardiac myocyte volume, length, width, and thickness were determined by use of previously validated techniques. Isolated myocytes from myopathic hearts exhibited increased volume, length, width, and length-to-thickness ratio compared with normal myocytes (P<0.05). However, there were no differences in any parameter between myocytes from ischemic and nonischemic cardiomyopathic hearts. Long-term LVAD support resulted in a 28% reduction in myocyte volume, 20% reduction in cell length, 20% reduction in cell width, and 32% reduction in cell length-to-thickness ratio (P<0.05). In contrast, LVAD support was associated with no change in cell thickness. These cellular changes were associated with reductions in left ventricular dilation and left ventricular mass measured echocardiographically in 6 of 10 LVAD-supported patients.


CONCLUSIONS
These studies suggest that the regression of cellular hypertrophy is a major contributor to the "reverse remodeling" of the heart after LVAD implantation. The favorable alterations in geometry that occur in parallel fashion at both the organ and cellular levels may contribute to reduced wall stress and improved mechanical performance after LVAD support.
Department of Internal Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA.
A
A
Zafeiridis
V
V
Jeevanandam
S R
SR
Houser
K B
KB
Margulies
D001794:Blood Pressure; D002467:Cell Nucleus / Q000473:pathology; D004452:Echocardiography; D005260:Female; D006333:Heart Failure / Q000209:etiology / Q000503:physiopathology / Q000601:surgery; D016027:Heart Transplantation; D006353:Heart-Assist Devices; D006439:Hemodynamics; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D016277:Ventricular Function, Left