Evolution of human cardiac myocyte dimension during prolonged mechanical support (original) (raw)
Related papers
Circulation. Heart failure, 2011
Unloading a failing heart with a left ventricular assist device (LVAD) can improve ejection fraction (EF) and LV size; however, recovery with LVAD explantation is rare. We hypothesized that evaluation of myocyte contractility and biochemistry at the sarcomere level before and after LVAD may explain organ-level changes. Paired LV tissue samples were frozen from 8 patients with nonischemic cardiomyopathy at LVAD implantation (before LVAD) and before cardiac transplantation (after LVAD). These were compared with 8 nonfailing hearts. Isolated skinned myocytes were purified and attached to a force transducer, and dimensions, maximum calcium-saturated force, calcium sensitivity, and myofilament cooperativity were assessed. Relative isoform abundance and phosphorylation levels of sarcomeric contractile proteins were measured. With LVAD support, the unloaded EF improved (10.0±1.0% to 25.6±11.0%, P=0.007), LV size decreased (LV internal dimension at end diastole, 7.6±1.2 to 4.9±1.4 cm; P<...
Journal of the American College of Cardiology, 2014
In animal models of heterotopic transplantation, mechanical unloading of the normal, nonhypertrophic heart results in atrophy. Primarily on the basis of these animal data, the notion that chronic left ventricular assist device (LVAD)-induced unloading will result in atrophy has dominated the clinical heart failure field, and anti-atrophic drugs have been used to enhance the cardiac recovery potential observed in some LVAD patients. However, whether unloading-induced atrophy in experimental normal heart models applies to failing and hypertrophic myocardium in heart failure patients unloaded by continuous-flow LVADs has not been studied. The study examined whether mechanical unloading by continuous-flow LVAD leads to myocardial atrophy. We prospectively examined myocardial tissue and hemodynamic and echocardiographic data from 44 LVAD patients and 18 untransplanted normal donors. Cardiomyocyte size (cross-sectional area) decreased after LVAD unloading from 1,238 ± 81 μm(2) to 1,011 ± ...