Function of Cardiac Myocytes in Ischemicheart Disease: Comparative Changes in Right and Left Ventricular Cells
The contraction and relaxation velocities of single myocytes isolated from failing and nonfailing left and right human ventricles have been compared in order to investigate the possible contribution of cellular changes to the diastolic dysfunction seen in vivo. Myocytes from the failing right ventricle (RV) showed slowed relaxation compared to those from nonfailing, and the change was quantitatively similar to that seen in the failing left ventricle (LV). Poor relaxation was observed in RV myocytes from patients with ischemic heart disease, idiopathic dilated cardiomyopathy, and congenital heart disease. Division of patients into groups with high and low pulmonary artery pressure (PAP) showed a significant relation between raised PAP and slow relaxation of RV myocytes. Cells from the high PAP group were also longer, but not wider, than those from the low PAP group. β-adrenoceptor desensitization was evident in RV myocytes from failing heart, but did not diger in magnitude between high and low PAP groups. As we have previously shown for the LV, diastolic dysfunction in the RV may be related to changes in myocyte function.
KeywordsRight Ventricular Pulmonary Artery Pressure Sarcomere Length Primary Pulmonary Hypertension Contraction Amplitude
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