QT dispersion(QTd,equals maximal minus minimal QT interval on a standard ECG) has been shown to reflect inhomogeneity of myocardial repolarization and cardial electrical instability, hence,been proposed to be associat...QT dispersion(QTd,equals maximal minus minimal QT interval on a standard ECG) has been shown to reflect inhomogeneity of myocardial repolarization and cardial electrical instability, hence,been proposed to be associated with ventricular arrhythmias.But the intrinsical mechanism of QTd is incompletely understood. Contributing to QTd are differences of action potential duration(APD) in the three-dimensional structure of ventricular myocardium, which is identified to own three cell subtypes:endocardial, midmyocardial(M cells) and epicardial cells.And findings suggest that regional differences in the duration of the M cell action potential may lead transmural and spatial dispersion of repolarization. Autonomic nerves by combining receptors on the myocardial cells,especially M cells affect significantly the APD.Concordance between heterogeneity of ventricular myocardium and heterogeneity of autonomic innervation in heart provide support for the role of autonomic nerve in the generation of the QT dispersion.展开更多
文摘QT dispersion(QTd,equals maximal minus minimal QT interval on a standard ECG) has been shown to reflect inhomogeneity of myocardial repolarization and cardial electrical instability, hence,been proposed to be associated with ventricular arrhythmias.But the intrinsical mechanism of QTd is incompletely understood. Contributing to QTd are differences of action potential duration(APD) in the three-dimensional structure of ventricular myocardium, which is identified to own three cell subtypes:endocardial, midmyocardial(M cells) and epicardial cells.And findings suggest that regional differences in the duration of the M cell action potential may lead transmural and spatial dispersion of repolarization. Autonomic nerves by combining receptors on the myocardial cells,especially M cells affect significantly the APD.Concordance between heterogeneity of ventricular myocardium and heterogeneity of autonomic innervation in heart provide support for the role of autonomic nerve in the generation of the QT dispersion.
