A tetrodotoxin-sensitive persistent sodium current, I(pNa), was found in guinea pig ventricular myocytes by whole-cell patch clamping. This current was characterized in cells derived from the basal left ventricular subendocardium, midmyocardium, and subepicardium. Midmyocardial cells show a statistically significant (P<0.05) smaller I(pNa) than subendocardial and subepicardial myocytes. There w...

A finite element model for the diastolic anine left vcntricle based on large deformation theory has been developed. The myecardial stress-strain relation determined by the diastoric pressure-yolume relation was used in this study, The ventricle was assumed as a homogeneous, isotropic, thick-walled solid of revolution with variable thickness. The predicted shapes based on the model were in close...

The classical ischemic cascade anticipates perfusion disturbances to precede the development of wall motion abnormalities, but does not account for regional heterogeneity of both perfusion and function. In this issue of JACC: Cardiovascular Imaging, Xie et al. (1) examine the impact of subendocardial ischemia (identified using real-time myocardial contrast echocardiography [MCE]) on myocardial ...

The adequacy of intraoperative epicardial mapping as a guide to surgical procedures performed to terminate ventricular arrhythmias was investigated. Ligation of the anterior septal or left anterior descending coronary artery in 28 dogs produced ventricular arrhythmias that were studied 24-36 hours following occlusion. The sites of origin of 26 tachycardias were determined to be in the subendoca...

he mechanism of myocardial infarction and Tunexpected sudden cardiac death remains incompletely defined. The frequent absence of complete coronary arterial obstruction in both these conditions' has challenged the concept of arterial obstruction followed by infarction or sudden death or both. Several independent observations are herein developed into a working hypothesis for the pathogenesis of ...

Background Myocardial perfusion and strain (in particular longitudinal strainLS) are reduced in severe aortic stenosis (AS). It is thought that reduced perfusion occurs in the subendocardium secondary to increased LV pressure, leading to fibrosis and reduced LS. This relationship between perfusion, diffuse fibrosis and multidirectional myocardial strain has not been previously investigated in m...

Eosinophilic myocarditis is a disease characterized by eosinophilic infiltration of the myocardium, consisting of acute necrotic stage, thrombotic stage, and fibrotic stage. Although T1 mapping has been increasingly used in various cardiac pathologies, there has been no report of T1 mapping in eosinophilic myocarditis. We report a case of 75-year-old female with eosinophilic myocarditis, whose ...

Background The effects of ischemia are first realized in the subendocardium and progress transmurally. Hence, detection of the transmural extent of myocardial perfusion (MP) defects has important diagnostic/prognostic implications. Systolic MP imaging using ECG-gated methods has been shown to provide improved visualization of subendocardial defects [1]. We developed an innovative non-ECGgated p...

In 1845, Johannes Evangelista Purkinje (Purkyně) discovered gelatinous fibers in the ventricular subendocardium. Later, they were called Purkinje fibers. However, he could not determine the function of that strange tissue and thought it was muscular. In 1906, Sunao Tawara finally described its function as the conducting system (Figure). In the last 3 decades, there has been rapid progress in th...