OBJECTIVE In this study we investigated whether differences exist or develop in patients with aortic or mitral valve disease in myofibrillar contractile function and contractile protein composition between subendo- and subepicardial human ventricular tissue. Isometric tension, its calcium sensitivity and contractile protein composition were studied in left ventricular subendo- and subepicardial...

The experimental and clinical possibilities for studying cardiac arrhythmias in human ventricular myocardium are very limited. Therefore, the use of alternative methods such as computer simulations is of great importance. In this article we introduce a mathematical model of the action potential of human ventricular cells that, while including a high level of electrophysiological detail, is comp...

Considering that the left ventricle is a thick-walled body that maintains its volume while reducing intracavitary volume by two thirds, it should come as no surprise that the ventricular wall thickens during systole and that there is a transmural gradient in wall thickening. Wall thickening on the inner wall may exceed values of 40% measured by a variety of techniques. These values far exceed t...

Background—Transthoracic epicardial catheter ablation is an emerging catheter ablation strategy being used clinically at increasing frequency. However, the efficacy of standard RF ablation on the epicardial surface of the heart is hindered by (1) the lack of convective cooling of the ablation electrode and (2) the varying presence of epicardial adipose tissue interposed between the ablation ele...

Mutations in minK-related peptide 1 (MiRP1), the product of the KCNE2 gene, have been associated with malignant ventricular arrhythmia syndromes related to impaired repolarization. MiRP1 interacts with a variety of ion-channel alpha-subunits, dysfunction of which could account for arrhythmia syndromes; however, the observation of very low-level expression of MiRP1 in ventricular tissue has led ...

Increased ventricular expression of several genes, including atrial natriuretic factor (ANF), has been documented in experimental models of cardiac hypertrophy. It remains to be clarified whether altered expression of these genes is a consistent marker of the hypertrophy itself or a marker of some parallel pathogenetic process. Using a transgenic mouse model of hypertrophic cardiomyopathy as a ...

A simplified quantitative ionic model of cardiac action potential, which reproduces accurate restitution curves, is used in conjunction with global tissue characteristics such as rotational cell anisotropy and periodic boundaries to study the transition from ventricular tachychardia (VT) to ventricular fibrillation (VF). We give an explanation for the experimental observation that there is a mi...

a 5-day-old female holstein calf was necropsied because of lethargy, recumbency and anorexia. at necropsy, multiple gross defects were evident in several organs, including unclosed sutures of skull bones, asymmetrical orbits, doming of the skull bones, hydrocephalus, hydranencephaly, cleft palate, brachygnathia, ventricular septal defect, mitral valve dysplasia and rudimentary lungs. on microsc...

this is a report of the first proved case of congenital toxoplasmosis in iran in an infant who died with hypothermia and lethargia 29 days after birth. both parents showed serological evidence of toxoplasmosis and, the finding in the mother indicated recent infection. the baby, during her short life, showed prominent neurological disorders and hepatosplenomegaly. toxoplasms were demonstrated in...

background: we sought to assess right ventricular (rv) systolic and diastolic functions via tissue doppler imaging (tdi) in order to discriminate right-to-left (bidirectional) from left-to-right intracardiac shunts. methods: a tissue doppler velocity study via doppler echocardiography was performed in 20 patients with left-to-right shunt (without evidence of significant pulmonary hypertension) ...