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BACKGROUND In cardiac hypertrophy, ECG T-wave changes imply an abnormal sequence of ventricular repolarization. We investigated the hypothesis that this is due to changes in the normal regional differences in action potential duration. We assessed the contribution of potassium- and calcium-dependent currents to these differences. Both the altered sequence(More)
OBJECTIVE To compare the properties of single myocytes isolated from different layers of the basal region of the left ventricle and to test the hypothesis that differences in the delayed rectifier current (IK) contribute to regional differences in action potential duration. METHODS Myocytes were isolated from basal sub-endocardial, mid-myocardial and(More)
OBJECTIVE To test the hypothesis that changes in the normal regional distribution of potassium and calcium currents contribute to the different regional changes in action potential duration in isoprenaline-induced hypertrophy in rats. METHODS Hypertrophy was elicited in rats by seven daily injections of isoprenaline. Left ventricular myocytes were(More)
Cardiac hypertrophy was induced in rats by daily injection of isoproterenol (5 mg/kg ip) for 7 days. Membrane voltage and currents were recorded using the whole cell patch-clamp technique in left ventricular myocytes from control and hypertrophied hearts. Ryanodine-sensitive delayed afterdepolarizations (DADs) and transient inward current (I(ti)) appeared(More)
OBJECTIVE The aim was to look for membrane current changes as a basis for the prolongation of action potential duration in left ventricular myocytes following abdominal aortic coarctation. METHODS Immature female guinea pigs underwent laparotomy and an aortic coarctation was fashioned immediately distal to the renal arteries. After 20 weeks the hearts(More)
Patients with classical heat stroke are different in many ways from those with exertional injury; contrasts included difference in demographic factors, prior general health, in-hospital complications and laboratory abnormalities (lactate, liver enzymes, pH, electrolytes). Severe hyperkalemia, acute renal failure, rhabdomyolysis and disseminated(More)
Major regional differences in the electrical properties of myocytes from ventricular muscle have been described previously, on the basis of samples taken from a maximum of three regions in each heart. In order to define the topographical basis for such differences, we studied the electrical and mechanical properties of single myocytes isolated from 20(More)
Regional differences in action potential characteristics and membrane currents were investigated in subendocardial, midmyocardial and subepicardial myocytes isolated from the left ventricular free wall of guinea-pig hearts. Action potential duration (APD) was dependent on the region of origin of the myocytes (P < 0.01, ANOVA). Mean action potential duration(More)
The general anatomy of the cardiac conduction system (CCS) has been known for 100 years, but its complex and irregular three-dimensional (3D) geometry is not so well understood. This is largely because the conducting tissue is not distinct from the surrounding tissue by dissection. The best descriptions of its anatomy come from studies based on serial(More)