Microscopic discontinuities in electrical activation were assessed in synthetic strands of neonatal rat myocytes cultured on a growth-directing matrix. An optical method using voltage-sensitive dye (RH-237) and a photodiode technique was used for recordings of membrane potential changes with subcellular resolution. Spatial resolution of the method (diameter of measurement area, 5.5 microns; int...

Function of potential bypass tracts for the atrioventricular conduction was examined in isolated rabbit hearts using microelectrodes, a suction electrode, and bipolar electrocardiographic leads. After the normal A-V conduction was blocked by acetylcholine, conduction to the ventricle occurred with a much shorter A-V conduction time and without significant QRS change, when a point at the root of...

Heat conduction modelling ........................................................................................................................... 1 Case studies ........................................................................................................................................... 2 Analytical solutions.........................................................................

Proton conduction is a fundamental process in biology and in devices such as proton exchange membrane fuel cells. To maximize proton conduction, three-dimensional conduction pathways are preferred over one-dimensional pathways, which prevent conduction in two dimensions. Many crystalline porous solids to date show one-dimensional proton conduction. Here we report porous molecular cages with pro...

THE CONCEPT of concealed conduction was introduced into electrocardiography to explain a lengthening of, or change in, the refractory period of the atrioventricular conduction system caused either by atrial activity that fails to propagate to the ventricles or by ventricular activity that fails to reach the atria. Standard electrocardiograms do not provide a direct demonstration of the partial ...

Heat conduction modelling ........................................................................................................................... 1 Case studies ........................................................................................................................................... 2 Analytical solutions.........................................................................

We look at a basic introduction to classical models of heat conduction, with a few examples including both finite and infinite systems, with techniques appropriate to each based on the boundary and initial conditions. Portions of the paper follow chapter 11 of Theoretical Mechanics of Particles and Continua [1], where I have attempted to expand the analysis in an attempt to provide clarity wher...

or by rapid atrial pacing. Activation times were measured with intracardiac electrode catheters positioned at the right ventricular inflow tract (RVIT), right ventricular apex (RVA), right ventricular outflow tract (RVOT), left ventricular apex (LVA) and left ventricular outflow tract (LVOT). The activation after beginning of QRS in milliseconds ± 1 SD and the number of patients studied at each...