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We have developed an analytical method based on Mathieu functions to solve Poisson's equation in homogeneous right elliptical cylinders. We apply the method to a detailed study of the electric-potential distribution in the bulk and on the surface of ohmic conductors of such a shape, fed by a current dipole located at any inside position. Contrary to a common opinion in electrocardiology, the potential contour map on the surface of cylinders of pronounced ellipticity has more than one maximum and one minimum if the dipole is located close and parallel to the symmetry plane containing the axes of greatest lengths, i.e., the ellipse major axis and the cylinder axis. The extrema are located near the intersection with the plane normal to the previous one and containing the dipole axis. We discuss the cases of cylinders with different ellipticity and dimension ratio, focusing on the evolution of the number and position of the surface-potential extrema as a function of the location and orientation of the dipole with respect to the nearby boundary. [ABSTRACT FROM AUTHOR]

Eleven open chest, artificially ventilated rats were used to observe and compare the intracellular potential changes induced in the right and left ventricles by an acute right ventricular overload. Graded right ventricular hypertension was produced by external constriction of the main pulmonary artery. Transmembrane potentials were obtained using floating glass microelectrodes filled with 3 mol·litre−1 KCl and connected to a cathode follower through a silverchloride-silver junction.Following right ventricular overload, the level of the resting potential was depolarised by 20% on the right ventricle and by 4% on the left (P <0.001). The repolarisation was not significantly affected. A significant correlation (P <0.01) was observed between the increase of right ventricular pressure and the depolarisation of resting right ventricular potential.The right ventricular distension which occurs in our experimental model thus induces a diastolic depolarisation of right ventricular muscle cells which cannot be neglected in the interpretation of the peripheral ECG changes. [ABSTRACT FROM PUBLISHER]

The anaphylactic shock of the rabbit is characterized by an acute right ventricular overload, accompanied by severe alterations of cardiac electrogenesis. During shock, the mean QRS vector, as measured from the algebraic sum of the Q, R, and S deflections on the three leads, shifts to the right, inferiorly and anteriorly. An injury current quickly appears. The TQ vector points away from the right ventricle. A progressive depolarization on the right ventricular wall is displayed by suction electrodes and the suppression of right ventricular hypertension by a cross circulation produces an almost immediate disappearance of the injury current. The geneses of these electrical alterations are briefly discussed. The possibility of an anaphylactic reaction at the level of the coronary arterial wall, previously mentioned in the literature, seems unlikely. The role of the haemodynamic changes and of the increased right ventricular blood pool is thought to be predominant. [ABSTRACT FROM PUBLISHER]