Showing papers by "M. Ramasubba Reddy published in 2017"
TL;DR: In this paper, a 2D anisotropic transmural section of the ventricular myocardium is modeled using the TP06 equations and the cells are interconnected with gap junction conductances (GJC).
10 citations
TL;DR: Normal pacing rates can induce a multi focal TdP when sufficient number of M-cells simultaneously undergo spontaneous calcium release (SCR) events.
4 citations
TL;DR: Based on the simulation studies and experimental validations, cross method is found to be the optimal current injection method to attain better data acquisition and image reconstruction.
Abstract: A comparative study of different bipolar current injection methods viz. Adjacent method, Cross method and Opposite method used in Electrical Impedance Tomography(EIT) is reported in this paper. Different electrode configurations are considered for current injection and voltage measurement to identify the one which yields better signal strength. Sensitivity of different current injection methods to inhomogeneity at different locations is examined. The effect of conductivity contrast on boundary voltages is studied by varying the conductivity of the inhomogeneity from 0.01mS/cm to 9.1mS/cm. Ill-posedness of the inverse problem is analyzed in terms of condition number for the aforementioned methods. Reconstruction of two closely placed inhomogeneities is done using Levenberg Marquardt method for different current injection methods to compare the resolution and corresponding error voltage is determined. Experiments are conducted using agar phantoms to validate some of the results obtained from the simulations. Based on the simulation studies and experimental validations, cross method is found to be the optimal current injection method to attain better data acquisition and image reconstruction.
3 citations
01 Oct 2017
TL;DR: Reduction of intercellular conductance in a midmyocardial island can cause a non-sustained reentrant arrhythmia to develop due to premature pacing beats and addition of hyperkalaemic conditions in the ischemic zone has the effect of prolonging the arrhythmmia.
Abstract: Ischemia in presence of drug induced long QT syndrome 2 (LQTS2) predisposes the tissue to Torsade de pointes (TdP). Reentrant arrhythmias occurring during phase 1B of ischemia have been primarily associated with areas of cellular uncoupling and hyperkalaemia. This study aims to investigate how a region of lowered gap junction conductance (GJC) in presence of LQTS2 can initiate a TdP. Here, a discrete grid of 250x100 cells interconnected using GJCs is taken representing a portion of the transmural wall with anisotropic conduction velocities. LQTS2 is introduced by reducing the potassium current (IKr) of all cells to 50%. An ischemic zone is located almost in the centre of the mid myocardium layer in the form of an elliptic inhomogeneity with varying percentage reduction of GJC compared to the surrounding. Results show that reduction of intercellular conductance in a midmyocardial island can cause a non-sustained reentrant arrhythmia to develop due to premature pacing beats. Addition of hyperkalaemic conditions in the ischemic zone has the effect of prolonging the arrhythmia.
1 citations