Session S53.1

Effects of Activation Origin on the Subcutaneous ECG with Horizontal and Vertical Bipolar Lead Orientation

J Väisänen*, J Requena-Carrión, J Hyttinen

Tampere University of Technology
Tampere, Finland

The use of subcutaneous ECG monitors is increasing and clinical studies have shown their efficiency and usefulness in detecting various cardiac arrhythmias and ECG patterns. Locations of the measurement electrodes have major role in all bioelectric measurement and modeling provides effective tools when e.g. the effects of implant orientation on ECG are studied. The present study applies modeling methods to study the simulated ECG of a subQ monitor with bipolar electrode combination. The methods applied were lead field and finite difference modeling (FDM) approaches together with a state-machine based cardiac activation model. The objective of the study was to analyze how different locations of ectopic activation affect the ECG obtained with horizontal and vertical electrode orientation. We applied a FDM model of the realistic 3D male thorax containing 2.6 million elements. The ectopic activation was set to originate from 6 different locations and conduct through both ventricles. The origins of activation were “AV-node”, mid-septum, apex, posterior left ventricular (LV) wall, postero lateral LV wall, anteroseptal LV wall. We had implants in 64 locations on anterior side of the thorax and implanted approximately 5 mm under the skin. We analysed the correlation between the ECG signals of horizontal and vertical orientations. The correlations between horizontal and vertical electrode orientation vary between -99 % and 99 %. The effects of orientation on the signal are smallest in the left thoracic region and highest on right upper thorax. There are differences between different origins of ectopic activation but for all 6 activation sequences the same implantation locations have either high or low correlations between orientations. The location of the implant has significant effects on the orientation effects. The applied methods serve effective means of studying the properties of subQ monitors with different activation sequences.

(Abstract Control Number: 102)