Local activation time (LAT) maps help to understand the path of electrical excitation in cardiac arrhythmias. They can be generated automatically from intracardiac electrograms using various criteria provided by commercial electroanatomical mapping systems. This study compares existing criteria and a novel method based on the non-linear energy operator (NLEO) with respect to their precision and robustness.
Simultaneous biatrial electroanatomical mapping was performed in a 54 year old woman using two 64-electrode basket catheters. Local activation time (LAT) maps were extracted retrospectively for single atrial excitations during sinus rhythm using the non-linear energy operator (NLEO). Considering both ampltiude and frequency information, the NLEO has shown to be a reliable estimator for the LAT. This paper presents an approach for creating biatrial LAT maps using the NLEO for single atrial excitations. The varying propagation pattern of individual beats reveals the presence and location of supraventricular extrasystoles.
Intracardiac electrograms are essential for the diagnosis and treatment of various cardiac arrhythmias. To gain reliable information about structural alterations of underlying tissue, it is necessary to interpret these electrograms correctly. Therefore it has to be understood how other parameters influence the signal. Realistic 3D geometries were created and simulated using the bidomain model. Based on these simulations, the influences of catheter orientation, tissue thickness and conduction velocity on the amplitudes of intracardiac electrograms were evaluated.