Pasteless, Active, Concentric Ring Sensors for Directly Obtained Laplacian Cardiac Electrograms
Peter P. Tarjan
Abnormal propagation paths and velocities characterize cardiac arrhythmias. Conventional surface ECGs provide only global information and tend to smooth the original signal in time, making it difficult to determine the moment of activation (MoA) at a specific point. We developed an active tripolar concentric ring sensor capable of detecting the Laplacian electrogram (LECG) resolution. The signal conditioning amplifiers and their power supply are mounted directly on the back of the sensor. The uniquely designed instrumentation amplifier (IA) provides high input impedance, therefore skin preparations is not necessary. The inherent common mode rejection(CMR) from the tripolar concentric ring sensor and the high common mode rejection ratio (CMRR=117dB) from the IA yield 0.7μVrms noise level at the output with gain of 1000. The Directly Obtained Laplacian Cardiac Electrogram is obtained in real time without digital signal processing.