Pasteless, active, concentric ring sensors for directly obtained Laplacian cardiac electrograms

Chih Cheng Lu, Peter P. Tarjan

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


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 0.7 μ Vrmsnoise level at the output with gain of 1000. The Directly Obtained Laplacian Cardiac Electrogram is obtained in real time without digital signal processing.

Original languageEnglish (US)
Pages (from-to)199-203
Number of pages5
JournalJournal of Medical and Biological Engineering
Issue number4
StatePublished - Dec 1 2002


  • Active sensor
  • Concentric ring electrodes
  • Laplacian ECG

ASJC Scopus subject areas

  • Biophysics


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