Testing of a New T-Wave Subtraction Algorithm as an Aid to Localizing Ectopic Atrial Beats
Methods: We developed an automated computerized program (BARD DUO LAB SYSTEM™) designed to subtract the QRS-T wave complex from the surface electrogram and uncover a previously obscured P wave. The purpose of the present study was to validate this program. The surface ECG from 21 patients undergoing atrial pacing during electrophysiologic study (group I) and 10 patients with atrial tachycardia (group II) were analyzed and the derived P-wave morphology assessed using correlation waveform analysis (CWA) and visual grading by three reviewers.
Results: The algorithm successfully uncovered the P wave in each surface ECG. For the 21 patients in group I, average CWA comparing the derived P wave with the previous paced P wave was 83%. Average CWA for group II was 82%. Visual grading of the match between derived P waves and paced P waves revealed a 21/21 match in group I patients and a 12/12 match in 9/10 of group II patients.
Conclusions: An ectopic atrial P wave obscured by a coincident QRS-T wave complex can be accurately uncovered using this new algorithm. Addition of this technique to existing methods may improve the diagnosis of atrial arrhythmias and aid in the localization and ablation of ectopic atrial foci.
Document Type: Research Article
Affiliations: 1: Tufts University School of Medicine, New England Medical Center Hospitals, Boston, MA, USA 2: University of Oklahoma, Tulsa, OK, USA 3: Bard Electrophysiology, Lowell, MA, USA
Publication date: January 1, 2003