BACKGROUND: Identifying the timing and morphology of an ectopic P wave from the surface electrogram can aid in the diagnosis and localization of @entity943 . Given the relatively short coupling interval of @entity11706 , the P wave is often obscured by the larger amplitude QRS-T wave complex. A method to uncover such "buried" P waves using a standard 12-lead surface ECG would be clinically useful and could potentially be a noninvasive guide to catheter ablation of focal @entity591 . METHODS: We developed an automated computerized program (BARD DUO LAB SYSTEM trade mark ) 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 @entity1 undergoing atrial pacing during electrophysiologic study (group I) and 10 @entity1 with @entity591 (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 @entity1 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 @entity1 and a 12/12 match in 9/10 of group II @entity1 . 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 @entity943 and aid in the localization and ablation of ectopic atrial foci.

Testing of a new T-wave subtraction algorithm as an aid to localizing ectopic XXXX .

@entity591 :: ('MESH:D013610', 'Disease') :: ['atrial tachycardia'] @entity11706 :: ('MESH:D018880', 'Disease') :: ['atrial ectopic beats'] @entity1 :: ('9606', 'Species') :: ['patients'] @entity943 :: ('MESH:D001145', 'Disease') :: ['atrial arrhythmias']
@entity11706 :: (MESH:D018880,Disease) :: ['atrial beats']
