title: Signal-averaged electrocardiograms in patients with atrial fibrillation or flutter.
abstract: The signal-averaged QRS complex that is prolonged because of low amplitude late potentials predicts ventricular tachycardia. This study investigated if signal-averaged low amplitude atrial potentials predict atrial fibrillation or flutter (AFF). Low amplitude potentials were considered to be high-frequency, high amplitude P (HiFP) duration recorded between 50 and 250 Hz at 1.0 mm/microV amplitude minus unfiltered P (UnFP) duration at 0.1 mm/microV. In nine normals, HiFP averaged 115.6 msec +/- 9.8 SD. HiFP were wider in 26 control patients (133.5 msec +/- 15.7, p less than 0.005) but HiFP-UnFP (11.2 msec +/- 8.5) and signals less than 10 microV terminating HiFP inscription (21.7 msec +/- 23.4) were similar to normal values. Seventeen patients with paroxysmal or recently cardioverted AFF did not have significantly longer intervals than controls (HiFP averaged 138.8 msec +/- 23.0, HiFP-UnFP 13.2 msec +/- 9.3, and signals less than 10 microV 32.4 msec +/- 19.5). Therefore, signal-averaged P waves do not identify patients with AFF.
authors.affiliation: Department of Internal Medicine, University of Nebraska College of Medicine, Omaha.
authors.forename: T R
authors.initials: TR
authors.lastname: Engel
authors.forename: N
authors.initials: N
authors.lastname: Vallone
authors.forename: J
authors.initials: J
authors.lastname: Windle
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000503:physiopathology*; D001282:Atrial Flutter / Q000188:drug therapy / Q000503:physiopathology*; D004562:Electrocardiography / Q000379:methods*; D005069:Evaluation Studies as Topic; D006801:Humans; D008875:Middle Aged; D011336:Probability; D011446:Prospective Studies; D013610:Tachycardia / Q000209:etiology; D013997:Time Factors
chemical_list: D000889:Anti-Arrhythmia Agents