title: Signal-averaged P-wave analysis of normal controls and patients with paroxysmal atrial fibrillation: a study in gender differences, age dependence, and reproducibility.
abstract: BACKGROUND
  Atrial fibrillation is often first recognized after a complication such as embolic stroke has occurred. Limited data are available for the prospective identification of patients at risk for developing atrial fibrillation.
  
  
  OBJECTIVE
  Demonstration of areas of slow conduction in the atrium by means of P-wave signal averaging may identify individuals at risk for atrial fibrillation.
  
  
  METHODS
  P-wave signal averaging from the surface electrocardiogram was performed in 199 normal controls and 81 patients with paroxysmal atrial fibrillation using an automated, P-triggered, high-resolution signal for analysis.
  
  
  RESULTS
  Of the variables measured, the filtered P-wave duration and P-wave integral were significantly different between controls and patients (filtered P-wave duration 120 +/- 9 vs. 145 +/- 21 and P-wave integral 666 +/- 208 vs. 868 +/- 352), whereas the terminal root-mean-square (RMS) voltages (RMS 20, RMS 30, RMS 40) showed no significant differences between the two groups. Regression analysis of the first and second measurement of the filtered P-wave duration obtained during consecutive tests showed excellent reproducibility (r and r2 of 0.96 and 0.92). The duration of the filtered P wave showed no age dependence but was shorter in women.
  
  
  CONCLUSIONS
  Utilizing the 90th percentile value of the filtered P-wave duration of 133 ms in men and 130 ms in women, the sensitivity was 80 and 81%, the specificity 92 and 90%, the positive predictive value 84 and 73%, and the negative predictive value 90 and 93%, respectively.
authors.forename: Anwer
authors.initials: A
authors.lastname: Dhala
authors.forename: Donald
authors.initials: D
authors.lastname: Underwood
authors.forename: Robert
authors.initials: R
authors.lastname: Leman
authors.forename: Ernest
authors.initials: E
authors.lastname: Madu
authors.forename: Dainia
authors.initials: D
authors.lastname: Baugh
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ozawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kasamaki
authors.forename: Qiuzhen
authors.initials: Q
authors.lastname: Xue
authors.forename: Shankara
authors.initials: S
authors.lastname: Reddy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000503:physiopathology; D016022:Case-Control Studies; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012044:Regression Analysis; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012737:Sex Factors