Frequency of attacks and P wave signal-averaged ECG in patients with paroxysmal atrial fibrillation

A. Michellucci, L. Padeletti, A. Mezzani, S. Salvi, F. Bacci, M. Martelli, M. C. Porciani, A. Chelucci, E. Di Vincenzo, C. Rostagno, G. F. Gensini

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To evaluate if the frequency of atrial fibrillation attacks was related to abnormalities of P wave-triggered signal-averaged ECG (template comparing method, at least 400 beats) we studied 42 patients with lone paroxysmal atrial fibrillation (LPAF). They were divided into 30 patients having 3 attacks a year or less (LF, mean age 54 ± 12 years, mean elapsed time from the first episode 6 ± 3 years) and 12 patients having one or more attacks a month (HF, mean age 59 ± 9 years, elapsed time from the first episode 7.7 ± 3 years). LF and HF were compared with a group of normal subjects (N, mean age 53 ± 13 years). Statistically significant differences were absent as to age (LF vs HF vs N) and to elapsed time from the first episode (LF vs HF). Time domain parameters: duration of filtered (40-300 Hz) P wave (FPW) of the spatial magnitude and of unfiltered P wave of X, Y, and Z leads; maximal voltage of FPW (Vmax); time to Vmax; RMS of total FPW and of its last 10, 20, 30, 40, and 50 msec. Frequency domain parameters (FFT of the entire P wave, Blackmann-Harris window, magnitude vs frequency): area between 0.5 and 130 Hz (0.5-130, μV2), between 0.5 and 50 Hz (0.5-50, μV2), and between 10 and 130 Hz (10-130, μV2) of orthogonal X, Y, and Z leads. Only frequency domain parameters showed statistically significant differences (ANOVA with Bonferroni's t-test) between LF and HF. HF showed significantly higher mean values of 0.5-130 (175 ± 130 vs 101 ± 45, p <0.005) and 0.5-50 (171 ± 130 vs 99 ± 45, p <0.001) of X and of 10-130 of Z (120 ± 73 vs 72 ± 70, p <0.02) than LF. When the criterions 0.5-50X > 180 μV2, 0.5-130X > 175 μV2, and 10-130Z > 80 μV2 were used, predictive accuracies between LF and HF were respectively 81%, 83%, and 78%; positive predictive values were 75%, 86%, and 60%; negative predictive values were 82%, 83%, and 89%. In conclusion, FFT of signal-averaged P wave gives promising results in identifying LPAF with high frequency of atrial fibrillation attacks.

Original languageEnglish
Pages (from-to)967-978
Number of pages12
JournalNew Trends in Arrhythmias
Issue number4
Publication statusPublished - 1993


  • P wave
  • paroxysmal atrial fibrillation
  • signal averaging

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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