title: Effect of ECG filter settings on J-waves.
abstract: BACKGROUND
  While J-waves were observed in healthy populations, variations in their reported incidence may be partly explicable by the ECG filter setting.
  
  
  METHODS
  We obtained resting 12-lead ECG recordings in 665 consecutive patients and enrolled 112 (56 men, 56 women, mean age 59.3±16.1years) who manifested J-waves on ECGs acquired with a 150-Hz low-pass filter. We then studied the J-waves on individual ECGs to look for morphological changes when 25-, 35-, 75-, 100-, and 150Hz filters were used.
  
  
  RESULTS
  The notching observed with the 150-Hz filter changed to slurring (42%) or was eliminated (28%) with the 25-Hz filter. Similarly, the slurring seen with the 150-Hz filter was eliminated on 71% of ECGs recorded with the 25-Hz filter. The amplitude of J-waves was significantly lower with 25- and 35-Hz than 75-, 100-, and 150-Hz filters (p<0.0001).
  
  
  CONCLUSIONS
  The ECG filter setting significantly affects the J-wave morphology.
authors.affiliation: Department of Cardiology and Clinical Examination, 1-1 Idaigaoka, Yufu City, Oita, Japan. Electronic address: mikinak@oita-u.ac.jp.
authors.forename: Mikiko
authors.initials: M
authors.lastname: Nakagawa
authors.affiliation: Laboratory Medicine, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Tsunemitsu
authors.affiliation: Laboratory Medicine, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Sayo
authors.initials: S
authors.lastname: Katoh
authors.affiliation: Laboratory Medicine, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Kamiyama
authors.affiliation: Laboratory Medicine, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Nario
authors.initials: N
authors.lastname: Sano
authors.affiliation: Department of Cardiology and Clinical Examination, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Ezaki
authors.affiliation: Department of Cardiology and Clinical Examination, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Miyazaki
authors.affiliation: Department of Cardiology and Clinical Examination, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Teshima
authors.affiliation: Department of Cardiology and Clinical Examination, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Yufu
authors.affiliation: Department of Cardiology and Clinical Examination, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Naohiko
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Department of Cardiology and Clinical Examination, 1-1 Idaigaoka, Yufu City, Oita, Japan.
authors.forename: Tetsunori
authors.initials: T
authors.lastname: Saikawa
mesh_terms: D000465:Algorithms; D016477:Artifacts; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
keywords: ECG filter; Electrocardiogram; J-waves