title: Simultaneous assessment of electrocardiographic parameters for risk stratification: validation in healthy subjects.
abstract: BACKGROUND
  Sudden cardiac death represents a major public health problem, but in the general population the identification of those subjects at very high risk remains poor. Simultaneous multiparametric ECG analysis can improve the identification of high-risk patients.
  
  
  METHODS
  Five-min ECG recordings at a 5 MHz sampling rate (extended length-XL-ECG, Mortara Instruments, Milwaukee, WI, USA) were acquired in 105 healthy subjects (age range 21 to 80 years), equally distributed for age decades and sex, and three additional recordings, 30 min apart, were repeated in 30 subjects on the second day. The following parameters were recorded and analyzed: the RR interval, QRS duration, QT interval corrected according to the Bazett and Fridericia formulae, QT dispersion, T wave complexity, activation-recovery interval dispersion, standard deviation of the RR intervals, filtered QRS duration, the square root of the mean voltage of the last 40 ms of the filtered QRS, and the length of time that the terminal vector magnitude complex remains < 40 microV.
  
  
  RESULTS
  QRS duration, activation-recovery interval dispersion, and filtered QRS differed in the two sexes. The standard deviation of the RR intervals, T wave complexity and QT dispersion were significantly correlated with age. The reproducibility was good for each parameter.
  
  
  CONCLUSIONS
  The XL-ECG allows the simultaneous calculation of eight adequately reproducible different parameters the values of which are in agreement with those of the literature. Thus, XL-ECG is a reliable time- and cost-saving tool.
authors.affiliation: Department of Internal Medicine and Cardiology, University of Florence, Florence, Italy. michelucci@unifi.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Michelucci
authors.forename: David
authors.initials: D
authors.lastname: Mortara
authors.forename: Chiara
authors.initials: C
authors.lastname: Lazzeri
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Barletta
authors.forename: Andrea
authors.initials: A
authors.lastname: Capalbo
authors.forename: Toni
authors.initials: T
authors.lastname: Badia
authors.forename: Riccarda
authors.initials: R
authors.lastname: Del Bene
authors.forename: Claudio
authors.initials: C
authors.lastname: Bano
authors.forename: Gian Franco
authors.initials: GF
authors.lastname: Gensini
authors.forename: Franco
authors.initials: F
authors.lastname: Franchi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001145:Arrhythmias, Cardiac / Q000175:diagnosis* / Q000453:epidemiology*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D015716:Electrocardiography, Ambulatory / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D018570:Risk Assessment