title: Ventricular arrhythmias are not a short-term reproducible phenomenon--why long recording monitoring is necessary.
abstract: BACKGROUND
  The variability of ventricular arrhythmias (VA) among different days of the week is not well detected by one-day Holter monitoring.
  
  
  OBJECTIVE
  To evaluate whether there are differences in VA distribution pattern during long recording period.
  
  
  METHODS
  The EKG was recorded for 14 h per day during 7 days by Holter system in 34 consecutive pat ventricular couplets and non-sustained ventricular tachycardia (NSVT) recording from patients provided graphic data. We applied the Hurst method (H Coefficient) which evaluates whether a repetitive phenomenon is random or not. When the H is >0.5 and <1 means it is not random and implies a long-term memory effect. Considering the arrhythmic variability, the data were also analyzed by repetitive ANOVA comparing incidence of arrhythmias among the days.
  
  
  RESULTS
  Isolated PVCs and ventricular couplets during 98 h recording provided graphic of the occurrence. A trend of increasing and decreasing of arrhythmias was observed which looks erratic. The H coefficient, however, was significantly >0.5 for all patients. Repeated ANOVA showed statistic difference among days in 31 patients with isolated PVCs; in 26 with ventricular couplets and 19 with NSVT when analyzed per hour during week days (p < 0.05).
  
  
  CONCLUSIONS
  PVCs, ventricular couplets and NSVT are not a random phenomenon. Our data suggest the occurrence of ventricular arrhythmias had no similarity among the days, making unlikely that a single Holter recording for 24h may capture this phenomenon.
authors.affiliation: Federal University of Sao Paulo (UNIFESP), São Paulo, 04021-001, Brazil. Electronic address: mariareissp16@gmail.com.
authors.forename: Maria do Carmo Maia
authors.initials: Mdo C
authors.lastname: Reis
authors.affiliation: Federal University of Sao Paulo (UNIFESP), São Paulo, 04021-001, Brazil.
authors.forename: Nancy Christiane Ferreira
authors.initials: NC
authors.lastname: Silva
authors.affiliation: Federal University of Sao Paulo (UNIFESP), São Paulo, 04021-001, Brazil.
authors.forename: Angelo Amato Vincenzo
authors.initials: AA
authors.lastname: de Paola
authors.affiliation: Federal University of Sao Paulo (UNIFESP), São Paulo, 04021-001, Brazil.
authors.forename: Braulio Luna
authors.initials: BL
authors.lastname: Filho
mesh_terms: D000465:Algorithms; D003627:Data Interpretation, Statistical; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D015716:Electrocardiography, Ambulatory / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis*; D013997:Time Factors; D018879:Ventricular Premature Complexes / Q000175:diagnosis*
keywords: Holter monitoring; Ventricular arrhythmia; electrocardiogram