title: Temporal variability of ventricular arrhythmias in Boxer dogs with arrhythmogenic right ventricular cardiomyopathy.
abstract: BACKGROUND
  Arrhythmogenic right ventricular cardiomyopathy (ARVC) is prevalent in the Boxer. There is little information on the temporal variability of ventricular arrhythmias within affected dogs.
  
  
  OBJECTIVE
  To evaluate ambulatory electrocardiograms (AECG) from Boxers with ARVC for hourly variation in premature ventricular complexes (PVC) and heart rate (HR).
  
  
  METHODS
  One hundred and sixty-two Boxer dogs with ARVC.
  
  
  METHODS
  Retrospective, observational study of 1,181 AECGs collected from Boxer dogs at The Ohio State University from 1997 to 2004 was evaluated. The proportion of depolarizations that were PVCs was compared across each hour of the day, during six 4-hour periods of day, to the time after AECG application, and to the maximum and minimum HR.
  
  
  RESULTS
  A lower proportion of PVCs was noted during early morning (midnight to 0400 hours) as compared with the morning (0800-1200 hours) and late (1600-2000 hours) afternoon (P= .012). There was no increase in PVC proportion in the 1st hour after AECG application as compared with all other hours of the day (P= .06). There was poor correlation between maximum (rho= 0.19) and minimum (rho= 0.12) HR and PVC proportion.
  
  
  CONCLUSIONS
  The likelihood of PVC occurrence in Boxer dogs with ARVC was relatively constant throughout the day, although slightly greater during the hours of 0800-1200 and 1600-2000. A biologically important correlation with HR was not apparent. The role of autonomic activity in the modulation of electrical instability in the Boxer with ARVC requires further study.
authors.affiliation: Department of Veterinary Clinical Sciences, The Ohio State University College of Veterinary Medicine, Columbus, OH, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Scansen
authors.forename: K M
authors.initials: KM
authors.lastname: Meurs
authors.forename: A W
authors.initials: AW
authors.lastname: Spier
authors.forename: S
authors.initials: S
authors.lastname: Koplitz
authors.forename: R D
authors.initials: RD
authors.lastname: Baumwart
mesh_terms: D000818:Animals; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000503:physiopathology / Q000662:veterinary*; D004283:Dog Diseases / Q000503:physiopathology*; D004285:Dogs; D004452:Echocardiography / Q000662:veterinary; D006339:Heart Rate / Q000502:physiology; D011446:Prospective Studies; D012189:Retrospective Studies; D013997:Time Factors