title: Holter monitoring in clinically healthy Cavalier King Charles Spaniels, Wire-haired Dachshunds, and Cairn Terriers.
abstract: BACKGROUND
  Few reported studies describe normal values from 24-hour ECG (Holter) recordings of small breed dogs.
  
  
  OBJECTIVE
  To investigate influence of breed, age, sex, body weight, degree of recording artifact, and mitral valve prolapse (MVP) on Holter recordings of 3 breeds of small dogs that have differing predispositions for myxomatous mitral valve disease. The study also assessed if heart rate (HR) at clinical examination (HRex) was associated with HR during Holter monitoring and evaluated the reproducibility of Holter variables.
  
  
  METHODS
  Fifty clinically healthy, privately owned dogs of the breeds Cavalier King Charles Spaniel (CKCS), Wire-haired Dachshund (wD), or Cairn Terrier (CT).
  
  
  METHODS
  Prospective, longitudinal observational study. Dogs were recruited for clinical examination, echocardiography, and Holter monitoring. In 8 CKCS, Holter recordings were performed twice with a 7-day interval. Arrhythmia and heart rate variability (HRV) analysis (time and frequency domain analysis) were performed on Holter recordings.
  
  
  RESULTS
  Fifteen out of 27 Holter derived variables were significantly associated with breed (P < .03), but not with age (P > .7), sex (P > .2), body weight (P > .7), degree of recording artifact (P > .4), or MVP (P > .6). During Holter recording, minimum (P = .0001) and mean HR (P = .0001) were higher in CKCS compared with wD. CKCS had significantly lower values than wD, CT, or both in 10 out of 13 HRV variables (P < .03). Minimum and mean HR during Holter recording were correlated with HRex (r = 0.55, P = .0003). HR and time domain variables had a coefficient of variation <10%.
  
  
  CONCLUSIONS
  There is an influence of breed on Holter-derived variables in 3 breeds of small dogs. Arrhythmia and HRV analysis can be performed on 24-hour ambulatory ECG (Holter) recordings. Arrhythmia analysis includes HR measurements and identification of arrhythmias.
authors.affiliation: Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark. cer@life.ku.dk
authors.forename: C E
authors.initials: CE
authors.lastname: Rasmussen
authors.forename: S
authors.initials: S
authors.lastname: Vesterholm
authors.forename: T P
authors.initials: TP
authors.lastname: Ludvigsen
authors.forename: J
authors.initials: J
authors.lastname: Häggström
authors.forename: H D
authors.initials: HD
authors.lastname: Pedersen
authors.forename: S G
authors.initials: SG
authors.lastname: Moesgaard
authors.forename: L H
authors.initials: LH
authors.lastname: Olsen
mesh_terms: D000818:Animals; D049628:Body Size / Q000502:physiology*; D004285:Dogs / Q000502:physiology*; D015716:Electrocardiography, Ambulatory / Q000662:veterinary*; D005260:Female; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results