title: Effects of treatment with ivabradine and atenolol on reproducibility of echocardiographic indices of left heart size and function in healthy cats.
abstract: OBJECTIVE
  Data on reproducibility of echocardiographic indices in cats are commonly derived from studies in healthy, non-treated animals. However, medical treatment may alter reproducibility of such data possibly influencing interpretation of results of clinical trials assessing the effects of drugs on cardiovascular function. The objectives were therefore to investigate the effects of ivabradine and atenolol on reproducibility of echocardiographic indices of left heart function.
  
  
  METHODS
  Eight healthy cats.
  
  
  METHODS
  Repeated echocardiographic examinations were performed by two observers in mildly sedated cats at baseline and after four weeks of treatment (Group 1, ivabradine 0.3 mg/kg q12 h PO, n = 4; Group 2, atenolol 6.25 mg/cat q12 h PO, n = 4) in a prospective, double-blind, randomized study. Test reliability was determined by estimating measurement variability, within-day interobserver variability, and between-day intraobserver variability of all echocardiographic indices. Variability was expressed as coefficient of variation (CV) and the absolute value below which the difference between two measurements lay with 95% probability. Effects of treatments on variability were compared using linear mixed effects models ANOVA and Fisher's exact test.
  
  
  RESULTS
  Overall, CVs ranged from 0.5 to 50.6% at baseline, 0.5-45.5% after ivabradine, and 0.5-23.3% after atenolol. Reproducibility of all variables determined did neither improve nor worsen consistently after either treatment although atenolol exhibited a tendency toward higher reliability with none of the CVs exceeding 24% as compared to ivabradine.
  
  
  CONCLUSIONS
  Treatment of healthy cats with either atenolol or ivabradine had only minor effects on reproducibility of echocardiographic data. Whether these findings can be extrapolated to cats with hypertrophic cardiomyopathy deserves further study.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Sabine C
authors.initials: SC
authors.lastname: Riesen
authors.forename: Karsten E
authors.initials: KE
authors.lastname: Schober
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Cervenec
authors.forename: John D
authors.initials: JD
authors.lastname: Bonagura
mesh_terms: D000818:Animals; D001262:Atenolol / Q000494:pharmacology*; D016279:Atrial Function, Left / Q000187:drug effects; D001552:Benzazepines / Q000494:pharmacology*; D002317:Cardiovascular Agents / Q000494:pharmacology*; D002415:Cats; D004311:Double-Blind Method; D004452:Echocardiography / Q000662:veterinary; D005260:Female; D006325:Heart Atria / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000187:drug effects*; D006339:Heart Rate; D006352:Heart Ventricles / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000187:drug effects*; D000077550:Ivabradine; D015203:Reproducibility of Results; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D001552:Benzazepines; D002317:Cardiovascular Agents; D000077550:Ivabradine; D001262:Atenolol