title: Atrial Fibrillation as a Prognostic Indicator in Medium to Large-Sized Dogs with Myxomatous Mitral Valvular Degeneration and Congestive Heart Failure.
abstract: BACKGROUND
  The prevalence and prognostic importance of atrial fibrillation (AF) on survival in nonsmall breed dogs with myxomatous mitral valvular disease (MMVD) and congestive heart failure (CHF) remain unknown.
  
  
  OBJECTIVE
  To identify the prevalence of AF in nonsmall breed dogs with CHF because of MMVD and to characterize the impact of AF on survival outcome.
  
  
  METHODS
  Sixty-four client-owned dogs (>15 kg) with MMVD and CHF.
  
  
  METHODS
  Retrospective review of medical records for dogs weighing >15 kg with MMVD treated for CHF.
  
  
  RESULTS
  Thirty-three dogs presented with AF or developed AF during follow-up examinations, and 31 dogs were free of AF until cardiac-related death. For dogs with AF, median survival time (MST) was 142 days (range: 9-478) while dogs without AF lived 234 days (range: 13-879 days). AF increased risk of cardiac-related death (HR = 2.544; 95% CI = 1.41-4.59; P = .0019) when compared to dogs without AF. MST was significantly prolonged for dogs with AF whose rates were adequately controlled (<160 bpm; 171 days; n = 13) when compared to dogs that failed to respond to negative chronotropic agents (61 days; n = 20; P = .032). The administration of combination treatment (diltiazem and digoxin) significantly decreased median HR to 144 bpm (range: 84-218 bpm) in dogs with AF and significantly prolonged MST (diltiazem+digoxin: 130 days versus diltiazem: 35 days, P = .0241) when compared to diltiazem alone.
  
  
  CONCLUSIONS
  Inadequately controlled AF is associated with a higher rate of mortality. Optimization of therapeutic strategies for the rate control of AF remains determined.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL.
authors.forename: S W
authors.initials: SW
authors.lastname: Jung
authors.affiliation: Department of Mathematics and Statistics, Auburn University, Auburn, AL.
authors.forename: W
authors.initials: W
authors.lastname: Sun
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA.
authors.forename: L G
authors.initials: LG
authors.lastname: Griffiths
authors.affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA.
authors.forename: M D
authors.initials: MD
authors.lastname: Kittleson
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D049628:Body Size; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D008297:Male; D008945:Mitral Valve Prolapse / Q000150:complications / Q000473:pathology / Q000662:veterinary*; D012189:Retrospective Studies
chemical_list: D000889:Anti-Arrhythmia Agents
keywords: Atrial fibrillation; Congestive heart failure; Myxomatous valvular disease; Prognosis