title: Clinical, echocardiographic, and electrocardiographic abnormalities in Boxers with cardiomyopathy and left ventricular systolic dysfunction: 48 cases (1985-2003).
abstract: OBJECTIVE
  To identify clinical, echocardiographic, and electrocardiographic abnormalities in Boxers with cardiomyopathy and echocardiographic evidence of left ventricular systolic dysfunction.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  48 mature Boxers.
  
  
  METHODS
  Medical records were reviewed for information on age; sex; physical examination findings; and results of electrocardiography, 24-hour ambulatory electrocardiography, thoracic radiography, and echocardiography.
  
  
  RESULTS
  Mean age of the dogs was 6 years (range, 1 to 11 years). Twenty (42%) dogs had a systolic murmur, and 9 (19%) had ascites. Congestive heart failure was diagnosed in 24 (50%) dogs. Seventeen (35%) dogs had a history of syncope. Mean fractional shortening was 14.4% (range, 1% to 23%). Mean left ventricular systolic and diastolic diameters were 4.5 cm (range, 3 to 6.3 cm) and 5.3 cm (range, 3.9 to 7.4 cm), respectively. Twenty-eight (58%) dogs had a sinus rhythm with ventricular premature complexes (VPCs), and 20 had supraventricular arrhythmias (15 with atrial fibrillation and 5 with sinus rhythm and atrial premature complexes). Sixteen of the dogs with supraventricular arrhythmias also had occasional VPCs. Morphology of the VPCs seen on lead II ECGs was consistent with left bundle branch block in 25 dogs, right bundle branch block in 8, and both in 11.
  
  
  CONCLUSIONS
  Results suggest that Boxers with cardiomyopathy and left ventricular dysfunction frequently have arrhythmias of supraventricular or ventricular origin. Whether ventricular dysfunction was preceded by electrical disturbances could not be determined from these data, and the natural history of myocardial disease in Boxers requires further study.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Baumwart
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Meurs
authors.forename: Clarke E
authors.initials: CE
authors.lastname: Atkins
authors.forename: John D
authors.initials: JD
authors.lastname: Bonagura
authors.forename: Teresa C
authors.initials: TC
authors.lastname: DeFrancesco
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Keene
authors.forename: Shianne
authors.initials: S
authors.lastname: Koplitz
authors.forename: Virginia
authors.initials: V
authors.lastname: Luis Fuentes
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Miller
authors.forename: William
authors.initials: W
authors.lastname: Rausch
authors.forename: Alan W
authors.initials: AW
authors.lastname: Spier
mesh_terms: D000818:Animals; D009202:Cardiomyopathies / Q000175:diagnosis / Q000503:physiopathology / Q000662:veterinary*; D004283:Dog Diseases / Q000175:diagnosis / Q000503:physiopathology*; D004285:Dogs; D004452:Echocardiography / Q000379:methods / Q000662:veterinary; D015716:Electrocardiography, Ambulatory / Q000379:methods / Q000662:veterinary; D005260:Female; D008297:Male; D013902:Radiography, Thoracic / Q000379:methods / Q000662:veterinary; D012189:Retrospective Studies; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000503:physiopathology / Q000662:veterinary*