title: The effect of pimobendan on left atrial pressure in dogs with mitral valve regurgitation.
abstract: BACKGROUND
  The effects of pimobendan on left atrial pressure (LAP) in dogs with mitral valve disease (MR) have not been documented in a quantitative manner.
  
  
  OBJECTIVE
  The objective was to document and study the short-term effects of pimobendan on LAP and echocardiographic parameters in MR dogs.
  
  
  METHODS
  Eight healthy Beagle dogs weighing 10.0-14.7 kg (3 males and 5 females; aged 2 years) were used.
  
  
  METHODS
  Experimental, cross-over, and interventional study. Dogs with surgically induced MR received pimobendan at either 0.25 mg/kg or 0.50 mg/kg p.o. q12h for 7 days and then, after a 7-day wash-out period, the other dosage. LAP was measured for 30 minutes at baseline and again on days 1, 2, 4, and 7 of pimobendan administration.
  
  
  RESULTS
  Mean LAP was significantly decreased after the administration of 0.25 mg/kg (15.81 ± 5.44 mmHg to 12.67 ± 5.71 mmHg, P < .001) and 0.50 mg/kg (15.76 ± 5.45 mmHg to 10.77 ± 5.23 mmHg, P < .001). Also, the 0.50 mg/kg group led to a significantly lower LAP (P < .01) compared with the 0.25 mg/kg group. Significant reduction was seen for the first time 4 days after the administration of 0.25 mg/kg and a day after the administration of 0.50 mg/kg.
  
  
  CONCLUSIONS
  Pimobendan decreased LAP in a dose-dependent manner in dogs with acute MR caused by experimental chordal rupture. This study did not evaluate adverse effects of high-dose pimobendan, and additional studies in clinical patients are warranted.
authors.affiliation: Department of Veterinary Surgery, Faculty of Veterinary Medicine, Tokyo University of Agriculture and Technology, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Suzuki
authors.forename: R
authors.initials: R
authors.lastname: Fukushima
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: L
authors.initials: L
authors.lastname: Hamabe
authors.forename: D
authors.initials: D
authors.lastname: Aytemiz
authors.forename: H
authors.initials: H
authors.lastname: Huai-Che
authors.forename: S
authors.initials: S
authors.lastname: Nakao
authors.forename: N
authors.initials: N
authors.lastname: Machida
authors.forename: R
authors.initials: R
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D016279:Atrial Function, Left / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D018592:Cross-Over Studies; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D019560:Echocardiography, Three-Dimensional; D005260:Female; D008297:Male; D008944:Mitral Valve Insufficiency / Q000188:drug therapy / Q000662:veterinary*; D011724:Pyridazines / Q000008:administration & dosage / Q000627:therapeutic use*; D013686:Telemetry / Q000662:veterinary; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D011724:Pyridazines; D014665:Vasodilator Agents; C041648:pimobendan