Effects of pimobendan for mitral valve regurgitation in dogs.
Pimobendan has a dual mechanism of action: it increases myocardial contractility by increasing calcium sensitization to troponin C and it promotes vasodilation by inhibiting PDEIII. This study examined the effects of pimobendan on cardiac function, hemodynamics, and neurohormonal factors in dogs with mild mitral regurgitation (MR). The dogs were given 0.25 mg/kg of pimobendan orally every 12 hr for 4 weeks. With pimobendan, the heart rate and stroke volume did not change, but the systolic blood pressure gradually decreased and the degree of mitral valve regurgitation tended to decrease. Renal blood flow was significantly increased and the glomerular filtration rate was slightly increased at 2 and 4 weeks. Furthermore, over the 4-week period, the plasma norepinephrine concentration decreased significantly, the systolic index increased slightly, the left atrial diameter and the left ventricular diameters decreased significantly, and the heart size improved. Given these results, pimobendan appears to be useful for treating MR in dogs. However, further long-term studies of pimobendan involving a larger number of dogs with mild and moderate MR are needed to establish the safety of pimobendan and document improvements in quality of life.
Kanno
Nobuyuki
N
Laboratory of Veterinary Internal Medicine, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University, Fujisawa, Japan.
Kuse
Hiroshi
H
Kawasaki
Masaya
M
Hara
Akashi
A
Kano
Rui
R
Sasaki
Yoshihide
Y
D000450:Aldosterone / Q000097:blood; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002316:Cardiotonic Agents / Q000494:pharmacology*; D002395:Catecholamines / Q000097:blood; D004283:Dog Diseases / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D004285:Dogs; D015150:Echocardiography, Doppler / Q000662:veterinary; D005919:Glomerular Filtration Rate / Q000187:drug effects / Q000502:physiology / Q000662:veterinary; D008297:Male; D008944:Mitral Valve Insufficiency / Q000097:blood / Q000188:drug therapy* / Q000473:pathology / Q000662:veterinary*; D018377:Neurotransmitter Agents / Q000097:blood; D011724:Pyridazines / Q000494:pharmacology*; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology; D012083:Renin / Q000097:blood
D002316:Cardiotonic Agents; D002395:Catecholamines; D018377:Neurotransmitter Agents; D011724:Pyridazines; C041648:pimobendan; D000450:Aldosterone; D009320:Atrial Natriuretic Factor; D012083:Renin