title: Decreased sympathetic tone after short-term treatment with enalapril in dogs with mild chronic mitral valve disease.
abstract: Heart rate variability (HRV) and echocardiography were performed in 14 dogs with mitral regurgitation (MR) before and after 14 days of 0.5mg/kg/day of enalapril treatment. All dogs were in heart failure stages B1 and B2. After enalapril treatment, left ventricular end diastolic diameter (LVEDd), left ventricular end diastolic diameter normalized for body weight (LVEDdN) and percent mitral regurgitant jet decreased (P<0.05). The diastolic blood pressure decreased (P<0.05). Increased time domain parameters of HRV were found. For frequency domain analysis, the total frequency (TF) increased significantly (P<0.05). The normalized low frequency (LF norm) decreased while normalized high frequency (HF norm) increased causing significant reduction in LF/HF (P<0.05). Before enalapril treatment, LF was correlated with end diastolic volume (EDV) (P<0.01) and LVEDd (P<0.05). In conclusion, MR dogs receiving enalapril treatment for 14 days had increased cardiac parasympathetic tone while sympathetic tone was suppressed. The decreased sympathetic activity corresponded to the reduction in cardiac preload and afterload.
authors.affiliation: Graduate Program in Animal Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri Dunant Rd, Patumwan, Bangkok 10330, Thailand.
authors.forename: Chayanon
authors.initials: C
authors.lastname: Chompoosan
authors.affiliation: Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri Dunant Rd, Patumwan, Bangkok 10330, Thailand. Electronic address: bchollad@chula.ac.th.
authors.forename: Chollada
authors.initials: C
authors.lastname: Buranakarl
authors.affiliation: Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Henri Dunant Rd, Patumwan, Bangkok 10330, Thailand.
authors.forename: Narongsak
authors.initials: N
authors.lastname: Chaiyabutr
authors.affiliation: Small Animal Teaching Hospital, Faculty of Veterinary Science, Chulalongkorn University, Henri Dunant Rd, Patumwan, Bangkok 10330, Thailand.
authors.forename: Winai
authors.initials: W
authors.lastname: Chansaisakorn
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D004283:Dog Diseases / Q000188:drug therapy / Q000503:physiopathology*; D004285:Dogs; D004452:Echocardiography / Q000662:veterinary; D004562:Electrocardiography / Q000662:veterinary; D004656:Enalapril / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D016014:Linear Models; D008297:Male; D008944:Mitral Valve Insufficiency / Q000188:drug therapy / Q000503:physiopathology / Q000662:veterinary*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril
keywords: Dogs; Enalapril; Heart rate variability; Mitral regurgitation