title: EFFECTS OF INTRAVENOUS DEXMEDETOMIDINE ON CARDIAC CHARACTERISTICS MEASURED USING RADIOGRAPHY AND ECHOCARDIOGRAPHY IN SIX HEALTHY DOGS.
abstract: Dexmedetomidine is a highly specific and selective α2-adrenergic receptor agonist widely used in dogs for sedation or analgesia. We hypothesized that dexmedetomidine may cause significant changes in radiographic and echocardiographic measurements. The objective of this prospective cross-sectional study was to test this hypothesis in a sample of six healthy dogs. Staff-owned dogs were recruited and received a single dose of dexmedetomidine 250 μg/m(2) intravenously. Thoracic radiography and echocardiography were performed 1 h before treatment, and repeated 10 and 30 min after treatment, respectively. One observer recorded cardiac measurements from radiographs and another observer recorded echocardiographic measurements. Vertebral heart score and cardiac size to thorax ratio on the ventrodorsal projection increased from 9.8 ± 0.6 v to 10.3 ± 0.7 v (P = 0.0007) and 0.61 ± 0.04 to 0.68 ± 0.03 (P = 0.0109), respectively. E point-to-septal separation and left ventricle internal diameter in diastole and systole increased from 2.4 ± 1.1 to 6.6 ± 1.9 mm, 32.3 ± 8.1 to 35.5 ± 8.8 mm, and 19.4 ± 6 to 27.0 ± 7.2 mm, respectively (P < 0.05). Fractional shortening and sphericity index decreased from 40.7 ± 5.8 to 24.4 ± 2.9%, and 1.81 ± 0.07 to 1.58 ± 0.04, respectively (P < 0.05). Moderate-to-severe mitral regurgitation and mild pulmonic regurgitation occurred in all dogs after dexmedetomidine administration. Findings indicated that dexmedetomidine could cause false-positive diagnoses of valvular regurgitation and cardiomegaly in dogs undergoing thoracic radiography and echocardiography.
authors.affiliation: Department of Veterinary Medicine, Veterinary Medical Teaching Hospital, College of Veterinary Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Hsien-Chi
authors.initials: HC
authors.lastname: Wang
authors.affiliation: Department of Veterinary Medicine, Veterinary Medical Teaching Hospital, College of Veterinary Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Cih-Ting
authors.initials: CT
authors.lastname: Hung
authors.affiliation: Department of Veterinary Medicine, Veterinary Medical Teaching Hospital, College of Veterinary Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Wei-Ming
authors.initials: WM
authors.lastname: Lee
authors.affiliation: Department of Veterinary Medicine, Veterinary Medical Teaching Hospital, College of Veterinary Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Kui-Ming
authors.initials: KM
authors.lastname: Chang
authors.affiliation: Department of Veterinary Medicine, Veterinary Medical Teaching Hospital, College of Veterinary Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Kuan-Sheng
authors.initials: KS
authors.lastname: Chen
mesh_terms: D061605:Administration, Intravenous / Q000662:veterinary; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000494:pharmacology*; D003430:Cross-Sectional Studies; D020927:Dexmedetomidine / Q000008:administration & dosage*; D004452:Echocardiography / Q000662:veterinary; D006321:Heart / Q000000981:diagnostic imaging* / Q000187:drug effects*; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology*; D011446:Prospective Studies
chemical_list: D018712:Analgesics, Non-Narcotic; D006993:Hypnotics and Sedatives; D020927:Dexmedetomidine
keywords: cardiomegaly; dexmedetomidine; echocardiography; regurgitation; vertebral heart score