Vet360, December 2016 - Page 21

CARDIOLOGY Radiographic Identification of the Cardiac Chambers: Clockface Analogy A MPA RA LAu 12 9 3 LA A RAu 6 12 9 3 6 RV LV Figure 1: DV view of the normal cardiac silhouette Dorsoventral view 11:00 - 01:00 : aortic arch 01:00 - 02:00 : main pulmonary artery 02:30 - 03:00 : left auricle 05:00 - 09:00 : right ventricle 09:00 - 11:00 : right atrium RV LV Figure 2: Lateral view of the normal cardiac silhouette Lateral view 12:00 - 02:00 : left atrium 02:00 - 05:00 : left Ventricle 05:00 - 09:00 : right ventricle 09:00 - 10:00 : main pulmonary artery & right auricle 10:00 - 11:00 : aortic arch KEY: A=Aorta; LA = Left atrium; LAu = Left auricle; LV = Left Ventricle; MPA = Main pulmonary artery; RA = Right atrium; RAu = Right auricle; RV = Right ventricle. Calculation of The Vertebral Heart Score (VHS) 1. Using a lateral thoracic radiograph, ensure the thoracic vertebrae T4 to T12 are clearly delineated. 2. Using calipers, measure the longest axis of the cardiac silhouette from the carina of the mainstem bronchus to the apex (designated “L”). 3. Transfer this long axis measurement to the vertebrae, starting at the cranial edge of T4, and count the number of vertebrae that fall within the caliper points. 4. Using calipers, measure the short axis at the widest part of the cardiac silhouette, perpendicular to the long axis measurement (designated “W”). 5. Transfer this short axis measurement to the vertebrae, starting at the cranial edge of T4, and count the number of vertebrae that fall within the caliper points. 6. Sum the two measurements. VHS = W + L L4 W W L Considerable breed variation exists with the VHS. The suggested mean value for dogs was 9,7 ± 0,5 v (range 8,5 - 10,5 v). Breed specific normals have been established. Boxer - 11.6 ± 0.8 v Cavalier King Charles Spaniel - 10,6 ± 0,5 v German Shepherd Dog - 9,7 ± 0,7 v Labrador Retriever 10,8 ± 0,6 v Yorkshire Terriers - 9,7 ± 0,5 v. SOURCE: BSAVA Manual of Canine a [[HܘXX[XY[ˈYΈX\\XܚXHۋ \[YHY\[[\Y\K[XY\\\H[[HY\’\YH PSPT M B