Objective—To determine the prevalence of various radiographic findings for dogs with cardiac tamponade (CT) attributable to pericardial effusion (PE) and to determine the sensitivity and specificity of such findings for identification of affected dogs.
Animals—50 dogs with CT attributable to PE and 23 control dogs (10 healthy dogs and 13 dogs with cardiac diseases other than CT).
Procedures—Thoracic radiographic images of dogs were evaluated by an observer who was unaware of the dogs' medical histories. For each dog, a vertebral heart score, globoid appearance of the cardiac silhouette, and convexity of the dorsocaudal aspect of the cardiac silhouette were determined.
Results—The sensitivity and specificity of enlargement of the cardiac silhouette (vertebral heart score, ≥ 10.7) for identification of dogs with CT attributable to PE were 77.6% and 47.8%, respectively. The sensitivity and specificity of a globoid appearance of the cardiac silhouette for identification dogs with CT were 41.9% and 40.0%, respectively. The sensitivity and specificity of a convex appearance of the dorsocaudal aspect of the cardiac silhouette for identification of dogs with CT were 57.1% and 35.0%, respectively.
Conclusions and Clinical Relevance—Results of this study indicated none of the evaluated radiographic variables was highly (> 90%) sensitive or specific for identification of dogs with CT attributable to PE. Thoracic radiographic findings should not be considered reliable for identification of dogs with CT attributable to PE.
To better understand spatial relationships between principal bronchi and other intrathoracic structures by use of CT images of dogs of various somatotypes.
93 dogs that underwent thoracic CT.
Information was collected from medical records regarding signalment and physical examination and echocardiographic findings. Two investigators recorded multiple measurements on a thoracic axial CT image from each dog.
Thoracic height-to-width ratio (H:W) was associated with left principal bronchus (LPB) and right principal bronchus (RPB) H:W, aortic-LPB separation, focal LPB narrowing, and aortic-vertebral overlap. Thoracic H:W was not associated with dog age, weight, sex, or brachycephalic breed. Twenty-five (27%) dogs had focal LPB narrowing, compared with 5 (5%) dogs with focal RPB narrowing (P < 0.001). Ten of 25 dogs had overlap or contact between vertebrae, aorta, LPB, and heart, suggesting a cumulative compressive effect on the LPB, while 15 had LPB-aorta contact and lack of contact between the aorta and thoracic vertebrae, suggesting an aortic constrictive effect on the LPB. None had LPB narrowing without contact from surrounding structures. Inter-rater agreement was high.
In dogs that underwent CT and were not selected for clinical suspicion of bronchial disease, principal bronchial morphology was associated with thoracic conformation. Focal LPB narrowing occurred more often than RPB narrowing. Focal LPB narrowing occurred with evidence of extraluminal compression, with or without contact between aorta and vertebrae. Brachycephalic breed could not be used for predicting thoracic H:W.
Objective—To evaluate the usefulness of Doppler-derived peak flow velocity through the left ventricular outflow tract (LVOT Vmax) and effective orifice area indexed to body surface area (EOAi) in puppies to predict development of subaortic stenosis (SAS) in the same dogs as adults.
Procedures—Cardiac auscultation and echocardiography were performed on 2- to 6-month-old puppies, then repeated at 12 to 18 months. Subaortic stenosis was diagnosed when LVOT Vmax was ≥ 2.3 m/s in adult dogs with left basilar systolic murmurs.
Results—All puppies with EOAi < 1.46 cm2/m2 had SAS as adults. All adults with EOAi < 1.29 cm2/m2 had SAS. An LVOT Vmax > 2.3 m/s in puppyhood was 63% sensitive and 100% specific for SAS in adulthood. In puppies, LVOT Vmax was more strongly associated with a future diagnosis of SAS (area under the curve [AUC], 0.89) than was EOAi (AUC, 0.80). In puppies, the combination of LVOT Vmax and EOAi yielded slightly higher sensitivity (69%) and specificity (100%) for adult SAS than did LVOT Vmax alone. In unaffected and affected dogs, LVOT Vmax increased significantly from puppyhood to adulthood but EOAi did not.
Conclusions and Clinical Relevance—In Golden Retriever puppies, LVOT Vmax > 2.3 m/s and EOAi < 1.46 cm2/m2 were both associated with a diagnosis of SAS at adulthood. The combination of these 2 criteria may result in higher sensitivity for SAS screening. Unlike LVOT Vmax, EOAi did not change during growth in either unaffected Golden Retrievers or those with SAS.
To investigate the effects of dexmedetomidine (DXM) and its subsequent reversal with atipamezole (APM) on the echocardiogram and circulating concentrations of cardiac biomarkers in cats.
14 healthy cats.
Cats underwent echocardiography and measurements of circulating cTn-I and NT-proBNP concentrations before (PRE) and during (INTRA) DXM sedation (40 µg/kg IM) and 2 to 4 (2H POST) and 24 (24H POST) hours after reversal with APM.
Administering DXM significantly decreased heart rate, right ventricular and left ventricular (LV) outflow tract velocities, and M-mode–derived LV free-wall thickness; increased LV end systolic diameter and volume; and caused valvar regurgitation. While sedative effects resolved within 25 minutes of APM reversal, the evolution of echocardiographic changes was mixed: LV ejection fraction and mitral valvar regurgitation score were different at 2H POST than at both INTRA and PRE (partial return toward baseline), LV end-diastolic volume was different PRE to INTRA and INTRA to 2H POST but not different PRE to 2H POST (full return toward baseline), and M-mode–derived LV free-wall thickness was significantly different from PRE to INTRA and PRE to 2H POST (no return toward baseline). Serum cTn-I and plasma NT-proBNP concentrations increased significantly with DXM, which remained significant 2H POST.
Administration of DXM and APM reversal produced changes in echocardiographic results and in circulating cTn-I and NT-proBNP concentrations. Understanding these changes could help veterinarians differentiate drug effects from cardiac disease.