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63 NOVEMBER/DECEMBER 2017 ■ TVPJOURNAL.COM PEER REVIEWED recent report showing that clopidogrel prolonged the time to recurrent thromboembolism in cats with cardiomyopathy. 2 Other medications, such as atenolol, may be initiated in a cat with preclinical heart disease, especially if left ventricular outflow obstruction is detected echocardiographically. However, minimal evidence supports this recommendation. For dyspneic cats, point-of-care cage-side thoracic ultrasonography is useful to aid in the clinical decision to treat for heart failure or respiratory disease. This is performed in the emergency department, often in the oxygen cage, with the cat in sternal recumbency to reduce stress. The goals of brief ultrasonography in this situation are to determine whether the left atrium is enlarged, screen for pericardial and pleural effusion, and determine whether hyperechoic lung artifacts (B-lines) are present, which could indicate interstitial fluid ( Figures 2 and 3 ). A recent study showed high sensitivity and specificity of B-lines to detect CHF in cats (87% and 89%, respectively). 3 Cage-side ultrasonography may also be useful to briefly assess left ventricle size and function; however, routine echocardiography is required to fully assess the underlying cardiac disease. Case notes: Because of Elvis's clinical instability, cage- side thoracic ultrasonography is indicated to assess left atrial size and screen for pleural effusion, which is clinically suspected on the basis of physical examination. Full echocardiography should be postponed until Elvis is stabilized; however, this initial assessment indicates the need for thoracocentesis and medical intervention for suspected CHF. The presence of B-lines suggests concurrent pulmonary edema, and the enlarged left atrium supports CHF as the diagnosis. RADIOGRAPHY Initial diagnostic imaging for cardiac disease may include thoracic radiography because it is relatively inexpensive and available to most veterinarians. Moderate to severe cardiac enlargement can be appreciated on thoracic radiography; however, this modality is insensitive for the detection of mild cardiac disease and cannot depict concentric hypertrophy of the ventricle. Case notes: Thoracic radiography is not a good screening tool for cats like Tux. Thoracic radiography is the test of choice for dyspneic cats to determine whether respiratory signs are caused by CHF. Cardiomegaly, pulmonary vascular distention, BOX 1 Cardiac Diseases That Can Cause Congestive Heart Failure in Cats • Hypertrophic cardiomyopathy • Restrictive cardiomyopathy • Dilated cardiomyopathy • Unclassified cardiomyopathy • Arrhythmogenic right ventricular cardiomyopathy • Valvular disease • Congenital disease FIGURE 2. Two-dimensional cage-side thoracic ultrasonogram from Elvis showing pleural effusion and an enlarged left atrium (LA). LV, left ventricle; RA, right atrium. FIGURE 3. Cage-side thoracic ultrasonogram from Elvis showing B-lines consistent with interstitial edema. Rib shadows are noted. Photo courtesy of Teresa DeFrancesco, DVM, DACVIM (Cardiology), DACVECC, North Carolina State University, College of Veterinary Medicine.