A three-year-old male castrated Domestic Shorthair cat presented to Cornell University Hospital for Animals Emergency Service on referral for evaluation of acute-onset dyspnea, pleural effusion, and cardiomegaly. The patient had a recent history of stridorous breathing at rest, tachypnea, hypothermia, and restlessness. He was initially taken to a nearby emergency clinic where thoracic radiographs and ultrasound revealed pleural effusion and cardiomegaly. The patient received oxygen therapy, furosemide, butorphanol, diphenhydramine, and intravenous fluids, and was referred to Cornell University Hospital for Animals.

On presentation, the patient was mildly tachypneic but was otherwise bright, alert, responsive, and had no other abnormalities on physical exam. Initial diagnostics revealed a markedly-elevated creatine kinase (30,784 U/L, reference interval [RI]: 74 to 386 U/L ), and troponin (1.69 ng/mL, RI: 0 to 0.11ng/mL ), azotemia, elevated D-Dimers, AST, and ALT, and an inflammatory leukogram. Thoracic ultrasound revealed moderate pleural and pericardial effusions that, when sampled percutaneously, were consistent with a high protein transudate. An echocardiogram revealed an abnormal structure in the region of the left auricle of the heart. A contrast-enhancing thoracic computed tomography angiography (CTA) scan revealed a moderately, diffusely enlarged left auricle that contained a focal, medium-sized (1.6 x 1.2 x 1.2 cm), soft tissue non-contrast enhancing mass. The mass was surrounded by a small amount of contrast material. Additionally, the left cranial, right cranial, and right middle lung lobes contained mild-to-moderate, patchy pulmonary opacification. The patient’s problem list included the left auricular mass, cranioventral lung opacification, and bicavitary effusion. Based on diagnostic evidence, the highest differential for the cardiac mass was a thrombus within a severely dilatated left auricle, although neoplasia was also considered. The patient was taken to surgery for thoracic exploration and pericardiectomy. A left auriculectomy was performed using a 3-row vascular stapler, loop ligation, and scalpel excision. The patient recovered from anesthesia and was discharged to the care of the owner. The patient represented to CUHA Emergency service a week later for dyspnea. Thoracocentesis produced non-clotting sanguinous fluid that had a packed cell volume (PCV)/total solids (TS) of 20/5.1, which matched the peripheral PCV/TS of 19/6.2. The patient was readmitted and taken to surgery for surgical revision of the leaking auriculectomy site. Additional ligatures and a porcine collagen patch were placed, resulting in hemostasis. The patient recovered from surgery and continued to improve over the next few days.

There are no prior reports of a cardiac auriculectomy being performed in a cat. This presentation will discuss the thorough diagnostic work-up and surgical procedures for this case, as well as the possible underlying pathophysiology that lead to the clinical disease.