J Med Primatol 2000: 29: 42–45 Printed in Ireland - all rights resered. Dilative cardiomyopathy leading to congestive heart failure in a male squirrel monkey (Saimiri sciureus ) Tolwani RJ, Waggie KS, Green SL, Tolwani AJ, Lyons DM, Schatzberg AF. Dilative cardiomyopathy leading to congestive heart failure in a male squirrel monkey (Saimiri sciureus ). J Med Primatol 2000; 29:42 – 45. © Munksgaard, Copenhagen Abstract: A 17-year-old, 1-kg, colony-housed, male squirrel monkey (Saimiri sciureus ) developed clinical signs of congestive heart failure. The monkey presented with lethargy, increased heart and respiratory rates, and mild abdominal distention. The clinical history, laboratory analysis, and radiographic findings were consistent with heart failure due to dilative cardiomyopathy. Gross and microscopic examination of the heart confirmed a dilative cardiomyopathy. This is the first report describing congestive heart failure caused by dilative cardiomyopathy in a squirrel monkey. Spontaneous dilative cardiomyopathy may be infre- quently observed in the squirrel monkeys because they are not rou- tinely housed in the research environment during their advancing years. Ravi J. Tolwani 1 , Kim S. Waggie 1, *, Sherril L. Green 1 , Ashita J. Tolwani 3 , David M. Lyons 2 , Alan F. Schatzberg 2 1 Departments of Comparative Medicine, and 2 Psychiatry and Behavioral Science, Stanford University School of Medicine, Stanford, CA 94305; 3 Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294 Key words: congestive heart failure – dilative cardiomyopathy – squirrel monkey Accepted October 7, 1999. Dr. Ravi J. Tolwani, Stanford University School of Medicine, Department of Com- parative Medicine, RAF 1, Quad 7, Building 330, Stanford, CA 94305-5410. Tel: +1 650 725 3879; fax: +1 650 725 0940; e-mail: rtolwani@leland.stanford.edu Case History A 17-year-old, 1-kg, colony-born, male squirrel monkey (Saimiri sciureus ) was noted to be lethargic and sitting at the bottom of the cage. This monkey was a member of a colony of squirrel monkeys maintained for behavioral studies. All members of the colony underwent routine annual health assessments and were maintained on Teklad 20% Monkey Diet (Harlan, Madison, WI). Physi- cal examination of this monkey revealed a normal heart rate, a moderately increased respiratory rate, and an increase in respiratory effort. The monkey had a mild abdominal distention. Thoracic auscul- tation revealed muffled heart sounds with signifi- cant rales, rhonchi and bilateral wheezing. Thoracic radiographs revealed a globally enlarged cardiac silhouette resulting in the dorsal displace- ment of the trachea. Cranial and caudal cardiac borders were difficult to visualize. There was also a significant amount of bilateral infiltrate, with ob- scuring of both hemidiaphragms (Fig. 1). Radio- graphic findings of global cardiac enlargement are consistent with dilative cardiomyopathy, pericar- dial effusion, or cardiac tampanade. Infiltration around the hilar area is most consistent with pul- monary edema. Loss of visualization of the di- aphragm may result from bilateral pleural effusion, as can be seen with congestive heart failure. Serum biochemistries revealed panhypoproteine- mia: hypoproteinemia (total solids, 1.9 g/dl), hy- poalbuminemia (0.9 g/dl), and a hypoglobulinemia (1 g/dl), consistent with ascites and the loss of protein into the pleural and abdominal space. Hypocalcemia (6 mg/dl), which often accompanies hypoalbuminemia, was also present. Serum-ionized calcium was not determined. Urinalysis was nor- mal. The complete blood cell count and differential revealed a stress neutrophilia (85% neutrophils), lymphopenia (14% lymphocytes), and a moderate anemia consistent with chronic disease (hematocrit of 22.9%; red blood cell (RBC) count of 4.17 × 10 6 /l; hemoglobin 7.4 g/dl). Venous blood-gas analysis indicated that the monkey was acidotic, hypercapic, and hypoxic (pH 7.22; HCO 3 31.1 * Present address: ZymoGenetics, 1201 Eastlake Avenue East, Seattle, WA 98102. 42