A 6-week-old 17.3-kg (38.1-lb) male alpaca cria was evaluated at The Ohio State University Veterinary Medical Center because of dyspnea, anorexia, and lethargy of 3 days' duration. The cria's rectal temperature was 98.5°F (36.9°C), heart rate was 120 beats/min, and respiratory rate was 48 breaths/min. Findings of cardiac auscultation were unremarkable; thoracic auscultation revealed decreased lung sounds ventrally. The mucous membranes were pink and moist with a capillary refill time of < 2 seconds. The cria had increased respiratory effort with an abdominal component; inspiratory stridor was noted in the cranial portion of the thorax. Thoracic radiography revealed an enlarged, globoid cardiac silhouette and a diffuse unstructured interstitial lung pattern. Hematologic abnormalities included anemia (Hct, 16%; reference range, 24% to 35%), neutrophilia (15.3 × 109 cells/L; reference range, 2.1 × 109 cells/L to 9.5 × 109 cells/L), and monocytosis (3.2 × 109 cells/L; reference range, 0 × 109 cells/L to 0.6 × 109 cells/L); findings were consistent with an inflammatory leukogram. Serum biochemical analysis revealed hypoproteinemia (4.4 g/dL; reference range, 5.3 to 7.6 g/dL) and hypoalbuminemia (2.0 g/dL; reference range, 2.6 to 4.7 g/dL).
Doppler echocardiography revealed severe pericardial effusion with fibrinous strands in the pericardial space, mild right atrial and right ventricular enlargement, and mild mitral valve and tricuspid valve regurgitation. Cardiac motion was characterized by a rhythmic swinging motion within the pericardial space. There was mild collapse of the right ventricle, and the left ventricle appeared subjectively normal in size. The Doppler velocity of the mitral valve regurgitation (5.5 m/s) was considered normal. The Doppler velocity of the tricuspid valve regurgitation (3.3 m/s) was considered high, corresponding to a systolic pressure gradient across the tricuspid valve of 44 mm Hg and an estimated right ventricular systolic pressure of approximately 50 mm Hg (reference range, 20 to 30 mm Hg). The blood flow across the pulmonic valve had a laminar flow profile with a peak velocity of 1.1 m/s, which ruled out pulmonic valve stenosis. Electrocardiography was also performed (Figure 1).
Ferasin L, Ogden DM, Davies SJ, et al. Electrocardiographic parameters of normal alpacas (Lama pacos). Vet Rec 2005; 157:341–343.
Barlow AM, Mitchell KA, Visram KH. Bovine tuberculosis in llama (Lama glama) in the UK. Vet Rec 1999; 145:639–640.
Barr BS, Seco O, Axon J, et al. Successful treatment of pericarditis in a pregnant llama. J Vet Emerg Crit Care 2001; 11:287–291.
Nichols S, Anderson DE, Schober KE. Subtotal pericardiectomy for treatment of constrictive effusive pericarditis in a llama cria. J Camel Pract Res 2007; 14:33–37.
Kienle RD. Pericardial disease and cardiac neoplasia. In: Kittleson MD, Kienle RD, eds. Small animal cardiovascular medicine. St Louis: Mosby Inc, 1998;413–432.
Surawicz B, Knilans TK. Pericarditis and cardiac surgery. In: Surawicz B, Knilans TK, eds. Chou's electrocardiography in clinical practice. 5th ed. Philadelphia: Saunders, 2001;239–255.
Sacks E, Widman LE. Nonlinear heart model predicts range of heart rates for 2:1 swinging in pericardial effusion. Am J Physiol 1993; 264:H1716–H1722.
Surawicz B, Fisch C. Cardiac alternans: diverse mechanisms and clinical manifestations. J Am Coll Cardiol 1992; 20:483–499.
Brody DA. A theoretical analysis of intracavitary blood mass influence on the heart-lead relationship. Circ Res 1956; 4:731–738.
Hamlin RL, Smith CR. Categorization of common domestic mammals based upon their ventricular activation process. Ann N Y Acad Sci 1965; 127:195–203.
Margiocco ML, Scansen BA, Bonagura JD. Camelid cardiology. Vet Clin North Am Food Anim Pract 2009; 25:423–454.
Friedman HS, Gomes JA, Tardio AR, et al. The electrocardiographic features of acute cardiac tamponade. Circulation 1974; 50:260–265.
Friedman HS, Lajam F, Gomes JA, et al. Demonstration of a depressor reflex in acute cardiac tamponade. J Thorac Cardiovasc Surg 1977; 73:278–286.
Castaner A, Kostreva DR, Kampine JP. Changes in autonomic nerve activity during acute pericardial tamponade. Cardiology 1980; 66:163–173.
LeWinter MM, Kabbani S. Pericardial diseases. In: Zipes DP, Libby P, Bonow RO, et al, eds. Braunwald's heart disease. 7th ed. Philadelphia: Elsevier Saunders, 2005;1757–1780.