Suspected iatrogenic paradoxical embolization in a cat

A cat was evaluated for a 5-year history of progressive, episodic, exercise-induced cyanosis and panting. Diagnostic testing demonstrated tetralogy of Fallot with predominant right-to-left shunting and right-sided heart failure. Following diagnostic catheterization, the cat developed clinical signs consistent with systemic arterial thromboembolization and was euthanized. Necropsy findings included multiple thrombi within the right atrium and ventricle, and thromboemboli within the terminal aorta and right common carotid artery, a condition most consistent with iatrogenic paradoxical embolization secondary to diagnostic catheterization. Paradoxical embolization and thromboembolic complications of diagnostic catheterization are discussed.     

Diagnosis of right coronary artery to right atrial fistula in a dog using two-dimensional echocardiography

A five-year-old boxer dog developed cardiac murmurs, complete heart block and car-diomegaly associated with vegetative bacterial endocarditis. Using two-dimensional echocardiography, vegetative lesions of the aortic valves and extension of the vegetations into the proximal right coronary artery and adjacent atrial septum were identified. The vegetation within the atrial septum appeared as a cavitated mass which protruded into the right atrium. Fistulae within the atrial septal vegetation permitting communication between the coronary artery and right atrium were observed with colour Doppler echocardiography. The dog died despite medical treatment. Post mortem examination confirmed the echo-cardiographic findings. Vegetative endocarditis with invasion into the right coronary artery and atrial septum producing fistulae and communication with the right atrium has not been reported previously in dogs. Doppler echocardiography proved useful in demonstrating the abnormal anatomy, intraluminal fistular blood flow and its communication with the right atrium.     

Right atrioventricular valve dysplasia in a meerkat

A 7-y-old, captive, intact female meerkat (Suricata suricatta) was presented with lethargy, decreased appetite, dyspnea, and distended abdomen. At autopsy, the right atrium was markedly dilated, and the right atrioventricular valve (RAV) was dysplastic with shortened or absent chordae tendineae and direct attachment of the valve to the papillary muscles, which, in turn, were fused and abnormally positioned. The right ventricle was considered to be hypertrophied. Also present were hydrothorax, ascites, atelectasis, and hepatic congestion. A diagnosis of RAV dysplasia was made. Histologic findings included hypertrophy of cardiomyocytes and marked centrilobular hepatic congestion and hemorrhage, which were consistent with right-sided heart failure.     

Symptomatic partial anomalous pulmonary venous connection in a kitten

A 3-month-old intact female American Shorthair cat, with syncope and tachypnea, underwent cardiac examination which identified no heart murmur or gallop. Thoracic radiography disclosed mild generalized enlargement of the cardiac silhouette and a bronchial and interstitial pattern throughout the lungs. Echocardiography identified tubular structures near the left atrium. After agitated saline contrast imaging, persistent left cranial vena cava with unroofed coronary sinus was suspected. Computed tomography angiography showed the right cranial, right caudal and left caudal pulmonary veins draining into the coronary sinus and flowing into the right atrium. The left cranial pulmonary vein drained normally into the left atrium. Partial anomalous pulmonary venous connection (PAPVC) was diagnosed. The kitten was treated with diuretics but died of heart failure 2 months later. Permission for necropsy was not granted. This case represents symptomatic PAPVC in a kitten. Most pulmonary veins were connected abnormally with the coronary sinus. The prognosis was grave because of refractory heart failure.     

A cardiac vascular hamartoma in a calf: Ultrasonographic and pathologic images

A right atrial mass was observed by ultrasound in a 3-month-old red Holstein calf. Differential diagnoses included endocarditis or tumor. Due to the poor prognosis, the calf was euthanized. On gross examination, there was a marked dilation of the right atrium. A round, poorly delineated, 2 cm mass was visualized in the right atrium. Microscopic findings were consistent with a vascular hamartoma.     

Pulmonary hypertension and right-sided heart failure in an adult llama with hepatic disease

CASE DESCRIPTION: A 13-year-old llama was examined because of lethargy, inappetence, and syncope. CLINICAL FINDINGS: Physical examination revealed muffled heart and lung sounds and peripheral edema. Clinicopathologic abnormalities included lymphopenia, hyperglycemia, prerenal azotemia, mild hyponatremia, mild hypoalbuminemia, and high gamma-glutamyltransferase and creatine kinase activities. On ultrasonography, the liver appeared hyperechoic and ascites and pleural effusion were seen. Echocardiography revealed severe dilatation of the right atrium, right ventricle, and pulmonary artery; severe tricuspid regurgitation; and high right ventricular systolic pressure consistent with right-sided heart failure secondary to pulmonary hypertension. TREATMENT AND OUTCOME: Treatment with furosemide was attempted, but because of failing health, the llama was euthanized 4 weeks later. Macronodular cirrhosis of the liver, glomerulonephritis, and intimal fibrosis and medial hypertrophy of muscular pulmonary arteries were seen on histologic examination of postmortem specimens. CLINICAL RELEVANCE:Findings in this case were similar to those reported for human patients with portopulmonary hypertension secondary to hepatic cirrhosis. Pulmonary hypertension secondary to hepatic disease should be considered in the differential diagnosis of right-sided heart failure.     

Partial anomalous pulmonary venous connection in a dog

A 2-year-old male intact Belgian Malinois was presented for exercise intolerance. A grade III/VI left basilar systolic murmur was detected. Echocardiography revealed moderate right atrial and ventricular dilation and increased pulmonic outflow velocity. Thoracic radiographs showed right heart enlargement and a dilated caudal vena cava. In addition, on the left lateral projection, an enlarged aberrant right cranial pulmonary lobar vein was suspected to be diverging ventrally from the course of the right cranial lobar bronchus and inserting more ventrally than normal in the region of the right atrium. A left-to-right pulmonary vascular shunt was suspected, and the patient underwent further diagnostics under general anesthesia. An agitated saline study was positive, suggestive of a concurrent right to left shunt. A right heart catheterization was performed. Angiography was inconclusive. Oximetry testing revealed an increase in oxygen saturation within the right atrium at the level of the caudal cava supportive of a left-to-right shunt in this region. Computed tomography angiography revealed a large single pulmonary vein that anomalously entered into the caudolateral aspect of the right atrium (left-to-right shunt) and was suspicious for a small arteriovenous malformation between the right caudal pulmonary artery and the right pulmonary vein returning to the left atrium (right to left shunt). The patient was diagnosed with a partial anomalous pulmonary venous connection and a possible arteriovenous malformation.     

BACTERIAL ENDOCARDITIS WITH THROMBUS FORMATION AND ABSCESSATION IN A HORSE

A 2.5 year old Appaloosa stallion with progressive weight loss and a heart murmur was diagnosed as having vegetative endocarditis of the right atrioventricular valves with a mass in the right atrium. The ultrasonographic appearance of the lesion was characterized by extreme reverberation. On postmortem examination, a 9 cm diameter thrombus was found within the right atrium and auricle, occupying approximately 80% of the chamber volume. Additionally, a lenticular abscess extended throughout the parietal cusp of the right atrioventricular valve. Histologic examination revealed that the lesions were septic with numerous gram positive cocci in short chains, suggestive of Streptococcus equi , and gram negative rods.     

RECOMMENDATIONS FOR STANDARDS IN TRANSTHORACIC TWO-DIMENSIONAL ECHOCARDIOGRAPHY IN THE DOG AND CAT*

Recommendations are presented for standardized imaging planes and display conventions for two-dimensional echocardiography in the dog and cat. Three transducer locations (“windows”) provide access to consistent imaging planes: the right parasternal location, the left caudal (apical) parasternal location, and the left cranial parasternal location. Recommendations for image display orientations are very similar to those for comparable human cardiac images, with the heart base or cranial aspect of the heart displayed to the examiner's right on the video display. From the right parasternal location, standard views include a long-axis four-chamber view and a long-axis left ventricular outflow view, and short-axis views at the levels of the left ventricular apex, papillary muscles, chordae tendineae, mitral valve, aortic valve, and pulmonary arteries. From the left caudal (apical) location, standard views include long-axis two-chamber and four-chamber views. From the left cranial parasternal location, standard views include a long-axis view of the left ventricular outflow tract and ascending aorta (with variations to image the right atrium and tricuspid valve, and the pulmonary valve and pulmonary artery), and a short-axis view of the aortic root encircled by the right heart. These images are presented by means of idealized line drawings. Adoption of these standards should facilitate consistent performance, recording, teaching, and communicating results of studies obtained by two-dimensional echocardiography.     

Cor triatriatum dexter of unusual morphology in a miniature schnauzer

A five-year-nine-month-old, male entire, miniature schnauzer presented for further investigation of pleural effusion. Echocardiography revealed a perforated membrane dividing the right atrium into two chambers: the true right atrium (a small, lower-pressure, cranioventral chamber communicating with the tricuspid valve and right ventricle) and the accessory right atrium (a larger, higher-pressure, caudodorsal chamber), consistent with a cor triatriatum dexter. This was confirmed using computed tomography angiography. Imaging studies revealed that both the cranial and caudal vena cava entered the higher-pressure accessory right atrium and the coronary sinus entered both the accessory and true right atrial chambers. This differed from the more usual canine cor triatriatum dexter presentation with the cranial vena cava entering the lower-pressure cranial chamber and the caudal vena cava entering the higher-pressure caudal chamber. Balloon membranostomy was successful in reducing the pressure gradient between the two right atrial chambers with subsequent resolution of the clinical signs. The patient continues to do well after three-years of follow-up.     

Cor triatriatum sinister with incomplete atrioventricular septal defect in a cat

An 11-month-old, 3 kg, female domestic shorthair cat was referred to evaluate cardiac structure and function. Echocardiography revealed the membrane dividing the left atrium into two chambers, a large defect in the lower part of the atrial septum, and turbulent blood flow from the distal left atrium into the right atrium. These findings suggested cor triatriatum sinister (CTS) with incomplete atrioventricular septal defect (AVSD). The cat was treated with medications for management of congestive heart failure. In the end, she died from right-sided heart failure 17 months after the initial presentation. At necropsy, a fibromuscular membrane with a round orifice in the left atrium and an ostium primum defect were confirmed, and the definitive diagnosis of CTS with incomplete AVSD was made. To our knowledge, this study presents the first case report of CTS with incomplete AVSD in a cat.     

Intrapericardial neuroendocrine tumour in a dog

An 11-year-old neutered male Border Terrier presented for pericardiectomy after a nine-month history of tricavitary effusion, dyspnoea and lethargy. Transthoracic echocardiography revealed a fluid-filled structure at the heart base, starting at the mid-right ventricle and extending to the middle of the right atrium. Almost complete compression of the right atrium and the cranial vena cava was noted. Thoracic computed tomography revealed a heterogeneously enhancing and poorly marginated mass within the cranial aspect of the pericardium. A median sternotomy and subtotal pericardiectomy were performed. A non-distinct fluid-filled structure within the pericardium adhered to the epicardium was visualised. The structure was removed via marsupialisation along with extirpation of enlarged sternal lymph nodes. Histopathological examination of the sternal lymph nodes revealed expansile, well-demarcated, unencapsulated nodules of neoplastic cells consistent with a neuroendocrine tumour suspected to be thyroid in origin. After surgery, intractable pleural effusion resulted in euthanasia. Intrapericardial ectopic thyroid tumours are rarely reported in animals. The location of the mass and unusual presentation may have made it challenging for echocardiography to identify this neoplasia. Thoracic computed tomography at an earlier stage may have identified the neoplasia and potentially allowed for surgical intervention.     

HEMANGIOSARCOMA IN THE MAIN PULMONARY ARTERY OF A DOG

The clinical, radiological and necropsy findings in a five-year old dog with a hemangiosarcoma in the main pulmonary artery are described. Hemangiosarcoma in this location has not been previously described in the dog, the typical location in the heart being the right atrium and auricle. The tumor in this dog caused both a perfusion deficit to the right lung and obstruction of right ventricular outflow, which eventually caused right heart failure.     

Recommendations for Standards in Transthoracic Two-Dimensional Echocardiography in the Dog and Cat

Recommendations are presented for standardized imaging planes and display conventions for two-dimensional echocardiography in the dog and cat. Three transducer locations ("windows") provide access to consistent imaging planes: the right parasternal location, the left caudal (apical) parasternal location, and the left cranial parasternal location. Recommendations for image display orientations are very similar to those for comparable human cardiac images, with the heart base or cranial aspect of the heart displayed to the examiner's right on the video display. From the right parasternal location, standard views include a long-axis four-chamber view and a long-axis left ventricular outflow view, and short-axis views at the levels of the left ventricular apex, papillary muscles, chordae tendineae, mitral valve, aortic valve, and pulmonary arteries. From the left caudal (apical) location, standard views include long-axis two-chamber and four-chamber views. From the left cranial parasternal location, standard views include a long-axis view of the left ventricular outflow tract and ascending aorta (with variations to image the right atrium and tricuspid valve, and the pulmonary valve and pulmonary artery), and a short-axis view of the aortic root encircled by the right heart. These images are presented by means of idealized line drawings. Adoption of these standards should facilitate consistent performance, recording, teaching, and communicating results of studies obtained by two-dimensional echocardiography. (Journal of Veterinary Internal Medicine 1993; 7:247–252. Copyright © 1993 by the American College of Veterinary Internal Medicine.)     

Gross anatomy of the heart of the alpaca (Vicugna pacos,Linnaeus 1758)

The available information about anatomical characteristics of the cardiovascular system of the alpaca (Vicugna pacos, Linnaeus 1758) is scarce. The general objective of this work was to describe its heart anatomy. We dissected six adult animals and five neonates. The heart of the alpaca was located in the middle mediastinum, with a craniocaudal extension from the third to the sixth rib. No ligament that connected the fibrous pericardium to the sternum or to the diaphragm was detected. In the right atrium, there was a developed crista terminalis and small pectinate muscles. In the right ventricle, the septomarginal trabecula was very large. From the proximities of the interventricular septum arose small septomarginal trabeculae that ended in carnous trabeculae of the septal wall. The left atrium included little developed pectinate muscles. On the left ventricle, both papillary muscles were bilobed. Two left septomarginal trabeculas were detected in this ventricle. The left subclavian artery was originated from the aortic arch separately from the brachiocephalic trunk, and bicarotid trunk was present. The other branches of the subclavian artery were similar to the domestic ruminants. The arterial supply of the heart was of the right type. In conclusion, the heart anatomy of alpaca and the irrigation of thoracic cavity were more similar to those of old world camels and different from domestic ruminants.     

Cardiopulmonary values in dogs with artificial model of caval syndrome in heartworm disease.

Cardiopulmonary values were determined in dogs with an artificial model of heartworm caval syndrome, which was produced by insertion of heartworm-like silicone tubes into the tricuspid valve orifice and right atrium. Fifteen to 25 tubes with some knots were inserted in 6 dogs (knot group), and 7 to 11 tubes (small-number group) or 29 to 37 tubes (large-number group) without a knot in 3 dogs, respectively. After tube insertion, angiographic contrast medium infused into the right ventricle regurgitated to the right atrium in all cases, and the regurgitation was the most severe in the large-number group. On electrocardiographic findings, the atrial and/or ventricular premature beat developed. The height of a- and v-wave of right atrial pressure curves elevated in all groups. The elevation in v-wave was obvious in the large-number group. The pulmonary arterial pressure tended to fall or to elevate slightly, and total pulmonary resistance increased in all groups. The right cardiac output decreased significantly in all cases. The right heart hemodynamics of the model might resemble those in spontaneous cases without disturbed pulmonary circulation.     

Ectopic thyroid carcinoma infiltrating the right atrium of the heart in a dog

A 12-year-old intact female shih tzu dog was diagnosed with an ectopic thyroid carcinoma infiltrating the right atrium of the heart. Echocardiography and computed tomography were helpful in diagnosis; a definitive diagnosis was made based on postmortem histopathology and immunohistochemistry. The patient lived 428 days beyond diagnosis with only medical management.     

DOPPLER ECHOCARDIOGRAPHY IN THE NORMAL DOG: PART II

Doppler echocardiography was used to determine blood flow velocities in the normal canine heart. The areas examined were the mitral valve, left atrium, tricuspid valve, right atrium, aortic valve, left ventricular outflow tract, pulmonic valve and right ventricular outflow tract. This study then statistically evaluated the influence of breed, age, sex, heart rate, mass and various interactions of these factors on the cardiac flow values determined. Mass and heart rate had the most significant effect on the various determinations with decreasing mass and increasing heart rates generally resulting in increasing peak and mean velocities. The pulmonary artery was statistically judged as being the flow area most susceptible to such influences. Comparisons were made between pulsed and continuous wave Doppler for peak velocities over the four valve areas with only aortic flow, as measured from the left caudal view, showing a significant difference between the two techniques. Mitral flow as compared to tricuspid flow showed a statistically significant difference between peak late diastolic velocities only. The ratio of early mitral diastolic flow to late mitral diastolic flow was always greater than one. Pulmonary flow showed a number of statistically significant differences when compared to aortic flow.