Endocardial fibroelastosis in a dog

Endocardial fibroelastosis is an uncommon congenital heart disease in dogs that may be manifested by signs of left-sided congestive heart failure. A three-month-old, male, Fila Brasileiro dog developed signs of generalised heart failure. Physical examination revealed normal temperature, ascites, and pale and cyanotic mucous membranes. The pup died just after radiography which revealed ascites, hepatomegaly, severe cardiac enlargement and pulmonary oedema. At necropsy, serosanguineous fluid in the thorax and abdomen, pulmonary oedema, right ventricular dilatation, hypertrophy and dilatation of the left ventricle, and mitral valve incompetence were observed. The histopathological examination demonstrated that the thickening of the endocardium of the left atrium and left ventricle was due to the presence of elastic and collagen fibres, although there were no signs of an inflammatory process.     

Echocardiographic detection of pulmonic valve rupture in a horse with right-sided heart failure

Pulmonic valve rupture was determined to be the cause of severe right-sided heart failure in a 20-year-old Thoroughbred gelding. A flail in the intermediate pulmonic valve cusp was detected by 2-dimensional echocardiography. Significant pulmonic and tricuspid valvular regurgitation were confirmed by Doppler echocardiography. Despite treatment, the horse's condition deteriorated, and euthanasia was performed. At necropsy, a tear in the pulmonary artery extending into the right valve cusp and a tear at the base of the intermediate valve cusp were identified at the junction of the right and intermediate pulmonic valve cusps. Careful echocardiographic evaluation of the pulmonic valve is warranted for horses with right-sided heart failure, for which more common causes cannot be found.     

Surgical Palliation of Severe Tricuspid Valve Stenosis in a Dog by Use of Fontan's Procedure

OBJECTIVE: To describe surgical treatment of tricuspid valve stenosis using the Fontan procedure in a young dog. STUDY DESIGN: Case report. SAMPLE POPULATION: One client-owned dog RESULTS: A six month old female Labrador retriever was diagnosed with tricuspid obstruction. The dog had a displaced tricuspid valve and small right ventricle and had progressed to right-sided (backward) cardiac failure. A Fontan procedure (connection of the right atrium to the pulmonary artery with a prosthetic conduit) was performed. Within three days the right atrial pressure had dropped from a preoperative value of 33 mm Hg to 8 mm Hg and the ascites was significantly reduced. The dog died suddenly two months after surgery. Postmortem examination of the heart showed a greatly enlarged right atrium and hypoplastic right ventricle. The tricuspid valve leaflets were fused and displaced ventrally leaving an opening measuring 3x5 mm between the chambers. The conduit was intact with no evidence of leakage or thrombosis. CONCLUSIONS: Palliation of tricuspid stenosis using the Fontan procedure can be performed in dogs. Sudden death may occur and is most likely because of cardiac arrythmias.     

Transient tricuspid valve regurgitation following surgical treatment of cor triatriatum dexter in a dog

Echocardiographically documented tricuspid valve regurgitation appeared immediately after surgical treatment of cor triatriatum dexter in a two-month-old rottweiler. Medical treatment was instituted with benazepril, spironolactone and furosemide. Pimobendan was added after five months, and all treatment was discontinued two months later when clinical signs of ascites and hepatomegaly had resolved and tricuspid valve regurgitation was markedly reduced on echocardiography. To the authors' knowledge, this is the first report describing the development and spontaneous improvement of haemodynamically significant tricuspid valve regurgitation following surgical treatment of cor triatriatum dexter in a dog. It is hypothesised that the increase in right atrial volume and pressure following cor triatriatum dexter repair and transient ischaemia of papillary muscles led to dilatation of the right atrioventricular annulus and subsequent severe tricuspid valve regurgitation in the face of an anatomically normal valve. Time and pharmacological preload reduction as well as normalisation of right atrial inflow and subsequent cardiac remodelling substantially reduced tricuspid valve regurgitation and eliminated clinical signs of heart failure. It is also possible that heart recovery has been spontaneous.     

Tricuspid valve stenosis caused by fibrous adhesions to an endocardial pacemaker lead in a dog

Acquired tricuspid valve stenosis (TVS) is a rare complication of endocardial lead placement in humans that has not been described in the veterinary literature. We describe a 6.5-year-old Border terrier that was presented with right-sided congestive heart failure 5.5 years after placement of a transvenous pacemaker. Severe TVS was confirmed by cardiac ultrasonography and appeared to be secondary to excessive endocardial pacemaker lead within the right atrium. Repositioning of the lead proved impossible and subsequent postmortem examination demonstrated fusion of the tricuspid valve (TV) leaflets around the endocardial lead with associated narrowing of the tricuspid valve orifice. In addition, the loop of the endocardial lead was anchored by thick fibrous tissue to the right atrial wall. This case report suggests that if sufficient endocardial lead is left inside the heart, in dogs undergoing transvenous pacemaker therapy, the redundant lead can become adherent to the tricuspid valve apparatus and cause valvular stenosis.     

Anatomically corrected malposition (ACM) with subpulmonary infundibulum in a calf: clinico-morphologic case report.

A Japanese black calf with cyanosis, tachycardia, tachypnea and systolic murmur died of hypoxemia and cardiac insufficiency on the 38th day after birth. We could not establish the diagnosis during it's life. However, anatomically corrected malposition (ACM) with ventricular septal defect was confirmed at autopsy. There was situs solitus of the viscera and atria with atrio-ventricular discordance and ventriculo-arterial concordance. The ventricles demonstrated l-loop, i.e. on the right-sided ventricle there was a markedly enlarged morphologic left ventricle, and on the left-sided ventricle there was a hypoplastic morphologic right ventricle with a stenotic tricuspid valve and Ebstein-like deformity. The right posterior aorta originated from the left ventricle. The pulmonary artery arose from the left-sided right ventricle via infundibulum. There was a fibrous continuity between the aortic and mitral valve. We considered that this is the first reported case of bovine ACM.     

Bidirectional flow across a perforate cor triatriatum dexter in a dog with concurrent pulmonary,tricuspid, and mitral valve dysplasia

A 10-week-old male intact mixed breed dog presented for evaluation of suspected right-sided congestive heart failure. Echocardiographic imaging revealed a perforate cor triatriatum dexter (CTD), along with pulmonary valve stenosis and tricuspid and mitral valve dysplasia. In typical CTD cases, there is unidirectional blood flow across the dividing membrane, from the caudal into the cranial right atrial chambers. Owing to right-sided pressure alterations caused by the concurrent valvar defects, color Doppler imaging demonstrated bidirectional flow across the CTD membrane.     

Congenital malformations of the tricuspid valve in domestic carnivores: a retrospective study of 50 cases

A retrospective study was done on 14 cats and 36 dogs diagnosed with right atrioventricular valve malformations (RAVM), either tricuspid dysplasia (n = 38) or Ebstein's anomaly (n = 12). Comparison with a large reference population including 85 250 animals allowed an epidemiologic analysis of these RAVM, demonstrating that Labrador, Boxer and Chartreux cats had a 35, 7 and 11-fold higher risk respectively to be affected by one of these heart diseases than other breeds, without sexual predisposition. In 93% of cases, cardiac auscultation revealed a heart murmur, whose grade was not significantly correlated with the echographic stages of the valvular disease. The echocardiographic examination confirmed the frequent association between RAVM and other congenital anomalies, particularly mitral dysplasia, in 84% and 20% of tricuspid dysplasia and Ebstein anomaly respectively. Last, the prognosis of RAVM was worsened by atrial fibrillation and right-sided heart failure.     

Rupture of an aortic sinus aneurysm in a 15-year-old broodmare

A 15-year-old, Standardbred broodmare with an aortic sinus aneurysm developed rupture of the aneurysm with subsequent rupture of a tricuspid valve chorda tendinae, tricuspid regurgitation, acute right-sided congestive heart failure, and pulmonary thromboembolism. Shunting of blood from the aorta through the ruptured aneurysm into the right ventricle resulted in decreased renal perfusion and acute renal failure. Initially, treatment of the mare with analgesics, fluids, and digoxin resulted in clinical improvement, but the mare's condition deteriorated after 8 days and the mare was euthanatized due to unrelenting pain and a poor prognosis. Echocardiography was useful in diagnosis of the cardiac disease in the broodmare.     

Vegetative endocarditis in six cats

Between 1990 and 1997 vegetative endocarditis was diagnosed in six neutered cats (three males, three females) aged between 3 and 9 years. Two cats were purebred (one Persian and one Tonkinese), the remaining four being domestic short haired cats. The diagnosis was made using echocardiography (five cases) or at necropsy (one case). Concurrent involvement of the aortic and mitral valve was noted in four cats, the aortic valve alone was affected in one case, and the tricuspid valve in another. A likely microbiological diagnosis was obtained in three cats: a Bartonella species in two cats based on positive blood culture and a Streptococcus species in one cat based on Gram stain of valve lesions at necropsy. In another cat, Gram-positive cocci were demonstrated histologically in tricuspid vegetations. Invariably, cats had signs of congestive heart failure (left-sided in five cats, right-sided in one), and this was the major factor contributing to mortality in four cases. Signs referable to sepsis were prominent in only two patients. Appropriate medical therapy, consisting of antimicrobials and drugs to treat congestive heart failure, resulted in survival for 5 and 11 months, respectively, in two cases. The other cats died within 2 weeks of diagnosis, including two which received aggressive treatment in hospital.     

Use of a modified open patch-graft technique and valvulectomy for correction of severe pulmonic stenosis in dogs: eight consecutive cases

SUMMARY A modified open patch-graft technique was used to correct congenital pulmonic stenosis in 8 dogs. Pulmonary valve dysplasia was moderate to severe in all cases, based upon clinical and echocardiographic criteria, and 3 dogs were in right-sided congestive heart failure at the time of surgery. Seven of the 8 dogs survived the surgery. One surviving dog displayed cerebral cortical dysfunction, the remaining 6 had no detectable neurological sequelae. Right ventricular failure was alleviated in all 7 surviving dogs, but right ventricular dilatation persisted post-operatively. Pulmonary valvulectomy and open patch-grafting provides an effective means of alleviating signs of congestive heart failure caused by pulmonary valve dysplasia, even In the presence of severe infundibular hypertrophy and dynamic outflow obstruction.     

Clinical and pathological characterisation of primary pulmonary hypertension in a dog

Primary pulmonary hypertension was diagnosed in an eight-year-old labrador retriever on the basis of echocardiographic findings of severe right ventricular eccentric hypertrophy, abnormally high systolic and diastolic pulmonary arterial pressures calculated by applying the modified Bernoulli equation to the tricuspid and pulmonary insufficiency peak velocities, and the absence of any underlying disease known to cause secondary pulmonary hypertension. The clinical abnormalities developed gradually, from exercise intolerance starting early in life to terminal right-sided congestive heart failure. Consistent histopathological findings were severe intimal and medial thickening of small arteries and arterioles that led to vascular obliteration.     

Pulmonic stenosis in the dog: 29 cases (1975-1984)

In a retrospective study of 29 dogs with congenital pulmonic stenosis, we evaluated the clinical, radiographic, angiocardiographic, and cardiac catheterization data. Eighteen dogs had no clinical signs of disease and were referred for evaluation of a previously detected cardiac murmur, 5 dogs had congestive right-sided heart failure, and 5 dogs were examined for exercise intolerance or syncope. Dogs with heart failure tended to be older than dogs without clinical signs of heart failure (19.3 months vs 12 months). All dogs had radiographic or electrocardiographic evidence of right ventricular enlargement. Poststenotic dilatation of the main pulmonary artery and apparent pulmonary undercirculation were observed frequently on survey radiographs. Isolated pulmonic valve dysplasia, representing a range of angiographic pulmonic valve abnormalities, was evident in 88% of the available 26 angiographic studies, whereas subvalvular stenosis was uncommon and observed in only 2 dogs. Muscular hypertrophy of the right ventricular infundibulum and supraventricular crest were observed in 96% and 25% of the angiocardiograms, respectively. Poststenotic dilatation of the main pulmonary artery was observed in every dog. A ratio between the width of the main pulmonary artery and the valve annulus was useful in identifying pulmonic stenosis and distinguishing this anomaly from other congenital malformations. The degree of poststenotic dilatation did not appear to be related to the severity of the systolic pressure gradient, which ranged from 20 to 228 mm of Hg (mean, 93 mm of Hg).(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of Systolic Cardiac Function Before and After Treatment of Atrial Fibrillation in Horses With and Without Additional Cardiac Valve Insufficiencies

Clinical, electrocardiographic and echocardiographic examinations were conducted before therapy and 4 days after conversion to normal sinus rhythm in 15 horses with a history of atrial fibrillation of 2-6 months duration. Seven horses showed no other signs of cardiac disease. Four horses suffered additionally from mitral valve insufficiency, while six horses had aortic valve insufficiency, including two of the four horses with mitral valve insufficiency, but none had signs of congestive heart failure. Doppler echocardiographic estimates of various variables were made for assessment of systolic heart function. These included heart rate, stroke volume, cardiac output and cardiac output per kg of body weight (heart index). After conversion to normal sinus rhythm, the horses without heart valve insufficiency showed a statistically significantly decreased heart rate (-24%) and cardiac output (-3%), but an increase in stroke volume (+8.4%) and heart index (+9%). The horses with heart valve insufficiency experienced a statistically significant decrease in heart rate (-21%) after conversion to normal sinus rhythm, but showed an increase in all other variables. Cardiac output increased statistically significantly by 20%, stroke volume by 54% and heart index by 58%.     

Transmembrane stent placement for cor triatriatum dexter in six dogs

ObjectivesReport the long-term outcomes following transmembrane stent placement as a therapy for Cor Triatriatum Dexter (CTD).Materials and methodsRetrospective case series including six dogs with CTD treated with transmembrane stent placement. Follow-up information was obtained including the persistence of presenting clinical signs, additional therapies required, and survival.ResultsThe median follow-up time was 24 months (range 15–76 months). Long-term outcome was deemed excellent in four dogs (67%), good/fair in one dog (17%), and poor in one dog (17%). Three dogs had persistence of clinical signs of variable severity. These three dogs were Labrador Retrievers or their crosses with varying degrees of tricuspid valve dysplasia (TVD), two of which also had a right to left shunting patent foramen ovale (PFO). One of these three dogs died 23 months post-stent placement during attempted open-heart repair of the TVD and PFO. Another is alive 15 months post-operatively stable on medical therapy for right-sided congestive heart failure secondary to TVD. The final dog demonstrated improved but persistent mild exercise intolerance up to 76 months post-operatively associated with mild TVD and a concurrent PFO.ConclusionsTransmembrane stent placement for CTD is a viable long-term treatment option with improvement or resolution of clinical signs. In the presence of concurrent congenital heart disease, specifically Labradors with TVD, additional therapies may be necessary with a corresponding impact on prognosis.     

Cardiac fibrosarcoma in a dog

A cardiac fibrosarcoma involving the right ventricular free wall, the interatrial septum, and proximal portion of the interventricular septum, with a 2-cm diameter protrusion into the right atrial lumen, was found at necropsy of a 2-year-old Miniature Schnauzer. Severe distortion of the tricuspid valve and narrowing of the aortic and pulmonic outflow tracts had caused the dog to develop right-sided cardiac failure and to have syncopal episodes. A tentative antemortem diagnosis of congenital pulmonic stenosis had been made on the basis of results of physical examination and diagnostic work-up. Evaluation of the case exemplifies the difficulty encountered in diagnosing cardiac tumors before the patient's death.     

Pulmonary hypertension as a cause of atrial fibrillation in young horses: four cases (1980-1989)

Four young horses of various breeds and suffering from atrial fibrillation died of heart failure. All had markedly high pulmonary arterial pressure, right-sided cardiomegaly, and lack of histologic lesions in the right atrium or pulmonary parenchyma. Three horses had hypertrophy and/or necrosis of the tunica media of the pulmonary vasculature. Clinical signs of disease, physiologic data, and pathologic findings indicated that these horses had primary pulmonary hypertension with secondary right-sided cardiac ventricular hypertrophy and dilatation, atrial fibrillation, and heart failure.     

Pulmonary Hypertension and Cardiac lnsuff iciency in Three Cows with Primary Lung Disease

Increased pulmonary arterial pressures as a result of pulmonary disease are described in two cows with chronic pneumonia and one cow with acute pneumonia. Based on clinical signs of congestive right heart failure, increased pulmonary arterial pressure, and right ventricular hypertrophy, cor pulmonale was diagnosed in one cow. Two cows had increased pulmonary arterial pressure and signs of right heart insufficiency, but right ventricular hypertrophy was not identified. Two of the cows had ventral edema and exercise intolerance. All cows had jugular venous distention and increased right atrial and pulmonary arterial pressures. Peripheral arterial PaO2 was decreased in two cows, and not measured in the third cow. Although an uncommon cause of congestive heart failure in cattle at low altitudes, pulmonary hypertension should be considered in cattle with clinical right heart failure.     

Congenital endocardial fibroelastosis in a dog

A 9-week-old Weimaraner was tentatively diagnosed clinically with congenital left-sided heart failure. On necropsy, diffuse fibroplasia over the left ventricular endocardium; small, deformed papillary muscles; and pulmonary congestion were evident. Microscopically, the fibroplasia extended into the myocardium and cardiomyocytes, and Purkinje fibers were degenerated, consistent with congenital endocardial fibroelastosis.     

Tricuspid valve dysplasia in fifteen dogs

Clinical findings in fifteen dogs with tricuspid valve dysplasia are described. Thirteen dogs had loud systolic heart murmurs. Eleven of them hat a palpable precordial thrill over the same location. In 14 dogs, right heart enlargement was suspected on thoracic radiographs and electrocardiography. Right atrial dilation was seen echocardiographically in all dogs. Fourteen dogs had additional right ventricular dilatation, some with hypertrophy as well. Doppler echocardiography revealed tricuspid valve regurgitation. Seven dogs remained free of clinical symptoms to date. If symptoms of decompensation develop with tricuspid dysplasia, diuretics, ACE inhibitors and eventually positive inotrope drugs are indicated. Antiarrhythmic drugs may become necessary in cases of supraventricular tachyarrhythmias.