Pulmonic stenosis caused by single coronary artery in dogs: four cases (1965-1984)

Single right coronary artery (CA) associated with pulmonic stenosis was found in 3 English Bulldogs and a Boxer, suggesting a genetic predisposition for the associated anomalies. The left main coronary branch arose from the single right CA, encircled the pulmonic root over hypoplastic pulmonic valves at the level of the obstruction, and appeared to be the primary cause of underlying pulmonic stenosis. Patch-graft surgery to relieve pulmonic stenosis caused death in 1 dog when the unrecognized anomalous CA was served during the procedure. The anomalous left CA was detectable by use of angiocardiography in all 4 dogs and was recognized before surgery in 2 of them. In 1 dog, a right ventricle-to-pulmonary trunk-bridging conduit was implanted to improve outflow from the right side of the heart.     

Quadricuspid aortic valve and associated abnormalities in the dog: Report of six cases

ObjectivesTo describe the clinical and echocardiographic findings in dogs with quadricuspid aortic valve (QAV).BackgroundQAV is a rare canine congenital heart disease which has been reported only three times in the young dog.Animals, materials and methodsSix dogs (0.3- to 13-year-old) with QAV diagnosed by two-dimensional echocardiography were retrospectively evaluated. Medical records, echocardiograms, and follow-ups were reviewed.ResultsAccording to aortic cusp morphology, QAV was classified as type A (n = 1), type B (n = 4) or type C (n = 1). QAV was associated with at least one other heart disease in all of the dogs including, ventricular septal defect (n = 1), enlarged left coronary ostium (n = 4), degenerative mitral valve disease (MVD, n = 1) and patent ductus arteriosus (PDA, n = 3). Mild to moderate aortic regurgitation was also detected in all dogs by continuous-wave and color-flow Doppler echocardiography. QAV was diagnosed in four asymptomatic dogs referred for evaluation of a heart murmur. The remaining two dogs had QAV and PDA with evidence of mild exercise intolerance and moderately retarded growth. The PDA was surgically corrected in both dogs and at the time of writing, 1–2.5 years after the initial diagnosis, none of the six animals shows evidence of clinical signs.ConclusionQAV is a cause of aortic insufficiency. It may incidentally be found by two-dimensional echocardiography in dogs of various ages in association with other congenital or acquired cardiac abnormalities.     

Mitral valve and tricuspid valve dysplasia in a 9‐week‐old Standardbred colt

A 9‐week‐old Standardbred colt was presented for investigation of dull demeanour, exercise intolerance and heart murmurs. Cardiac auscultation revealed a grade 5/6 holosystolic murmur and a grade 5/6 pansystolic murmur over the left and right cardiac apex respectively, and an irregularly irregular cardiac rhythm. Electrocardiographic examination findings were consistent with atrial fibrillation and tachycardia. Echocardiographic examination identified marked atrioventricular regurgitation and atrial dilation bilaterally, thickening of the mitral and tricuspid valves and dilation of the pulmonary artery consistent with pulmonary hypertension. No ventricular or atrial septal defect was present. Cardiomegaly and diffuse pulmonary oedema were evident on examination of lateral thoracic radiographs. Dysplasia of the mitral and tricuspid valves, eccentric cardiomegaly and pulmonary oedema were confirmed by post mortem examination. Dysplasia of the atrioventricular valves represents a rare cause of biventricular failure in the horse.     

Increased chymase-like activity in a dog with congenital pulmonic stenosis

ObjectivesThis study was intended to compare the tissue chymase-like activity and angiotensin converting enzyme (ACE) activity in the right and left ventricles of a dog with congenital pulmonic stenosis (PS), with normal dogs, and to discuss the potential clinical implications of these findings.Animals, materials and methodsStudy subjects included a one-year-old Beagle dog with spontaneous PS and six clinically normal Beagles. Chymase-like and ACE activities were determined in all hearts by high pressure liquid chromatography.ResultsIn the PS dog right ventricular (RV) chymase-like activity (49.79 nmol/min/g tissue) and left ventricular (LV) chymase-like activity (36.85 nmol/min/g tissue) were elevated vs normal Beagle dogs (mean ± standard deviation, RV: 20.17 ± 5.24 nmol/min/g, LV: 19.03 ± 3.27 nmol/min/g).ConclusionsActivation of the tissue RAA system was detected in a dog with congenital PS. This interesting finding should be pursued with further studies to validate this result, and to explore whether pharmacological blockade of chymase, or the angiotensin II receptor, represents a useful strategy to prevent myocardial remodeling in this condition.     

Annuloaortic ectasia in a four-month-old male Newfoundland dog: long-term follow-up and immunofluorescent study

A 4 month-old, 14.8 kg, male Newfoundland dog was presented for cardiovascular evaluation following detection of a heart murmur. Echocardiography revealed enlargement of the sinuses of Valsalva and marked, diffuse dilation of the ascending aorta (annuloaortic ectasia, AAE), with mild/equivocal subaortic stenosis (SAS). The dog was monitored over the duration of its lifetime, with serial echocardiograms performed at 5, 6, and 8 months and 1, 2, 3, 4, 8, and 10 years demonstrating persistent, diffuse dilation of the ascending aorta. The dog lived until it was 10 years old and died of metastatic carcinoma. Postmortem examination confirmed AAE and mild SAS. Hematoxylin and eosin and Weigert van Gieson stains were used to compare the ascending aorta to the descending aorta and left subclavian artery, and to compare aortic samples to those of three control dogs. Histopathologic evaluation revealed mild medial degeneration in the ascending aorta of all four dogs. Immunofluorescent microscopy was used for determining the deposition of proteins known to play a role in aortic aneurysms in humans: fibrillin-1 (FBN1), latent transforming growth factor beta binding protein 4 (LTBP4) and fibronectin. The ascending aorta of the AAE case demonstrated reduced deposition of FBN1, indicating that its loss may have contributed to aortic dilation. Diffuse, primary ascending aortic dilation is uncommonly reported in dogs; when it is, it carries a poor prognosis. This case provides an important example of marked dilation of the ascending aorta in a dog that lived with no associated adverse effects for 10 years.     

Pathogenesis of single right coronary artery and pulmonic stenosis in English Bulldogs

English Bulldogs are the most common breed to have pulmonic stenosis. Previous studies showed that this congenital heart abnormality in Bulldogs frequently is caused by a circumpulmonary left coronary artery originating from a single right coronary artery. Fetal anasarca also occurs often in Bulldogs and might represent congestive heart failure, but the cause is unknown. To determine if fetal anasarca is associated with a coronary anomaly and pulmonic stenosis, major coronary arteries were studied in 6 bulldog puppies with fetal anasarca. Five of the puppies had normal coronary arteries, and this led to the conclusion that fetal anasarca usually is not associated with major coronary abnormalities or pulmonic stenosis. The 6th puppy had single right coronary artery with circumpulmonary left coronary artery and moderate subvalvular pulmonic stenosis. Serial section histology suggests that the underlying cause of this syndrome is malformation of the left aortic sinus (of Valsalva) and inversion of the proximal segment of the left main coronary artery.     

Successful balloon angioplasty of pulmonary artery stenosis in two cats and associated complications

Two cats (2.5 months and 8 months old) were each evaluated due to a loud systolic murmur, and each was diagnosed with severe pulmonary artery stenosis at the bifurcation of the main pulmonary artery. Echocardiograms confirmed significant right atrial dilation and right ventricular dilation and/or hypertrophy that was progressive in one cat. Atenolol was initiated and the cats were referred for interventional therapy. Balloon angioplasty was performed via the jugular vein. In case 1, the pressure gradient across the stenosis was reduced from 169.7 mmHg to 23.6 mmHg and 52.4 mmHg across the left and right branch pulmonary arteries, respectively. In case 2, the stenotic echocardiographic gradient was reduced from 64 mmHg to 38.0 mmHg and 35.3 mmHg across the left branch and right-branched pulmonary arteries respectively. Both patients developed moderate to severe dynamic right ventricular outflow tract obstruction post angioplasty. Case 2 developed hypotension, desaturation, and ventricular arrhythmias intra-operatively. Case 1 was discharged but appeared to develop acute lung perfusion injury approximately 36 h after procedure that was manifested by radiographic pulmonary congestion and pulmonary infiltrate of the left lung fields. The congestion was successfully managed medically. Serial echocardiograms over the following 4 years in case 1 showed near complete resolution of the stenosis and associated right heart enlargement.     

Right coronary artery to left ventricle coronary cameral fistula in a cat

A six-month-old female intact domestic shorthair cat was presented for evaluation of a loud heart murmur. Transthoracic echocardiography revealed dilation of the left ventricle secondary to an abnormal vessel shunting blood into the left ventricular outflow tract at a high velocity during diastole. Multidetector computed tomography angiography revealed a coronary cameral fistula that originated at the right coronary artery, encircled the heart, and then terminated into the left ventricular outflow tract. This case report documents the first known case of a coronary cameral fistula in a cat. Multimodal imaging was an essential aspect to diagnosing the congenital lesion in this case.     

Persistent left cranial vena cava draining into the left atrium associated with pulmonary stenosis in a French bulldog

A 5-month-old female French bulldog was evaluated for the presence of a heart murmur. Through clinical and echocardiographic evaluations, a severe Type A pulmonary stenosis was diagnosed. Angiography during right ventricular catheterization for valvuloplasty revealed drainage from a persistent left cranial vena cava (PLCVC) into the left atrium; this was confirmed later by contrast echocardiography. This report is the first to describe this anatomical variant of a PLCVC in a dog.     

Dynamic right ventricular outflow tract (infundibular) stenosis and pectus excavatum in a dog

This is the first published report of a dog with dynamic right ventricular outflow tract (infundibular) stenosis, right ventricular hypertrophy, and pectus excavatum. A juvenile dog presented with a grade V/VI left base systolic heart murmur, tachycardia, and pectus excavatum. Diagnosis of the aforementioned conditions was based on radiography, electrocardiography, and echocardiography. At 9 1/2 wk of age the heart murmur was no longer audible and the right ventricular stenosis and hypertrophy had dissipated and regressed, respectively. Resolution may be associated with growth of the dog. A good prognosis is foreseen.     

Aberrant branch of the bronchoesophageal artery resembling patent ductus arteriosus in a dog

An anomalous shunt between the bronchoesophageal artery and pulmonary artery was diagnosed in a 1-year- old, 3.5 kg female Miniature Dachshund by selective contrast angiography. A cardiac murmur had been observed in the dog during examination at another hospital. The machinery murmur was auscultated at the left side of the base of the heart. Although thoracic radiography revealed mild cardiomegaly, the characteristic findings of patent ductus arteriosus (PDA), including as aortic arch enlargement and pulmonary artery enlargement were not observed. Echocardiography demonstrated shunting of blood flow presumably from the arterial duct at the pulmonary artery carina. Based on the above findings the case was diagnosed as PDA. Angiocardiography was performed to confirm the diagnosis in preparation for surgical treatment, but later we confirmed that the shunt vessel was not PDA, but apparently a branch of the bronchoesophageal artery. The shunt vessel was branching in a complicated manner and shunted to the pulmonary artery.     

Influence of combined angiotensin-converting enzyme inhibitors and spironolactone on serum K, Mg, and Na concentrations in small dogs with degenerative mitral valve disease

ObjectiveTo determine if the administration of an angiotensin-converting enzyme inhibitor (ACEI) plus spironolactone caused hyperkalemia, hypermagnesemia, or hyponatremia in elderly small dogs with degenerative mitral valve disease (MVD).BackgroundACEIs and spironolactone can increase serum potassium and magnesium concentrations and lower serum sodium concentrations. It has been recommended to either not combine these drugs or to do so with caution.Animals, material and methodsFifty client-owned dogs with MVD, left atrial dilation, and without congestive heart failure or azotemia were evaluated retrospectively. Baseline data sets, followed by 1–9 (mean = 2.66) data sets, comprised of serum urea nitrogen (SUN), creatinine, sodium, potassium, and magnesium concentrations, were tabulated. Each dog received an ACEI plus spironolactone for a mean of 23.8 ± 26.6 weeks (range: 2–150) and a median of 15 weeks. No cardiac drugs other than an ACEI and spironolactone were administered during the study period.ResultsThere were no significant differences between baseline and follow-up serum sodium or potassium concentrations. Serum magnesium concentrations increased significantly (p = 0.02) with time >20 weeks compared to baseline.ConclusionsThe combination of an ACEI and spironolactone results in no significant difference between baseline and follow-up serum sodium or potassium concentrations. Although serum magnesium concentrations may increase significantly with time >20 weeks compared to baseline concentrations, hypermagnesemia appears to be rare, mild, and unlikely to be of clinical importance. The combination of an ACEI and spironolactone is safe in elderly small dogs with MVD with normal SUN and creatinine concentrations.     

Sub-aortic stenosis in a Boxer dog

A 10-month-old Boxer dog with a heart murmur was submitted to left side cardiac angiography and found to have a severe sub-aortic stenosis.     

Plasma atrial natriuretic peptide concentration in warmblood horses with heart valve regurgitations

ObjectivesThis study measured plasma atrial natriuretic peptide (ANP) concentration in horses with heart valve regurgitations (HVR) with and without atrial and ventricular dilatation.BackgroundIn humans and small animals, plasma ANP concentration is increased in heart disease and correlates with the severity of clinical signs and heart enlargement.Animals, materials and methodsTen healthy horses (control) and 36 horses with HVR were evaluated by auscultation, electrocardiography, echocardiography, and determination of plasma ANP.ResultsControl horses demonstrated mean plasma ANP concentration of 21 ± 5.4 pg/mL. Of the 36 horses with HVR, 17 horses possessed normal echocardiographic heart size (group 1), 10 horses had a left atrial dilatation (group 2) and 9 horses had both left atrial and ventricular dilatation (group 3). Mean plasma ANP concentration of groups 1, 2 and 3 was 20.1 ± 5.6 pg/mL, 22.9 ± 11.0 pg/mL and 27.6 ± 17.4 pg/mL, respectively. The plasma ANP concentrations of HVR and control horses were not significantly different. The highest ANP concentrations were observed in horses with atrial and ventricular dilatation. No correlation between left atrial or ventricular size, weight, or sex and the plasma ANP concentration was found.ConclusionsNo significant differences in plasma ANP concentration was observed between groups. Further study, especially in horses with clinical signs of heart failure is needed.     

Methods and normal values for echocardiography in adult dairy cattle

ObjectiveThe objective of the study was to report normal ultrasonographic appearance and intra-cardiac dimensions in two dairy breeds and to calculate cardiac output (CO) using echocardiography.BackgroundIntra-cardiac dimensions, time indices and CO estimation have not previously been reported in adult cattle.Animals, materials and methodsEchocardiograms were obtained from healthy adult dairy cows (10 Jersey (J) and 12 Holstein Friesians (HF)) in the body weight range of 400 to 700 kg. Standard echocardiographic images were obtained from the left and right hemithoraces. Velocity time integrals were obtained in order to calculate CO using pulsed wave Doppler of aortic flow in the J cows. Measurements obtained included pulmonary artery and aortic diameters, left and right ventricular diameters (and calculated fractional shortening and left ventricular ejection fraction), left atrial size and time indices assessing valve function.ResultsHF cows had significantly (p < 0.05) larger pulmonary artery and aortic diameters, larger left atrial diameters and left ventricular internal diameters during diastole, but these were not different when corrected for body weight. Left and right ventricular dimensions, adjusted for body weight, were significantly larger (p = 0.02 and p = 0.035 respectively) in J cows when compared to HF cows. No differences were noted in the time indices between the two groups. No significant differences were noted in intra-operator variability and the only significant difference in inter-operator variability was in measurement of the pulmonary artery (p = 0.03; ICC = 0.63).ConclusionsIt is possible to obtain repeatable, reliable echocardiograms in order that meaningful intra-cardiac dimensions can be obtained in adult dairy cattle.     

Infective endocarditis of the aortic valve in a Border collie dog with patent ductus arteriosus

Infective endocarditis (IE) in dogs with cardiac shunts has not been reported previously. However, we encountered a dog with concurrent patent ductus arteriosus (PDA) and IE. The dog was a 1-year-old, 13.9-kg female Border collie and presented with anorexia, weight loss, pyrexia (40.4°C) and lameness. A continuous murmur with maximal intensity over the left heart base (Levine 5/6) was detected on auscultation. Echocardiography revealed a PDA and severe aortic stenosis (AS) caused by aortic-valve vegetative lesions. Corynebacterium spp. and Bacillus subtilis were isolated from blood cultures. The dog responded to aggressive antibiotic therapy, and the PDA was subsequently surgically corrected. After a series of treatments, the dog showed long-term improvement in clinical status.     

Balloon dilation of an imperforate cor triatriatum dexter in a Golden Retriever with concurrent double-chambered right ventricle and subsequent evaluation by cardiac magnetic resonance imaging

A 12-week-old male Golden Retriever was presented with signs of right-sided congestive heart failure and a grade V/VI left craniosternal systolic murmur. Echocardiography identified a double-chambered right ventricle and dilated coronary sinus (CS) running into an inter-atrial chamber. This was confirmed to be an imperforate cor triatriatum dexter (CTD) by selective angiographic studies. To the authors’ knowledge this is the first case reported of imperforate CTD successfully treated by membranostomy and balloon dilation. Cardiac MRI confirmed the echocardiographic and angiographic findings and provided a more precise understanding of the venous abnormalities.     

Clinical diagnosis of aneurysm of the right coronary artery in a white cockatoo (Cacatua alba)

A 16-year-old male white cockatoo was presented with lethargy and a decreased appetite. Auscultation between the second and third sternal rib revealed a heart murmur, which was confirmed by electrocardiographic and phonocardiographic examination to be systolic, with a shift of the heart axis to -152°. Radiographs showed lack of detail in the cranial part of the abdominal coelom, indicative of ascites and an enlarged cardiac shadow, while ultrasonographic examination revealed pericardial effusion and fluid accumulation in the cavitas peritonealis hepatica. An extra fluid-filled cavity was found at the atrioventricular junction in the right cardiac wall and colour Doppler examination demonstrated a turbulent jetstream of blood into the cavity, originating directly above the aortic valve. Non-selective angiocardiography confirmed the ultrasonographic observations. Findings were indicative of an aneurysm of the a. coronaria dextra (right coronary artery). This was confirmed by necropsy which revealed atherosclerosis to be the underlying cause.     

Tricuspid atresia in a foal

An Arabian crossbred foal was examined because of a suspected congenital cardiac anomaly. There was a grade V/V crescendo-decresendo holosystolic murmur and thrill in the left 4th intercostal space. The foal was slightly cyanotic and polycythemic. Electrocardiography suggested left ventricular hypertrophy. Angiography and cardiac and vascular pressure recordings led to a diagnosis of pulmonic stenosis. The foal died after cardiac bypass and corrective surgery. Postmortem examination revealed an enlarged right atrium, atresia of the tricuspid orifice, a large, fenestrated patent foramen ovale, eccentric left ventricular hypertrophy, and a large interventricular septal defect. The right ventricle had a small lumen and a relatively thick wall. There was valvular and supravalvular pulmonic stenosis, with poststenotic dilatation of the pulmonary artery. A single coronary artery originated from the anterior sinus of the aorta.