Genuine concurrent muscular subvalvular subaortic stenosis and muscular infundibular stenosis of the right ventricle in the heart of the pig

Summary Two cases of genuine concurrent muscular subvalvular aortic and muscular infundibular pulmonary stenosis in pigs are reported. The character of this morphophy-siological syndrome is discussed. The morphology of the heart of the pig predisposes this animal to the syndrome.     

Cutting balloon and high-pressure balloon dilation for palliative treatment of congenital double-chambered right ventricle and primary infundibular stenosis in a Golden retriever dog

Combined cutting balloon and high-pressure balloon dilation was performed in a dog with a double-chambered right ventricle and severe infundibular stenosis of the right ventricular outflow tract. The peak systolic pressure gradient across the stenosis decreased by 65% after dilation (from 187 mmHg before to 66 mmHg after) affirming the intervention as successful. However, early re-stenosis occurred within 3 months leading to exercise intolerance, exercise-induced syncope, and right-sided congestive heart failure. Cutting balloon followed by high-pressure balloon dilation provided temporary but not long-term relief of right ventricular obstruction in this dog.     

Congenital mitral stenosis,subvalvular aortic stenosis,and congestive heart failure in a duck

A 2.6-year-old duck was evaluated for respiratory difficulty. On the basis of physical, radiographic and echocardiographic findings, a diagnosis of congestive heart failure secondary to congenital mitral stenosis and subvalvular aortic stenosis was made. The duck did not respond well to medical therapy and was euthanized. The diagnosis was confirmed at necropsy.     

Surgical correction of subaortic stenosis via right ventriculotomy and septal resection in a dog

After 2 years of medical management with a beta-adrenoreceptor blocking agent, a 30-month-old castrated male Golden Retriever with subaortic stenosis was treated surgically because of progression of its condition. In an attempt to achieve complete relief of the left ventricular outflow obstruction, a modified Konno procedure consisting of right ventriculotomy and septal myectomy from the infundibular portion of the right ventricle was performed; this combination of procedures allowed wide resection of the septal portion of the left ventricular outflow obstruction. Two years after surgery, the mass of the dog's left ventricle had decreased and the peak calculated pressure gradient across the aortic valve had decreased to 40 mm Hg, compared with a preoperative value of 240 mm Hg; at that evaluation, the dog had gained weight and was able to play normally. It is suggested that use of this modified approach to the outflow tract may have a positive effect on long-term survival time in dogs with subaortic stenosis.     

Double-outlet right ventricle with an intact interventricular septum and concurrent hypoplastic left ventricle in a calf

A 3-day-old Hereford heifer calf presented for evaluation of lethargy and dyspnea, with persistent hypoxia despite supplemental oxygen therapy. A grade III/VI right apical systolic murmur was noted during cardiac auscultation. Echocardiography revealed a double-outlet right ventricle with an intact interventricular septum and concurrent hypoplastic left ventricle and tricuspid valve dysplasia. Post-mortem examination revealed additional congenital anomalies of ductus arteriosus, patent foramen ovale, and persistent left cranial vena cava. This report illustrates the use of echocardiographic images to diagnose a double-outlet right ventricle with an intact interventricular septum and a hypoplastic left ventricle in a calf.     

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.     

Genetic evidence of subaortic stenosis in the Newfoundland dog

Subaortic stenosis (SAS) is a cardiac disorder with a narrowing of the descending aorta below the left ventricular outflow tract of the heart. It occurs in several species and breeds. The Newfoundland is one of the dog breeds where it is more common and usually leads to death at early adulthood. It is still discussed to which extent SAS has a genetic background and what its mode of inheritance could be. Extensive pedigree data comprising more than 230,000 Newfoundland dogs from the European and North American population reaching back to the 19th century including 6023 dogs with a SAS diagnosis were analysed for genetic factors influencing SAS affection. The incidence and prevalence of SAS in the analysed Newfoundland population sample were much higher than those reported in previous studies on smaller population samples. Assuming that some SAS-affected dogs remained undiscovered or were not reported, these figures may even be underestimated. SAS-affected Newfoundland dogs were more often inbred and closer related to each other than unaffected dogs, which is an indicator for a genetic background of SAS. The sex had no significant impact on SAS affectedness, pointing at an autosomal inheritance. The only simple mode of inheritance that fitted the data well was autosomal codominant with lethal homozygosity and a penetrance of 1/3 in the heterozygotes.     

The relevance of echocardiography heart measures for breeding against the risk of subaortic and pulmonic stenosis in Boxer dogs

The aims of this study were to investigate the role and relative importance of auscultation and echocardiography traits as risk factors for the diagnosis of subaortic (SubAS) and pulmonic (PS) stenosis and to estimate the heritability (h(2)) of cardiac measurements taken through echocardiography for a random sample of Italian Boxer dogs. The data were cardiovascular examination results of 1,283 Italian Boxer dogs (686 females and 597 males) enrolled in the national screening program for heart defects arranged by the Italian Boxer Club. Examinations were performed during a 6-yr period by a group of 7 veterinary cardiologists following a standard protocol. Occurrence and severity of SubAS and PS were diagnosed, taking into account clinical and echocardiography findings such as the grade of cardiac murmur, direct ultrasound imaging of the anatomic obstructive lesions, and values of aortic or pulmonary blood flow velocities. A Bayesian logistic regression analysis was performed to identify clinical and echocardiography variables related to SubAS and PS diagnosis. Estimation of variance components for clinical and echocardiography traits was performed using a mixed linear animal model, Bayesian procedures, and the Gibbs sampler. Prevalence of SubAS (PS) was 8.4% (2.2) and 10.7% (6.4) for female and male dogs, respectively. Cardiac murmur, peak velocities, and annulus areas behaved as risk factors for SubAS and PS. The risk of a positive diagnosis for SubAS was 3 times greater for dogs with aortic annulus area <2.1 cm(2) relative to dogs with areas >2.37 cm(2), 84 times greater for dogs showing aortic peak velocities >2.19 m/s relative to dogs with peak velocities <1.97 m/s, and 41 times greater for dogs with moderate to severe murmur grades relative to dogs with absent murmur. Similar results were obtained for PS. The estimated h(2) for the occurrence of cardiac defects was 23.3% for SubAS and 8.6% for PS. Echocardiography and cardiac murmur grades exhibited moderate h(2) estimates and exploitable additive genetic variation. The estimated h(2) was 36, 24, and 20% for aortic annulus area, aortic peak velocity, and cardiac murmur score, respectively. For the area of the pulmonary annulus and peak pulmonary velocity, the estimated h(2) were smaller, ranging from 9.5 to 12.8%. These measures are candidate indicator traits that might be effectively used in dog breeding to reduce the prevalence and severity of cardiac defects.     

Primary infundibular stenosis and pedigree analysis in three Golden Retriever littermates

Three eight-week-old Golden Retriever puppy littermates were evaluated because of left basilar systolic murmurs and were diagnosed with primary infundibular stenosis. Pedigree analysis in this line was also performed to identify a mode of inheritance. All dogs were asymptomatic at the time of diagnosis; two of the three had congenital lesions in addition to primary infundibular stenosis. Two additional affected dogs were identified in the line, and pedigree analysis suggested an autosomal recessive mode of inheritance. Another, unrelated golden retriever was also identified with isolated infundibular stenosis in the record database. Primary infundibular stenosis should be considered in the differential diagnoses for golden retriever dogs with a left basilar systolic murmur, and is often associated with complex congenital cardiac disease. Primary infundibular stenosis may worsen in severity with time, and in this line of dogs an autosomal recessive pattern of inheritance is likely.     

Resection of a fibromuscular subaortic stenosis in a dog

The surgical correction of a case of fibromuscular subaortic stenosis in an Alsatian dog is described.     

Left coronary aneurysmal dilation and subaortic stenosis in a dog

A 6-month-old German shepherd dog was referred for evaluation of a cardiac murmur.Upon physical examination, the auscultated heart rate was 120 beats/min, and a grade IV/VI systolic heart murmur with a point of maximal intensity over the left heart base radiating up the neck was heard. The standard echocardiographic examination showed subaortic stenosis and an anechoic tubular structure extending from the sinus of Valsalva to the left ventricular posterior wall. Aneurysmal left coronary artery (CA) was confirmed by angiography. The dog was euthanized and post-mortem examination showed severe dilatation of the proximal left CA and confirmed the subaortic stenosis. Histopathology did not demonstrate abnormalities in the walls of the CA, aorta or pulmonary artery.The exact cause of the CA aneurysmal dilation remains unknown. Subaortic stenosis, elevated coronary vascular resistance or a congenital anomaly may have contributed to the dilation.To our knowledge, coronary aneurysmal dilation has never been described in dogs. Standard echocardiography provides reliable information on coronary anatomy.     

Familial subvalvular aortic stenosis in golden retrievers: inheritance and echocardiographic findings

Objectives : To describe the echocardiographic findings and pedigree analysis of golden retrievers with subvalvular aortic stenosis. Methods : Seventy‐three golden retrievers were evaluated by auscultation and echocardiography. A subcostal continuous‐wave Doppler aortic velocity ê2·5 m/s and presence of a left basilar systolic ejection murmur were required for diagnosis of subvalvular aortic stenosis. Three echocardiographic characteristics were recorded: evidence of aortic insufficiency, subvalvular ridge or left ventricular hypertrophy. A disease status score was calculated by totalling the number of echocardiographic ‐characteristics per subject. Results : Thirty‐two of 73 dogs were affected and their aortic velocities were as follows: range 2·5 to 6·8 m/s, median 3·4 m/s and standard deviation 1·2 m/s. Echocardiographic characteristics of 32 affected dogs were distributed as follows: left ventricular hypertrophy 12 of 32, aortic insufficiency 20 of 32 and subvalvular ridge 20 of 32. Disease status score ranged from 0 to 3 with a median of 2. There was a statistically significant correlation between aortic velocity and disease status score (r=0·644, P<0·0001). Subvalvular aortic stenosis was observed in multiple generations of several families and appears familial. Clinical Significance : Subvalvular aortic stenosis in the golden retriever is familial. Severity of stenosis correlates well with cumulative presence of echocardiographic characteristics (left ventricular hypertrophy, subvalvular ridge and aortic insufficiency).     

Surgical management of subvalvular aortic stenosis and mitral dysplasia in a golden retriever

A 12monthoid neutered male golden retriever was presented with a history of lethargy and exercise intolerance. Clinical examination, electrocardiography, radiography and echocardiography supported a diagnosis of fixed subvalvular aortic stenosis with a Doppler pressure gradient of 77.5 mmHg. Surgical inspection also revealed gross structural abnormalities of the mitral valve consistent with mitral dyspiasia. intervention consisted of resection of the dysplastic mitral valve and the subvalvular aortic stenosis. The mitral valve was replaced with a bioprosthetic valve. Total cardiopulmonary bypass time was 65 minutes and aortic crossclamp time was 55 minutes. A full recovery was made and 11 months postoperatively the aortic transvalvular gradient was 30 mmHg. At the time of writing, 12 months after surgery, the dog was clinically normal and requires no medication.     

Surgical correction of subvalvular aortic stenosis using cardiopulmonary bypass in a dog

A three-month-old male Golden Retriever had symptoms including exercise intolerance, dyspnea and syncope and was diagnosed with subvalvular aortic stenosis. Cardiac catheterization revealed a left ventricular-aortic systolic pressure gradient of 90 mm Hg. Surgical correction of the condition was achieved using cardiopulmonary bypass. The subvalvular fibrous lesion was resected through an aortotomy. The stenosis was dilated from 8.5 mm to 12.0 mm in diameter. Postoperatively the dog was asymptomatic. Seven months after surgery, the pressure gradient decreased to 44 mm Hg. However, after another three months, the dog died suddenly without any premonitory signs. Postmortem examination revealed that pathologic changes caused by increased left ventricular pressure overload were not severe.     

Primary pulmonic infundibular stenosis in 12 cats: Natural history and the effects of balloon valvuloplasty

ObjectivesTo evaluate the natural history of primary pulmonic infundibular stenosis in cats and the effects of balloon valvuloplasty.BackgroundPrimary pulmonic infundibular stenosis is an uncommon congenital defect in cats. The natural history of the disease has not been described. Information regarding balloon valvuloplasty in the cat is limited.AnimalsRecords between January 1, 1999 and December 31, 2005 were reviewed and cats with a confirmed echocardiographic diagnosis of primary pulmonic infundibular stenosis, a complete medical history, and no evidence of significant systemic disease were identified.MethodsEchocardiographic, electrocardiographic, and radiographic findings are described. The natural history of those with severe disease was compared to those with mild to moderate disease. Balloon valvuloplasty was performed in six of the cats. The technique used is described.ResultsA stenotic gradient ≥70 mmHg and a right ventricular outflow tract (measured at the level of the stenosis) to pulmonary valve annulus ratio of ≤0.25 were consistent with clinical and echocardiographic severe disease. Cats with severe disease had a very guarded prognosis with a high incidence of congestive heart failure (CHF). Balloon valvuloplasty was successfully performed in 4 of the cats and appeared to improve prognosis, especially if performed prior to the development of CHF. Concurrent hypertrophic cardiomyopathy complicated the outcome in some cats.ConclusionsSevere primary pulmonic infundibular stenosis carries a very guarded prognosis in the cat. Balloon valvuloplasty should be considered in the presence of severe disease and should be performed prior to the development of CHF if possible. The presence of concurrent hypertrophic cardiomyopathy may complicate the prognosis.     

Usefulness of the indexed effective orifice area in the assessment of subaortic stenosis in the dog

To evaluate the usefulness of the Doppler-derived effective orifice area (EOA) in assessing the hemodynamic severity of subaortic stenosis (SAS) in dogs, 2-dimensional and Doppler echocardiographic examinations were performed in 16 dogs with SAS, 22 normal adult dogs, and 22 normal puppies. The EOA was calculated by the continuity equation using the stroke volume determined in the right ventricular outflow tract. The EOA was significantly lower (P < .001 ) in the SAS dogs (0.76+/-0.45 cm2) and in the normal puppies (1.58+/-1.00 cm2) than in the normal adult dogs (2.34+/-0.78 cm2). The EOA indexed for body surface area (IEOA) was significantly lower (0.89+/-0.48 cm2/m2) in SAS dogs than in the normal puppies (2.42+/-0.85 cm2/m2) or adults (2.22+/-0.76 cm2/m2). The normal dogs (adults and puppies) had an IEOA of > or =1.25 cm2/m2. Among the demographic and echocardiographic parameters measured in this study, only the indexed EOA was significantly associated (P = .03) with the occurrence of adverse events (eg, syncope, episodic weakness, ventricular arrhythmias). This study demonstrates the usefulness and feasibility of the indexed EOA as measured by Doppler echocardiography for noninvasive assessment of SAS severity in dogs.