Successful interventional occlusion of muscular ventricular septal defect in a dog

Ventricular septal defect (VSD) is a rare congenital heart disease in dogs. Hemodynamically important interventricular defects must be closed to improve the prognosis. This case report describes successful interventional transcatheter closure of a muscular VSD in a young Maltese and poodle mixed-breed dog with a large muscular interventricular defect (~5 mm in diameter) with a high rate of left-to-right shunt flow. The VSD was closed with a customized Amplatzer-type VSD occluder via a percutaneous transvenous (jugular) approach. We concluded that interventional occlusion of a muscular VSD with an Amplatzer-type occluder is a viable treatment option for dogs. A regular follow-up study for this dog is ongoing and has not detected complications. Key clinical message: Interventional occlusion of a muscular VSD with an Amplatzer-type occluder is a viable treatment option for dogs.

Simultaneous surgical repair of a cardiac myxoma causing left ventricular outflow tract obstruction and a ventricular septal defect in a small dog

Background

Cardiac myxomas are benign tumours that can occur in any heart chamber or valve. They are extremely rare in dogs. We present a novel case involving a cardiac myxoma in the left ventricular outflow tract (LVOT) and a ventricular septal defect (VSD) in a small dog.

Case Description

A female miniature dachshund (age, 7 months; weight, 2.88 kg) presented with growth insufficiency, lethargy, and a cardiac murmur. Echocardiography revealed a small polypoid mass in the LVOT and a membranous VSD. Simultaneous surgeries were performed to resect the mass (aortotomy) and close the VSD (right atriotomy) using low-flow cardiopulmonary bypass with surface-cooling hypothermia and retrograde cardioplegia. The tumour was histopathologically identified as a myxoma. The dog survived with no cardiac complications for 11 years after surgery.

Conclusion

To our knowledge, this is the first report of ante-mortem diagnosis and simultaneous surgical repair of a cardiac myxoma obstructing the LVOT and a VSD in a small-breed dog. In addition to describing this complicated case, this report presents what we believe is the first reported use of retrograde cardioplegia during open-heart surgery in a small-breed dog.

Transjugular occlusion of large patent ductus arteriosus with an Amplatzer™ muscular ventricular septal defect occluder in a 3-month-old dog

Background

Cardiologists close most patent ductus arteriosus (PDA) defects in dogs using the Amplatz® canine duct occluder via a transarterial approach. However, this approach can be problematic in small dogs due to the small femoral artery diameter. In such cases, cardiologists have opted to use coils or vascular plugs deployed from a transvenous approach. However, in small dogs with large PDA, the risk of device protrusion into the pulmonary artery, incomplete closure, or device embolization, often leads to surgical PDA closure via thoracotomy.

Case Description

The present report describes a 3-month-old male 6 kg Border collie with a large, PDA which was successfully occluded using the Amplatzer™ muscular ventricular septal defect (mVSD) device from a transvenous approach after closure attempts with an Amplatzer™ vascular plug II failed.

Conclusion

This is the first case report in veterinary medicine of PDA closure with an Amplatzer™ mVSD occluder device. This approach, described in PDA closure in people, could be considered in minimally invasive PDA closure in small dogs with challenging anatomy.

Surgical correction of an infundibular pulmonic stenosis and ventricular septal defect in a Shetland Sheepdog

A four-month-old male Shetland Sheepdog presented with exercise intolerance. Physical examination revealed an IV/VI left cranial systolic heart murmur. Echocardiography showed a severe infundibular pulmonic stenosis and a concomitant restrictive ventricular septal defect. As clinical signs of congestive right-sided heart failure worsened and were refractory to medical treatment, surgical correction was advised. Via sternotomy, with cardiopulmonary bypass and cardioplegic cardiac arrest, ventricular septal defect closure and resection of the stenotic infundibular band were performed through right ventriculotomy, followed by patch enlargement. Postoperative recovery was uneventful and echocardiography showed complete resolution of the stenosis and successful closure of the ventricular septal defect. Follow-up echocardiography revealed restenosis after seven weeks and recurrence of right-sided heart failure three months postoperatively. Stenting of the restenosis was attempted via a hybrid procedure with sternotomy and direct transventricular approach. The dog developed fatal ventricular fibrillation during stent deployment. This is the first dog in which surgical right ventricular patch enlargement under cardiopulmonary bypass is reported for the treatment of a primary infundibular pulmonic stenosis.

Cor triatriatum sinister with dextrocardia in association with ostium secundum atrial septal defect, subpulmonary ventricular septal defect and bicuspid pulmonary valve in a pig

Necropsy of a 52-day-old Camborough pig revealed numerous cardiac malformations. The positional relationship of the atria, ventricles and great vessels was a mirror image type (I, L and L): inverted arrangement of the atria, with a left-sided right atrium and right-sided left atrium (situs inversus); inverted arrangement of the ventricles, with a left-sided morphological right ventricle and right-sided morphological left ventricle (L-loop); and aortic valve to the front left relative to the pulmonary valve (L-malposed). The major malformations included an ostium secundum atrial septal defect, cor triatriatum sinister (CTS), a subpulmonary ventricular septal defect and a bicuspid pulmonary valve. Histological examination revealed myocyte hypertrophy, focal myocardial necrosis and calcification in the left morphological right ventricle of the heart. To the best of our knowledge, this is the first report of CTS in pigs. Although the individual malformations found in the present case are not unique, an unusual combination of these cardiac malformations has not been described in animals.

Un cas de situs inversus complet associé à une communication interventriculaire et des anomalies oculaires chez une chienne croisée de 3 ans

A case of complete situs inversus associated with an interventricular communication and ocular abnormalities in a 3-year-old mixed-breed female dog. A 3-year-old female dog was referred for exploration of a murmur concomitant with lethargy. An echocardiogram reveals an inversion of the position of the cardiac chambers and the presence of an interventricular communication. A computed tomography examination of the thorax and abdomen highlights the known cardiac abnormalities as well as the association of a complete situs inversus. The clinical examination also reveals ocular malformations (deviation of the eyeballs and asymmetry of the fundus). This article highlights the variety of abnormalities that can be associated with the complete inversion of the organs and demonstrates that there may be variants to the more classic picture usually encountered in humans (respiratory manifestations related to Kartagener syndrome).(Translated by Dr Serge Messier).

Pulmonary artery banding in a cat with a perimembranous ventricular septal defect and left-sided congestive heart failure

CASE DESCRIPTION A 6-month-old sexually intact male domestic shorthair cat was referred for evaluation of a heart murmur and ventricular septal defect (VSD). CLINICAL FINDINGS Physical examination revealed a grade 5/6 right apical systolic heart murmur. Findings on thoracic radiography were consistent with moderate right and left ventricular enlargement, left atrial enlargement, and enlargement of the pulmonary arteries and veins; an interstitial pulmonary pattern was also evident. Echocardiography revealed a perimembranous VSD with left-to-right shunting combined with trace mitral valve regurgitation. The cat later developed a dry cough, the intensity of the heart murmur increased to grade 6/6, and signs of left-sided congestive heart failure developed. TREATMENT AND OUTCOME Medical treatment included enalapril maleate and furosemide. When the cat's condition worsened despite medical treatment, palliative pulmonary artery banding was performed. During surgery, blood pressure in the pulmonary artery was measured with a pulmonary artery catheter, and pulmonary artery banding was successfully achieved with a polytetrafluoroethylene band and hemoclips. The pulmonary-to-systemic blood flow ratio was reduced from 3 to 1.5, and signs of congestive heart failure resolved within 2 weeks after surgery. CLINICAL RELEVANCE Findings suggested that cats with a VSD and pulmonary-to-systemic flow ratio > 3 or with congestive heart failure attributable to a VSD could be considered candidates for palliative pulmonary artery banding to alleviate clinical signs. However, further investigation into long-term prognosis with objective outcome measurements and with multiple cases is needed. (J Am Vet Med Assoc 2019;254:723-727).

Unraveling the Genetics Behind Equid Cardiac Disease

There have been some advances in understanding the genetic contribution to ventricular septal defects in Arabians, sudden death in racehorses, and atrial fibrillation in racehorses. No genetic analyses have been published for aortic rupture in Friesians or atrioventricular block in donkeys despite strong evidence for a genetic cause. To date, no genetic mutation has been identified for any equid cardiac disease. With the advancement of genetic tools and resources, we are moving closer to discoveries that may explain the heritable basis of inherited equid cardiac disease.

Clinical, cytogenetic and molecular genetic characterization of a tandem fusion translocation in a male Holstein cattle with congenital hypospadias and a ventricular septal defect

Hypospadias, disorder of sex development (DSD), is a sporadic congenital abnormality of the genital region in male ruminants, which is characterized by a non-fused urethra during fetal development. Detailed clinical examination classified the hypospadias phenotype of a male Holstein calf studied here as the perineal type. In combined use of cytogenetic analysis and whole genome sequencing, a non-mosaic, pseudo-monosomy 59, XY + tan(18;27) was detected. This chromosomal aberration had its origin in a tandem fusion translocation of the bovine autosomes (BTA) 18 and 27 with an accompanying loss of genomic sequences mainly in the distal end of BTA 18 and the proximal end of BTA 27. The resulting phenotype included hypospadias, growth retardation and ventricular septal defect.

Dilatable pulmonary artery banding for ventricular septal defect: surgical technique and case report of three cats

Pulmonary artery banding (PAB) is a viable but underreported palliative option for hemodynamically significant ventricular septal defect in small animals. A significant challenge associated with PAB is judging the degree of band tightening, which can be further complicated when animals are immature and still growing at the time of PAB. If a pulmonary artery band is overtightened or becomes progressively too tight after surgery, the result can be reversal of shunt flow with potentially devastating consequences. Placement of a band that could be percutaneously dilated using a balloon catheter affords a minimally invasive option for partially or completely relieving the band should it become too tight after PAB. This report describes a surgical technique for placement of a dilatable pulmonary artery band, reviews guidelines for tightening the band, and reports the outcome of three cats undergoing the procedure. All three cats showed evidence of reduced hemodynamic load after PAB for a period of up to three years after PAB.

Vertebral Malformation, Syringomyelia, and Ventricular Septal Defect in a Dromedary Camel (Camelius Dromedarius)

An occipitoatlantoaxial malformation and ventricular septal defect (VSD) were diagnosed in a 36-hour-old female camel. Physical examination revealed a firm protrusion of the dorsal aspect of the atlas and axis, tilting of the head to the left, and a grade V/VI systolic murmur. Neurological examination revealed proprioceptive deficits and ataxia of all 4 limbs. Radiographic examination and necropsy demonstrated malformation, fusion of the atlas to the occiput and hypoplasia of the dens of the axis, and subluxation of the atlantoaxial joint. Dorsoventral laxity of the atlantoaxial joint was also present, with compression of the cervical spinal cord. A 1.5-cm-diameter VSD was observed also. Histopathologic examination of the cervical spinal cord revealed a cavity extending from the level of the first to fourth cervical segment, dorsal to the central canal, 5 cm long and 1–2 mm in diameter. The cells around the cavity were positive for glial fibrillary acidic protein and sporadically positive for vimentin. This cavitary structure was consistent with syringomyelia, which was lined by glial cells, surrounded by edematous white matter with Wallerian-like degeneration and with neuronal necrosis in the adjacent dorsal horns.

Echocardiographic diagnosis and necropsy findings of a congenital ventricular septal defect in a stranded harbor porpoise

A live-stranded harbor porpoise Phocoena phocoena was found on the west coast of the Dutch island Texel (North Sea) and transported to a rehabilitation center for small cetaceans, where it underwent a veterinary health check. Cardiac auscultation revealed a systolic cardiac murmur with the point of maximal intensity in the right hemithorax with an intensity of IV out of VI. Transthoracic echocardiography revealed a congenital ventricular septal defect with left-to-right shunting. Because the left atrium was not dilated according to the reference range of canine left atrium to aortic ratio, the presence of congestive heart failure was considered very unlikely. Therefore, this congenital cardiac anomaly was thought to be a clinically non-relevant incidental finding and would not explain the weakness, coughing, anorexia, vomiting, and diarrhea. Because the animal was still unable to swim or eat by itself after 2 wk of supportive care, it was euthanized. Post-mortem examination confirmed the presence of a ventricular septal defect. The weight of the heart relative to the animal's length was greater than expected, using linear regression analysis on the lengths and cardiac weights of 71 other stranded wild harbor porpoises without macroscopic cardiac pathologic changes. This finding suggests that the left ventricle had an eccentric hypertrophy because of volume overload resulting from the intracardiac shunt. This is the first report of a congenital cardiac anomaly and its ante-mortem diagnosis in this species. Data presented for the other 71 harbor porpoises may provide reference values for this species.

[Congenital cardiac anomalies (pentalogy of Fallot) in a two year old ram with brachygnathia inferior]

In a nearly two-year-old ram, descending from a breeding trial to investigate the effects of shortness of the lower jaw (brachygnathia inferior), a congenital cardiac anomaly was observed. At the age often months the affected animal, a cross breed of Cameroon Sheep and East Friesian Milk Sheep, showed exercise-induced respiratory distress for the first time. Auscultation revealed a loud systolic heart murmur (grade 5) on both sides of the thorax, most prominent over the left third intercostal space at shoulder height. Postmortem examination of the ram's heart showed a pentalogy of Fallot, consisting of a pulmonic stenosis, a ventricular septal defect, an overriding aorta, a right ventricular hypertrophy and a patent foramen ovale. A genetic defect has to be considered as a possible reason.

Angeborene Herzerkrankungen beim Hund: Eine retrospektive Analyse

In a time period of 6 years, 158 congenital cardiac defects were diagnosed in 146 dogs at the Clinic for Small Animal Medicine University of Zurich. In respect to all dogs with cardiac disease, these were 23.5% of the cases. Most common defects were subaortic stenosis (SAS, 31.5%), pulmonic stenosis (PS, 23.3%), ventricular septal defect (VSD, 14.4%), patent ductus arteriosus (PDA, 13.7%) and tricuspid dysplasia (TD, 7.5%). Complex defects were found in 8.2% of the dogs. Although single dogs per breed were affected by various defects, some breed-related tendencies could be observed. We found PS more numerously in boxers and Jack Russell Terriers whereas SAS, VSD and TD were also found in breeds reported to be predisposed. Congenital cardiac defects are an important clinical entity, and knowledge of prevalence is helpful when considering the differential diagnosis and for making a tentative diagnosis in an individual case.

Situs inversus totalis associated with subaortic stenosis, restrictive ventricular septal defect, and tricuspid dysplasia in an adult dog

A rare association between situs inversus totalis (SIT), restrictive ventricular septal defect, severe subaortic stenosis, and tricuspid dysplasia was observed in an adult mixed-breed dog. Primary ciliary dyskinesia and Kartagener's syndrome were excluded. After 15 mo the dog died suddenly. The association between SIT and congenital heart diseases is discussed.

Antemortem diagnosis of a ventricular septal defect in a California sea lion Zalophus californianus

A yearling California sea lion Zalophus californianus stranded in poor body condition, and on physical examination a heart murmur was audible bilaterally. The sea lion was diagnosed with a left-to-right shunting membranous ventricular septal defect (VSD) using B-mode, color-flow Doppler and continuous-wave Doppler echocardiography. A left-to-right intracardiac shunting lesion was confirmed during cardiac angiographic computed tomography. The VSD defect was verified during the necropsy examination. On histologic examination concurrent mild multifocal myocarditis with focal mild ventricular free-wall myocardial necrosis were identified. A specific cause for the myocarditis and myocardial necrosis was not found, and association with the VSD and resultant myocardial dysfunction was presumed. This is the first report of the antemortem diagnosis of a VSD in a marine mammal and the first report of a VSD in a California sea lion.

[Case report: double-chambered right ventricle (DCRV), ventricular septal defect, and double caudal vena cava in a cat]

The clinical signs and symptoms, radiographic and echocardiographic findings, and the results of cardiac post-mortem and histopathological examination of a 1-year-old female European shorthair cat with a double-chambered right ventricle (DCRV), small ventricular septal defect, and double caudal vena cava are described. A review of the literature is given with respect to the symptoms, diagnostic techniques, and therapy of DCRV in the cat. DCRV is a rare congenital defect in which stenosis inside the right ventricle causes symptoms similar to those seen in pulmonary stenosis. A diagnosis can be made by echocardiography. Little is known about its natural history and prognosis. Medical treatment, balloon dilatation, and surgery have been used to treat this defect with variable outcome. A double caudal vena cava is not clinically relevant.

Surgical correction of a partial atrioventricular septal defect with a ventricular septal defect in a dog

Echocardiography of a dog with a cardiac murmur revealed an ostium primum septal defect, a ventricular septal defect, and mitral valve malformation with regurgitation. The mitral valve and tricuspid valve were separated and displaced at the same level as the ventricular septum. The mitral valve had a cleft in the septal cusp. Cardiac catheterization and angiocardiography showed a left-to-right shunt and a "goose-neck sign," which indicated an elongated left ventricular outflow tract. The diagnosis of a partial atrioventricular septal defect with ventricular septal defect was made. Surgical correction was successfully performed under extracorpo-real circulation using a cardiopulmonary bypass system.

Aortic endocarditis associated with a perforated septal membranous aneurysm in a boxer dog

Perimembranous ventricular septal defect is a common congenital heart disease in the dog. It can partially or completely close with age by development of a membranous ventricular septal aneurysm. Aortic endocarditis is a reported complication of ventricular septal defect and membranous ventricular septal aneurysm in human beings. This report describes a case of aortic endocarditis associated with a membranous ventricular septal aneurysm perforated by a small ventricular septal defect in a boxer dog.

Clinical and echocardiographic features of primary infundibular stenosis with intact ventricular septum in dogs

BACKGROUND

Primary infundibular stenosis is a rare congenital defect in which the right ventricle is divided into a proximal "high-pressure" chamber and a distal "low-pressure" chamber. The condition can be misdiagnosed as ventricular septal defect or valvular pulmonic stenosis and the disease severity underestimated. The purpose of this study was to provide a detailed clinical and echocardiographic description of this anomaly in a series of dogs.

HYPOTHESIS

Several anatomic forms of infundibular stenosis exist. High resolution two-dimensional echocardiography could differentiate 3 gross anatomic substrates. Knowledge of the anatomy of the obstructing lesion could influence options for corrective interventions.

ANIMALS

Thirteen dogs examined at the Ontario Veterinary College teaching hospital from 1994 to 2005 with an ultrasound diagnosis of subpulmonic stenasis.

METHODS

A retrospective review was made of case records from 1994 to 2005.

RESULTS

Thirteen dogs were identified as having primary infundibular stenosis, with apparent increased prevalence in Golden Retrievers (8/13, 62%) and Siberian Huskies (3/13, 23%). Three types of infundibular lesions were identified by ultrasound in 11/13 dogs: a fibrous diaphragm (6), fibromuscular (4), and muscular obstruction (1). Two dogs with a fibrous diaphragm underwent direct surgical dilation without the use of cardiopulmonary bypass or inflow occlusion, resulting in substantial reduction of the severity of stenosis.

CONCLUSION AND CLINICAL IMPORTANCE

Accurate determination of the severity of the stenosis and the anatomy of the obstructing lesion are important in devising a treatment strategy. Recognition of the fibrous diaphragm by echocardiography identifies a subset of dogs potentially amenable to surgical dilation without the need for cardiopulmonary bypass.

Comparison of Right Atrium Incision and Right Ventricular Outflow Incision for Surgical Repair of Membranous Ventricular Septal Defect Using Cardiopulmonary Bypass in Dogs

OBJECTIVE

To compare right atrium incision (RAI) and right ventricular outflow incisions (RVI) for surgical repair of membranous ventricular septal defect (VSD) facilitated by cardiopulmonary bypass (CPB).

STUDY DESIGN

Retrospective study.

ANIMALS

Dogs (n=10) with VSD.

METHODS

Medical records of dogs that had VSD repair were reviewed. Membranous VSD without any malformation and abnormality was confirmed on several clinical examinations and by angiocardiography. RAI (5 dogs) and RVI (5 dogs) was used for VSD access and repair facilitated by CPB. Procedure comparison was by surgical duration, postoperative recovery period, and occurrence of postoperative arrhythmia.

RESULTS

Duration of surgery was similar for RAI and RVI; however, postoperative recovery time was significantly reduced with RAI. Significant moderate operative damage occurred with right atrium incision.

CONCLUSIONS

Right atrium incision was more effective than RVI for repair of membranous VSD using CPB.

CLINICAL RELEVANCE

RAI should be considered in preference to RVI for repair of membranous VSD using CPB.

Surgical correction of ventricular septal defect with aortic regurgitation in a dog

An 8-month-old entire Miniature Dachshund, weighing 4.2 kg, was presented for examination following delvelopment of a cough. Ventricular septal defect had been diagnosed tentatively in its infancy on the basis of a cardiac murmur detected by auscultation and echocardiography. Echocardiography using a B mode right parasternal long-axis view showed a defect at the atrioventricular junction and a thickened cusp of the aortic valve prolapsing into the defect. Colour-flow Doppler showed shunt blood flow across the defect at the level of the atrioventricular junction, from left to right. The sinus of Valsalva was dilated, with turbulent blood flow. Aortic regurgitation was also observed. Cardiac catheterisation studies confirmed the diagnosis of a supracristal ventricular septal defect with aortic regurgitation. Despite medication with digoxin, enalapril and aminophylin, started from the first admission, left ventricular internal dimensions gradually increased, and fractional shortening of the left ventricle gradually decreased. Surgery, with the aid of extracorporeal circulation, to close the ventricular septal defect, was performed 1 year after the initial examination. The aortic valve was left untreated. Postoperatively, the systolic murmur disappeared. Shunt flow from the left to the right ventricle was no longer observed on echocardiography, however there was still a small amount of aortic regurgitation during diastole visualised with colour-flow Doppler echocardiography. The prolapse of the cusp of the aortic valve on B-mode echocardiography was no longer observed and thickening of the cusp had not progressed. Left ventricular function measurement using M mode echocardiography showed a reduced left ventricular volume overload with reduced left ventricular internal dimensions and increased fractional shortening. The cough was relieved and no follow-up medication was scheduled. Early surgical closure of the ventricular septal defect improved the patient's condition and controlled prolapse and thickening of the aortic valve.

Ventricular septal defects in cattle: a retrospective study of 25 cases

Clinical and complementary examination, pathological findings, and outcome were reviewed for 25 heifers diagnosed with ventricular septal defect (VSD). Age at presentation ranged from 36 h to 21 mo. The most common reasons for consultation were chronic respiratory problems (11 cases; 44%) or assessment of heart murmur (5 cases; 20%). A pansystolic murmur on the right thoracic side was audible in 20 cases (80%). Pneumonia that interfered with adequate cardiac auscultation was found in 15 calves (60%). Echocardiography was useful in establishing the final diagnosis of VSD (sensitivity of 94%). Prognosis was poor: only 10 calves were discharged and no heifer out of the 6 cases for which follow-up information was available had a productive life in the herd. Inadequate reproductive performance was owners' most common complaint (4 of 6 heifers).

Quadricuspid Aortic Valve and Associated Abnormalities in a Dog

An 11-month-old, female Scottish terrier was presented with a history of a heart murmur. The electrocardiogram showed signs of left ventricular enlargement, and radiography confirmed generalized cardiomegaly. Echocardiography revealed four equally sized aortic valve cusps. A ventricular septal defect, with systolic left-to-right shunting, and aortic regurgitation into both ventricles were also present. The dog was free of clinical signs 1 year after diagnosis.

Echocardiographic Diagnosis of Congenital Membranous Ventricular Septal Aneurysm in the Dog and Cat

Membranous ventricular septal aneurysm was diagnosed by echocardiography in 17 dogs and three cats. The aneurysm appeared as a thin membrane protruding into the right ventricle from the margins of a congenital ventricular septal defect (VSD). The aneurysm was intact in nine dogs and two cats and perforated by a small VSD in eight dogs and one cat. Other congenital heart defects were present in seven dogs. In all animals, the aneurysm was an incidental finding observed during echocardiographic examination, and it did not appear to directly cause any cardiac dysfunction.

Echocardiographic diagnosis of muscular ventricular septal defect in a cynomolgus monkey (Macaca fascicularis)

There have been only a few case reports of heart disease in monkeys. In the case we present, a cardiac murmur was auscultated in a 26-month-old male cynomolgus monkey during a routine physical examination. Echocardiography of this monkey revealed features indicating blood flow from the left ventricle to the right ventricle through the ventricular septum. These findings clarified that the animal had a muscular interventricular septal defect.

Coexisting tricuspid valve dysplasia and ventricular septal defect in a young patas monkey (Erythrocebus patas)

A 1.5-kg, 6-mo-old male patas monkey (Erythrocebus patas) was cyanotic and panting. Evaluation of the heart by electrocardiography, thoracic radiography, two-dimensional echocardiography, and Doppler color-flow echocardiography revealed a ventricular septal defect (VSD) with right-to-left shunting as well as tricuspid valve dysplasia with dilated annulus of the tricuspid ring, dilated right atrium, dilated right ventricle, and deformity of the tricuspid valve. Because of the severity of the cardiac disease, the patas monkey had complications recovering from anesthesia and died 3 days later. Gross postmortem findings included VSD, tricuspid dysplasia, and cerebral hemorrhage.

Patent Ductus Arteriosus Ligation and Pulmonary Artery Banding in a Kitten

Patent ductus arteriosus (PDA) and ventricular septal defect were diagnosed in a 2-month-old, 0.9-kg, male kitten. This combination of PDA and ventricular septal defect in a cat has not been previously described. Surgical ligation of the PDA, together with palliation of the ventricular septal defect by pulmonary artery banding with a silastic band, successfully improved the kitten’s condition.

Transcatheter closure of congenital ventricular septal defects in 3 dogs with a detachable coil

The purpose of this study was to evaluate the feasibility, safety, and efficacy of transcatheter closure in dogs with a congenital perimembranous ventricular septal defect (VSD) by using a detachable coil. No dogs showed any symptoms, and results of chest X-rays and ECGs were normal. The diameters of VSD ranged from 2 to 4 mm on echocardiogram. The defect was 2-2.5 mm from the aortic valve. A detachable coil (size 5 mm with 5 loops) designed for patent ductus arteriosus was delivered via the transarterial route. The device was successfully employed in all dogs. A minimal residual shunt was observed in all dogs even though Qp/Qs decreased. Hemolysis and a rate-dependent right-bundle branch block were observed in 1 dog, but there was no clinical significance. No major complication was noted. Pathologic examination after 1 year revealed that the coils were covered with tissue without significant damage to the His-Purkinje conduction system. In conclusion, transcatheter closure of a small perimembranous VSD with a detachable coil can be achieved without major complications or significant pathologic damage at the lesion site.

Percutaneous transcatheter coil embolization of a ventricular septal defect in a dog

A 4-month-old male French Bulldog weighing 5.0 kg (11 lb) was referred for a heart murmur. A grade 3/6 systolic murmur was detected at the left heart base and a grade 4/6 systolic murmur was detected at the right heart base. By use of color-flow Doppler ultrasonography and cardiac catheterization, a diagnosis of supracristal ventricular septal defect (VSD) with accompanying aortic regurgitation was made. Percutaneous transcatheter coil embolization was used to close the VSD. Because residual shunt was detected via echocardiography after coil implantation, the residual shunt was followed periodically via echocardiography to detect spontaneous closure of the VSD. Volume overload in the left ventricle was detected in the dog 131 days after admission. Additional coils were placed 137 days after admission. Hemolysis resulting in hemoglobinuria was detected, but this complication was mild. In the dog of this report, results of coil occlusion for correction of VSD were promising. Thus, coil occlusion should be considered as an alternative treatment for VSD in dogs.

Atypical hypoplastic left ventricular syndrome in a calf

An 8-day-old male Angus calf was presented to the University of Illinois, Veterinary Teaching Hospital, Urbana, IL, for lethargy, weakness, and poor suckle reflex. Clinical evaluation revealed a strong left-sided heart murmur and a split S2 sound. The calf died within 48 hours. Necropsy revealed a combination of the following cardiac defects: left ventricular hypoplasia, high ventricular septal defect, left auricular atresia with mitral valve aplasia, patent foramen ovale, patent ductus arteriosus, and pulmonary trunk atresia. Mild suppurative pneumonia with pulmonary edema and congestion were also present. This combination of defects appears to be similar to the hypoplastic left heart syndrome in humans and is reported here for the first time in cattle.

Left ventricular outflow tract-right atrial communication (Gerbode type defect) associated with bacterial endocarditis in a dog

Left ventricular (LV) outflow tract-right atrial (RA) communication associated with bacterial endocarditis is described in a 6-year-old intact male Great Pyrenees dog with a 4- to 5-day history of fever, lethargy, weight loss, severe regenerative anemia, and asplenia. Typical vegetative mural endocardial lesions were observed grossly. Histologic evaluation revealed small gram-negative coccobacilli that were consistent with Bordetella avium-like organisms. These bacteria were associated with severe endocardial inflammation characterized by neutrophilic infiltration, extensive necrosis of endocardium, and fibrin deposition. LV-RA shunt (Gerbode defect) is a rare cardiac defect in humans that can be either congenital or, more rarely, secondary to septic endocarditis, valve replacement procedures, or thoracic trauma. B. avium-like organisms causing septicemia and endocarditis in immunocompromised and asplenic human patients have been described. To our knowledge, no previous descriptions of Gerbode defect associated with bacterial endocarditis in domestic animals have been reported in veterinary literature.

Spontaneous resolution of an isolated ventricular septal defect in a dog

A 5-month-old Maltese was examined because of a holosystolic heart murmur. Results of echocardiography were suggestive of a small isolated interventricular septal defect. Color flow and pulsed-wave spectral Doppler echocardiography confirmed that there was left-to-right blood flow through the defect during systole and diastole. Because of the small size of the defect, the large systolic pressure differential between the ventricles (72.6 mm Hg), and the lack of clinical signs, the small amount of left-to-right shunting was considered clinically unimportant, and no medication or treatment was recommended. Seven months later, the dog was re-examined, and trans-septal blood flow was no longer seen. Isolated interventricular septal defects are a common congenital heart disorder in some breeds of dogs. Such defects may be subclinical in some dogs. In others, they cause a wide spectrum of clinical problems. Findings in this dog suggest that interventricular septal defects may close spontaneously in some dogs.

Open surgical repair of tetralogy of Fallot in dogs

Tetralogy of Fallot is a congenital heart defect that causes cyanosis, severe progressive weakness and activity intolerance, polycythemia, and shortened life span in dogs. Open surgical repair of tetralogy of Fallot consisting of closure of the ventricular septal defect and reconstruction of the right ventricular outflow tract via a right ventriculotomy during cardiopulmonary bypass is feasible in severely affected dogs. Successful surgical repair can completely resolve clinical signs associated with the defect.

Ventricular septal defect in a houbara bustard (Chlamydotis undulata macqueenii)

A ventricular septal defect was found in a juvenile captive-bred houbara bustard (Chlamydotis undulata) that died suddenly. The case history indicated that the bird had a retarded growth and maturation rate. Gross pathology demonstrated massive internal hemorrhage, an enlarged heart with an interventricular septal defect, one shrunken liver lobe, and hypoplastic kidneys. Histologically, the liver was characterized by fatty degeneration, and there was hydropic degeneration of the cardiac muscle fibers. We suggest that the occurrence of this defect led to cardiac insufficiency, which resulted in sudden death caused by hemorrhage from the liver.

Ventricular septal defect in a blue duiker (Cephalophus monticola)

A 9-mo-old female blue duiker (Cephalophus monticola) weighing 3.9 kg was diagnosed with a cardiac murmur during quarantine examination. Evaluation of the heart by auscultation, electrocardiography, two-dimensional echocardiography, and Doppler color-flow echocardiography revealed a restrictive outlet ventricular septal defect with left atrial and left ventricular dilation. Trivial mitral, tricuspid, and aortic regurgitation was also noted. Though the duiker was clinically asymptomatic at the time of cardiac evaluation, it was found dead 1 wk later. The cause of death was not determined.

Double-chambered right ventricle in a dog

A 32-month-old spayed female Pug was referred for an MRI study due to convulsions. The MRI examination indicated encephalitis. However, echocardiography and pathological examinations revealed that this case had a ventricular septal defect and double chambered right ventricle which is a rare congenital heart disease in the dog. An anomalous muscle bundle crossed the right ventricular outflow tract, dividing the right ventricle into 2 chambers.

Congenital ocular anomalies and ventricular septal defect in a dromedary camel (Camelus dromedarius)

A 5-wk-old female dromedary camel (Camelus dromedarius) was clinically diagnosed with bilateral corneal dermoids, incomplete congenital cataracts, a left persistent hyaloid artery (PHA), and a ventricular septal defect (VSD). The corneal dermoids were removed by lamellar keratectomy, and vision improved in the left eye. Thirteen months after dermoid surgery, the calf was presented for enlargement of the right eye. Glaucoma was confirmed in the right eye, and corneal fibrosis and cataract were noted in the left eye. Persistence of the VSD was confirmed by cardiac ultrasonography. The calf was euthanized, and necropsy findings confirmed VSD. Histopathologic examination revealed bilateral corneal thinning and fibrosis, cataracts with retrolental fibroplasia, and retinal dysplasia. Additional changes in the right globe were anterior segment dysgenesis, ruptured lens capsule, chronic phacoclastic uveitis, and retinal separation. The PHA was confirmed in the left eye.

Persistent left cranial vena cava associated with multiple congenital anomalies in a six-week-old puppy

A six-week-old male puppy was presented with a distended abdomen, dypsnoea and cyanosis. Auscultation revealed a grade II/VI systolic murmur. Thoracic radiographs showed gross cardiomegaly. An electrocardiogram revealed a narrow-complex tachycardia, deep S waves in leads I, II, III and aVF, and negative P waves in lead III. Two-dimensional echocardiography showed a high ventricular septal defect and marked dilation of the right-sided chambers. There was also an echolucent structure lateral to the left atrium at a site corresponding to the coronary sinus. Contrast echocardiography revealed right-to-left shunting through the septal defect. Necropsy confirmed the existence of a septal defect in the membranous part of the septum and a persistent left cranial vena cava with dilation of the coronary sinus. In addition, a small patent ductus arteriosus and tricuspid dysplasia were present.

Diagnosis and surgical repair of partial atrioventricular septal defects in two dogs

Partial atrioventricular (AV) septal defects consist of an ostium primum defect and malformation of the septal cusp of the mitral valve. A partial AV septal defect was diagnosed by means of echo-cardiography in 2 dogs. Transatrial septal blood flow was high enough in both dogs to warrant surgical correction. Defects were repaired through right fifth intercostal thoracotomies, with the aid of cardiopulmonary bypass. An incision was made in the right atrium to expose the AV septal defect, and the mitral valve was inspected through the septal defect. The cleft in the septal cusp of the mitral valve was repaired with mattress sutures of 6-0 polypropylene. The septal defect was closed with autogenous pericardium harvested from the right aspect of the pericardial sac. Both dogs survived surgery and were alive 15 and 42 months, respectively, after surgery, however, 1 dog developed progressive mitral regurgitation after surgery. Partial AV septal defects can be successfully repaired in dogs. Long-term prognosis probably depends on the adequacy of the mitral valve repair.

Retrospective study of congenital heart defects in 151 dogs

The case records of 151 dogs diagnosed with congenital heart disease were reviewed retrospectively. The most common defect was aortic stenosis, accounting for 35 per cent of all cases, followed by pulmonic stenosis (20 per cent), ventricular septal defect (12 per cent), patent ductus arteriosus (11 per cent), mitral valve dysplasia (8 per cent), tricuspid valve dysplasia (7 per cent), endocardial fibroelastosis (1.9 per cent) and tetralogy of Fallot (0.6 per cent). Fifty-one breeds were represented, with golden retrievers, German shepherd dogs and boxers predominating. No overall sex predilection was obvious. Seventy-five per cent of the dogs were asymptomatic at presentation. The defects most often associated with presenting symptoms, such as dyspnoea, syncope, ascites, failure to grow and depression, were mitral valve dysplasia, atrial septal defect, tricuspid valve dysplasia and endocardial fibroelastosis. The latter presented with the most severe signs of heart failure. In some cases of aortic stenosis and pulmonic stenosis, where the defect could not be accurately visualised with two-dimensional echocardiography, Doppler echocardiographic examination was needed for definitive diagnosis.

Open resection for subvalvular aortic stenosis in dogs

OBJECTIVE

To describe the surgical technique for open resection of congenital subvalvular aortic stenosis in dogs and to determine outcome of dogs undergoing the procedure.

DESIGN

Uncontrolled clinical trial.

ANIMALS

17 dogs with congenital discrete subvalvular aortic stenosis.

PROCEDURE

Dogs were placed on cardiopulmonary bypass by catheterizing the femoral artery and both vena cavae. The aorta was cross clamped, and cold cardioplegia solution was administered. The aortic root then was opened with a curvilinear incision. A subvalvular discrete fibrous ring was resected in all dogs. Septal myectomy was performed simultaneously on 11 dogs.

RESULTS

15 of 17 dogs survived the operation and were discharged from the hospital. Mean +/- SD maximal instantaneous aortic systolic pressure gradient measured by means of Doppler echocardiography was significantly reduced from 119 +/- 42 mm of Hg before surgery to 41 +/- 10 mm of Hg 12 months after surgery. Despite substantial reduction in the systolic pressure gradient, 4 of 15 dogs died suddenly between 7 days and 30 months after surgery. Three of the 4 dogs that died suddenly had pressure gradients > or = 180 mm of Hg and ventricular tachycardia before surgery. Eleven dogs were still alive between 1 and 48 months after surgery.

CLINICAL IMPLICATIONS

The procedure resulted in substantial reductions in systolic pressure gradients in dogs with severe congenital subvalvular aortic stenosis. However, some dogs with severe aortic stenosis died suddenly after surgery. Thus, this surgery should not be considered curative. Proof of a survival benefit in dogs undergoing this surgery will have to await longer term follow-up.

Different effect of inhaled nitric oxide on yucatan micropig with and without congenital ventricular septal defect

A strain of Yucatan micropigs is known to have heritable ventricular septal defects (VSDs) and thus may develop overflow pulmonary hypertension. Since inhaled nitric oxide (NO) selectively dilates pulmonary vessels, we determined its hemodynamic and co-agulatory effects in this new animal model. Eight Yucatan micropigs were anesthetized with midazolam, piritramide (a synthetic opioid) and vecuronium bromide. The presence and the size of the VSD were determined by using transesophageal color flow Doppler echocardiography. Four animals showed VSDs of 1-2 mm size. Inhaled NO was then administered with increasing inspired concentrations of 0, 5, 10, 20, 40, 80 and again 0 ppm NO for 10-min periods. NO inhalation did not affect heart rate, right cardiac output, mean arterial pressure, pulmonary arterial wedge pressure, or central venous pressure. Inhaled NO in animals with proven VSDs decreased pulmonary artery pressure (PAP) in a dose dependent manner; 5 ppm NO reduced mean PAP from 25 +/- 2.3 mm Hg to 18 +/- 0.8 mm Hg (p < 0.05), while pulmonary vascular resistance (PVR) decreased from 954 +/- 143 dyn.cm. s-5 to 661 +/- 88 dyn.cm.s-5 (p < 0.01) at the same dose. The maximum reduction in mean PAP and PVR occurred when 80 ppm NO was inhaled. Yucatan micropigs without VSDs did not respond hemodynamically to NO inhalation. Methemoglobin levels remained unchanged during the entire study. Platelet function was assessed according to the method of BREDDIN and BORN (BORN 1962). Initial aggregation and slope were affected when NO inhalation commenced. Yucatan micropigs with VSDs may represent a suitable model for further research of the in vivo effects of inhaled NO.

Ventricular septal defect repair in a small dog using cross-circulation

A haemodynamically significant ventricular septal defect was diagnosed in a 3-month-old male Cavalier King Charles Spaniel. A median sternotomy was performed and the 6.5 kg dog placed on cardiopulmonary bypass using pump-assisted cross-circulation. A 10 mm diameter peri-membranous ventricular septal defect was closed using a continuous suture of 4-0 polypropylene, via a 2.5 cm incision in the right ventricular outflow tract. The duration of cardiopulmonary bypass was 90 minutes. Complications in the immediate postoperative period were mild and easily managed.

Evaluation of ventricular septal defects in horses using two-dimensional and Doppler echocardiography

Ventricular septal defects (VSDs) were diagnosed in 27 horses; in 26 affected horses systolic murmurs were detected over both sides of the chest. Holodiastolic decrescendo murmurs were also detected in 5 horses. Standardbreds and Arabian horses were over-represented, while Thoroughbred horses were under-represented, when compared to the hospital population (P < 0.0001). Five horses had previously raced successfully, one 2-year-old was training successfully and close to racing, and 4 horses had competed successfully in other types of competition. Eleven horses had a history of exercise intolerance or poor performance, 5 horses were stunted and 3 horses were in congestive heart failure at the time of presentation. The VSD murmur was detected as an incidental finding in 14 horses. Membranous VSD were most commonly detected (in 23/27 affected horses) and were typically found underneath the septal leaflet of the tricuspid valve and the right and/or noncoronary leaflet of the aortic valve. Muscular VSDs were much less common and were located in any portion of the muscular septum. The VSDs ranged in size from 1-4.6 cm (maximal diameter) in affected horses. A left to right shunt through the VSD was detected in 26/27 affected horses with Doppler echocardiography. The peak velocity of shunt flow detected through the VSD was 0-5.8 m/s. The interventricular pressure gradients estimated from the peak shunt velocity obtained with Doppler echocardiography were 0-135 mmHg. Right ventricular pressures estimated with Doppler echocardiography were 15-84 mmHg, similar to invasively obtained measurements of right ventricular pressure in 80% of horses in which right sided cardiac catheterisation was performed (n = 5). Left ventricular and left atrial volume overload was detected in the majority (23/27) of horses. Right atrial and right ventricular volume overload was severe in 3 horses with muscular VSDs, mild in 1 horse with a perimembranous VSD, and mild in 2 horses with membranous VSDs. Concurrent left ventricular dysfunction was detected in 2 horses. Aortic valve prolapse was seen in 7 horses associated with the membranous location of the VSD; 6 of these horses had very mild (1+) or mild (2+) aortic regurgitation. Severe (4+) aortic regurgitation was present in one horse, severe mitral regurgitation in 2 horses, severe tricuspid regurgitation in 3 horses, and severe pulmonary regurgitation was detected in 2 horses. Mitral valve prolapse, tricuspid valve dysplasia, a flail aortic valve leaflet, and a bicuspid pulmonary valve were additional findings detected in one horse each. Post mortem examinations were performed in 8 horses which confirmed the echocardiographic findings. Sixteen out of 27 horses had a history of racing or competing successfully either before or after the diagnosis of the VSD. Two horses were useful pleasure horses, 3 horses presented in congestive heart failure, 1 horse developed signs of congestive heart failure, 2 horses were lost to follow-up and 2 are still alive but are small and stunted. The successful racehorses usually had a membranous VSD that measured < or = 2.5 cm in its largest diameter and a peak velocity of shunt flow through the VSD of > or = 4 m/s. Two-dimensional (2-D) and Doppler echocardiography is useful in assessing the haemodynamic significance of VSDs in horses and can be used to help formulate a prognosis for life and performance.