Self-Reported Management of Incidentally Detected Heart Murmurs in Puppies: A Survey among Veterinarians

BACKGROUND

Heart murmurs in puppies can be innocent or pathologic; the latter is almost always related to a congenital heart disease. Differentiating between these murmurs can be challenging for practicing veterinarians, but this differentiation is essential to ensure the best prognosis for puppies having a congenital heart disease. Our study aimed to reveal how veterinarians manage puppies with a heart murmur.

METHODS

A web-based questionnaire was sent to Dutch and Belgian veterinary practices.

RESULTS

Data from 452 respondents were analyzed. Though 88% of the respondents find detecting a heart murmur easy, only 9% find differentiating innocent murmurs from pathologic murmurs in puppies easy. Of the respondents, only 80% recommend immediate additional examination when detecting a loud heart murmur during the first veterinary health check at 6 weeks of age. Most of the respondents are aware that normal growth and the absence of clinical signs do not exclude severe congenital heart disease. Of the respondents, 31% were uncertain whether early surgical intervention could lead to improved outcomes.

CONCLUSIONS

Veterinarians are aware of the importance of echocardiography for puppies with a loud heart murmur, and recognize their limitations when differentiating an innocent from a pathological heart murmur in a puppy.

Surgical Correction of Infundibular Muscular Ventricular Septal Defect in a Cat: A Case Report

Ventricular septal defects (VSDs) can lead to congestive heart failure and pulmonary hypertension, particularly in patients with large shunts. However, no surgical treatment for feline VSD has been reported. Here, we elucidated the first surgical correction of an infundibular muscular VSD in a one-year-old Ragdoll cat, atypically located and classified under the Soto classification rather than the standard Kirklin classification, through cardiac arrest using cardiopulmonary bypass-a method rarely used in feline cardiac surgery. Detailed echocardiography revealed that the defect required intervention owing to left heart and main pulmonary artery enlargement. Despite the VSD being located on the contralateral side, as anticipated in the preoperative examinations, the choice of median sternotomy allowed for the successful closure of the defect. Conversely, the insertion of two cannulas into the ascending aorta resulted in damage to the adjacent thoracic duct, causing transient chylothorax, which was resolved with conservative treatment. Cardiac arrest induced by a cardioplegic solution facilitated the surgical procedure, although it leads to anemia in cats. However, on postoperative day 490, the patient exhibited only minor residual shunting, with normalized heart size, and remained healthy. This technique appears to be a viable treatment option for congenital heart disease in cats.

Cardiac Disease and Screening in Breeding Dogs

Acquired and congenital heart diseases are relatively common in dogs, particularly in certain breeds. Modes of inheritance and genetic causes have been established for several cardiac diseases within various breeds. Breed screening is used to try and reduce the prevalence of certain canine cardiac diseases. Although breed screening seems to help reduce the prevalence of canine heart disease, the outcomes of specific breeding programs are variable and depend on multiple factors.

Acquired infundibular pulmonary stenosis associated with a congenital membranous ventricular septal defect (Gasul phenomenon) in a dog and discussion regarding causes of infundibular stenosis

An aclinical Havanese dog was diagnosed with a membranous restrictive ventricular septal defect. The patient was represented later in their natural history due to the development of syncope. At that time the patient was diagnosed with acquired pulmonary infundibular stenosis. Balloon dilation of the stenosis was performed successfully twice over the patient's lifetime. The patient died suddenly approximately 14 months after the second balloon dilation. A discussion regarding primary infundibular pulmonary stenosis versus causes of acquired infundibular pulmonary stenosis including anomalous muscle bundles (double chamber right ventricle), tetralogy of Fallot, and infundibular stenosis is presented.

Progressive Right Ventricular Obstruction Caused by a Double-Chambered Right Ventricle Resulting in Shunt-Reversal via a Concomitant Congenital Ventricular Septal Defect and Subsequent Erythrocytosis in a Dog

A 3-year-old Chihuahua was presented because of exercise intolerance, respiratory distress, and syncopal episodes. At the age of 10 weeks, the dog was diagnosed with a congenital small left-to-right shunting ventricular septal defect and a mild right ventricular outflow tract obstruction via echocardiography. At that time, the dog was asymptomatic, but the breeder’s veterinarian heard a murmur. Both cardiac defects were judged to be clinically non-relevant at that time. However, at 3 years of age, echocardiography revealed a severe right ventricular obstruction, known as a double-chambered right ventricle, along with right-to-left shunting via the ventricular septal defect. Because of chronic hypoxemia due to the right-to-left shunting, erythrocytosis developed. Flow reversal via the shunt was caused by a progressively worsening right ventricular obstruction leading to a supra-systemic right ventricular systolic pressure. Because of the poor prognosis, the dog was euthanized, and the heart was submitted for post-mortem examination. Gross pathologic findings revealed the close proximity of the right ventricular obstructive lesion to the ventricular septal defect. Histopathology revealed localized muscular hypertrophy and severe endocardial fibrosis. The suspected pathogenesis of the progressive obstruction was infiltrative myocardial fibrosis due to turbulent blood flow from the left-to-right shunting ventricular septal defect, as described in humans.

Echocardiographic changes in the progress of reverse shunt and improvement to left-to-right shunt after medical treatment in dogs with bidirectional patent ductus arteriosus or ventricular septal defect: A report of two cases

Two Maltese dogs were referred for evaluation of a congenital heart disease: one was diagnosed with patent ductus arteriosus and the other was diagnosed with a ventricular septal defect. The PDA patient was diagnosed with congenital heart disease 2 weeks ago and the VSD patient about 11 months ago at another hospital. Echocardiographic findings revealed a bidirectional shunt condition, and the dogs were treated with medical management using sildenafil and oxygen inhalation. After medical management, the dogs returned to clinically normal conditions, and echocardiographic findings revealed a return to left-to-right shunt tendency. These dogs had no clinical signs associated with heart disease 3 years after treatment. This case report describes changes in echocardiography findings according to the progression of the reverse shunt and the possibility of improvement to a left-to-right shunt after medical treatment.

Information Provided by Breeders and Referring Veterinarians about the Presence and Meaning of a Murmur to Owners of Newly Purchased Puppies with a Later Confirmed Congenital Heart Disease

Background: A recent study revealed that only 10% of puppies diagnosed with a congenital heart disease were referred for murmur investigation to a veterinary cardiology specialist while the puppies were in the breeders' possession. Whether the new owners had been informed about the presence of a murmur before purchasing a puppy was not investigated. Methods: New owners whose dogs were diagnosed with a congenital heart disease at the authors' institution in a 1-year period received a questionnaire during the consult after cardiac auscultation but before performing an echocardiogram. The main study aims were to reveal whether the breeders had informed the new owners about the presence of a murmur before purchasing the puppy, and whether the owners would have still chosen to buy that specific puppy if they had known about a potentially present congenital heart disease. Results: Of the 60 interviewed owners, 72% would have refrained from buying the puppy if they had known about the presence of a congenital heart disease. However, only 23% of them were informed about the presence of a cardiac murmur before purchase. Conclusions: Most owners would have chosen to buy a healthy puppy without a heart disease if they had been informed.

Spontaneous closure of an isolated congenital perimembranous ventricular septal defect in two dogs

Background

Though spontaneous closure of isolated congenital ventricular septal defects in humans is very common, it has been rarely reported in dogs.

Case presentation

A 4 month old Havanese dog and a 4.5 month old Chihuahua x Jack Russell terrier cross were presented for murmur evaluation to the authors’ institution. Both puppies were clinically healthy and had a loud systolic murmur on the right hemithorax. Echocardiography in both dogs revealed a small, isolated, restrictive perimembranous congenital ventricular septal defect. No echocardiographic signs of left ventricular volume overload or pulmonary hypertension were present. Re-check auscultation in both dogs revealed the absence of a murmur, and echocardiography showed no flow through the interventricular septum. In the 9 kg Havanese dog and the 4 kg mixed breed dog, spontaneous closure occurred at 13–17 months and 12–30 months, respectively.

Conclusions

In both dogs the spontaneous closure of a congenital perimembranous ventricular septal defect took place in a young adult age. The mechanism of closure remains unclear.

Age of puppies at referral to veterinary cardiology specialists for murmur investigation

Background

Cardiac auscultation is an important screening test at the first health examination of puppies because most clinically relevant congenital cardiac anomalies cause a loud murmur from birth. This retrospective study aimed to investigate the age at which dogs with suspected congenital cardiac anomalies were referred to a veterinary cardiology specialist for murmur investigation. A secondary aim was to establish the time interval between the visit to the cardiologist and the first available murmur documentation. The digital archive of a veterinary teaching hospital was searched for dogs with congenital cardiac anomalies and puppies with innocent murmurs during a 5-year period. Dogs had to be referred because of a murmur, and they had to undergo physical examination and echocardiography by a veterinary cardiology specialist. The health certificate section of the pet passport, and the medical records from the referring veterinarian, were reviewed to identify the date when the murmur was first documented.

Results

Of the 271 included dogs, 94% had a congenital cardiac anomaly and 6% had an innocent murmur. The dogs’ median age was 190 days when they were examined by the cardiologist. Only 10% of the dogs were referred by the breeder’s veterinarian, while 90% of the dogs were referred by the new owner’s veterinarian. The median age of the first available murmur documentation by a first opinion veterinary practitioner was 95 days.

Conclusions

Only 10% of the puppies in the present study were referred to a veterinary cardiology specialist for murmur investigation before they were sold to a new owner. Referral prior to re-homing would have been feasible if the murmur had been detected and documented by the breeder’s veterinarian, if referral was offered by the breeder’s veterinarian and the referral was accepted by the breeder.

Key considerations in the approach to congenital heart disease in dogs and cats

Congenital heart disease is an important subset of all cardiovascular disease in dogs and cats that is present at birth and most often detected in young animals but can be diagnosed in adulthood. The range of abnormalities that can occur during development of the heart is vast incorporating simple and complex defects, varying degrees of severity and clinical presentations that include heart failure and cyanosis. While some defects do not result in morbidity in an individual animal, others cause severe clinical signs and death at a young age. Advances in imaging and expanding treatment options offer increasingly more possibilities in the diagnosis and management of congenital heart disease which is the focus of this review. The objective is to provide a broad overview of current practice and highlight key aspects to guide practitioners in their approach to congenital heart disease diagnosis and knowledge of available treatment options.

Prevalence and characteristics of ventricular septal defects in a non-racehorse equine population (2008-2019)

BACKGROUND

Ventricular septal defects (VSDs) are the most common congenital cardiac defect in horses.

OBJECTIVES

To identify prevalence, age, breed, and sex distribution of VSD and to describe associated clinical and ultrasonographic findings.

ANIMALS

Hospital-based population of 21 136 horses presented to the equine internal medicine department.

METHODS

Medical records over a 12-year period were reviewed for VSD confirmed by ultrasonography. Age, breed, sex, sport discipline, murmur, clinical signs, outcome, VSD type, VSD size, shunt velocity, cardiac dimensions, concomitant cardiac anomalies, and valvular regurgitations were recorded.

RESULTS

From 1894 horses that underwent echocardiography, 54 had a VSD: 42 as an isolated lesion and 12 as part of complex congenital heart disease (CHD). Median age was 5 years (range, 0-26) and 1 year (range, 0-8), respectively. Warmbloods and males were overrepresented. In the isolated VSD group, only 15% had associated clinical signs and most horses had a perimembranous VSD (pmVSD; 36/42). Horses with a pmVSD and clinical signs showed a significantly lower maximal shunt velocity (3.77 vs 5.20 m/s; P < .001), higher VSD/Aortic root (Ao) diameter (0.52 vs 0.38; P = .05), higher left atrium/Ao diameter (1.94 vs 1.22; P < .001), and higher pulmonary artery/Ao diameter (1.15 vs 0.88; P = .005) compared to horses without clinical signs. All horses with complex CHD had clinical signs and abnormal cardiac dimensions.

CONCLUSION AND CLINICAL IMPORTANCE

Most isolated VSD were diagnosed only at a later age and were not associated with clinical signs. Horses with complex CHD were more likely to have or develop clinical signs at younger age.

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).

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.

Combined double chambered right ventricle, tricuspid valve dysplasia, ventricular septal defect, and subaortic stenosis in a dog

BACKGROUND

Double chambered right ventricle (DCRV) is a congenital heart anomaly where the right ventricle is divided into two chambers. We describe, for the first time, an unusual combination of DCRV combined with some other congenital heart defects.

CASE PRESENTATION

A 1.2-year-old Golden Retriever was presented with lethargy, exercise intolerance and ascites. Physical examination revealed an irregularly irregular pulse and a grade V/VI, systolic, right cranial murmur. Electrocardiography revealed widened and splintered QRS complexes with a right bundle-branch block pattern. Radiography demonstrated right-sided cardiomegaly. Two-dimensional echocardiography identified a DCRV with tricuspid valve dysplasia. The patient died despite abdominocentesis and 4 days of oral pharmacotherapy, and necropsy revealed an anomalous fibromuscular structure that divided the right ventricle into two compartments. Another finding was tricuspid valve dysplasia with hypoplasia of the posterior and septal leaflets. The anterior leaflet was prominent, being part of the anomalous structure that divided the right ventricle. Necropsy also identified a perimembranous ventricular septal defect and mild subaortic stenosis. Histopathological examination of the fibromuscular band that separated the right ventricle identified longitudinally oriented layers of dense fibrous connective tissue and myocardial cells arranged in a plexiform pattern. The muscular component was well represented at the ventral area of the fibromuscular band, and was absent in the central zone. Superficially, the endocardium presented areas of nodular hyperplasia covering mainly the fibrous part of the abnormal structure. The nodules were sharply demarcated and were composed by loosely arranged connective tissue with myxoid appearance, covered by discrete hyperplastic endocardium.

CONCLUSIONS

Concomitant cardiac malformations involving DCRV, tricuspid valve dysplasia, perimembranous ventricular septal defect and mild subaortic stenosis have not been previously described in veterinary medicine, and are reported here for the first time. Moreover, this is the first report of a canine patient with tricuspid valve dysplasia (TVD) and DCRV where the anterior leaflet is part of an anomalous structure dividing the right ventricle (RV) into two separate compartments.

Hybrid Surgical Approach Using Amplatzer Occluder for Treatment of VSD in a Cat

Ventricular septal defect (VSD) is among the most common feline congenital heart malformations. Although usually treated by pulmonary artery banding or pharmacotherapy, neither method is curative. Curative procedures have been performed in humans. Treatment of VSD is usually not required in dogs and cats, but is necessary in cases of non-restrictive VSD. Dogs with non-restrictive VSD are treated either using surgical correction under open-heart surgery, or percutaneous insertion of an occluder under interventional radiation. In our experience, neither method alone is appropriate for treating ventricular septal defect in cats with non-restrictive VSDs. We have applied a hybrid surgical method in a 13-month-old, female Maine Coon cat weighing 3.5 kg. A catheter was inserted and an occluder placed directly at the defect through thoracotomy. This method is less invasive than open-heart surgery and requires no special equipment, using direct puncture of the heart to minimize the distance to the defect and improving maneuverability. By combining the advantages of both surgical defect closure and occlusion guided by interventional ultrasound, treatment that could not be performed with either method alone became possible. In this case, the VSD could not be embolized, but some important points were suggested regarding surgical treatment of VSD in cats. One is that a sizing balloon catheter may be the most accurate method to measure VSD in cats. Amplatzer occlusion of a large non-restrictive VSD in a cat is currently not an option, but the described hybrid technique may still be an option for smaller non-restrictive VSDs. However, criteria and adjustments must be considered carefully.

Anatomic, histopathologic, and echocardiographic features in a dog with an atypical pulmonary valve stenosis with a fibrous band of tissue and a patent ductus arteriosus

Background

Congenital pulmonary valve stenosis and patent ductus arteriosus are common congenital heart defects in dogs. However, concurrence of atypical pulmonary valve stenosis and patent ductus arteriosus is uncommon. This report describes the anatomic, histopathologic, and echocardiographic features in a dog with concomitant pulmonary valve stenosis and patent ductus arteriosus with atypical pulmonary valve dysplasia that included a fibrous band of tissue.

Case presentation

A 1.5-year-old intact female Chihuahua dog weighing 3.3 kg presented with a continuous grade VI cardiac murmur, poor exercise tolerance, and an intermittent cough. Echocardiography indicated pulmonary valve stenosis, a thickened dysplastic valve without annular hypoplasia, and a type IIA patent ductus arteriosus. The pulmonary valve was thick line-shaped in systole and dome-shaped towards the right ventricular outflow tract in diastole. The dog suffered a fatal cardiac arrest during an attempted balloon pulmonary valvuloplasty. Necropsy revealed pulmonary valve dysplasia, commissural fusion, and incomplete opening and closing of the pulmonary valve because of a fibrous band of tissue causing adhesion between the right ventricular outflow tract and the dysplastic intermediate cusp of the valve.

Conclusions

A fibrous band of tissue between the right ventricular outflow track and the pulmonary valve should be considered as a cause of pulmonary valve stenosis. Pulmonary valve stenosis and patent ductus arteriosus can have conflicting effects on diastolic and systolic dysfunction, respectively. Therefore, beta-blockers should always be used carefully, particularly in patients with a heart defect where there is concern about left ventricular systolic function.