Retrospective study of congenital heart defects in 151 dogs

The Genetics of Canine Pulmonary Valve Stenosis

There have been recent advancements in understanding the genetic contribution to pulmonary valve stenosis (PS) in brachycephalic breeds such as the French Bulldog and Bulldog. The associated genes are transcriptions factors involved in cardiac development, which is comparable to the genes that cause PS in humans. However, validation studies and functional follow up is necessary before this information can be used for screening purposes.

Prophylactic use of a lidocaine constant rate infusion versus saline in dogs undergoing balloon valvuloplasty for management of pulmonic stenosis: A randomized control trial

OBJECTIVE

To evaluate the effect of a prophylactic lidocaine constant rate infusion (CRI) on the incidence and malignancy of catheter-induced ventricular ectopic complexes (VECs) during balloon valvuloplasty for management of pulmonic stenosis in dogs.

STUDY DESIGN

Single-centre, prospective, randomized study.

ANIMALS

Client-owned dogs (n = 70) with pulmonic stenosis.

METHODS

Dogs were randomly assigned to one of two anaesthetic protocols: administration of lidocaine 2 mg kg-1 bolus followed by a CRI (50 μg kg-1 minute-1; group LD) or a saline placebo (group SL) during balloon valvuloplasty. All dogs were premedicated with methadone (0.3 mg kg-1) intramuscularly and a digital three-lead Holter monitor was applied. Anaesthetic co-induction was performed with administration of alfaxalone (2 mg kg-1) and diazepam (0.4 mg kg-1), and anaesthesia was maintained with isoflurane vaporised in 100% oxygen. CRIs were started on positioning of the dog in theatre and discontinued as the last vascular catheter was removed from the heart. All dogs recovered well and were discharged 24 hours postoperatively. Blinded Holter analysis was performed by an external veterinary cardiologist using commercially available dedicated analysis software; p < 0.05.

RESULTS

Of the 70 dogs enrolled in the study, 61 were included in the final analysis: 31 in group LD and 30 in group SL. There was no significant difference between sinus beats (p = 0.227) or VECs (p = 0.519) between groups. In group LD, 19/31 (61.3%) dogs had a maximum ventricular rate ≥250 units and 20/30 (66.7%) dogs in group SL (p = 0.791).

CONCLUSION AND CLINICAL RELEVANCE

In this study, the use of a prophylactic lidocaine bolus followed by CRI in dogs undergoing balloon valvuloplasty for management of pulmonic stenosis did not significantly decrease the incidence nor the malignancy of VECs during right heart catheterization compared with a saline CRI.

Case report: Imaging features of aorta-right atrial tunnel in a dog using two-dimensional echocardiography and computed tomography

A 7-year-old castrated male Pomeranian dog weighing 5 kg presented with a right-sided continuous murmur without any clinical signs. Thoracic radiographs indicated cardiomegaly and right atrial (RA) bulging. Echocardiography revealed a tunnel originating from the right coronary sinus of Valsalva and terminating in the RA. Contrast echocardiography revealed pulmonary arteriovenous anastomoses. Computed tomography (CT) demonstrated a tortuous shunting vessel that originated from the aorta extending in a ventral direction, ran along the right ventricular wall, and was inserted into the RA. Based on these diagnostic findings, the dog was diagnosed with the aorta-RA tunnel. At the 1-year follow-up visit without treatment, the dog showed no significant change except for mild left ventricular volume overload and mildly decreased contractility. To the best of our knowledge, this is the first case report of an aorta-RA tunnel that has been described in detail using echocardiography and CT in a dog. In conclusion, the aorta-RA tunnel should be included in the clinical differential diagnoses if a right-sided continuous murmur is heard or shunt flow originating from the aortic root is identified.

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.

Systolic function in dogs with pulmonic stenosis of different severities and the effect of balloon valvuloplasty

INTRODUCTION/OBJECTIVES

Pulmonic stenosis (PS) is one of the most common congenital heart diseases in dogs leading to right ventricular (RV) pressure overload, myocardial remodeling, and potential RV dysfunction. Our objectives were to investigate the extent of RV systolic dysfunction in canine PS and to examine the immediate influence of balloon valvuloplasty (BV) on systolic function.

ANIMALS, MATERIALS AND METHODS

This prospective study evaluated 72 dogs with PS and 86 healthy dogs. Echocardiographic parameters of systolic function included normalized tricuspid annular plane systolic excursion (N-TAPSE), normalized systolic myocardial tissue Doppler velocity of the lateral tricuspid annulus (N-RVFW-S'), fractional area change, and speckle-tracking longitudinal endocardial RV strain. Forty-four dogs underwent BV and were re-examined after surgery.

RESULTS

Systolic function at the basal segment of the RV was significantly lower in the PS group when compared to healthy dogs (mean N-TAPSE 4.29 ± standard deviation 1.18 mm/kg^0.285 vs. 5.60 ± 1.29 mm/kg^0.285; median N-RVFW-S' 5.28 [lower-upper 25% quantile 4.35-6.43 cm/s/kg^0.186] vs. 7.82 [6.73-8.79 cm/s/kg^0.186]; all P<0.001). Global longitudinal RV endocardial strain showed no significant difference between the two groups (-28.50 ± 6.23% vs. 28.61 ± 4.64%; P=0.886), but segmental strain analyses revealed basal hypo- and potential compensatory hyperkinesis of the apical RVFW. Furthermore, BV affected most parameters of systolic function, but not the segmental strain values and N-TAPSE.

CONCLUSIONS

Right ventricular basal longitudinal systolic function is decreased in dogs with PS in comparison to a healthy cohort. Regional and global function does not necessarily coincide.

Evaluation of two probes for transesophageal echocardiography in small dogs: imaging capabilities, image quality, and usability

INTRODUCTIONS

Patient size is a limiting factor for transesophageal echocardiography (TEE) in small dogs. The objective of this study was to describe imaging capabilities of two probes for TEE in small dogs.

ANIMALS, MATERIALS, AND METHODS

Prospective study in 10 client-owned dogs weighing <4 kg with congenital heart disease (CHD). Dogs had TEE performed with a microprobe (10T-D, GE Medical) and intracardiac echocardiography (ICE) catheter-based probe (AcuNav™, Biosense Webster) in the esophagus in alternating order. Ease of placement, ability to acquire images of the CHD, image quality, and probe limitations were recorded.

RESULTS

Median weight was 2.4 kg (range, 1.0-3.2). Congenital abnormalities included patent ductus arteriosus (n = 9) and pulmonary valve stenosis (n = 1). The 10T-D microprobe was easy to place (n = 8) or achievable with gentle manipulation (n = 2), and image quality of the CHD was optimal (n = 8), adequate (n = 1), or poor (n = 1). The ICE probe was difficult to place in the esophagus even with an external support system (n = 9) or could not be placed (n = 1), and image quality of the CHD was optimal (n = 2), adequate (n = 3), or poor (n = 5). Both probes provided images in a 1.0-kg dog. Probe limitations included lack of lateral motion (microprobe), the need for an external support system (ICE probe) and inability to consistently maintain contact with the esophagus (ICE probe).

CONCLUSION

The 10T-D microprobe provided high-quality TEE images more consistently than the ICE probe in the majority of dogs in this study; however, the lack of lateral motion can diminish its utility in some dogs.

Congenital ventricular outflow tract obstructions in Boxer dogs: Results of a 17-year cardiovascular breed screening program in France (3126 dogs)

INTRODUCTION

Ventricular outflow tract obstructions including aortic (AS) and pulmonic stenosis (PS) are the most common canine congenital heart diseases, with Boxer dogs being predominantly affected. This has led to the French Boxer club adopting a mandatory national control program against AS and PS. The objective of this retrospective study was to analyze the results of 17 years of this cardiovascular breed screening program (2005-2021).

MATERIALS AND METHODS

The records of untreated and non-anesthetized adult Boxer dogs screened between 2005 and 2021 were retrospectively reviewed. All dogs underwent physical examination and standard transthoracic echocardiography with concomitant ECG tracing. All examinations were reviewed by one single board-certified specialist in cardiology.

RESULTS

Out of the 3126 dogs screened during the study period, 3001 dogs (female:male sex ratio = 2.2, median age [IQR] = 1.6 years [1.2-2.1]) were recruited for data analysis. A total of 218 operators were involved in the screening program. For most Boxer dogs (i.e., 93.8% for AS and 94.5% for PS), a single examination was required to obtain a definitive cardiac status, although most operators were non-specialist general practitioners. A left basilar systolic heart murmur was detected in all dogs with AS and PS, but also in 7.4% dogs free of heart diseases. A significantly higher proportion of the latter was detected when operators were board-certified specialists (P<0.001). Lastly, when comparing the start and the end of the breeding program, among dogs diagnosed with AS and PS (n = 364) in a French referral cardiology center, Boxer went from the 1st affected breed by AS to the 3rd, and from the 3rd affected breed by PS to the 6th.

CONCLUSION

This 17-year screening program has experienced a strong involvement of veterinarians, breeders, and owners throughout France. This may have contributed to reduce AS and PS prevalence in Boxer dogs at the studied referral cardiology center.

Transjugular Patent Ductus Arteriosus Occlusion in Seven Dogs Using the Amplatzer Vascular Plug II

Simple Summary

This study outlines the authors’ experience using the Amplatzer Vascular Plug II device for occlusion of patent ductus arteriosus (PDA) in dogs through a right transjugular approach, never before described in veterinary medicine for this purpose. The obtained results demonstrate that the use of the Amplatzer Vascular Plug II via a transvenous right jugular approach is a feasible and effective method, even in small-sized patients. The authors’ experience is that the transvenous approach is a safe and effective method for PDA occlusion in dogs. Furthermore, the right jugular approach provides easier and faster vascular access than the femoral one. The authors affirm that this approach, together with the properties of the Amplatzer Vascular Plug II and its wide size selection, potentially provide a novel method that can complement the current available methods for transcatheter PDA occlusion.

Abstract

Although vascular plugs for the closure of patent ductus arteriosus (PDA) have been validated in dogs, studies are lacking on its use as a first-choice device with a transjugular approach. The present case series describes the transvenous right jugular embolization of PDA using an Amplatzer Vascular Plug II in seven dogs of different ages, breeds, and body weights. Complete closure of the PDA was demonstrated in all cases. All dogs showed significant hemodynamic reduction of pulmonary overcirculation and left heart size after the procedure and at following echocardiographic check-ups. Transjugular PDA occlusion using an Amplatzer Vascular Plug II can thus be considered as a safe alternative to the arterial or venous femoral approach using an Amplatzer canine ductal occluder (ACDO), particularly in puppies with small femoral vessels.

Effect of preoperative administration of atenolol to dogs with pulmonic stenosis undergoing interventional procedures

Background

Beta‐blockade is sometimes used in dogs with pulmonic stenosis with the intent of reducing frequency of ventricular arrhythmias during right heart catheterization.

Objectives

To evaluate if pretreatment with atenolol reduces frequency of ventricular arrhythmias, anesthetist interventions, or shortens procedure time.

Animals

Thirty dogs with pulmonic stenosis scheduled for interventional procedures.

Methods

Single center, prospective, randomized, open‐label study. Dogs were randomized to treatment with atenolol or no treatment preoperatively for a minimum of 10 days. Variables recorded included heart rate, arrhythmias and complexity, total procedure time and administration of antiarrhythmic treatment, vasopressors, positive chronotropes, or fluid boluses.

Results

Fifteen dogs were enrolled in each group. Dogs receiving atenolol had lower mean heart rates during the procedure (atenolol 100 ± 11 bpm vs untreated 115 ± 19 bpm, P = .01). There were no significant differences between the atenolol and untreated groups in the frequency of ventricular ectopic complexes (535 [6‐5296] vs 553 [79‐2863], P = .9), ventricular couplets (46 [0‐481] vs 29 [3‐121], P = .59), ventricular triplets (20 [0‐265] vs 16 [1‐82], P = .67), ventricular tachycardia (8 [0‐224] vs 8 [1‐118], P = .99), proportion exhibiting R‐on‐T phenomenon (11/15 vs 14/15, P = .33), proportion receiving intraoperative lidocaine (1/15 vs 3/15, P = .6), vasopressors/positive chronotropes (11/15 vs 5/15, P = .06), or fluid boluses (12/15 vs 7/15, P = .13). The procedure time was similar (atenolol 41 [23‐68] min vs untreated 35 [18‐98] min, P = .91).

Conclusions and Clinical Importance

No benefit of preoperative atenolol treatment was identified in this small group of dogs.

Red blood cell abnormalities occur in dogs with congenital ventricular outflow tract obstruction

OBJECTIVE

To document RBC abnormalities in dogs with congenital ventricular outflow tract obstruction.

ANIMALS

62 dogs with pulmonic stenosis (PS) or aortic stenosis (AS) and 20 control dogs were recruited.

PROCEDURES

The proportions of RBCs that were schistocytes, acanthocytes, and keratocytes were assessed. Complete blood cell counts were performed. Tested variables included hemoglobin concentration, hematocrit, and erythrocyte count.

RESULTS

Median (interquartile range [IQR]) peak systolic Doppler-derived trans-stenotic pressure gradient (∆P) values were 161 mm Hg (108 to 215 mm Hg) and 134 mm Hg (125 to 165 mm Hg) for dogs with PS and AS, respectively. Hematologic abnormalities were detected in most dogs with AS or PS (54/62 [87%]) versus 8/20 [40%] in control dogs, with schistocytes found in 40 of 62 (65%; median, 0.1% RBCs; IQR, 0% to 0.3%), acanthocytes in 29 of 62 (47%; median, 0.3% RBCs; IQR, 0% to 0.9%), keratocytes in 39 of 62 (63%; median, 0% RBCs; IQR, 0% to 0.2%), and hemolytic anemia in 4 dogs with PS. No significant association was identified between these abnormalities and ∆P. However, 3 of 4 dogs with anemia had a ∆P > 200 mm Hg (range, 242 to 340 mm Hg). The dog with the highest ∆P value also had the most severe anemia and schistocytosis, and both resolved after balloon valvuloplasty.

CLINICAL RELEVANCE

Poikilocytosis is common in dogs with congenital ventricular outflow tract obstruction, with anemia only observed in few dogs with high ∆P values.

Genetics of canine subvalvular aortic stenosis (SAS)

Subvalvular aortic stenosis (SAS) is one of the most common congenital heart defects of dogs. The disease is characterized by obstruction of the left ventricular outflow tract, resulting in pressure overload on the left ventricle. The etiology of obstruction is a fibromuscular nodule, ridge, or ring of tissue that increases aortic outflow tract velocity. This review is focused on the prevalence, inheritance pattern, and current genetic insights of canine SAS. The prevalence of this disease was reported at 4.7 % in a large veterinary referral hospital. The mode of inheritance for this disease has also been described in breeds with a high disease prevalence such as the Bullmastiff, Bouvier des Flandres, Dogue de Bordeaux, Golden Retriever, Newfoundland, and Rottweiler. Genetic investigations seeking to identify causative mutations for SAS are lacking with only a single published variant associated with SAS in Newfoundlands.

Expression Profile of Circulating MicroRNAs in Dogs With Cardiac Hypertrophy: A Pilot Study

This study aimed to identify the expression profile of circulating microRNAs in dogs with eccentric or concentric cardiac hypertrophy. A total of 291 microRNAs in serum samples of five dogs with myxomatous mitral valve degeneration (MMVD) and five dogs with pulmonic stenosis (PS) were compared with those of five healthy dogs using microarray analysis. Results of microarray analysis revealed up-regulation of cfa-miR-130b [fold change (FC) = 2.13, p = 0.014), down-regulation of cfa-miR-375 (FC = 1.51, p = 0.014), cfa-miR-425 (FC = 2.56, p = 0.045), cfa-miR-30d (FC = 3.02, p = 0.047), cfa-miR-151 (FC = 1.89, p = 0.023), cfa-miR-19b (FC = 3.01, p = 0.008), and cfa-let-7g (FC = 2.53, p = 0.015) in MMVD group which showed eccentric cardiac hypertrophy, up-regulation of cfa-miR-346 (FC = 2.74, p = 0.032), down-regulation of cfa-miR-505 (FC = 1.56, p = 0.016) in PS group which showed concentric cardiac hypertrophy, and down-regulation of cfa-miR-30c (FC = 3.45, p = 0.013 in MMVD group; FC = 3.31, p = 0.014 in PS group) and cfa-let-7b (FC = 11.42, p = 0.049 in MMVD group; FC = 5.88, p = 0.01 in PS group) in both MMVD and PS groups. In addition, the unsupervised hierarchical clustering of differentially expressed microRNAs in each group resulted in complete separation of healthy dogs from dogs with heart diseases. Therefore, eleven microRNAs among 291 microRNAs were identified as differentially expressed circulating microRNAs related to MMVD or PS in dogs. This pilot study demonstrates that the microRNAs identified in this study could be possible candidates for novel biomarker or therapeutic target related to cardiac hypertrophy in dogs.

Clinical features and outcome of dogs and cats with bidirectional and continuous right-to-left shunting patent ductus arteriosus

Background

Studies describing the clinical progression of animals with reverse patent ductus arteriosus (PDA) are lacking.

Objectives

To describe the signalment, presenting signs, echocardiographic features, and survival in a group of dogs and cats with bidirectional and continuous right‐to‐left PDA.

Animals

Forty‐six client‐owned animals included, comprising 43 dogs and 3 cats with bidirectional or continuous right‐to‐left PDA.

Methods

Retrospective multicenter study. Medical records and echocardiographic findings reviewed from animals diagnosed with bidirectional or continuous right‐to‐left PDA. Impact of ductal morphology, spectral Doppler flow profile, PCV, sildenafil treatment at presentation, sildenafil dose, severity of pulmonary hypertension, general anesthesia with or without surgery and the presence of right‐sided congestive heart failure (R‐CHF) on crude mortality rate were evaluated via Mantel‐Cox log rank comparison of Kaplan‐Meier survival curves. Univariable and multivariable Cox proportional hazards analysis was performed, and hazard ratio (HR) (95% confidence intervals [CI]) was presented.

Results

Hindlimb collapse was the most common presenting sign in dogs (n = 16). Clinical signs in cats were variable. Median survival time was 626 days in dogs (range 1‐3628 days). Dogs with R‐CHF had a shorter median survival time (58 days vs 1839 days, P = .03). Dogs treated with sildenafil at initial presentation survived longer (1839 days vs 302 days, P = .03), which was the only independent predictor of survival (HR 0.35, CI 0.15‐0.86, P = 0.021).

Conclusions and Clinical Importance

Dogs and cats with reverse PDA have a variable clinical presentation and prognosis. Survival time was longer in animals prescribed sildenafil at diagnosis. Dogs with R‐CHF at presentation have a worse overall outcome.

Congenital Heart Disease in Dogs: A Retrospective Study of 95 Cases

The aim of the study was to estimate the prevalence of congenital heart diseases in dogs attending 2 veterinary hospitals in Brazil and to identify possible associations between these conditions and epidemiological characteristics. A retrospective study was carried out in the cardiology sections of 2 veterinary hospitals during a period of 70 months from January 2012 and October 2017. Of a total of 6710 dogs that attended the cardiology sections of the hospitals, 109 congenital heart diseases were identified in 95 patients, representing a prevalence of 1.6%. Findings consistent with previous literature included subaortic stenosis and pulmonic stenosis as the most commonly diagnosed conditions, in addition to a higher predisposition of females to patent ductus arteriosus (PDA). In contrast, the novel findings included a higher prevalence of atrial septal defect and a lower prevalence of patent ductus arteriosus. The majority of the animals included were over 1 year of age at the time of diagnosis (67%) especially in the subaortic stenosis group. Also, a predisposition of the Maltese to ventricular septal defect was observed. The information obtained in the present study contributes to research that describes epidemiological characteristics of dogs with congenital heart disease in a previously unreported location.

Mitral valve dysplasia in eight English Springer Spaniels

INTRODUCTION

To describe the signalment, physical examination, and echocardiographic findings of a series of English Springer Spaniels (ESSs) diagnosed with congenital mitral valve dysplasia (MD).

ANIMALS

Eight client-owned ESSs with congenital MD referred for murmur investigation and/or suspected congestive heart failure (CHF).

MATERIALS AND METHODS

Retrospective case series. Medical records and echocardiograms were reviewed to collect relevant data. Echocardiograms were assessed for the following abnormalities consistent with MD: thickened valve leaflets or leaflet tips, a 'hockey stick' appearance to the valve leaflets, abnormal length of one leaflet with respect to the other, and tethering of one or both leaflets to the papillary muscles.

RESULTS

All eight dogs showed the typical echocardiographic lesions associated with MD: thickened leaflet tips (5/8), 'hockey stick' appearance (5/8), elongated anterior leaflet (4/8), tethering of one or both leaflets (7/8). Seven of the eight dogs presented in CHF. Six of the eight dogs had left ventricular dilation in both systole and diastole. Two of the eight dogs had reduced systolic function as assessed by ejection fraction/fractional shortening; however end-systolic volume index was increased in 6/8 dogs. Two dogs subsequently developed atrial fibrillation.

CONCLUSIONS

Congenital MD should be considered in ESSs with a left-sided apical systolic murmur, particularly in younger dogs. The valve changes seen are similar to those reported in other breeds with MD (thickened leaflet tips, hockey stick appearance to open leaflet tips, abnormal leaflet tethering, abnormally shaped leaflets) and may result in marked remodeling and CHF.

Endocardial fibroelastosis in a dog with congestive heart failure

In a 6-month-old, intact female, Japanese spitz presenting with severe dyspnea, lung ultrasonography revealed confluent B lines associated with severe echocardiographic left sided volume overload and systolic dysfunction. A congenital shunt or valvular dysplasia was not demonstrable. On electrocardiogram, there was a constant sinus rhythm, respectively sinus tachycardia. Cardiac troponin I was normal. Within 2 days of admission, the dog died of heart failure. On macroscopic postmortem examination, the left ventricle and atrium were markedly dilated, and the left ventricular endocardium had a mild diffuse whitish appearance. Histopathology revealed moderate to severe thickening of the left ventricular endocardium, composed mostly of abundant elastic fibers and fewer collagen fibers, diagnostic for endocardial fibroelastosis. In addition, there were mild degenerative changes of the atrioventricular valves. Endocardial fibroelastosis is a rare congenital disease and should be considered in a young dog if more common causes of echocardiographic dilated cardiomyopathy phenotype are ruled out.

Epidemiological study of congenital heart diseases in dogs: Prevalence, popularity, and volatility throughout twenty years of clinical practice

The epidemiology of Congenital Heart Diseases (CHDs) has changed over the past twenty years. This study aimed to evaluate the prevalence of CHDs in the population of dogs recruited in a single referral center (RC); compare the epidemiological features of CHDs in screened breeds (Boxers) versus non-screened (French and English Bulldogs, German Shepherds); investigate the association of breeds with the prevalence of CHDs; determine the popularity and volatility of breeds over a 20-year period; analysed the trends of the most popular breeds in the overall population of new-born dogs registered in the Italian Kennel Club (IKC) from 1st January 1997 to 31st December 2017. The RC's cardiological database was analysed, and 1,779 clinical records were included in a retrospective observation study. Descriptive statistics and frequencies regarding the most representative breeds and CHDs were generated. A logistic regression model was used to analyse the trends of the most common CHDs found in single and in cluster of breeds. The relationship between breed popularity and presence of CHDs was studied. The most common CHDs were Pulmonic Stenosis, Patent Ductus Arteriosus, Subaortic Stenosis, Ventricular Septal Defect, Aortic Stenosis, Tricuspid Dysplasia, Atrial Septal Defect, Double Chamber Right Ventricle, Mitral Dysplasia, and others less frequent. The most represented pure breeds were Boxer, German Shepherd, French Bulldog, English Bulldog, Maltese, Newfoundland, Rottweiler, Golden Retriever, Chihuahua, and others in lower percentage. Chihuahuas, American Staffordshire Terriers, Border Collies, French Bulldogs, and Cavalier King Charles Spaniel were the most appreciated all of which showed a high value of volatility. This study found evidence for the value of the screening program implemented in Boxers; fashions and trends influence dog owners' choices more than the worries of health problems in a breed. Effective breeding programs are needed in order to control the diffusion of CHDs without impoverishing the genetic pool.

Heart rhythm during episodes of collapse in boxers with frequent or complex ventricular ectopy

OBJECTIVES

To describe heart rhythm during collapse events in boxer dogs using ambulatory electrocardiogram and determine the predictive value of frequent or complex ventricular ectopy for collapse associated with ventricular tachycardia.

MATERIALS AND METHODS

A total of 659 ambulatory electrocardiogram recordings from 429 boxer dogs were identified from a database in the UK. Summary statistics described the frequency and complexity of ventricular ectopy during all recordings, recordings in which collapse occurred and associated boxer demographics. Positive predictive values were calculated to investigate whether frequent ventricular ectopy was useful to predict heart rhythm during episodes of collapse.

RESULTS

Of the 659 ambulatory electrocardiogram recordings, 250 recordings showed <50 single ventricular beats (Group 1), and frequent (≥50) or complex ventricular ectopy were observed in 409 recordings (Group 2). A total of 90 collapse events were observed in 72 ambulatory electrocardiograms from 68 dogs, comprising 30 dogs in Group 1 and 38 dogs in Group 2. In both groups, sinus rhythm was the most frequent collapse rhythm, followed by neurally mediated collapse and then ventricular tachycardia. The proportion of dogs that displayed ventricular tachycardia-associated episodic collapse given that they had frequent (≥50) or complex ventricular ectopy in the study population was 0.11 [95% confidence interval = 0.01 to 0.21].

CLINICAL SIGNIFICANCE

These results challenge the preconception that UK boxer dogs with collapse will have ventricular tachycardia and, consequently, the authors recommend definitive diagnosis of the cause of episodic collapse to guide selection of therapeutic drugs.

Epidemiological, clinical, and echocardiographic features, and outcome of dogs with Ebstein's anomaly: 32 cases (2002-2016)

INTRODUCTION/OBJECTIVES

Ebstein's anomaly (EA) is a congenital heart disease characterized by apical displacement of the tricuspid valve leaflets in the right ventricle. The objective of this retrospective study was to investigate the signalment, clinical features, echocardiographic findings, and outcome of dogs with EA.

ANIMALS, MATERIALS AND METHODS

Medical records of 40 dogs with EA were reviewed. Echocardiographic variables used to assess EA severity in human pediatrics were also evaluated (e.g. displacement index, Celermajer index, Carpentier class, and apex-mitral annulus:apex-tricuspid annulus distance ratio).

RESULTS

Labrador retriever was the most commonly recruited breed (24 of the 40 dogs, 60%). Eight of the 40 dogs with EA had hemodynamically compromising concurrent heart (n = 7) or respiratory diseases (n = 1). A right apical systolic heart murmur (median grade = 5/6) was detected in the remaining 32 dogs, without any other clinical sign related to EA in 19 of the 32 dogs (59%). Median (interquartile range) values of the displacement index and Celermajer index were 17.4 mm/m² (12.0-21.9) and 100% (50-130), respectively. Median time to all-cause death was 74 months, and 72% dogs (95% confidence interval, 50-86%) had not succumbed to cardiac death (CD) 160 months after diagnosis. Univariate analyses showed that the time from diagnosis to CD was associated with the presence of clinical signs, ascites, severe right atrial dilation, palpable thrill, and a Celermajer index ≥100%.

DISCUSSION

Right atrial enlargement is significantly associated with decreased survival time of dogs with EA although most may live for years and may not die from CD.

CONCLUSIONS

These results support medium to long-term survival for most dogs with EA.

Applied Veterinary Informatics: Development of a Semantic and Domain-Specific Method to Construct a Canine Data Repository

Animals are used to study the pathogenesis of various human diseases, but typically as animal models with induced disease. However, companion animals develop disease spontaneously in a way that mirrors disease development in humans. The purpose of this study is to develop a semantic and domain-specific method to enable construction of a data repository from a veterinary hospital that would be useful for future studies. We developed a two-phase method that combines semantic and domain-specific approaches to construct a canine data repository of clinical data collected during routine care at the Matthew J Ryan Veterinary Hospital of the University of Pennsylvania (PennVet). Our framework consists of two phases: (1) a semantic data-cleaning phase and (2) a domain-specific data-cleaning phase. We validated our data repository using a gold standard of known breed predispositions for certain diseases (i.e., mitral valve disease, atrial fibrillation and osteosarcoma). Our two-phase method allowed us to maximize data retention (99.8% of data retained), while ensuring the quality of our result. Our final population contained 84,405 dogs treated between 2000 and 2017 from 194 distinct dog breeds. We observed the expected breed associations with mitral valve disease, atrial fibrillation, and osteosarcoma (P < 0.05) after adjusting for multiple comparisons. Precision ranged from 60.0 to 83.3 for the three diseases (avg. 74.2) and recall ranged from 31.6 to 83.3 (avg. 53.3). Our study describes a two-phase method to construct a clinical data repository using canine data obtained during routine clinical care at a veterinary hospital.

Successful transcatheter pulmonary valve implantation in a dog: first clinical report

Transcatheter pulmonary valve (TPV) implantation is a therapeutic approach approved by the United States Food and Drug Administration for human patients with failing pulmonary conduits in 2010 and for failing bioprosthetic surgical pulmonary valves in 2017. We report here the first successful transcatheter implantation of a stented valve in a pulmonary position in a dog with congenital pulmonary valve disease. A 3-year-old, 10.9 kg, client-owned Beagle dog was referred for a follow-up visit after a percutaneous balloon valvuloplasty performed 22 months before for treatment of a severe type A valvular pulmonary stenosis. The Doppler-derived peak pressure gradient was 348 mmHg before the procedure and 66 mmHg 24 h after. The dog was lethargic. Echocardiography revealed a mild pulmonary stenosis (pressure gradient-43 mmHg), severe pulmonary regurgitation, and secondary severe right ventricular and right atrial dilation. Worsening of right heart dilation was observed 2 months later despite medical therapy. A TPV implantation was performed using a prestented Melody bovine jugular bioprosthetic valve. The dog recovered uneventfully and was discharged 10 days after the procedure. Right heart dilation resolved within 15 days. The dog was doing well 7 months after valve implantation. This case demonstrates that TPV implantation with a stented valve is technically feasible in dogs with severe pulmonary valve disease. Stringent postoperative care, with particular attention to thrombosis and infectious endocarditis, and appropriate sizing and positioning of the valve stent are keys to the success of this procedure.

A pilot study evaluating cutting and high-pressure balloon valvuloplasty for dysplastic pulmonary valve stenosis in 7 dogs

INTRODUCTION

This case series describes early experience and technical aspects of cutting balloon dilation followed by high-pressure balloon pulmonary valvuloplasty in dogs with dysplastic pulmonary valve stenosis.

ANIMALS

Seven client-owned dogs were enrolled in this study.

METHODS

Dogs were prospectively enrolled based on echocardiographic diagnosis of severe pulmonary valve dysplasia, defined as marked valve thickening with variable degrees of annular hypoplasia or subvalvar fibrous obstruction and a peak echocardiography-derived transpulmonary pressure gradient higher than 100 mmHg. Preinterventional and postinterventional hemodynamic data and transthoracic pressure gradients were obtained for all dogs. Recheck echocardiography varied in timing by client convenience, with maximum follow-up 35 months after intervention.

RESULTS

No intraprocedural or periprocedural mortality was observed. The only major complication was partial avulsion of a cutting blade related to exceeding recommended burst pressure of the device, which was not associated with obvious clinical consequence. Invasive hemodynamic measurements demonstrated an average reduction of 46% in peak systolic right ventricular-to-pulmonary artery pressure gradient (range, 31-77%). The echocardiographic results 24 h after procedure demonstrated an average reduction in pressure gradient of 43% (range, 20-66%), with late follow-up demonstrating an average reduction of 35% (range, 10-57%) compared with preprocedural echocardiography.

CONCLUSIONS

This procedure is a feasible therapeutic transcatheter intervention for dogs with dysplastic pulmonary valves and appears safe in this small cohort. The ideal selection criteria and rate of restenosis for this procedure is under investigation, and long-term follow-up and a large, randomized, controlled study are necessary to demonstrate efficacy.

Valvular aortic stenosis in three cats

Aortic stenosis affects 0.028% of cats in a shelter population, with valvular aortic stenosis compromising almost half of these cases. Of congenital heart diseases reported in cats, aortic stenosis is the second most common one, affecting 17% of these cases. Existing literature on valvular aortic stenosis is scant, and thus, presentation and prognosis of affected animals is poorly understood. In this case series, we describe three cats with confirmed valvular aortic stenosis. All cases were diagnosed echocardiographically, and all three had visible aortic valve leaflet fusion and a poststenotic dilation of the ascending aorta. Congestive heart failure developed in all three cases, and prognosis was poor. This case report highlights the existence of aortic valve dysplasia in cats and may allow clinicians a better understanding of the clinical presentation of this congenital abnormality.

Speckle-Tracking Echocardiography in Dogs With Patent Ductus Arteriosus: Effect of Percutaneous Closure on Cardiac Mechanics

BACKGROUND

Patent ductus arteriosus (PDA) is 1 of the most common congenital heart defects in dogs and percutaneous closure is effective in achieving ductal closure; PDA closure is associated with abrupt hemodynamic changes.

HYPOTHESIS

A marked decrease in standard parameters of systolic function as assessed by M- or B-mode echocardiography after PDA closure was identified in previous studies. Speckle tracking echocardiography can provide further insight into the effect of PDA closure on cardiac mechanics in dogs affected by PDA.

ANIMALS

Twenty-five client-owned dogs with PDA.

METHODS

Prospective study. Dogs were recruited over a 2-year period. Complete echocardiographic evaluation was performed before and 24 hours after PDA closure, including standard (end-diastolic volumes indexed to body surface area in B- and M-mode [EDVIB /M ], end-systolic volumes indexed to body surface area in B- and M-mode [ESVIB /M ], allometric scaling in diastole [AlloD] and systole [AlloS], pulmonary flow to systemic flow [Qs/Qp], ejection fraction [EF], and fractional shortening [FS]), and advanced speckle-tracking echocardiography (STE): global longitudinal, radial, circumferential and transverse strain (S), and strain rate (SR).

RESULTS

Patent ductus arteriosus closure was associated with statistically significant decreases in EDVIM /B and ESVIM /B , AlloD and AlloS, SI, EF, and FS. A statistically significant decrease in the absolute values of radial, transverse, and circumferential S and SR was observed, whereas longitudinal S and SR did not change significantly.

CONCLUSION AND CLINICAL IMPORTANCE

Patent ductus arteriosus closure by percutaneous approach is associated with marked decreases of conventional echocardiographic parameters as a result of the changes in loading conditions, but no evidence of systolic dysfunction was identified by means of STE, as none of the S and SR values were below reference ranges. In the short term, contractility is enhanced in the long axis (long S/SR values were not statistically different before and after closure) and decreases to normal values in short axis (circumferential, radial, and transversal S/SR decreased to normal reference range).

Echocardiographic Assessment of Cardiac Function by Conventional and Speckle-Tracking Echocardiography in Dogs with Patent Ductus Arteriosus

Background

Patent ductus arteriosus (PDA) is one of the most common congenital heart defects in dogs. Advanced echocardiographic techniques such as speckle‐tracking echocardiography (STE) have not been extensively used to evaluate cardiac function in affected dogs.

Hypothesis

Advanced echocardiographic techniques are more sensitive than standard echocardiographic techniques in analyzing systolic function in dogs with PDA.

Animals

Forty‐four client‐owned dogs: 34 dogs with PDA (preoperative evaluation) and 10 healthy sex‐ and weight‐matched controls.

Methods

Prospective study. Dogs were recruited over a 2‐year period. Complete echocardiographic evaluation was performed, including conventional (end‐diastolic volumes indexed to body surface area in B and M‐mode [EDVI_B/M], end‐systolic volumes indexed to body surface area in B and M‐mode [ESVI_B/M], allometric scaling in diastole and systole [AlloD/S], pulmonary flow to systemic flow [Qp/Qs], ejection fraction [EF] and fractional shortening [FS]) and speckle‐tracking echocardiography ([STE]: global longitudinal, radial and circumferential strain [S] and strain rate [SR]).

Results

Dogs with PDA had significantly different EDVI_B/M, ESVI_B/M, AlloD/S, Qp/Qs and all STE‐derived parameters (global longitudinal S and SR, global circumferential S and SR, global radial S and SR)compared to healthy dogs. No correlation was found between standard techniques (EDVI_B/M, ESVI_B/M, AlloD/S, Qp/Qs) and STE‐derived parameters (global longitudinal, circumferential and radial S and SR).

Conclusion and Clinical Importance

Conventional parameters routinely used to assess systolic function (EF and FS) were not different between the groups; STE‐derived parameters identified subtle changes in cardiac systolic function and contractility between the 2 groups of dogs. Based on these findings, STE may be a more appropriate tool to assess cardiac contractility in dogs with PDA.

Tricuspid valve dysplasia: A retrospective study of clinical features and outcome in dogs in the UK

The objective of this study was to determine the demographic, clinical and survival characteristics and to identify risk factors for mortality due to tricuspid valve dysplasia in UK dogs. Records of client-owned dogs diagnosed with tricuspid valve dysplasia at a referral centre were retrospectively reviewed. Only dogs diagnosed with tricuspid valve dysplasia based on the presence of a right-sided heart murmur identified prior to one year of age, and confirmed with Doppler echocardiography, were included. Dogs with concomitant cardiac diseases, pulmonary hypertension and/or trivial tricuspid regurgitation were excluded. Analysed data included signalment, reason for presentation, clinical signs, electrocardiographic and echocardiographic features, survival status and cause of death. Survival times and risk factors for mortality were evaluated using Kaplan-Meier curves and Cox regression. Eighteen dogs met inclusion criteria. Border collies were over-represented (p= 0.014). Dogs were most frequently referred for investigation of heart murmur. The most common arrhythmia was atrial fibrillation (n=3). Median survival time from diagnosis of tricuspid valve dysplasia was 2775 days (range 1-3696 days; 95% CI 1542.41-4007.59) and from onset of right-sided congestive heart failure was 181 days (range 1-2130 days; 95% CI 0-455.59). Syncope was the sole risk factor for cardiac death. In this population of UK dogs, tricuspid valve dysplasia was uncommon but, when severe, frequently led to right-sided congestive heart failure. Prognosis was favourable for mild and moderate tricuspid dysplasia. Survival time was reduced with right-sided congestive heart failure but varied widely. Risk of cardiac death was significantly increased if syncope had occurred.

Correlation of neuter status and expression of heritable disorders

BACKGROUND

Gonadectomy, or neutering, is a very common surgery for dogs having many positive effects on behavior, health, and longevity. There are also certain risks associated with neutering including the development of orthopedic conditions, cognitive decline, and a predisposition to some neoplasias. This study was designed specifically to identify if a correlation exists between neuter status and inherited conditions in a large aggregate cohort of dogs representing many different breeds.

RESULTS

Neutered dogs were at less risk for early and congenital conditions (aortic stenosis, early onset cataracts, mitral valve disease, patent ductus arteriosus, portosystemic shunt, and ventricular septal defect) than intact dogs. Neutering was also associated with reduced risk of dilated cardiomyopathy and gastric dilatation volvulus in males. Neutering was significantly associated with an increased risk for males and females for cancers (hemangiosarcoma, hyperadrenocorticism, lymphoma, mast cell tumor, and osteosarcoma), ruptured anterior cruciate ligament and epilepsy. Intervertebral disk disease was associated with increased risk in females only. For elbow dysplasia, hip dysplasia, lens luxation, and patellar luxation neutering had no significant effect on the risk for those conditions. Neutering was associated with a reduced risk of vehicular injury, a condition chosen as a control.

CONCLUSIONS

In this retrospective study, several conditions showed an increased risk associated with neutering whereas other conditions were less likely to be expressed in neutered dogs. The complexity of the interactions between neutering and inherited conditions underscores the need for reflective consultation between the client and the clinician when considering neutering. The convenience and advantages of neutering dogs that will not be included in a breeding program must be weighed against possible risk associated with neutering.

Dissecting the Role of the Extracellular Matrix in Heart Disease: Lessons from the Drosophila Genetic Model

The extracellular matrix (ECM) is a dynamic scaffold within organs and tissues that enables cell morphogenesis and provides structural support. Changes in the composition and organisation of the cardiac ECM are required for normal development. Congenital and age-related cardiac diseases can arise from mis-regulation of structural ECM proteins (Collagen, Laminin) or their receptors (Integrin). Key regulators of ECM turnover include matrix metalloproteinases (MMPs) and their inhibitors, tissue inhibitors of matrix metalloproteinases (TIMPs). MMP expression is increased in mice, pigs, and dogs with cardiomyopathy. The complexity and longevity of vertebrate animals makes a short-lived, genetically tractable model organism, such as Drosophila melanogaster, an attractive candidate for study. We survey ECM macromolecules and their role in heart development and growth, which are conserved between Drosophila and vertebrates, with focus upon the consequences of altered expression or distribution. The Drosophila heart resembles that of vertebrates during early development, and is amenable to in vivo analysis. Experimental manipulation of gene function in a tissue- or temporally-regulated manner can reveal the function of adhesion or ECM genes in the heart. Perturbation of the function of ECM proteins, or of the MMPs that facilitate ECM remodelling, induces cardiomyopathies in Drosophila, including cardiodilation, arrhythmia, and cardia bifida, that provide mechanistic insight into cardiac disease in mammals.

Epidemiology, presentation and population genetics of patent ductus arteriosus (PDA) in the Dutch Stabyhoun dog

Background

Patent ductus arteriosus (PDA) is one of the most common congenital heart defects in dogs and is considered to be a complex, polygenic threshold trait for which a female sex predisposition has been described. Histological studies in dogs suggest that smooth muscle hypoplasia and asymmetry of the ductus tissue is the major cause of PDA. The Stabyhoun population is small and a predisposition for PDA has been suggested. The aims of this study were to describe the incidence, presentation from a clinical and histopathological perspective, and the population genetics of PDA in the Dutch Stabyhoun population.

Results

Forty-six cases were identified between 2000 and 2013. Between 2009 and 2012 the birth incidence of PDA in the Stabyhoun breed was 1.05 %. We estimated this to be 7–13 times higher than expected in the general dog population. Twelve of the 46 cases were part of a litter in which more than one sibling was affected. There was no sex predilection in our case cohort. Dogs diagnosed in adulthood showed severe cardiomegaly. The mean inbreeding coefficient of the reference population of Stabyhoun dogs was 31.4 % and the actual and effective numbers of founders were 14 and 6.5, respectively. The heritability of PDA was 0.51 (±0.09) for the reference population and 0.41 (±0.10) for the phenotyped population. Histopathology of sections of the PDA from two dogs showed findings similar to those described in other breeds although the smooth muscle of the ductus adjacent to the pulmonary artery appeared more hypoplastic than that in the ductus adjacent to the aorta.

Conclusions

The Stabyhoun breed shows a strong predisposition for PDA. Apart from the absence of a higher incidence in females, no other significant features distinguish PDA in Stabyhouns from the condition in other dog breeds. Heritability and the mean inbreeding coefficient are both very high making the Dutch Stabyhoun breed particularly suited to the study of inherited risk factors for PDA.

Transesophageal echocardiography to diagnose anomalous right coronary artery type R2A in dogs

OBJECTIVES

To assess the feasibility of transesophageal echocardiography (TEE) as an alternative to angiography for the diagnosis of R2A coronary artery (CA) abnormalities.

ANIMALS

Twenty-two dogs with a diagnosis of type R2A CA anomaly were reviewed/analyzed.

METHODS

A retrospective study of case records. Transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), angiography, and follow-up investigations of pulmonic stenosis (PS) with R2A CA were carried out to compare different diagnostic methods.

RESULTS

Based on the TTE morphology, PS with an aberrant CA was suspected in all dogs (n = 22) and later confirmed by angiography in 18 cases (18/22), and necropsy in two cases (2/22). In 12 cases (12/22), TEE and angiography were both performed and confirmed the diagnosis of an R2A anomaly. Two cases (2/22) were diagnosed only with TEE.

CONCLUSIONS

Transesophageal echocardiography may be considered an effective tool to diagnose CA abnormalities, in particular when TTE is inconclusive. Transesophageal echocardiography offers detailed and easily reproducible views of coronary ostia, and the spatial relationship between the right common CA and the great arteries. Although it is not possible to define the course of the more distal coronary branches, TEE has proven reliable in recognizing those elements that can constitute a risk for the execution of a balloon valvuloplasty (BV). Therefore, TEE can be used to confirm this type of CA anomaly and prevent a BV, which is contraindicated in these cases. In addition, TEE avoids any further vascular access, radiation exposure, and contrast medium injection.

Ten inherited disorders in purebred dogs by functional breed groupings

Background

Analysis of 88,635 dogs seen at the University of California, Davis Veterinary Medical Teaching Hospital from 1995 to 2010 identified ten inherited conditions having greater prevalence within the purebred dog population as compared to the mixed-breed dog population: aortic stenosis, atopy/allergic dermatitis, gastric dilatation volvulus (GDV), early onset cataracts, dilated cardiomyopathy, elbow dysplasia, epilepsy, hypothyroidism, intervertebral disk disease (IVDD), and hepatic portosystemic shunt. The objective of the present study was to ascertain if disorders with higher prevalence in purebreds were restricted to particular breed group classifications within the purebred population, specifically the American Kennel Club breed grouping or groups with genomic similarities based upon allele sharing. For each disorder, healthy controls seen at the hospital during that same time period were matched for age, weight, and sex to each affected dog to determine risk of disease presentation in the purebred group as compared to that of the mixed-breed population. To enhance reliability of the analyses, sampling of matched healthy to affected dogs was repeated 50 times. For each comparison, the purebred subgroups to mixed-breed odds ratio was determined as was the mean P value used to test this ratio.

Results

For aortic stenosis, GDV, early onset cataracts, dilated cardiomyopathy, elbow dysplasia, epilepsy, and portosystemic shunt, most purebred groups were not statistically distinct from the mixed-breed population with higher prevalence in purebreds restricted to distinct subsets of purebred dogs. The conditions of atopy/allergic dermatitis, hypothyroidism, and IVDD were more pervasive across the purebred population with many groups having higher prevalence than the mixed-breed population. The prevalence of IVDD in purebred terrier groups was statistically lower than that observed for mixed-breed dogs.

Conclusions

The results offer an assessment of the distribution of inherited disorders within purebred dogs and illustrate how mixed-breed and subpopulations of purebred dogs do not differ statistically in prevalence for certain disorders. Some disorders appear linked to common ancestors providing insight into disease allele origin whereas others may be due to selection for common structural morphology. Knowledge of the origin of a condition may aid in reducing its prevalence in the dog population as a whole.

Electronic supplementary material

The online version of this article (doi:10.1186/s40575-015-0021-x) contains supplementary material, which is available to authorized users.

A single codon insertion in PICALM is associated with development of familial subvalvular aortic stenosis in Newfoundland dogs

Familial subvalvular aortic stenosis (SAS) is one of the most common congenital heart defects in dogs and is an inherited defect of Newfoundlands, golden retrievers and human children. Although SAS is known to be inherited, specific genes involved in Newfoundlands with SAS have not been defined. We hypothesized that SAS in Newfoundlands is inherited in an autosomal dominant pattern and caused by a single genetic variant. We studied 93 prospectively recruited Newfoundland dogs, and 180 control dogs of 30 breeds. By providing cardiac screening evaluations for Newfoundlands we conducted a pedigree evaluation, genome-wide association study and RNA sequence analysis to identify a proposed pattern of inheritance and genetic loci associated with the development of SAS. We identified a three-nucleotide exonic insertion in phosphatidylinositol-binding clathrin assembly protein (PICALM) that is associated with the development of SAS in Newfoundlands. Pedigree evaluation best supported an autosomal dominant pattern of inheritance and provided evidence that equivocally affected individuals may pass on SAS in their progeny. Immunohistochemistry demonstrated the presence of PICALM in the canine myocardium and area of the subvalvular ridge. Additionally, small molecule inhibition of clathrin-mediated endocytosis resulted in developmental abnormalities within the outflow tract (OFT) of Xenopus laevis embryos. The ability to test for presence of this PICALM insertion may impact dog-breeding decisions and facilitate reduction of SAS disease prevalence in Newfoundland dogs. Understanding the role of PICALM in OFT development may aid in future molecular and genetic investigations into other congenital heart defects of various species.

Tetralogy of Fallot and atrial septal defect in a white Bengal Tiger cub (Panthera tigris tigris)

A 3-week-old female white Bengal Tiger cub (Panthera tigris tigris) presented with acute onset tachypnoea, cyanosis and hypothermia. The cub was severely hypoxaemic with a mixed acid-base disturbance. Echocardiography revealed severe pulmonic stenosis, right ventricular hypertrophy, high membranous ventricular septal defect and an overriding aorta. Additionally, an atrial septal defect was found on necropsy, resulting in the final diagnosis of Tetralogy of Fallot with an atrial septal defect (a subclass of Pentalogy of Fallot). This report is the first to encompass arterial blood gas analysis, thoracic radiographs, echocardiography and necropsy findings in a white Bengal Tiger cub diagnosed with Tetralogy of Fallot with an atrial septal defect.

What the Inbred Scandinavian Wolf Population Tells Us about the Nature of Conservation

The genetic aspects of population health are critical, but frequently difficult to assess. Of concern has been the genetic constitution of Scandinavian wolves (Canis lupus), which represent an important case in conservation. We examined the incidence of different congenital anomalies for 171 Scandinavian wolves, including the immigrant founder female, born during a 32-year period between 1978 and 2010. The incidence of anomalies rose from 13% to 40% throughout the 32-year study period. Our ability to detect this increase was likely facilitated by having considered multiple kinds of anomaly. Many of the found anomalies are likely associated with inbreeding or some form of genetic deterioration. These observations have implications for understanding the conservation needs of Scandinavian wolves. Moreover, these observations and the history of managing Scandinavian wolves focus attention on a broader question, whether conservation is merely about avoiding extinction of remnant populations, or whether conservation also entails maintaining genetic aspects of population health.

The occurrence and suspected mode of inheritance of congenital subaortic stenosis and tricuspid valve dysplasia in Dogue de Bordeaux dogs

The Dogue de Bordeaux (DdB) breed has gone through several genetic 'bottle necks' and has a relatively small effective population size. Importing new stock into Israel has been limited, further narrowing the already restricted local gene-pool and increasing the chances of inherited defects. In 56 DdB dogs examined between 2003 and 2010, the authors sought to study the proportion congenital subaortic stenosis (SAS) and tricuspid valve dysplasia (TVD). The aim was also to identify a probable mode of inheritance (MOI) using segregation and pedigree analyses of genealogical data available from 13/21 DdB dogs diagnosed with these conditions between 2004 and 2007. Among all breeds in the country, TVD was highest in the DdB breed, which also displayed the second highest proportion of SAS. Echocardiographic measurements and selected physical examination findings from 26 normal DdB dogs, 18 DdB dogs with SAS, and 12 DdB dogs with TVD are reported. Based on pedigree and segregation analyses, the most probable MOI appeared to be autosomal recessive. Pedigree analyses helped to identify three ancestors that might have introduced these two congenital heart defects into the local DdB population. Excluding those three dogs and their progeny from future mating could therefore reduce the prevalence of these diseases in the DdB population in Israel. The unusual local breeding circumstances may offer a unique opportunity to identify associated SAS and TVD genes in the DdB, as well as in other dog breeds.