Cor triatriatum dexter in 17 dogs.

OBJECTIVES: The objective of this study was to report the signalment, presentation, clinical and imaging findings, interventions, and outcomes in a group of dogs with cor triatriatum dexter (CTD). ANIMALS: Seventeen client-owned dogs. METHODS: Medical records were reviewed retrospectively for signalment, history, physical examination findings, imaging and diagnostic findings, presence of concurrent congenital cardiac defects, description of interventional procedures, therapy information, and outcomes. RESULTS: Age at presentation ranged from two to 110 months, with 10 of 17 dogs (59%) aged <12 months. There was an equal distribution between the sexes. Peritoneal effusion was the most common presenting complaint, in 10 of 17 dogs (59%). The CTD was an isolated finding in 3 of 17 dogs (18%); the remaining 14 of 17 (82%) dogs had concurrent cardiac disease, with congenital anomalies present in 12 of 17 (70%). All except one of these 12 dogs had at least one additional condition affecting the right heart. Tricuspid valve dysplasia was the most common congenital comorbidity, present in 9 of 17 dogs (53%). Seven dogs (41%) underwent interventional treatment of their CTD. In 7 of 17 (41%) cases, the CTD was considered to be incidental and the dogs were asymptomatic; therefore, no interventions were performed. The remaining three cases were euthanized or lost to follow-up. CONCLUSIONS: Cor triatriatum dexter in dogs is commonly seen in association with other right-sided congenital cardiac anomalies and may be an incidental finding. Dogs with CTD obstructing right atrial inflow can have a good outcome after intervention. Dogs with no clinical signs associated with the CTD may remain asymptomatic into adulthood.

Effect of sildenafil and pimobendan on intracardiac heartworm infections in four dogs.

Four dogs, referred for management of heartworm (HW) disease, were found to have HWs entangled in their tricuspid valve apparatus. None of the dogs were actively hemolyzing or showed signs of acute cardiovascular collapse that would have necessitated emergency transvenous HW extraction, and surgery was not performed at time of presentation. The dogs received pimobendan and sildenafil within 24 h of identifying HW in the tricuspid valve apparatus, and the HW moved to the pulmonary arteries within 2 days in most cases (median 2 days, range 1-14 days). All dogs survived to discharge from the original hospital admission and were subsequently treated with adulticide (melarsomine) without complication. All dogs were HW antigen negative 6 months after their last melarsomine injection. Four dogs appeared to respond positively to medical management aimed at decreasing pulmonary arterial pressure and improving the right ventricular function, but movement of HW out of the heart for other reasons cannot be excluded. This therapeutic option is not advised when dogs with HW disease are presented for acute collapse, ongoing hemolysis, and hypotension as surgical extraction is still considered the best option in these cases. It remains unknown if medical management is a safe option for all dogs with intracardiac HW without clinical signs of caval syndrome. Controlled prospective studies are required to determine the efficacy and safety of this treatment regimen in comparison with surgical extraction.

Prevalence and diagnostic characteristics of non-clinical mitral regurgitation murmurs in North American Whippets.

OBJECTIVES: To assess the prevalence of functional ejection murmurs and murmurs of mitral regurgitation (MR) due to myxomatous mitral valve disease in healthy whippets; to assess the diagnostic value of auscultation to detect MR; and investigate the relationship between age and presence of echocardiographically documented MR (MRecho). ANIMALS: A total of 200 healthy client-owned Whippets, recruited at national shows between 2005 and 2009 were involved in this study. METHODS: Cross-sectional study. Dogs were examined by auscultation by one examiner and Doppler echocardiography by another, and results were compared. Prevalence of types of murmurs and MRecho were calculated and correlated to age. Accuracy of auscultation to predict MRecho was calculated. RESULTS: Left-sided systolic heart murmurs were detected in 185/200 (93%) of dogs. Left apical systolic murmurs (Lapex) were detected in 57/200 (29%) and left basilar systolic murmurs (Lbase) in 128/200 of the dogs (64%). MRecho was present in 76/200 (38%) dogs. Prevalence MRecho was correlated with age (r = 0.96, p=0.0028). Mitral regurgitation detected by echocardiography was present in 12/78 (15%) of the dogs ≤ 2 years of age and in 59% of the dogs at 7-8 years old. Detection of Lapex predicted MRecho with sensitivity 65%, specificity 94%, positive predictive value 86%, and negative predictive value 81%; and accuracy improved when only dogs with more intense Lapex (grade ≥ 3/6) were considered. CONCLUSIONS: Systolic murmurs are common in North American Whippets and this breed exhibits a high prevalence of MRecho, which may be documented at a relatively early age. Whippets with non-clinical MRecho may not be identifiable by auscultation alone; echocardiographic examination may be required to exclude a diagnosis of MR. Louder heart murmurs allow more accurate localization in this population.

Pyloric obstruction secondary to epicardial pacemaker implantation: a case report.

A 10-year old Lhasa Apso dog was presented for an acute history of exercise intolerance and hind limb weakness. High grade second degree atrioventricular block with an atrial rate of 200 beats per minute, ventricular rate of 40 beats per minute and an intermittent ventricular escape rhythm, was diagnosed on electrocardiograph. A transdiaphragmatic, unipolar, epicardial pacemaker was implanted without immediate surgical complications. Severe vomiting was noted 12 h post-operatively. Abdominal ultrasound and a barium study supported a diagnosis of pyloric outflow obstruction and exploratory abdominal surgery was performed. The pyloric outflow tract appeared normal and no other causes of an outflow obstruction were identified. The epicardial generator was repositioned from the right to the left abdominal wall. Pyloric cell pacing was presumed to be the cause for the pyloric obstruction and severe vomiting, and this was thought to be due to close proximity of the pacemaker generator to the pylorus situated in the right abdominal wall. Repositioning of the pulse generator to the left abdominal wall resulted in resolution of vomiting.

Palliative balloon dilation of pulmonic stenosis in a dog with tetralogy of Fallot.

A 6-month-old Beagle with tetralogy of Fallot underwent balloon valvuloplasty of the pulmonary valve. Balloon valvuloplasty was successful and resulted in palliation of clinical signs and an improved quality of life for approximately 9 months. After 9 months, the dog became symptomatic and a modified Blalock-Taussig shunt procedure was successfully performed. Based on this report, balloon valvuloplasty in dogs with tetralogy of Fallot appears to be a feasible technique that may result in improvement of clinical signs. In addition, it may allow for the delay of the more invasive surgical palliation and provide time for weight gain and development of the pulmonary vascular bed for greater ease of surgical shunt creation.