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Dilated cardiomyopathy (DCM) is a frequent cause of cardiac disability, congestive heart failure (CHF), and arrhythmic death in dogs. The etiology of DCM is usually idiopathic/genetic, but some causes of a DCM phenotype are reversible. The disease is classified into preclinical (occult) and clinical (overt) stages; the latter stems from heart failure with reduced ejection fraction. DCM is further characterized by clinical, electrocardiographic, circulating biomarker, and imaging abnormalities. The diagnosis of clinical DCM with CHF is straightforward; however, identification of the preclinical stage can be challenging. Echocardiography is central to the diagnosis of both stages and characterized by left ventricular (LV) systolic dysfunction with progressive chamber dilation and variable enlargements of the left atrium and right-sided chambers. Left ventricular dilation is defined by increased LV end-diastolic volumes, areas, and internal dimensions normalized to body size or indexed to the aorta. Systolic dysfunction is characterized by decreased LV ejection fraction, increased end-systolic volume, and reduced shortening across minor and longitudinal LV axes. Dyssynchrony can confound the interpretation of linear indices of systolic function. A comprehensive echocardiogram in DCM includes two-dimensional and M-mode studies, spectral and tissue Doppler imaging, and potentially three-dimensional echocardiography and myocardial strain imaging. Echocardiographic findings should be interpreted within the context of identifiable risks and comorbidities, physical diagnosis, complementary diagnostic testing, and limitations of current reference intervals. Ambiguous examinations should be repeated. Specific echocardiographic criteria for the diagnosis of DCM are proposed to encourage discussion and additional outcome and breed-specific echocardiographic studies of canine DCM.

BackgroundFactors associated with outcome in dogs diagnosed with infective endocarditis (IE) are not well characterized.ObjectivesEvaluate outcome and prognostic factors in dogs with IE.AnimalsOne hundred and thirteen dogs with IE.MethodsMedical records for dogs that fulfilled the modified Duke criteria between 2005 and 2020 were retrospectively reviewed. Signalment, preexisting conditions, clinicopathologic findings, treatment regimen, and outcomes were recorded. Univariate logistic regression was performed to identify categorical factors associated with mortality, and then multivariate analysis was performed.ResultsDogs were categorized as survivors (n=47), non-survivors (n=57), or lost to follow-up (n=9). Survival to discharge and at 1month was documented in 79 (70%) of 113 and 56 (54%) of 104 dogs, respectively, with median survival time (MST) of 72 days. Risk factors associated with mortality included development of congestive heart failure (odds ratio [OR], 11.8; 95% confidence interval [CI], 1.4-97.8), thromboembolic events (OR, 5.7; 95% CI, 2.3-14.4), and acute kidney injury (OR, 6.2; 95% CI, 2.0-18.8). Administration of antithrombotic medications was associated with survival (OR, 0.35; 95% CI, 0.13-0.97). Dogs that were not treated with antithrombotics had MST of 92 days, whereas dogs treated with antithrombotics did not reach MST during the study period. The heart valves involved and etiologic agent identified did not correlate with outcome.Conclusion and clinical importanceDogs with IE that had thromboembolic events, acute kidney injury, or congestive heart failure had higher risk of mortality. Administration of antithrombotics was associated with prolonged survival time.

A 10‐year‐old female spayed mixed breed dog was evaluated for diarrhea and vomiting. Diagnostic imaging demonstrated the presence of an intracardiac mass. A modified Seldinger technique was used to access the right jugular vein, and an endomyocardial biopsy forceps was introduced through a sheath to obtain several biopsies. Histopathology and immunohistochemistry demonstrated a paraganglioma. The dog underwent 1 fraction of radiotherapy and l‐asparaginase chemotherapy and was discharged. The dog developed a pulmonary thromboembolism 2 days after radiotherapy and chemotherapy, and the owner elected humane euthanasia. Although long‐term assessment of treatment response was unable to be performed, this novel diagnostic option could be considered for similar cases due to success in obtaining a histopathologic diagnosis, which is essential in developing a disease‐specific treatment plan. This report also describes the use of radiotherapy for primary treatment of an intracardiac neoplasm, which can be a consideration in the future.

Background Prior studies have suggested that pimobendan is associated with several positive effects in cats, including improved survival in cats with congestive heart failure and improved left atrial function in research colony cats with hypertrophic cardiomyopathy (HCM) and normal cats. However, there is still a paucity of pharmacodynamic data refuting or supporting the use of pimobendan in a clinical cat population. This clinical trial aimed to evaluate the pharmacodynamic effects and tolerability of a single dose of pimobendan in cats with HCM. Echocardiograms and Doppler-derived systolic blood pressures were performed in 21 client-owned cats with subclinical HCM at baseline and 90-min after oral administration of 1.25 mg of pimobendan (Vetmedin). Seven additional cats were evaluated post-placebo administration to account for intra-day variability. Results Heart rate, systolic blood pressure, and murmur grade were not significantly different between baseline and post-pimobendan evaluations. Left auricular blood flow velocity, left atrial size, and left ventricular fractional shortening were not significantly different between baseline and post-pimobendan evaluations. Mean (± standard deviation) tissue Doppler peak systolic velocity of the mitral annulus was significantly higher following pimobendan (7.4 cm/s ± 1.5 vs 8.5 ± 1.6; p = 0.02). Median (min, max) left-ventricular outflow tract maximum velocity was significantly higher following pimobendan [1.9 m/sec (1.5, 3.4) vs 2.6 m/sec (2.0, 4.0); p = 0.01]. Mean right-ventricular outflow tract maximum velocity was also significantly higher following pimobendan (1.5 m/s ± 0.51 vs 2.0 ± 0.53; p = 0.004). Mean left atrial fractional shortening was significantly higher following pimobendan (28% ± 6 vs 32% ± 7; p = 0.02). No adverse events were observed following pimobendan administration. Right ventricular outflow tract velocity was significantly higher following placebo in control cats (1.02 ± 0.21 versus 1.31 ± 0.31; p = 0.01). No other significant differences were detected. Conclusions In client-owned cats with HCM, pimobendan acutely increased left atrial function and mildly increased left ventricular systolic function. Left ventricular outflow tract velocity was increased after pimobendan. Pimobendan was well tolerated in the acute setting in cats with HCM. The findings of this prospective, acute-dosing study confirm previous findings in research animals and retrospective analyses and suggest that chronic dosing studies are safe and warranted.

Radiographic assessment of heart size is important for clinical management of dogs with cardiovascular disease (CVDz). We sought to compare the ability of vertebral heart size (VHS), vertebral left atrial size (VLAS), and radiologists' assessment of left atrial size (RadLAE) to predict echocardiographic left atrial size (EchoLAE), an important marker of left heart disease severity. We also compared the ability of VHS and VLAS to predict echocardiographic criteria for ACVIM stage B2 (EchoB2) in dogs with myxomatous mitral valve disease (MMVD). This prospective observational study enrolled 183 dogs with known or suspected CVDz that had an echocardiographic examination and thoracic radiographs obtained within 24 h. Compared to increased VHS, VLAS 2.3 was a more accurate predictor of EchoLAE (P = .002). VLAS 2.3 and RadLAE (both P .0001) were independently associated with EchoLAE but VHS was not (P = .45). Optimal cutoffs for VLAS and VHS to predict EchoLAE were 2.3 vertebrae (sensitivity [Sn] = 90.3%, specificity [Sp] = 73.6%) and 11.1 vertebrae (Sn = 75.8%, Sp = 76.0%), respectively. Diagnostic accuracy of VLAS (AUC 0.84, 95% CI 0.73-0.92) and VHS (AUC 0.78, 95% CI 0.66-0.88) to predict EchoB2 in dogs with subclinical MMVD (n = 64) were not significantly different (P = .17). Results demonstrate that VLAS and RadLAE were superior indicators of EchoLAE compared to VHS in dogs with known or suspected CVDz. Both VLAS and VHS are useful predictors of EchoB2 in dogs with subclinical MMVD. When echocardiography is unavailable, VLAS represents a useful radiographic measurement to aid clinical management of dogs with known or suspected CVDz.

Background Reliability of echocardiographic measurements of left atrial (LA) size, an important marker of disease severity, has not been reported in dogs with myxomatous mitral valve disease (MMVD). Objectives To define and compare reliability of left atrial dimension/diameter (LAD), LAD indexed to aortic valve diameter (LAD/AoD), left atrium-to-aortic root ratio (LA/Ao), left atrial volume acquired from a right parasternal long-axis (LAVRPLx ), and left apical view (LAVLAP ) in dogs with subclinical MMVD. Animals Nine dogs with subclinical MMVD. Methods Prospective reproducibility study. Dogs underwent 12 echocardiographic examinations by 2 operators on the mornings and afternoons of 3 nonconsecutive days within 1 week. Reliability (measurement variability) was quantified using coefficients of variation (CV) and 95% repeatability/reproducibility coefficients (95% RC). A mixed-model analysis of variance (ANOVA) was used to determine if time of day, day, and operator were significant sources of variability for each index. Results Linear measurements (LAD, LAD/AoD, and LA/Ao) exhibited less within-day, between-day, and interoperator variability (CVs, 3.9%-12.5%) than did volume estimate measurements (LAVRPLx and LAVLAP ; CVs, 11.8%-17.9%). Of the linear measurements, LA/Ao exhibited greater variability (CVs, 9.9%-12.5%) compared to LAD and LAD/AoD (CVs, 3.9%-4.9%). Operator was a significant (P = .005) source of variability for LA/Ao. Conclusions and clinical importance Compared to other linear measurements, LA/Ao was the least reproducible and most dependent on operator. The 95% RC for each LA size index are provided to help identify clinically relevant changes (beyond intraoperator or interoperator variability) during serial echocardiographic examinations of dogs with subclinical MMVD.

Quantitative measurements are commonly implemented to objectively evaluate heart size in dogs. However, recent studies suggest that the phase of cardiac cycle can impact vertebral heart score, thereby potentially influencing clinical management. This study used fluoroscopy to assess the impact of the cardiac cycle on quantitative cardiovascular measurements in healthy dogs of various breeds.This was a prospective study. Multiple cardiac and respiratory cycles were recorded fluoroscopically. Peak inspiratory end-systole and end-diastole frames were captured from 49 dogs in right lateral recumbency. Vertebral heart score (VHS), cardiothoracic ratio (CTR), vertebral left atrial size (VLAS), and caudal vena cava diameter ratio (CVCDR) measurements were performed. Mean cardiac measurements were compared between cardiac cycle phases, and the impact of body condition score (BCS), weight, thoracic conformation, sex, and age was evaluated.Cardiac cycle had a significant impact on VHS (mean difference: 0.36 ± 0.14 vertebral units between systole and diastole; p 0.001) and CTR (mean difference: 2.2 ± 1.2% between systole and diastole; p 0.001). Cardiac cycle had no significant impact on VLAS or CVCDR. Increasing BCS significantly increased variation between systole and diastole in CTR measurements (p = 0.024).The cardiac cycle has a significant effect on VHS and CTR but does not impact VLAS or CVCDR. These findings should be taken into consideration during clinical use of these measurements, especially if a patient is being monitored for cardiac changes over time via serial radiographs.

Pulmonary hypertension (PH), defined by increased pressure within the pulmonary vasculature, is a hemodynamic and pathophysiologic state present in a wide variety of cardiovascular, respiratory, and systemic diseases. The purpose of this consensus statement is to provide a multidisciplinary approach to guidelines for the diagnosis, classification, treatment, and monitoring of PH in dogs. Comprehensive evaluation including consideration of signalment, clinical signs, echocardiographic parameters, and results of other diagnostic tests supports the diagnosis of PH and allows identification of associated underlying conditions. Dogs with PH can be classified into the following 6 groups: group 1, pulmonary arterial hypertension; group 2, left heart disease; group 3, respiratory disease/hypoxia; group 4, pulmonary emboli/pulmonary thrombi/pulmonary thromboemboli; group 5, parasitic disease (Dirofilaria and Angiostrongylus); and group 6, disorders that are multifactorial or with unclear mechanisms. The approach to treatment of PH focuses on strategies to decrease the risk of progression, complications, or both, recommendations to target underlying diseases or factors contributing to PH, and PH‐specific treatments. Dogs with PH should be monitored for improvement, static condition, or progression, and any identified underlying disorder should be addressed and monitored simultaneously.

Pimobendan might have favorable effects on renal function but this has not been well-studied in dogs with myxomatous mitral valve disease (MMVD).Determine the effects of standard-dose (SD_pimo) and high-dose pimobendan (HD_pimo) on glomerular filtration rate (GFR) and cardiac size and function in dogs with preclinical MMVD.Thirty nonazotemic dogs with stage B2 MMVD.Prospective, randomized, double-blinded, placebo-controlled clinical study. Dogs had an echocardiographic examination, assessment of GFR (iohexol clearance), N-terminal probrain natriuretic peptide (NT-proBNP), and quality of life (QOL) score at baseline and 7 to 10 days after placebo (n = 6), SD_pimo 0.2 to 0.3 mg/kg q12 (n = 12), or HD_pimo 0.5 to 0.6 mg/kg q12h (n = 12).No significant differences in GFR or QOL scores were detected between groups (PResults suggest that pimobendan (SD_pimo or HD_pimo) might not affect renal function in nonazotemic dogs with stage B2 MMVD. High-dose pimobendan did not demonstrate advantages over SD_pimo within the constraints of our study.

To describe the clinical characteristics, perioperative protocols, and outcomes in dogs diagnosed with ventricular fibrillation (VF) while undergoing pericardiectomy.Retrospective, multi-institutional study.Sixteen client-owned dogs.Cases were accrued through a listserve request posted to 3 subspecialty veterinary societies. Dogs were included if they developed VF during a pericardiectomy performed through an open or thoracoscopic approach. Data collected included signalment, history and physical examination, surgical approach, histopathology, treatment, and outcome.Indications for pericardiectomy included idiopathic chylothorax (n = 7), neoplasia (4), idiopathic pericardial effusion (4), and foreign body granuloma (1). Surgical approaches included thoracoscopy (12), intercostal thoracotomy (3) and median sternotomy (1). Electrosurgical devices were used to complete at least part of the pericardiectomy in 15 of 16 dogs. Ventricular fibrillation appeared to be initiated during electrosurgical use in 8/15 dogs. However, in 5/15 dogs it was not obviously associated with electrosurgical use. In 3/16 dogs the timing of initiation of VF was unclear. In 7/16 dogs, cardiac arrhythmias were noted prior to the development of VF. Fourteen of 16 dogs died from intraoperative VF.In most dogs ventricular fibrillation was a fatal complication of pericardiectomy. Ventricular fibrillation might be associated with the use of electrosurgical devices and cardiac manipulation during pericardiectomy although a causal link could not be established from the data in this study.Surgeons must be aware of the risk of VF during pericardial surgery. Electrosurgery might need to be used judiciously during pericardiectomy, particularly in dogs exhibiting cardiac arrythmias.

Background Broadly applicable reference intervals (RIs) for measurements of left atrial (LA) and left ventricular (LV) size and function generated prospectively using statistically appropriate methods are limited. Objectives To generate body size-independent RIs for linear, area, and volume measurements of LA size and LV size and function. Animals Healthy adult dogs (n = 122) of variable size and somatotype. Methods Prospective study. All dogs underwent an echocardiogram performed by the same examiner. Effects of body weight, sex, age, and heart rate were evaluated by regression and correlation analyses. Scaling exponents and prediction intervals were generated for linear measurements using the allometric equation. After normalization to body weight, 95% RIs were determined using nonparametric methods with 2.5 and 97.5 percentiles serving as the lower and upper limits (each with 90% confidence intervals), respectively. Results Linear LA and LV measurements were strongly correlated (R2 ≥ 0.79) with body weight. Scaling exponents were close to the expected 1/3 (0.299-0.392). Prediction intervals for linear measurements of LV chamber size were considerably narrower than previously reported. Weak correlations (r = -0.42 to -0.50) among LV fractional shortening, fractional area change, and ejection fraction and body weight were identified. No other meaningful relationships were identified between the measurements and sex, age, and heart rate. Conclusions and clinical importance Body size-independent RIs for several linear, area, and volume measurements of LA and LV size and function were generated prospectively from a large and diverse reference population and are available for clinical use.

OBJECTIVE To evaluate radiation exposure of dogs and cats undergoing procedures requiring intraoperative fluoroscopy and for operators performing those procedures. SAMPLE 360 fluoroscopic procedures performed at 2 academic institutions between 2012 and 2015. PROCEDURES Fluoroscopic procedures were classified as vascular, urinary, respiratory, cardiac, gastrointestinal, and orthopedic. Fluoroscopy operators were classified as interventional radiology-trained clinicians, orthopedic surgeons, soft tissue surgeons, internists, and cardiologists. Total radiation exposure in milligrays and total fluoroscopy time in minutes were obtained from dose reports for 4 C-arm units. Kruskal-Wallis equality of populations rank tests and Dunn pairwise comparisons were used to compare differences in time and exposure among procedures and operators. RESULTS Fluoroscopy time (median, 35.80 minutes; range, 0.60 to 84.70 minutes) was significantly greater and radiation exposure (median, 137.00 mGy; range, 3.00 to 617.51 mGy) was significantly higher for vascular procedures than for other procedures. Median total radiation exposure was significantly higher for procedures performed by interventional radiology-trained clinicians (16.10 mGy; range, 0.44 to 617.50 mGy), cardiologists (25.82 mGy; range, 0.33 to 287.45 mGy), and internists (25.24 mGy; range, 3.58 to 185.79 mGy). CONCLUSIONS AND CLINICAL RELEVANCE Vascular fluoroscopic procedures were associated with significantly longer fluoroscopy time and higher radiation exposure than were other evaluated fluoroscopic procedures. Future studies should focus on quantitative radiation monitoring for patients and operators, importance of operator training, intraoperative safety measures, and protocols for postoperative monitoring of patients.

Objective To report onset and progression of clinical signs of a neuroendocrine neoplasm (NEN) presumed metastatic to the choroid in a dog. Animals studied A 7.5-year-old female spayed German shepherd dog mix referred for advanced imaging and evaluation of a subretinal mass in the right eye. Procedures Procedures performed included general physical and ophthalmic examinations; ocular, orbital, and abdominal ultrasonography; thoracic radiographs; cranial magnetic resonance imaging; serologic testing for infectious agents; analysis of hematologic as well as serum and urine biochemical parameters; echocardiography; electrocardiography; cytologic assessment of lymph nodes; and histopathology and immunohistochemistry of the enucleated globe. Results Examination and imaging identified a pigmented mass within and expanding the superior choroid. Following enucleation, a choroidal NEN with tumor emboli in scleral blood vessels was diagnosed by histopathologic assessment and confirmed by immunohistochemical labelling. Despite extensive and repeated diagnostic testing over many months, a putative primary site was not identified until 19 months after the initial ocular signs were noted. At that time, a heart-base mass and congestive heart failure were highly suggestive of a chemodectoma. Conclusion This comprehensive report of a NEN presumed metastatic to the choroid in a dog suggests that ocular disease can be a very early and solitary sign of NEN in the dog.

Although deep learning has been explored extensively for computer‐aided medical imaging diagnosis in human medicine, very little has been done in veterinary medicine. The goal of this retrospective, pilot project was to apply the deep learning artificial intelligence technique using thoracic radiographs for detection of canine left atrial enlargement and compare results with those of veterinary radiologist interpretations. Seven hundred ninety‐two right lateral radiographs from canine patients with thoracic radiographs and contemporaneous echocardiograms were used to train, validate, and test a convolutional neural network algorithm. The accuracy, sensitivity, and specificity for determination of left atrial enlargement were then compared with those of board‐certified veterinary radiologists as recorded on radiology reports. The accuracy, sensitivity, and specificity were 82.71%, 68.42%, and 87.09%, respectively, using an accuracy driven variant of the convolutional neural network algorithm and 79.01%, 73.68%, and 80.64%, respectively, using a sensitivity driven variant. By comparison, accuracy, sensitivity, and specificity achieved by board‐certified veterinary radiologists was 82.71%, 68.42%, and 87.09%, respectively. Although overall accuracy of the accuracy driven convolutional neural network algorithm and veterinary radiologists was identical, concordance between the two approaches was 85.19%. This study documents proof‐of‐concept for application of deep learning techniques for computer‐aided diagnosis in veterinary medicine.

Background The clinical relevance of echocardiographic measurements of right heart size and function in dogs with pulmonary hypertension (PH) is unknown. Objective To determine if echocardiographic measurements of right heart size and right ventricular (RV) function are associated with survival times in dogs with PH. Animals Eighty‐two client‐owned dogs. Methods Retrospective study where data from medical records and baseline echocardiographic examinations were collected and measured in a standardized manner. Owners or primary veterinarians were contacted for outcome data. Results Enlargement of the right atrium (88%), RV (69%), and pulmonary artery (72%) was common. One‐third of the cases had reduced RV function quantified by two‐dimensional echocardiography‐derived tricuspid annular plane systolic excursion (TAPSE). Decreased TAPSE was significantly (P = .008) more common in dogs with PH not secondary to left heart disease (LHD; 43%) compared to dogs with PH secondary to LHD (14%) but median survival times (182, 95% confidence interval [CI] = 39‐309 versus 298, 95% CI = 85‐314 days, respectively) were not significantly different (P = .78). Right atrial area (hazard ratio [HR] = 2.72, 95% CI = 1.58‐4.70), TAPSE

Coronary artery anomalies have been reported in Bulldogs and present an increased risk when performing balloon valvuloplasty. Identification of coronary anomalies has been reported using multidetector-row computed tomographic (MDCT) angiography with electrocardiographic gating. However, the utility of non-electrocardiographic-gated 16-row computed tomographic for MDCT for the identification of coronary artery anatomy or anomalies to the authors' knowledge has not been fully investigated. The purpose of this study was to evaluate the feasibility of non-electrocardiographic-gated computed tomographic (CT) angiography to identify coronary anomalies in Bulldogs with pulmonary valve stenosis. In this prospective, observational study, Bulldogs with echocardiographically diagnosed pulmonary valve stenosis, an echocardiographically derived transpulmonic pressure gradient >70 mm Hg, and a clinician recommendation for balloon valvuloplasty were included. Anesthetized dogs underwent a 16-row MDCT non-electrocardiographic-gated CT angiography. A board-certified veterinary radiologist and board-certified veterinary cardiologist reviewed the CT angiography studies and identified the coronary artery anatomy. When normal coronary artery anatomy was detected on CT angiography, a right ventricular outflow tract fluoroscopic angiogram was performed and evaluated during levophase to confirm normal coronary anatomy prior to balloon valvuloplasty. Dogs with coronary anomalies noted on CT angiography were recovered from anesthesia and balloon valvuloplasty was not performed. All dogs (10/10; 100%) had interpretable images from the non-electrocardiographic-gated CT angiography. Coronary anomalies were identified in six dogs based on non-electrocardiographic-gated CT angiography, five with type R2A anomaly and one had a single left coronary ostium. Four dogs had normal coronary anatomy based on non-electrocardiographic-gated CT angiography. Balloon valvuloplasty was performed without incident in these four dogs. We conclude that non-electrocardiographic-gated CT angiography represents a noninvasive method for diagnosing coronary anomalies in Bulldogs with pulmonary valve stenosis.

Left ventricular (LV) and left atrial (LA) enlargement affect management and outcome of dogs with cardiac disease. Short-axis, two-dimensional echocardiographic (2DE) images, indexed to the aorta (Ao), are frequently used to identify cardiomegaly. Long-axis images offer complementary views of the left heart.Eighty healthy dogs and 25 dogs with MMVD.Healthy dogs were prospectively recruited to determine reference intervals (Clinical Laboratory Standards Institute methodology) for long-axis ratios. Measurement variability and repeatability were quantified by intraclass correlation coefficient and coefficient of variation. Mean long-axis ratios from dogs with MMVD were compared with healthy dogs (unpaired t-test). In addition, the proportion of MMVD dogs exceeding the 97.5 percentile by LV/Ao and a conventional, allometric method were compared (McNemar's test).Two-dimensional echocardiographic long-axis reference intervals were as follows: left ventricular to aortic dimension (LV/Ao) 1.8-2.5; left atrial to aortic dimension (LA/Ao) 1.8-2.4, and left atrial to left ventricular dimension (LA/LV) 0.9-1.1. Intraobserver and interobserver measurement agreement was good-to-excellent (intraclass correlation coefficients ≥0.84), and day-to-day variability was low (coefficient of variations4%). Left ventricular to aortic dimension, LA/Ao, and LA/LV were significantly greater in canine MMVD compared with healthy dogs (p0.001). The percentages of MMVD dogs demonstrating LV dilatation by LV/Ao and conventional method were 68% and 36%, respectively (p=0.043, 95% confidence interval for difference 7.9%, 56.1%).Simple 2DE long-axis ratios of LV/Ao, LA/Ao, and LA/LV are repeatable and demonstrate clinical utility for identifying LV and LA enlargement in dogs with MMVD.

Author(s): Nishimura, Satoko; Visser, Lance C; Belanger, Catherine; Oldach, Maureen S; Gunther-Harrington, Catherine T; Stern, Joshua A | Abstract: BackgroundVelocity ratio, velocity time integral (VTI) ratio, and pulmonary valve area indexed to body surface area (iPVA) are methods of assessment of pulmonary valve stenosis (PS) severity that are less dependent on blood flow. Studies evaluating these methods are limited.ObjectivesTo determine the effects of butorphanol, atenolol, and balloon valvuloplasty (BV) on velocity ratio, VTI ratio, iPVA, mean PG, and max PG.AnimalsTwenty-seven dogs with PS (max PG g50 mm Hg).MethodsProspective study. All dogs underwent an echocardiogram at baseline, 5-minutes after administration of butorphanol (0.2-0.25 mg/kg IV), and 2-to-4 weeks after atenolol (1-1.5 mg/kg q12h). Twenty-one of these were evaluated 24-hours after BV.ResultsThere were no significant differences (P g .05) amongst any of the methods of assessment of PS severity after butorphanol. After atenolol, mean (SD) of mean (57.0 [21.0] mm Hg) and max PG (93.1 [33.8] mm Hg) were significantly decreased (P ≤ .047) compared with baseline (65.2 [26.2] mm Hg and 108 [44.4] mm Hg, respectively). After atenolol, there were no significant (P ≥ .12) differences in velocity ratio (0.29 [0.09]), VTI ratio (0.18 [0.05]), or iPVA (0.43 [0.16] cm2 /m2 ) compared with baseline (0.30 [0.09], 0.19 [0.09], 0.44 [0.17] cm2 /m2 , respectively).Conclusions and clinical importanceAtenolol might reduce mean and max PG but does not alter less flow-dependent methods of assessment of PS severity (velocity ratio, VTI ratio, and iPVA) in dogs with PS. Results support an integrative approach to assessment of PS severity that includes less flow-dependent methods, particularly in states of altered flow or right ventricular function.

We sought to determine the prevalence and clinical significance of right heart remodeling and right ventricular (RV) dysfunction in dogs with pulmonary valve stenosis (PS). We also sought to evaluate repeatability of several measurements of severity of PS, right heart size, and RV function in dogs with PS.Several indices of right atrial (RA) size and RV size and function were prospectively evaluated in 48 dogs with PS. Regression analysis was used to determine if indices of right heart size and function were independently associated with maximum transpulmonary pressure gradient (max PG) and adverse clinical findings (exercise intolerance, syncope, or right heart failure). Eight dogs underwent a second echocardiogram performed by the same operator to assess repeatability of the echocardiographic indices, which was quantified by coefficient of variation (CV) and repeatability coefficient.Increased RA size (81%), increased RV wall thickness (83%), and decreased tricuspid annular plane systolic excursion (TAPSE [81%]) were common. Right atrial size, end-diastolic RV area, and RV wall thickness were independently associated with max PG. Decreased TAPSE was independently associated with adverse clinical findings. All indices except RA area (18.6%) and RV systolic velocity (20.7%) had CVs15%. Repeatability coefficients are available to help distinguish a true change versus measurement variability during serially obtained exams.Right heart remodeling and RV dysfunction are common in dogs with PS and are associated with echocardiographic and clinical severity. Results support the quantitative assessment of right heart size and function in dogs with PS.

Pulmonary hypertension (PH) is a common clinical condition associated with morbidity and mortality in both humans and dogs. Sildenafil, a phosphodiesterase-5 (PDE5) inhibitor causing accumulation of cGMP, is frequently used for treatment of PH. The authors previously reported a PDE5A:E90K polymorphism in dogs that results in lower basal cyclic guanosine monophosphate (cGMP) concentrations than in wild-type dogs, which could contribute to variability in the efficacy of sildenafil. In this study, response to sildenafil therapy was evaluated in dogs with PH by comparing echocardiographic parameters, quality-of-life (QOL) score, and plasma cGMP concentrations before and after sildenafil therapy. Overall, tricuspid regurgitation estimated systolic pressure gradient (PG) and QOL score were significantly improved after sildenafil therapy, and the plasma cGMP concentration was significantly decreased. Dogs that had a heterozygous PDE5A status had a significantly worse QOL score when compared to the wildtype group after sildenafil treatment. The simple and multiple regression analyses revealed a significant but weak prediction for the percent reduction in QOL score with sildenafil treatment by plasma cGMP level and by the PDE5A:E90K polymorphic status. This study showed that sildenafil treatment improved PH in dogs, and the PDE5A:E90K polymorphism blunted the efficacy of sildenafil in terms of QOL improvement.

OBJECTIVE To describe vertebral left atrial size (VLAS), a quantitative method to estimate left atrial (LA) size radiographically, and to determine its diagnostic value for prediction of echocardiographic LA enlargement in dogs with myxomatous mitral valve disease (MMVD) of varying severity. DESIGN Prospective observational study. ANIMALS 103 client-owned dogs with a left-sided systolic murmur. PROCEDURES For each dog, 3-view thoracic radiographs were obtained within 24 hours of an echocardiographic examination. The VLAS was measured on right and left lateral thoracic radiographs and compared with the left atrium-to-aortic root ratio acquired from short-axis (LA:AoSx) and long-axis (LA:AoLx) echocardiographic images. Left atrial enlargement was defined as an LA:AoLx ≥ 2.6 or LA:AoSx ≥ 1.6. Dogs were allocated to 4 groups on the basis of MMVD severity. RESULTS Of the 103 dogs, 15, 40, 26, and 22 were assigned to the control (no echocardiographic abnormalities), stage B1 (hemodynamically irrelevant MMVD), B2 (hemodynamically relevant MMVD), and C-D (MMVD with congestive heart failure) groups, respectively. Median VLAS, LA:AoSx, and LA:AoLx for the stage B2 and C-D groups were significantly greater than the corresponding medians for the control and stage B1 groups. There was a moderate positive correlation between VLAS and both LA:AoSx and LA:AoLx. Receiver operating characteristic analyses revealed that a VLAS ≥ 2.3 vertebrae was a useful predictor of LA enlargement. Intraobserver and interobserver agreements for VLAS measurements were high. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated VLAS was a repeatable and useful radiographic measurement for prediction of LA enlargement in dogs with MMVD.

Background Sotalol is a commonly used antiarrhythmic drug that may alter ventricular function. Objective To determine the effect of sotalol on echocardiographic indices of ventricular systolic function in dogs with ventricular arrhythmias. Animals Thirty-five client-owned dogs with ventricular arrhythmias. Methods Dogs with ventricular arrhythmias (n = 27) had an echocardiogram and 5-minute ECG performed at baseline and 2-4 hours post-sotalol (2-2.5 mg/kg PO once). Eight additional dogs underwent the same protocol but did not receive sotalol (within-day variability controls). Left ventricular (LV) internal dimension at end-systole normalized to bodyweight (LVIDs_N), LV ejection fraction (LV EF), LV shortening area, LV fractional shortening, tricuspid annular plane systolic excursion (TAPSE), and right ventricular systolic myocardial velocity were evaluated as indices of systolic function. Results All indices except TAPSE had mild decreases in systolic function post-sotalol (all P ≤ .0007) compared with baseline but only the percent change in LVIDs_N and LV EF were significantly (P ≤ .0079) different from the percent change of the same indices in control dogs. Sinus heart rate, ventricular premature complexes/5-minutes, and arrhythmia grade also were decreased post-sotalol (all P ≤ .01) compared with baseline when assessed by a 5-minutes ECG. No dog experienced an adverse event post-sotalol, including dogs with systolic dysfunction or atrial enlargement. Conclusions and clinical importance A single dose of sotalol may cause a mild decrease in LV systolic function in dogs with ventricular arrhythmias. Sotalol appears to be well tolerated, even in dogs with atrial enlargement or systolic dysfunction.

A cat was evaluated for an acute-onset of right pelvic limb paresis. Thoracic radiographs revealed normal cardiac size and tortuous pulmonary arteries. Abdominal ultrasound identified a heartworm (HW) extending from the caudal abdominal aorta into the right external iliac artery and right femoral artery. The cat was HW-antigen positive. Echocardiography revealed a HW within the right branch of the main pulmonary artery and evidence of pulmonary hypertension. An agitated-saline contrast echocardiogram revealed a small right to left intracardiac shunt at the level of the atria. Surgical removal of the HW was performed with no substantial postoperative complications. There was return of blood flow and improved motor function to the limb. The cat remains mildly paretic on the affected limb with no other clinical signs.

A 5-week-old Holstein heifer calf presented for emergency treatment of signs referable to gastrointestinal disease and hypovolemic shock. Fluid resuscitation uncovered clinical signs of primary cardiac disease and echocardiography revealed multiple congenital cardiac defects. Malformations included a cleft anterior mitral valve leaflet resembling an isolated cleft mitral valve and an apically-located muscular ventricular septal defect. The echocardiographic and postmortem findings associated with these defects are presented and discussed in this report.

To determine the feasibility, repeatability, intra- and interobserver variability, and reference intervals for 5 echocardiographic indices of right ventricular (RV) systolic function: tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), pulsed wave tissue Doppler imaging-derived systolic myocardial velocity of the lateral tricuspid annulus (S'), and speckle-tracking echocardiography-derived global longitudinal RV free wall strain and strain rate. To explore statistical relationships between RV systolic function and age, gender, heart rate, and bodyweight.80 healthy adult dogs.Dogs underwent 2 echocardiographic examinations. Repeatability and intra-observer and inter-observer measurement variability were quantified by average coefficient of variation (CV). Relationships between RV function and age, heart rate and bodyweight were estimated by regression analysis.All indices were acquired with clinically acceptable repeatability and intra- and inter-observer variability (CVs10%). No differences were identified between male and female dogs. Allometric scaling by bodyweight demonstrated significant, clinically relevant correlations between RV function and bodyweight (all p ≤ 0.001) as follows: TAPSE - strong positive correlation (r(2) = 0.75); S' - moderate positive correlation (r(2) = 0.31); strain rate - moderate negative correlation (r(2) = 0.44); FAC and strain - weak negative correlations (r(2) = 0.22 and 0.14, respectively). Strain rate and FAC were positively correlated with heart rate (r(2) = 0.35 and 0.31, respectively). Allometric scaling generated bodyweight-based reference intervals for these RV systolic function indices.Echocardiographic indices of RV systolic function are feasible to obtain, repeatable, and affected by bodyweight. Studies of these indices in dogs with cardiovascular disease are needed.

Introduction Golden retrievers are over-represented in cases of taurine-deficient dilated cardiomyopathy and recently a surge in cases has prompted further investigation. Objective To describe the clinical, dietary, and echocardiographic features in golden retrievers diagnosed with taurine deficiency and dilated cardiomyopathy, and to determine specific dietary associations. A second aim was to determine the whole blood taurine concentrations in a representative sample of healthy golden retrievers. Animals Twenty-four client-owned golden retrievers with documented taurine deficiency and dilated cardiomyopathy and 52 healthy client-owned golden retrievers. Methods In this multicenter prospective observational study, baseline and follow-up echocardiographic data, complete diet and medical histories, and whole blood, plasma, or serum taurine concentrations were obtained. Baseline and follow-up echocardiographic data were compared. Associations were evaluated between specific diets and taurine deficiency or congestive heart failure. The prevalence of low whole blood taurine concentrations in the healthy golden retrievers was calculated. Results Twenty-three of 24 dogs diagnosed with taurine deficiency and dilated cardiomyopathy were fed diets that were either grain-free, legume-rich, or a combination of these factors. None of these diets were feeding trial tested using Association of American Feed Control Officials (AAFCO) procedures. Twenty-three of 24 dogs had significant improvement in their echocardiographic parameters and normalization of taurine concentrations following diet change and taurine supplementation. Nine of 11 dogs diagnosed with congestive heart failure (CHF) had resolution of their congestion at follow-up with five no longer requiring diuretic therapy and four tolerating diuretic dose reduction by >50%. Conclusions Certain diets and diet characteristics were associated with the development of taurine deficiency. Taurine deficiency and dilated cardiomyopathy in golden retrievers is likely multifactorial, including a combination of dietary, metabolic, and genetic factors.

IntroductionGolden retrievers are over-represented in cases of taurine-deficient dilated cardiomyopathy and recently a surge in cases has prompted further investigation.ObjectiveTo describe the clinical, dietary, and echocardiographic features in golden retrievers diagnosed with taurine deficiency and dilated cardiomyopathy, and to determine specific dietary associations. A second aim was to determine the whole blood taurine concentrations in a representative sample of healthy golden retrievers.AnimalsTwenty-four client-owned golden retrievers with documented taurine deficiency and dilated cardiomyopathy and 52 healthy client-owned golden retrievers.MethodsIn this multicenter prospective observational study, baseline and follow-up echocardiographic data, complete diet and medical histories, and whole blood, plasma, or serum taurine concentrations were obtained. Baseline and follow-up echocardiographic data were compared. Associations were evaluated between specific diets and taurine deficiency or congestive heart failure. The prevalence of low whole blood taurine concentrations in the healthy golden retrievers was calculated.ResultsTwenty-three of 24 dogs diagnosed with taurine deficiency and dilated cardiomyopathy were fed diets that were either grain-free, legume-rich, or a combination of these factors. None of these diets were feeding trial tested using Association of American Feed Control Officials (AAFCO) procedures. Twenty-three of 24 dogs had significant improvement in their echocardiographic parameters and normalization of taurine concentrations following diet change and taurine supplementation. Nine of 11 dogs diagnosed with congestive heart failure (CHF) had resolution of their congestion at follow-up with five no longer requiring diuretic therapy and four tolerating diuretic dose reduction by >50%.ConclusionsCertain diets and diet characteristics were associated with the development of taurine deficiency. Taurine deficiency and dilated cardiomyopathy in golden retrievers is likely multifactorial, including a combination of dietary, metabolic, and genetic factors.

We sought to determine the feasibility, measurement variability, and within-day repeatability of tricuspid annular plane systolic excursion (TAPSE) measured by two-dimensional echocardiography (2D TAPSE), generate reference intervals for 2D TAPSE, assess agreement and correlation between 2D TAPSE and the conventional TAPSE measured by M-mode echocardiography (MM TAPSE), and to assess the ability of 2D TAPSE to track a drug-induced decrease in right ventricular (RV) function compared with MM TAPSE.Seventy healthy privately owned dogs of varying bodyweight.All dogs underwent a single echocardiogram to quantify RV function by both TAPSE methods. Ten dogs underwent a second echocardiogram 2-3 h after the first to assess within-day repeatability, and 20 different dogs underwent a second echocardiogram 3-h after atenolol (1 mg/kg per os (PO)). Intraobserver and interobserver measurement variabilities were assessed in 12 randomly selected studies using coefficients of variation. Statistical relationships between 2D TAPSE and bodyweight, gender, heart rate, and age were explored.2D TAPSE could be measured in all dogs. Coefficients of variation for repeatability and measurement variability were low (≤12%). Bodyweight-dependent reference intervals for 2D TAPSE were generated using allometric scaling. TAPSE methods were strongly correlated (r = 0.72; p0.0001) but 2D TAPSE measured consistently less than MM TAPSE (-1.6 [2.2] mm) when analyzed by Bland-Altman's method. Both TAPSE methods were significantly (p≤0.014) reduced after atenolol but percent decrease in 2D TAPSE (-16.2 [9.3]%) was significantly greater (p=0.03) than MM TAPSE (-7.5 [13.8]%).Two-dimensional echocardiography TAPSE appears well suited for clinical assessment of RV function. The TAPSE methods should not be used interchangeably.

Objectives We aimed to evaluate safety and efficacy of high-pressure balloon valvuloplasty (HPBVP) for treatment of canine severe pulmonary valve stenosis (PS). A secondary aim was to provide pre-procedure predictors of success. Animals Twenty-five dogs. Methods Prospective observational study. Dogs with severe PS (echocardiographically derived trans-pulmonary peak/maximum pressure gradient (EDPG) ≥80 mmHg) were recruited. All dogs underwent echocardiography before and 20–24hrs after HPBVP using a high-pressure balloon with rated burst pressures ranging from 12 to 18 ATM. Procedural success was defined as a post-HPBVP EDPG reduction of ≥50% or reduction into at least the moderate category of PS (50–79 mmHg). Optimal result was defined as a post-procedural EDPG ≤30 mmHg. Results Initial median (IQR) EDPG for all dogs was 96 (88, 127) mmHg with a post-operative median of 48 (36, 65) mmHg. The median EDPG reduction provided by HPBVP was 63% (39, 68); procedural success rate was 92% (23 dogs). Optimal results were achieved in 56% (14 dogs). There were no significant correlations between EDPG reduction and valve morphology (Type A and Type B) or severity of right ventricular hypertrophy. Pulmonary valve annulus diameter was the only echocardiographic variable that was significantly correlated to EDPG reduction (p = 0.02; r = −0.46). No dog experienced any anesthetic or surgical complications, and all patients survived the procedure. Conclusions In this cohort of 25 dogs with severe PS, HPBVP was safe and effective. The procedural success rate and high number of optimal results achieved with HPBVP suggest future randomized controlled trials comparing HPBVP to conventional valvuloplasty are warranted.

Functional assessment of the right ventricle (RV) is challenging and has been understudied compared with the left ventricle. However, advances in echocardiographic assessment of RV function permit the quantitative assessment of RV performance via numerous modalities. Many RV function indices have now been studied in large samples of healthy dogs, and studies suggest a clinical benefit to echocardiographic RV function assessment in dogs and cats. This article reviews relevant RV anatomy and physiology and highlights numerous indices of RV function assessment for dogs and cats. Imaging techniques, advantages and disadvantages, and clinical impact of these indices are discussed.

A coronary artery anomaly characterized by the presence of a single left coronary ostium with absence of the right coronary ostium and an anomalous prepulmonic right coronary artery course was observed in two dogs with concurrent congenital pulmonary valve stenosis. This unique coronary artery anatomy is similar to the previously described single right coronary ostium with anomalous prepulmonic left coronary artery, the so-called type R2A anomaly, in that an anomalous coronary artery encircles the pulmonary valve annulus. Both dogs of this report, a boxer and an English bulldog, were of breeds known to be at risk for the type R2A anomaly. As such, veterinarians should be aware that the echocardiographic presence of a left coronary ostium in a dog with pulmonary valve stenosis does not exclude the possibility of a prepulmonic coronary artery anomaly that may enhance the risk of complications during balloon pulmonary valvuloplasty. A descriptive naming convention for coronary artery anomalies in dogs is also presented, which may be preferable to the older coding classification scheme.

Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine. Background: Studies evaluating right ventricular (RV) structural and functional abnormalities in feline hypertrophic cardiomyopathy (HCM) are limited. Hypothesis: Right ventricular structural and functional abnormalities are present in cats with HCM and are associated with clinical severity. Animals: Eighty-one client-owned cats. Methods: Retrospective 2-dimensional (2D) echocardiographic study. Right atrial diameter (RAD), RV free wall thickness (RVFWd), RV internal dimension (RVIDd), RV fractional area change (FAC), and tricuspid annular plane systolic excursion (TAPSE) were measured in control cats (n = 26), cats with subclinical HCM (subclinical HCM; n = 31), and cats with HCM and congestive heart failure (HCM + CHF; n = 24). Results: Right heart size (RAD, RVFWd, and RVIDd) and RV function (FAC and TAPSE) significantly (all P

© 2016 American College of Veterinary Internal Medicine. Background: Echocardiographic assessment of diastolic function is challenging in cats, partially because of transmitral flow pattern fusion associated with high heart rates. With heart rate (HR) reduction, transmitral flow waveforms separate, allowing identification of diastolic dysfunction. Timolol, an ophthalmic, nonselective beta-blocker used in glaucoma is safe and transiently decreases HR in clinical trials. Hypothesis: Administration of timolol ophthalmic solution decreases HR and facilitates echocardiographic assessment of diastolic function in cats without inducing clinically relevant adverse effects. Animals: Twenty-five apparently healthy cats. Methods: Electrocardiograms and echocardiograms including transmitral flow patterns were evaluated before and 20 minutes after ocular administration of 1 drop of timolol 0.5% solution. Twenty cats underwent treatment with timolol, and 5 different cats served as untreated controls to evaluate the effects of acclimation to the hospital environment on HR. Results: Acclimation to the hospital had no effect on HR in control cats. After timolol administration, a significant median HR reduction of 25 bpm was observed (P < .0001). Timolol had no effect on E/A ratio in cats without E/A fusion (7/20, P = .44). Of the 13 cats with E and A waves that were fused before timolol application, separation of these waves was identified in 8 cats (62%) after timolol treatment. No bradyarrhythmias were noted after timolol administration, but 2 cats had first-degree atrioventricular block. Timolol resulted in resolution of dynamic outflow tract obstruction in 6 of 6 cats. Conclusions and clinical importance: Ocular administration of timolol safely decreases HR in cats and could facilitate assessment of diastolic function.

Objective—To examine effects of an autologous platelet-rich fibrin (PRF) membrane for enhancing healing of a defect of the patellar tendon (PT) in dogs. Animals—8 adult dogs. Procedures—Defects were created in the central third of the PT in both hind limbs of each dog. An autologous PRF membrane was implanted in 1 defect/dog, and the contralateral defect was left empty. Dogs (n = 4/time period) were euthanized at 4 and 8 weeks after surgery, and tendon healing was assessed grossly and histologically via a semiquantitative scoring system. Cross-sectional area of the PTs was also compared. Results—Both treated and control defects were filled with repair tissue by 4 weeks. There was no significant difference in the histologic quality of the repair tissue between control and PRF membrane—treated defects at either time point. At both time points, the cross-sectional area of PRF membrane—treated tendons was significantly greater (at least 2.5-fold as great), compared with that of sham-treated tendons. At 4 weeks, the repair tissue consisted of disorganized proliferative fibrovascular tissue originating predominantly from the fat pad. By 8 weeks, the tissue was less cellular and slightly more organized in both groups. Conclusions and Clinical Relevance—A PRF membrane did not enhance the rate or quality of tendon healing in PT defects. However, it did increase the amount of repair tissue within and surrounding the defect. These results suggested that a PRF membrane may not be indicated for augmenting the repair of acutely injured tendons that are otherwise healthy.

© 2015 Elsevier B.V. Objective: To quantify drug-induced changes in right ventricular (RV) systolic function after administration of pimobendan and atenolol. Animals: 80 healthy privately-owned dogs. Methods: Using a prospective, blinded, fully-crossed study design with randomized drug administration, RV systolic function was determined twice at two time periods; before and 3h after administration of pimobendan (0.25mg/kg PO) or atenolol (1mg/kg PO). Indices of RV systolic function included tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), pulsed-wave tissue Doppler-derived systolic myocardial velocity of the lateral tricuspid annulus (S'), and speckle-tracking-derived global longitudinal RV free wall strain and strain rate. The effect of treatment on percent change from baseline RV function was analyzed with a linear mixed model including the covariates heart rate, body weight, age, gender, drug sequence, and time period. Results: All indices showed a significant (p < 0.0001) increase and decrease from baseline following pimobendan and atenolol, respectively. Significant differences from baseline were attributed to drug treatment (p < 0.0001); whereas, effects of other covariates were not significant. The greatest percent changes, but also highest variability, were observed for S' and strain rate (p < 0.0001). Post-atenolol, a significantly greater proportion of dogs exceeded the repeatability coefficient of variation for FAC and S' compared to TAPSE (p≤0.007). Conclusions: Echocardiographic indices in healthy dogs tracked expected changes in RV systolic function following pimobendan and atenolol and warrant study in dogs with cardiovascular disease.

© 2016 American College of Veterinary Internal Medicine. Background: Noninvasive diagnosis of pulmonary hypertension (PH) primarily relies upon Doppler echocardiography of tricuspid regurgitation (TR). However, TR might be absent or difficult to measure. Hypothesis/Objectives: To determine the diagnostic value of right pulmonary artery distensibility (RPAD) index for prediction of Doppler-derived estimates of pulmonary artery (PA) pressure compared to other indices of PH in dogs. Animals: Sixty-nine client-owned dogs with TR. Methods: Prospective observational study. Dogs were allocated to groups according to TR pressure gradient (TRPG): TRPG 75 mmHg (n = 17). Right pulmonary artery distensibility index, acceleration time to peak PA flow (AT), AT: ejection time of PA flow (AT:ET) and main PA size: aorta size (MPA:Ao) were calculated in each dog. Results: Right pulmonary artery distensibility index demonstrated the strongest correlation (r = -0.90; P < .0001) to TRPG followed by MPA:Ao (r = 0.78; P < .0001), AT (r = -0.69; P < .0001) and AT:ET (r = -0.68; P < .0001). RPAD index possessed the most accurate cutoff (50 mmHg compared to AT (1.04; Sn 0.94, Sp 0.74). All intra- and interobserver measurement variabilities exhibited coefficients of variation ≤13%. Conclusions and Clinical Importance: Right pulmonary artery distensibility index is an accurate predictor of TRPG and should be particularly useful if TR is absent or difficult to measure.

Objectives To describe a series of dogs with pulmonary artery dissection and patent ductus arteriosus (PDA). Animals Eight dogs. Methods Retrospective case series. Results Pulmonary artery dissection was diagnosed in 8 dogs, 3 were Weimaraners. Four dogs presented in left-sided congestive heart failure, 4 presented for murmur evaluation and without clinical signs, and 1 presented in right-sided congestive heart failure. In 7 dogs the dissection was first documented concurrent with a diagnosis of uncorrected PDA. In the other dog, with pulmonary valve stenosis and PDA, the dissection was observed on autopsy examination 17 months after balloon pulmonary valvuloplasty and ductal closure. Median age at presentation for the 7 dogs with antemortem diagnosis of pulmonary artery dissection was 3.5 years (range, 1.5–4 years). Three dogs had the PDA surgically ligated, 2 dogs did not undergo PDA closure, 1 dog failed transcatheter occlusion of the PDA with subsequent surgical ligation, 1 dog underwent successful transcatheter device occlusion of the PDA, and 1 dog had the PDA closed by transcatheter coil delivery 17 months prior to the diagnosis of pulmonary artery dissection. The 2 dogs that did not have the PDA closed died 1 and 3 years after diagnosis due to heart failure. Conclusions Pulmonary artery dissection is a potential complication of PDA in dogs, the Weimaraner breed may be at increased risk, presentation is often in mature dogs, and closure of the PDA can be performed and appears to improve outcome.

A bicuspid aortic valve (BAV) demonstrating moderate valvular stenosis and mild insufficiency was identified in an asymptomatic 1-year-old male cryptorchid English bulldog by transthoracic and transesophageal echocardiography. The BAV was most consistent with type 3 morphology, based upon human classification. Pulmonary valve dysplasia with mild pulmonary stenosis and a suspected persistent left cranial vena cava were also identified. Although BAV is the most common congenital cardiac malformation in humans, it is rare in the dog.

To report signalment, history, indications, complications and outcome for 28 dogs and 5 cats in which 34 permanent epicardial pacing leads were surgically placed by transdiaphragmatic approach (32) or intercostal thoracotomy (2).Medical records (2005-2010) were reviewed. Signalment, age, species, gender, clinical signs, presence of structural heart disease and/or congestive heart failure, ECG diagnosis, body weight (10 or10 kg), and overall survival rate were recorded. Statistical correlations were made between these variables and major and minor complications rates.Except for body weight, no statistical differences were identified in prevalence of major (life threatening or requiring replacement of the pacemaker system) or minor (self-limiting) complications; dogs weighing10 kg had significantly more major complications (P = .03). There was a trend (P = .051) for lower survival in animals that had major complications.Larger dogs (10 kg) may be predisposed to more major complications with epicardial pacemaker (EP) implantation. Major complication rate and survival time are similar to those reported for transvenous pacing and therefore implantation of EPs remains a suitable alternative.

To compare the concentration of a representative growth factor (transforming growth factor-beta [TGF-β]1) eluted from a platelet-rich fibrin matrix (PRFMatrix), a platelet-rich fibrin membrane (PRFMembrane), and a whole blood clot (BC) over time, and to compare the mitogenic effect of the eluents from each construct.In vitro study.PRFMatrix, PRFMembrane, and BC (n=4/construct/time point).Each construct was placed in tissue culture wells containing media for 7 days. The media was collected and replenished on days 1, 3, 5, and 7 and the concentration of eluted TGF-β1 was measured by enzyme-linked immunosorbent assay. Canine tendon cells were subjected to additional aliquots of the conditioned media and the amount of cell proliferation compared.The media from both PRFM (PRFMatrix and PRFMembrane) constructs contained significantly more (P≤.026) TGF-β1 at days 1 and 3 and produced a significant increase (P≤.044) in cell proliferation at all time points compared with the BC. The PRFMembrane media contained significantly more (P≤.05) TGF-β1 at days 1 and 3 and produced a significant increase (P≤.002) in cell proliferation at all time points compared with the PRFMatrix.Both PRFM constructs are comprised of a dense fibrin scaffold that contains increased concentrations of TGF-β1 and are capable of increasing tendon cell proliferation over time when compared with a BC.The sustained increase in growth factor availability in PRFM constructs may be beneficial in the healing of biologically compromised tissues.

Numerous scaffolds have been proposed for use in connective tissue engineering. Although these scaffolds direct cell migration and attachment, many are biologically inert and thus lack the physiological stimulus to attract cells and induce mitogenesis and matrix synthesis. In the current study, a bioactive scaffold was created by combining a synthetic scaffold with growth factor-rich plasma (GFRP), an autologous concentration of growth factors derived from a platelet-rich plasma preparation. In vitro tendon cell proliferation and matrix synthesis on autologous GFRP-enriched scaffolds, autologous serum-enriched scaffolds, and scaffolds alone were compared. The GFRP preparation was found to have a 4.7-fold greater concentration of a sentinel growth factor (transforming growth factor-beta1) compared with serum. When combined with media containing calcium, the GFRP produced a thin fibrin matrix over and within the GFRP-enriched scaffolds. Cell proliferation assays demonstrated that GFRP-enriched scaffolds significantly enhanced cell proliferation over autologous serum and control groups at both 48 and 72 h. Analysis of the scaffolds at 14, 21, and 28 days revealed that GFRP-enriched scaffolds significantly increased the deposition of a collagen-rich extracellular matrix when compared with the other groups. These results indicate that GFRP can be used to enhance in vitro cellular population and matrix deposition of tissue-engineered scaffolds.