MANAGEMENT OF ATRIAL FIBRILLATION, VENTRICULAR ARRHYTHMIA, LEFT VENTRICULAR DYSFUNCTION, AND SUBSEQUENT CARDIOPATHOLOGIC EVALUATION IN AN ORANGUTAN (PONGO PYGMAEUS × ABELII).

A 37-yr-old male vasectomized hybrid orangutan (Pongo pygmaeus × abelii) was diagnosed with left ventricular dysfunction during a preventative health care examination. Treatment was initiated with carvedilol. The following year, this orangutan was evaluated for intermittent lethargy. Following observation of an irregular cardiac rhythm during an echocardiogram, a lead II electrocardiogram revealed atrial fibrillation and ventricular arrhythmia. Additional treatment included amiodarone, furosemide, spironolactone, clopidogrel, and aspirin. An improved activity level was noted, and follow-up testing showed restoration of a sinus rhythm, reduced frequency of ventricular arrhythmia, and improved left ventricular function. The orangutan died 27 mon after initial diagnosis of heart disease, and a complete necropsy was performed. This article describes successful diagnosis and management of structural and arrhythmic heart disease in an orangutan, emphasizing the role of cardiac disease screening and behavioral training in apes, as well as the value of matching thorough antemortem and postmortem cardiac evaluation.

Clinical assessment of heartworm-infected Beagles treated with a combination of imidacloprid/moxidectin and doxycycline, or untreated.

BACKGROUND: Administration of moxidectin topically and doxycycline PO has been utilized experimentally as an alternative treatment for heartworm disease. However, clinical effects of this protocol remain poorly characterized. OBJECTIVE: To evaluate the clinical and postmortem findings associated with administration of doxycycline and monthly 10% imidacloprid + 2.5% moxidectin (IMD + MOX, Advantage Multi/Advocate) to Dirofilaria immitis-experimentally infected as compared to nontreated control dogs. ANIMALS: Sixteen purpose-bred, female, Beagle dogs. METHODS: Prospective, blinded, experimental study. Animals with surgically transplanted adult heartworms were randomized into 2 study groups of equal size: a nontreated control group (n = 8) and an IMD + MOX and doxycycline-treated group (n = 8). Randomization was performed using a complete block design according to circulating microfilarial concentrations, measured before treatment. Serum biochemical profiles, CBCs, thoracic radiographs and echocardiograms were performed prior to and 3 weeks after transplantation, and monthly for 10 months. Postmortem gross and histopathologic evaluations were performed. RESULTS: Compared to control animals, mean ± SD serum alanine aminotransferase (181 ± 203 U/L vs 33 ± 7 U/L; P < .0001) and alkaline phosphatase (246 ± 258 U/L vs 58 ± 19 U/L; P < .0001) activities were significantly higher in the treated group on day 28. Radiographic and echocardiographic evidence of heartworm disease was observed in both groups; however, no significant differences in these variables were noted between groups. Mean ± SD pulmonary arterial thrombus score was significantly higher in the treated vs nontreated group (3.9 ± 0.4 and 1.5 ± 2.1, respectively; P = .01). CONCLUSIONS AND CLINICAL IMPORTANCE: The treatment protocol was well-tolerated with no clinically relevant adverse effects for any variable evaluated during the observational period.

GREAT APE HEART PROJECT GUIDELINES FOR THE ECHOCARDIOGRAPHIC ASSESSMENT OF GREAT APES.

Cardiovascular disease (CVD) has been identified as a major cause of mortality in all four great ape taxa in zoologic institutions. In an effort to better understand and treat CVD in captive great apes, a program called the Great Ape Heart Project (GAHP), based at Zoo Atlanta, collects and maintains a database of echocardiograms and other relevant medical information relating to the cardiac health status of great apes. Cardiac health assessments have become standard practice among North American zoos that house great apes and are recommended by all four great ape Species Survival Plans (SSP) for the assessment of CVD in captive great apes. As of December 31, 2017, more than 70 ape-holding institutions have submitted approximately 1,100 cardiac examinations of great apes to the GAHP, information from which is stored in the GAHP database. Transthoracic echocardiography is one of the most practical and cost-effective diagnostic imaging techniques for the evaluation of cardiac function in great apes. Standardization of echocardiographic measurements is critical for maximizing the diagnostic value of an echocardiographic exam and for utilization of stored information in comparative studies within and between the great ape taxa. The following manuscript offers suggestions for standardization of nomenclature, imaging technique, echocardiographic measurements, data storage, and reporting of cardiac exams for submission into the GAHP database with the goal of promoting consistency and quality in data collection.

Surgical resection of a left auricular aneurysm in a dog.

Aneurysmal dilation of the atrial appendage (auricle) is rare in humans and dogs. Congenital and acquired etiologies are hypothesized. Although right auricular aneurysm has been described in dogs, this is the first case report of an aneurysm of the left auricle of a dog with an intact pericardium. In humans, because complications of arrhythmia and thromboembolic disease have been reported, surgical resection of left auricular aneurysm is recommended. This report describes the successful surgical resection of a left auricular aneurysm in a dog, including a one-year follow up. Surgical resection can be considered in dogs with auricular aneurysm.

Approaches to Canine Heartworm Disease Treatment Among Alumni of a Single College of Veterinary Medicine.

This descriptive study was designed to ascertain the current heartworm treatment strategies employed by veterinary graduates of a single college of veterinary medicine, to assess the frequency with which each of these treatment strategies is prescribed, and to report the motivation behind the use of these treatment strategies. A survey containing a combination of multiple-choice and open-ended questions was distributed via e-mail with an online link during 2013 to graduates of the University of Georgia College of Veterinary Medicine. Demographic data and opinions regarding treatment for cases of canine heartworm disease (HWD) were obtained, and motivation for recommending different treatment strategies was assessed. Nearly all 170 respondents (99%) indicated that they recommend melarsomine dihydrochloride for first-line treatment of canine HWD. Exercise restriction (80%) and monthly heartworm preventive (75%) were components of the treatment approach to HWD with no clinical signs. The majority of respondents (74%) indicated that when first-line treatment recommendations were declined, they endorsed long-term administration of ivermectin (i.e., "slow-kill" method) despite current American Heartworm Society guidelines that recommend against the use of long-term macrocyclic lactone administration for the monotherapy treatment of canine HWD. Respondents also indicated that owners' financial concerns frequently result in modification of HWD treatment. Routine inclusion of exercise restriction is commonly, but not universally, utilized and may represent an opportunity for improvement in the management of this disease. In addition, when first-line recommendations for heartworm disease treatment are declined, a two-dose melarsomine protocol instead of the slow-kill method should be considered.

Treatment of supraventricular tachycardia in a horse.

OBJECTIVE: To describe the treatment of persistent supraventricular tachycardia (SVT) in a young horse in endurance training. CASE SUMMARY: A 6-year-old Arab gelding in endurance training presented for a dysrhythmia and decreased performance. SVT was diagnosed and conversion to a normal sinus rhythm was achieved following administration of a constant rate infusion of amiodarone. However, reversion to SVT occurred shortly after initiation of ridden exercise. A second attempt to convert the dysrhythmia with amiodarone failed, but normal sinus rhythm was achieved with transvenous electrical cardioversion (TVEC). Postmortem examination of the heart revealed extensive fibrous replacement of most of the left atrial myocardium; these changes likely provided the structural substrate for the dysrhythmia. The underlying cause of the fibrosis was not identified. NEW OR UNIQUE INFORMATION PROVIDED: SVT is a form of supraventricular tachyarrhythmia rarely diagnosed in the horse. A recent report has described sudden death of a horse following attempted conversion of SVT with oral flecainide acetate. In the present report, we describe short-term conversion of SVT in a horse using intravenous amiodarone with no significant adverse effects. When the dysrhythmia recurred, the animal was donated for teaching purposes and conversion was achieved with TVEC. Normal sinus rhythm persisted for 2 weeks until the horse was euthanized for postmortem evaluation of the heart. Intravenous amiodarone or TVEC could be considered as treatments for supraventricular tachyarrhyhmias other than atrial fibrillation in the horse.

Pharmacokinetic and pharmacodynamic evaluation of oral rivaroxaban in healthy adult cats.

OBJECTIVES: To determine the pharmacodynamics and pharmacokinetics of rivaroxaban (RVX), in healthy cats and to evaluate the clinicopathologic effects of various plasma RVX concentrations within target therapeutic ranges established for people. DESIGN: Prospective randomized cross-over study performed between July 2013 and November 2014. SETTING: Veterinary university teaching hospital. ANIMALS: Six healthy adult domestic shorthair cats (3 males, 3 females). INTERVENTIONS: Cats were treated with oral RVX at single, fixed doses (1.25, 2.5, 5 mg PO), q 12 h for 3 days (1.25 mg); q 24 h for 7 days (2.5 mg); and q 24 h for 28 days (1.25 mg). Blood samples were collected for complete blood count, blood chemistry, and RVX anticoagulant activity based on prolongation of dilute prothrombin time, activated partial thromboplastin time (aPTT), activated Factor X (FXa) inhibition (anti-Xa activity [aXa]) and high-pressure liquid chromatography tandem mass spectrometry determination of drug concentration. MEASUREMENTS AND MAIN RESULTS: Treated cats had no signs of hemorrhage or clinicopathologic off-target adverse effects. There were dose-dependent prolongations of coagulation times and increase in aXa, with peak effect at 3 hours postadministration. There was a direct correlation between plasma RVX concentration and dilute prothrombin time and aXa. Coagulation parameters returned to baseline by 24 hours after the last dose. CONCLUSIONS: Oral RVX was well tolerated by healthy cats with predictable pharmacokinetics and anticoagulant effects. Clinical studies of RVX are warranted in cats with heart disease.

Heart rate variability in horses with acute gastrointestinal disease requiring exploratory laparotomy.

OBJECTIVE: To describe heart rate variability (HRV) in horses with acute gastrointestinal disease that undergo exploratory laparotomy. We hypothesized that horses with ischemic gastrointestinal disease will have reduced HRV compared to horses with nonischemic lesions. We further hypothesized that a reduction in HRV will be associated with nonsurvival. DESIGN: Prospective, clinical, observational study. SETTING: University veterinary teaching hospital. ANIMALS: Horses presented for acute colic (n = 57) or elective surgical procedures (n = 10) were enrolled. INTERVENTIONS: Admission heart rate (HR) was recorded and within 2 hours of recovery from general anesthesia continuous telemetry was placed, monitored and recorded for 48-52 hours postoperatively. Stored electrocardiograms were manually inspected and R-to-R intervals were extracted and uploaded into HRV software for analysis. Time domain and frequency spectral analysis were investigated at Times 1 (2-10 h), 2 (16-24 h), 3 (30-38 h), and 4 (44-52 h) postoperatively. A two-way ANOVA for repeated measures was used for group comparisons. Logistic regression analysis was used to detect potential associations between admission HR, time and frequency domain variables, and nonsurvival. MEASUREMENTS AND MAIN RESULTS: Horses diagnosed with an ischemic gastrointestinal lesion (n = 22) at the time of surgery had significantly higher postoperative heart rates and reduced time domain-derived measures of HRV than horses with nonischemic gastrointestinal lesions (n = 35) or control horses (n = 10). Horses that survived to discharge had significantly lower postoperative HRs, higher time domain, and lower low frequency spectral measures of HRV compared to nonsurvivors. The multivariable logistic regression model had a receiver operating characteristic area under the curve (AUC) of 0.95 and was significantly better at predicting nonsurvival than admission HR (P = 0.0124). CONCLUSIONS: Reduced HRV was strongly associated with ischemic gastrointestinal disease and nonsurvival. HRV analysis is a noninvasive technique that may provide diagnostic and prognostic information pertinent to the management of postoperative horses with severe gastrointestinal disease.

Pulmonary edema secondary to a cardiac schwannoma in a dog.

A 4-year-old castrated labrador retriever presented for cardiac evaluation to determine the etiology of cardiogenic pulmonary edema diagnosed 1 month prior. A large pedunculated mass involving the ventral aspect of the mural mitral valve leaflet and the endocardial surface of the left ventricular free wall, resulting in severe mitral regurgitation, was identified on echocardiogram. Histopathology and immunohistochemistry of this mass and other endocardial masses identified at necropsy for S-100 protein were consistent with a diagnosis of schwannoma. To the authors' knowledge, this is the first case of a benign intracardiac schwannoma described in the left heart of a dog.

Microdose computed tomographic cardiac angiography in normal cats.

OBJECTIVES: To determine if microdose contrast-enhanced multi-detector computed tomographic angiography (MDCTA) allows characterization of cardiac chambers in lightly sedated normal cats. ANIMALS: Seven healthy domestic cats. METHODS: Lightly sedated normal cats were imaged pre-contrast and with microdose (0.22 ml/kg of non-ionic iodinated contrast medium, 300 mg I/ml) triple-phase MDCTA in a motion restriction device. RESULTS: On pre-contrast images, the aorta (median: 52.43 Hounsfield units [HU], range 27.35-76.74 HU) was outlined by significantly (p = 0.015) lower attenuating periaortic fat (-66.16 HU, -42.62 to -92.77 HU). On post-contrast images, median peak contrast enhancement in the right ventricle (111.77 HU, 36.09-141.60 HU) was achieved in 3.1 s (range 2.9-7.3 s), in the aorta (149.30 HU, 99.43-319.60 HU) and left atrium (180.83 HU, 88.53-266.84 HU) in 6.4 s (range 5.6-7.7 s) and in the left ventricle (147.89 HU, 57.23-245.77 HU) in 7.10 s (range 6.2-11.2 s). Significantly higher attenuation was measured between all chambers and walls, the right ventricular lumen and interventricular septum (median ratio 53.78 HU, range 0.21-83.20 HU), left ventricular lumen and left ventricular free wall (89.32 HU, 38.81-185.95 HU) and aorta and periaortic fat (190.43 HU, 143.22-425.44 HU) on post-contrast images. CONCLUSIONS: Sufficient biological contrast is available on survey CT to discriminate between the aorta and the left atrium, and microdose MDCTA provides sufficient contrast enhancement for adequate visualization of the heart chambers in normal cats.

Comparison of anesthesia with fully reversible dexmedetomidine-butorphanol-midazolam versus ketamine-midazolam in captive Asian small-clawed otters (Aonyx cinereus).

OBJECTIVE: To evaluate the efficacy and safety of a combination of dexmedetomidine, butorphanol, and midazolam administered IM for anesthesia in captive Asian small-clawed otters (Aonyx cinereus) and to compare this combination with a combination of ketamine and midazolam. DESIGN: Prospective crossover study. ANIMALS: 10 captive Asian small-clawed otters. PROCEDURES: A combination of either dexmedetomidine (0.03 mg/kg [0.014 mg/lb]), butorphanol (0.2 mg/kg [0.091 mg/lb]), and midazolam (0.15 mg/kg [0.068 mg/lb]) or ketamine (10.1 mg/kg [4.59 mg/lb]) and midazolam (0.3 mg/kg [0.14 mg/lb]) was administered IM to otters for immobilization to allow scheduled wellness examinations. Otters were intubated and administered 100% oxygen during the examination. Anesthesia was supplemented with isoflurane in oxygen if necessary. Routine medical procedures, including blood collection, radiography, echocardiography, dental scaling, vaccinations, and contraception administration, were performed as indicated during the immobilization. Physiologic, clinicopathologic, and anesthetic variables were recorded and compared. Otters given dexmedetomidine-butorphanol-midazolam were administered atipamezole (0.2 mg/kg [0.091 mg/lb]), naltrexone (0.6 mg/kg [0.27 mg/lb]), and flumazenil (0.05 mg/kg [0.023 mg/lb]) IM at the completion of the examination. RESULTS: The need for and duration of isoflurane administration were greater for ketamine-midazolam anesthesia, compared with dexmedetomidine-butorphanol-midazolam anesthesia. Recoveries were shorter and subjectively smoother with dexmedetomidine-butorphanol-midazolam. Heart rates were significantly higher during ketamine-midazolam anesthesia. Regardless of protocol, all otters developed hypothermia and hypercapnia during anesthesia. CONCLUSIONS AND CLINICAL RELEVANCE: Both protocols were safe and effective for this species, but the reversible nature of dexmedetomidine-butorphanol-midazolam resulted in more rapid recoveries than did ketamine-midazolam. Otters anesthetized with ketamine-midazolam may require additional anesthetic medications for routine examinations, and assisted ventilation and thermal support may be of benefit with either protocol.

A survey of Southeastern United States veterinarians' preferences for managing cats with diabetes mellitus.

This study evaluated primary practitioners' perceptions of managing feline diabetics. Surveys distributed during local continuing education events achieved a response rate of 46% (90/195). A mean of 74% feline diabetics required chronic insulin; 26% were transient diabetics. Choice of insulin was most influenced by duration of action: human recombinant protamine zinc insulin was ranked first (42%) and glargine second (27%). Dietary management was always/usually recommended by 97% respondents, with prescription or proprietary low-carbohydrate, high-protein diets recommended in 93% responses. More recent graduates (P=0.0419), those who worked in larger practices (P=0.0315), and those who saw more transient diabetics (P=0.0288) were more likely to recommend dietary change. In-house blood glucose curves (BGCs) were the most popular method of assessing glycemic control, while at-home BGCs were least popular, although their use correlated positively with annual diabetic caseload (r=0.43, P=0.0239). Owners mishandling insulin was cited as the most common cause of poor glycemic control, while clinical signs of acromegaly were rarely recognized.

Doppler echocardiographic diagnosis and surgical therapy of constrictive pericarditis in a cat.

A 4-year-old Ragdoll cat presented for dyspnea secondary to chylous pleural effusion to the University of Georgia Veterinary Teaching Hospital. Physical examination, complete blood count, serum chemistries, urinalysis, thoracic radiographs, abdominal radiographs, and thoracic fluid cytology and culture failed to identify an etiology for the chylous effusion. The patient tested negative for feline leukemia virus, feline immunodeficiency virus and heartworm disease. Respiration phasic influences on early diastolic trans-mitral, trans-tricuspid and pulmonary vein blood flow velocities during Doppler echocardiography were consistent with constrictive pericarditis. The cat underwent subtotal pericardectomy. The patient recovered without complication and is overtly healthy without radiographic or echocardiographic abnormalities 6-months post-surgery. Constrictive pericarditis should be considered in cats with idiopathic pleural effusion, with or without ascites, in which standard echocardiographic assessment is not suggestive of structural heart disease. If constrictive pericarditis is present, the Doppler characteristics outlined here may allow for this diagnosis to be made. Pericardectomy may be highly rewarding, although the specific etiology of the constrictive pericarditis may remain unknown.

Cardiomyopathy and right-sided congestive heart failure in a red-tailed hawk (Buteo jamaicensis).

A 15-year-old female red-tailed hawk (Buteo jamaicensis) was evaluated because of dyspnea, anorexia, and coelomic distension. Diagnostic imaging results confirmed severe coelomic effusion and revealed a markedly dilated right ventricle. The diagnosis was right-sided congestive heart failure. Results of measurements of vitamin E, selenium, lead, zinc, and cardiac troponin levels were normal or nondiagnostic. The hawk was treated with furosemide, antifungal and antimicrobial agents, and supplemental fluids and oxygen, but euthanasia was elected because of the poor prognosis and the practical difficulties associated with intensive case management. To our knowledge, this is the first described case of cardiomyopathy and congestive heart failure in a captive red-tailed hawk.

Assessment of serum N-terminal pro-B-type natriuretic peptide concentration for differentiation of congestive heart failure from primary respiratory tract disease as the cause of respiratory signs in dogs.

OBJECTIVE: To determine whether serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) concentration is useful in discriminating between cardiac and noncardiac (ie, primary respiratory tract disease) causes of respiratory signs (ie, coughing, stertor, stridor, excessive panting, increased respiratory effort, tachypnea, or overt respiratory distress) in dogs. DESIGN: Multicenter cross-sectional study. ANIMALS: P 115 dogs with respiratory signs. PROCEDURES: Dogs with respiratory signs were solicited for study. Physical examination, thoracic radiography, and echocardiography were used to determine whether respiratory signs were the result of cardiac (ie, congestive heart failure) or noncardiac (ie, primary respiratory tract disease) causes. Serum samples for NT-proBNP assay were obtained at time of admission for each dog. Receiver-operating characteristic curves were constructed to determine the ability of serum NT-proBNP concentration to discriminate between cardiac and noncardiac causes of respiratory signs. RESULTS: Serum NT-proBNP concentration was significantly higher in dogs with cardiac versus noncardiac causes of respiratory signs. In dogs with primary respiratory tract disease, serum NT-proBNP concentration was significantly higher in those with concurrent pulmonary hypertension than in those without. A serum NT-proBNP cutoff concentration > 1,158 pmol/L discriminated between dogs with congestive heart failure and dogs with primary respiratory tract disease with a sensitivity of 85.5% and a specificity of 81.3%. CONCLUSIONS AND CLINICAL RELEVANCE: Measuring serum NT-proBNP concentration in dogs with respiratory signs helps to differentiate between congestive heart failure and primary respiratory tract disease as an underlying cause.

Comparative diagnostic test characteristics of oscillometric and Doppler ultrasonographic methods in the detection of systolic hypertension in dogs.

Comparison of test characteristics allows a clinician to choose the optimal diagnostic test method for an individual patient. This study assessed the comparative test characteristics of noninvasive (NI) blood pressure measurement methods (oscillometric and Doppler) and used this information to develop optimal cutoff values for diagnosis of systolic hypertension in dogs by these NI methods. Simultaneous NI (oscillometric or Doppler methods) and invasive (arterial puncture [AP]) systolic blood pressure (SBP) measurements were obtained prospectively from normal dogs and dogs suspected of having systemic hypertension based on clinical signs. Oscillometric SBP readings were obtained from the distal hind limb (Osc-L, n = 54) or the proximal tail (T. n = 27). Doppler BP measurements were obtained using a forelimb cuff (n = 57). AP-SBP was categorized as hypertensive if > or = 160 mmHg, and sensitivity (Se). specificity (Sp), and likelihood ratios (LR) were calculated for diagnostic cutoff values ranging from 130 to 220 mmHg. Receiver operator characteristic (ROC) curves were analyzed to determine optimal cutoff values for diagnosis of AP-SBP > or = 160 mmHg. Optimal NI SBP cutoff values considered to reflect AP values > or = 160 mmHg were: Osc-L = 160 mmHg (Se: 65%, Sp: 85%. LR = 4.33: 1), Osc-T = 150 mmHg (Se: 84%, Sp: 75%, LR = 3.36: 1), and Doppler = 160 mmHg (Se: 71%,