Training the equine respiratory muscles: Ultrasonographic measurement of muscle size

BACKGROUND

Limited information exists regarding changes in the size of respiratory and locomotor muscles in response to exercise training in the Thoroughbred racehorse.

OBJECTIVES

To describe and compare the responses of the respiratory and locomotor muscles to conventional exercise training and inspiratory muscle training (IMT).

STUDY DESIGN

Prospective randomised controlled trial.

METHODS

Thoroughbred racehorses, in training for competition in National Hunt races, were recruited from two training establishments. Ultrasonographic images were obtained for selected muscles of the upper airway, diaphragm, accessory respiratory, and locomotor systems and their sizes measured. Examinations were performed at three timepoints: (A) when unfit, (B) following 12 weeks of conventional exercise training and (C) following 10-12 weeks continued training at race fitness. In addition, horses at yard 1 performed IMT, between timepoint B and C, and were randomly assigned into high-load (treatment) or low-load (control) group. Repeated measures models were constructed to compare the change in muscle measurements over time, and to investigate the effects of yard, previous airway surgery and IMT on the change in ultrasonographic size measurements obtained.

RESULTS

Upper airway muscle size increased in response to conventional race training between timepoints A-C, and B-C. Diaphragm size increased in response to conventional exercise training between timepoints A and B. The diaphragm size of horses that undertook high-load IMT was either maintained or increased, whereas diaphragm size decreased in horses that undertook low-load IMT or no IMT between timepoints B and C. A significant interaction between gluteal muscle size and airway surgery status was observed, with greater gluteal muscle thicknesses measured in horses that had not previously undergone airway surgery (left gluteal 3.9%, p < 0.001; right 4.5%, p = 0.04).

MAIN LIMITATIONS

Low number of horses underwent IMT.

CONCLUSIONS

Respiratory and locomotor muscles increase in size in response to conventional exercise training, with a further change in diaphragm size in response to inspiratory muscle training.

Training the equine respiratory muscles: Inspiratory muscle strength

BACKGROUND

Little is known about the response of the equine respiratory muscles to training.

OBJECTIVES

To measure an index of inspiratory muscle strength (IMSi) before and after a period of conventional exercise training (phase 1) and inspiratory muscle training (IMT), comparing high-load (treatment) and low-load (control) groups (phase 2).

STUDY DESIGN

Prospective randomised controlled trial.

METHODS

Phase 1: Twenty National Hunt Thoroughbred racehorses performed an inspiratory muscle strength test (IMST) twice on two occasions; when unfit at timepoint A (July), and when race fit at timepoint B (October). Phase 2: Thirty-five Thoroughbred racehorses at race fitness were randomly assigned into a high-load (treatment, n = 20) or low-load (control, n = 15) IMT group. The high-load group followed an IMT protocol that gradually increased the inspiratory pressure applied every 4 days. The low-load group underwent sham IMT with a low training load. The IMT was performed 5 days/week for 10 weeks. The IMST was performed twice on two occasions, timepoint B (October) and timepoint C (January). Conventional exercise training and racing continued during the study period. The peak IMSi values obtained from the different groups at timepoints A, B and C were compared using a Wilcoxon Signed Rank Test.

RESULTS

Phase 1: There was a significant increase in IMSi from timepoint A: 22.5 cmH₂ O (21-25) to timepoint B: 26 cmH₂ O (24-30) (p = 0.015). Phase 2: From timepoint B to C there was a significant increase in IMSi for the high-load group 34 cmH₂ O (28-36) (p = 0.001) but not the low-load group 26 cmH₂ O (24-30) (p = 0.929). The peak IMSi at timepoint C was significantly higher for the high-load than low-load group (p = 0.019).

MAIN LIMITATIONS

Single centre study with only National Hunt horses undergoing race-training included.

CONCLUSIONS

In horses undergoing race training there is a significant increase in IMSi in response to conventional exercise training and high-load IMT.

Prevalence of gastroesophageal reflux in dogs undergoing MRI for a thoracolumbar vertebral column pathology

OBJECTIVES

The aims of the study were to investigate the prevalence and extent of gastroesophageal reflux, and the prevalence of regurgitation in dogs undergoing thoracolumbar spine magnetic resonance imaging, and to explore possible associations of reflux and regurgitation with signalment (breed, age, sex, neuter status), bodyweight, body condition score and drugs used in the anaesthetic protocol.

MATERIALS AND METHODS

The thoracic part of the oesophagus was retrospectively assessed for presence and quantification of fluid on two T2 weighted sequences. Patient breed, age, sex, neuter status, weight and body condition score were recorded. Anaesthetic records were reviewed for the presence of regurgitation and detailed anaesthetic protocols.

RESULTS

Fifty percent [95% confidence interval (44.99, 56.81)] of included dogs had evidence of gastroesophageal reflux. Reflux was not associated with the individual breed, age, sex, neuter status or body weight. Brachycephalic dogs did not demonstrate significantly higher rates of reflux compared to non-brachycephalic dogs. A larger volume of reflux was associated with a higher chance of regurgitation.

CLINICAL SIGNIFICANCE

Gastroesophageal reflux is a common finding in dogs undergoing thoracolumbar spine magnetic resonance imaging. Dogs which regurgitated had higher volumes of reflux. Early detection and quantification of the volume of reflux is helpful as it may allow the anaesthetist to take measures which may reduce the risk of associated complications.

Improved Ca2+ release synchrony following selective modification of Itof and phase 1 repolarization in normal and failing ventricular myocytes

Loss of ventricular action potential (AP) early phase 1 repolarization may contribute to the impaired Ca2+ release and increased risk of sudden cardiac death in heart failure. Therefore, restoring AP phase 1 by augmenting the fast transient outward K+ current (Itof) might be beneficial, but direct experimental evidence to support this proposition in failing cardiomyocytes is limited. Dynamic clamp was used to selectively modulate the contribution of Itof to the AP and Ca2+ transient in both normal (guinea pig and rabbit) and in failing rabbit cardiac myocytes. Opposing native Itof in non-failing rabbit myocytes increased Ca2+ release heterogeneity, late Ca2+ sparks (LCS) frequency and AP duration. (APD). In contrast, increasing Itof in failing myocytes and guinea pig myocytes (the latter normally lacking Itof) increased Ca2+ transient amplitude, Ca2+ release synchrony, and shortened APD. Computer simulations also showed faster Ca2+ transient decay (mainly due to fewer LCS), decreased inward Na+/Ca2+ exchange current and APD. When the Itof conductance was increased to ~0.2 nS/pF in failing cells (a value slightly greater than seen in typical human epicardial myocytes), Ca2+ release synchrony improved and AP duration decreased slightly. Further increases in Itof can cause Ca2+ release to decrease as the peak of the bell-shaped ICa-voltage relationship is passed and premature AP repolarization develops. These results suggest that there is an optimal range for Itof enhancement that may support Ca2+ release synchrony and improve electrical stability in heart failure with the caveat that uncontrolled Itof enhancement should be avoided.

Validation of a focused echocardiographic training program in first opinion practice

BACKGROUND

The EPIC study defines criteria, including echocardiographic assessments of left atrial to aortic ratio (LA: Ao) and left ventricular internal diameter in diastole normalized for body weight (LVIDdN), for dogs with preclinical myxomatous mitral valve disease (MMVD) likely to benefit from pimobendan therapy. Access to echocardiography by a cardiologist is not universally available.

HYPOTHESIS/OBJECTIVES

Completion of a focused echocardiographic training program would result in accurate identification of dogs fulfilling the EPIC criteria by primary care veterinarians (PC).

PARTICIPANTS

Six PCs with no previous echocardiographic experience.

METHODS

Prospective diagnostic test accuracy study. After training, each PC evaluated ≤10 dogs that they believed to have preclinical MMVD. The evaluation was repeated by 1 of 3 cardiology diplomates, blinded to the PC's findings. Agreement between clinical assessments and echocardiographic measurements was assessed.

RESULTS

Fifty-seven dogs were evaluated by PCs; 1 dog was withdrawn because of congestive heart failure. The median time between PC and cardiologist evaluation was 0 days (range, 0-8). One incorrect diagnosis of MMVD was made by a PC (this dog had dilated cardiomyopathy [DCM]); preclinical MMVD was confirmed by the cardiologist in 55 dogs. No difference in LA: Ao (P = .96; CV = 6.9%) was detected between PCs and cardiologists. LVIDdN (1.69 cm/kg^0.294 (1.26-2.21) vs 1.73 cm/kg^0.294 (1.32-2.73); P = .001; CV = 6.5%), was significantly lower when measured by PCs vs cardiologists. PCs and cardiologists agreed regarding assessment of EPIC criteria in 49/56 dogs (Alpha = .761, 95% confidence interval 0.697-0.922).

CONCLUSIONS AND CLINICAL IMPORTANCE

The program effectively trained PCs to accurately assess EPIC criteria in dogs with preclinical MMVD.

The microvascular endothelial glycocalyx: An additional piece of the puzzle in veterinary medicine

The endothelial glycocalyx (eGlx) is a critically important structure lining the luminal surface of endothelial cells. There is increasing evidence, in human patients and animal models, for its crucial role in the maintenance of health. Moreover, its damage is associated with the pathogenesis of multiple disease states. This review provides readers with an overview of the eGlx; summarising its structure, essential functions, and evidence for its role in disease. We highlight the lack of studies regarding the eGlx in cats and dogs, particularly in naturally occurring diseases. Importantly, we discuss techniques to aid its study, which can be applied to veterinary species. Finally, we present targeted therapies aimed at preserving, and in some cases, restoring damaged eGlx.

Circulating hyaluronan as a marker of endothelial glycocalyx damage in dogs with myxomatous mitral valve disease and dogs in a hypercoagulable state

The endothelial glycocalyx (eGlx) lines the luminal surface of endothelial cells, maintaining vascular health. Glycocalyx damage is pathophysiologically important in many diseases across species however few studies have investigated its breakdown in naturally occurring disease in dogs. The aims of the study were to investigate eGlx damage in dogs with myxomatous mitral valve disease (MMVD) diagnosed on echocardiography, and dogs in a hypercoagulable state diagnosed using thromboelastography (TEG), by measuring serum hyaluronan concentrations. Serum hyaluronan was quantified in dogs with MMVD (n = 27), hypercoagulability (n = 21), and in healthy controls dogs (n = 18). Serum hyaluronan concentrations were measured using a commercially-available ELISA validated for use in dogs. Hyaluronan concentrations were compared among groups using Kruskal-Wallis tests, and post-hoc with Dunn’s tests. Serum hyaluronan concentrations (median [range]) were significantly increased in dogs with MMVD (62.4 [22.8–201] ng/mL; P = 0.031) and hypercoagulability (92.40 [16.9–247.6] ng/mL; P < 0.001) compared to controls (45.7 [8.7–80.2] ng/mL). Measurement of serum hyaluronan concentration offers a clinically applicable marker of eGlx health and suggests the presence of eGlx damage in dogs with MMVD and dogs in a hypercoagulable state.

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Few studies have investigated endothelial glycocalyx breakdown in disease in dogs.

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Serum hyaluronan is a clinically applicable marker of endothelial glycocalyx health.

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Serum hyaluronan was significantly increased in dogs with mitral valve disease.

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Serum hyaluronan was significantly increased in dogs in a hypercoagulable state.

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Increased serum hyaluronan may indicate glycocalyx shedding in these diseases.

Prevalence of ultrasonographic gastrointestinal wall changes in dogs with acute pancreatitis: A retrospective study (2012-2020)

Background

Ultrasonographic gastrointestinal wall changes in dogs with acute pancreatitis (AP) are not well characterized in the literature. No detailed studies have described their prevalence, characteristics, distribution, or clinical relevance.

Hypothesis/Objectives

Describe the prevalence of ultrasonographic gastrointestinal wall changes in a population of dogs with AP and evaluate for associations between the presence of gastrointestinal wall changes and clinical or clinicopathological variables.

Animals

Referral population of 66 client‐owned dogs with AP.

Methods

Retrospective search of clinical records to identify dogs with AP. Clinical variables, clinicopathological variables and ultrasonographic findings were reported using descriptive statistics. A binary logistic regression model was used to evaluate for associations between the presence of gastrointestinal wall changes and clinical or clinicopathological variables.

Results

Sixty‐six dogs were included. Forty‐seven percent of dogs (95% confidence interval [CI], 35.0%‐59.0%; n = 31) with AP had ultrasonographic gastrointestinal wall changes. Gastrointestinal wall changes were most common in the duodenum and identified in 71% (n = 22) of affected dogs. Of dogs with gastrointestinal wall changes, 74.2% (n = 23) had wall thickening, 61.3% (n = 19) had abnormal wall layering, and 35.5% (n = 11) had wall corrugation. In the multivariable model, only heart rate remained an independent predictor of ultrasonographic gastrointestinal wall changes (P = .02).

Conclusions and Clinical Importance

Ultrasonographic gastrointestinal wall changes in this population of dogs with AP were common. Increased heart rate was the only independent predictor of gastrointestinal wall changes, which might imply more severe disease. Additional studies are required to elucidate whether ultrasonographic gastrointestinal wall changes reflect disease severity in AP.

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

Background

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

Objectives

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

Animals

Thirty dogs with pulmonic stenosis scheduled for interventional procedures.

Methods

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

Results

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

Conclusions and Clinical Importance

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

Computed tomographic staging of dogs with anal sac adenocarcinoma

OBJECTIVES

To describe the CT appearance of anal sac adenocarcinoma lesions in a population of dogs including the relations between primary tumour, and locoregional and distant metastasis.

MATERIALS AND METHODS

Retrospective review of dogs with confirmed anal sac adenocarcinoma and available CT images of the thorax, abdomen and pelvis.

RESULTS

A population of 70 dogs were included in the study. No association was found between anal sac mass size and presence or absence of iliosacral lymph node enlargement. The prevalence of local metastatic disease characterised by iliosacral lymphadenomegaly in this study was 71%, with pulmonary metastases identified in 11% of cases. There were no cases of distant pulmonary metastasis without concurrent locoregional lymphadenomegaly.

CLINICAL SIGNIFICANCE

In our population of dogs local metastatic spread of anal sac adenocarcinoma was common, with a relatively low prevalence of pulmonary metastasis. The study demonstrates the importance of thorough rectal examination and/or imaging to assess the iliosacral lymph centre in this disease irrespective of the size of the anal sac mass.

Evaluation of serum cardiac troponin-I concentrations for diagnosis of infective endocarditis in dogs

Background

Infective endocarditis (IE) in dogs is associated with severe disease and a high case fatality rate but often presents with nonspecific clinical signs.

Hypothesis/Objectives

Serum concentration of cardiac troponin‐I (cTnI) is elevated in dogs with IE and can differentiate dogs with IE from dogs with other diseases with similar clinical features. Concentration of serum cTnI is negatively correlated with survival time in dogs with IE.

Animals

Seventy‐two client‐owned dogs; 29 with IE, 27 with stage‐B myxomatous mitral valve disease (MMVD), and 16 with immune‐mediated disease (IMD).

Methods

Retrospective clinical cohort study. Concentration of serum cTnI was measured in all dogs at time of diagnosis. Clinical findings and echocardiographic interpretation were also recorded. Statistical analyses included Kruskal‐Wallis test, pairwise Mann‐Whitney U tests, receiver operator characteristic, and Cox proportional hazards.

Results

Serum concentration of cTnI was significantly higher in the IE group (0.69 ng/mL [0.03‐80.8]) than in the MMVD (0.05 ng/mL [0.02‐0.11], P < .001) and IMD groups (0.05 ng/mL [0.03‐0.57], P < .001). Increased cTnI was a moderately accurate predictor of IE (area under the curve 0.857 (95% confidence interval [CI] 0.745‐0.968, P < .001). A cTnI cutoff of 0.625 ng/mL had 100% specificity (95% CI 90%‐100%) and 52% sensitivity (95% CI 33%‐70%) in this study sample. There was no association between cTnI concentration and survival time in dogs with IE (hazard ratio 1.013, 95% CI 0.993‐1.034, P = .2).

Conclusions and Clinical Importance

Cardiac troponin‐I concentrations are higher in dogs with IE compared to dogs with preclinical MMVD or IMD. In dogs with a compatible clinical presentation, serum cTnI concentrations >0.625 ng/mL are supportive of IE.

Inspiratory muscle training for the treatment of dynamic upper airway collapse in racehorses: A preliminary investigation

Exercise-induced upper airway collapse (UAC) probably occurs when the stabilising muscles of the upper airway are unable to withstand the dramatic changes in airflow and pressure that occurs during exercise. In racehorses, the mainstay of treatment is surgical intervention. In human athletes, exercise-induced laryngeal obstruction has been treated successfully with inspiratory muscle training (IMT). The aims of this study were: (1) to assess the feasibility of IMT in racehorses; and (2) describe the exercising endoscopy findings pre- and post-IMT in racehorses diagnosed with dynamic UAC. Horses undergoing IMT wore a mask with an attached threshold-valve to apply an additional load during inspiration, creating a training stimulus with the purpose of increasing upper airway muscle strength. Each horse underwent IMT once daily, while standing in the stable, 5-6 days/week for 10 weeks. Endoscopy recordings were analysed in a blinded manner using an objective grading scheme and subjective pairwise analysis. Seventeen horses successfully completed the IMT protocol, with full information available for 10 horses. Objective grading analysis showed a lower grade of vocal fold collapse (6/9 horses), palatal instability (7/10 horses) and intermittent dorsal displacement of the soft palate (5/7 horses) post-IMT. Pairwise subjective analysis suggested better overall airway function post-IMT in 3/10 horses. The main limitations of this preliminary investigation were the low number of horses examined and lack of a control population. Further research is required to investigate the effects of IMT on upper airway muscle strength and to evaluate its efficacy for prevention and treatment of UAC.

The equine diaphragm: A novel technique for repeatable ultrasound measurement

The diaphragm is an important respiratory muscle, playing a key role during exercise. In humans, diaphragm thickness increases in response to training and is correlated with inspiratory strength. In order to assess respiratory strength in the horse, new evaluation techniques are required and measurement of diaphragm thickness, in a non-invasive and repeatable manner, is a possible approach. The purposes of this four-part, prospective, pilot study were to develop and describe a repeatable method to measure the diaphragm thickness, using ultrasonography, in Thoroughbred racehorses. A standardized technique was developed whereby the ultrasound transducer was positioned 1 cm below a line between the cranioventral aspect of the tuber coxae and olecranon. The diaphragm thickness was measured on three occasions 1 week apart, by a single observer to determine the intraobserver repeatability, and by a second observer on one occasion to assess interobserver reproducibility. The diaphragm was observed in all intercostal spaces (ICS) from 7 to 17 on the left side, and 6 to 17 on the right side in a single horse. The thickest measurement (1.42 cm), obtained from 11 horses, was at ICS 11 on the left-side during inspiration. The narrowest measurement (0.56 cm) was obtained at ICS 16 on the right-side during expiration. There was no significant difference between the measurements obtained by a single observer on three occasions (P < .05). This is the first study to provide a detailed description of ultrasonographic imaging and measurement of the equine diaphragm. The novel technique developed to position the ultrasound transducer in a standardized location allowed examination and measurement of the diaphragm with good repeatability.

Focused cardiac ultrasound and point-of-care NT-proBNP assay in the emergency room for differentiation of cardiac and noncardiac causes of respiratory distress in cats

OBJECTIVE

To assess the accuracy of focused cardiac ultrasound (FOCUS) and point-of-care N-terminal proBNP assay in the emergency setting for differentiation of cardiac from noncardiac causes of respiratory distress in cats.

DESIGN

Prospective diagnostic accuracy study between 2014 and 2016.

SETTING

Emergency room at an urban university teaching hospital.

ANIMALS

Forty-one client-owned cats presenting for evaluation of respiratory distress.

INTERVENTIONS

Emergency clinicians made an initial diagnosis of noncardiac or cardiac cause of respiratory distress based on physical examination (PE) findings and history. The diagnoses were updated after performing FOCUS and point-of-care N-terminal B-type natriuretic peptide (POC-BNP). Reference standard diagnosis was determined by agreement of a board-certified cardiologist and critical care specialist with access to subsequent radiographs and echocardiograms.

MEASUREMENTS AND MAIN RESULTS

Forty-one cats were enrolled. Three cats with incomplete data and 1 cat with an uncertain reference standard diagnosis were excluded. The remaining 37 cats were used for analysis: 21 cardiac and 16 noncardiac cases. The ratio of left atrial to aortic root diameter (LA:Ao) measured by FOCUS was significantly correlated with LA:Ao measured by echocardiography (R = 0.646, P < 0.0001). Emergency clinicians correctly diagnosed 27 of 37 (73.0%), yielding a PE positive percent agreement = 76.2% (95% CI, 52.8-91.8%) and negative percent agreement = 68.8% (95% CI, 41.3-89.0%). Five noncardiac and 5 cardiac cats were misdiagnosed. Post FOCUS, overall percent agreement improved to 34 of 37 (91.9%), with positive percent agreement = 95.2% (95% CI, 76.2-99.9%) and negative percent agreement = 87.5% (95% CI, 61.7-98.5%). The POC-BNP yielded an overall percent agreement = 32/34 (94.1%), positive percent agreement = 100% (95% CI, 82.4-100.0%), and negative percent agreement = 86.7% (95% CI, 59.5-98.3%) in differentiating cardiac versus noncardiac cases.

CONCLUSIONS

FOCUS evaluation of basic cardiac structure and LA:Ao by trained emergency clinicians improved accuracy of diagnosis compared to PE in cats with respiratory distress. FOCUS and POC-BNP are useful diagnostics in the emergent setting.

Long-term biological variability and the generation of a new reference interval for plasma N-terminal pro-B-type natriuretic peptide in Labrador retrievers

OBJECTIVES

First, to investigate the biological variability of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in healthy Labrador retrievers and compare this with current laboratory recommendations for dilated cardiomyopathy screening. Second, to calculate a breed-specific reference interval and validate it in a retrospective cohort.

MATERIALS AND METHODS

Plasma NT-proBNP was measured in 51 clinically healthy Labrador retrievers at 0, 2, 4, 6 and 8 weeks. Coefficient of variation for individual dogs over time, the coefficient of variation for the group at each time point and the index of individuality were calculated. A reference interval was derived and tested on a clinical dataset available from four UK cardiology referral centres.

RESULTS

Median NT-proBNP was 865 pmol/L (315 to 2064 pmol/L). Mean individual coefficient of variation was 19% (95% CI: 16 to 21%) and group coefficient of variation was 43% (95% CI: 41 to 46%), with index of individuality at 0.44. The breed-specific reference interval was 275 to 2100 pmol/L. In the validation group, 93% of NT-proBNP measurements from healthy dogs were within the reference interval. NT-proBNP measurements exceeded the reference interval in 82% of dogs with dilated cardiomyopathy. The upper bound of the reference interval (2100 pmol/L) had a positive predictive value of 90% and a negative predictive value of 87% for identification of dilated cardiomyopathy in this population.

CLINICAL SIGNIFICANCE

Breed-specific reference intervals might improve the diagnostic accuracy of NT-proBNP measurement. Applying the currently recommended general cut-off value to Labradors is likely to result in frequent false positives and diagnosis would be improved by application of the new breed-specific reference interval calculated here.

Investigation of focused cardiac ultrasound in the emergency room for differentiation of respiratory and cardiac causes of respiratory distress in dogs

OBJECTIVE

To determine whether focused cardiac ultrasound (FOCUS) performed by emergency and critical care (ECC) specialists or residents in training improves differentiation of cardiac (C) versus non-cardiac (NC) causes of respiratory distress in dogs compared to medical history and physical examination alone.

DESIGN

Prospective cohort study (May 2014 to February 2016).

SETTING

University hospital.

ANIMALS

Thirty-eight dogs presenting with respiratory distress.

INTERVENTIONS

FOCUS.

MEASUREMENTS AND MAIN RESULTS

Medical history, physical examination, and FOCUS were obtained at presentation. Emergency and critical care clinicians, blinded to any radiographic or echocardiographic data, categorized each patient (C vs NC) before and after FOCUS. Thoracic radiography (within 3 h) and echocardiography (within 24 h) were performed. Percent agreement was calculated against a reference diagnosis that relied on agreement of a board-certified cardiologist and ECC specialist with access to all diagnostic test results. Reference diagnosis included 22 dogs with cardiac and 13 dogs with noncardiac causes of respiratory distress. In 3 dogs a reference diagnosis was not established. Prior to FOCUS, positive and negative percent agreement to detect cardiac causes was 90.9% (95% CI, 70.8-98.9) and 53.9% (25.1-80.8), respectively. Overall agreement occurred in 27 of 35 dogs (77.1%). Two C and 6 NC cases were incorrectly categorized. Following FOCUS, positive and negative percent agreement to detect cardiac causes was 95.5% (77.2-99.9) and 69.2% (38.6-90.9), respectively. Overall agreement occurred in 30 of 35 dogs (85.7%). Three dogs with discrepant pre-FOCUS diagnoses were correctly re-categorized post-FOCUS. One C and 4 NC cases remained incorrectly categorized. No correctly categorized dogs were incorrectly re-categorized following FOCUS. The proportions of dogs correctly classified pre- versus post-FOCUS were not significantly different (P = 0.25).

CONCLUSIONS

FOCUS did not significantly improve differentiation of C vs NC causes of respiratory distress compared to medical history and physical examination alone.

Measurements of echocardiographic indices and biomarkers of kidney injury in dogs with chronic kidney disease

Pathophysiological cardiac and renal interactions are termed cardiovascular-renal disorder (CvRD). Cardiovascular disease/dysfunction secondary to kidney disease (CvRD_K), is a leading cause of death in human chronic kidney disease (CKD) patients. The presence and clinical impact of CvRD_K in dogs with CKD is unknown. We hypothesized that echocardiographic measurements, and cardiac and renal biomarkers, will be altered in dogs with CKD and associated with survival. Eleven dogs with CKD (n = 6 IRIS stage 2, n = 5 IRIS stage 3) and without primary cardiac disease, plus 12 healthy age-matched control dogs, were recruited to this prospective observational study. Dogs underwent standard echocardiography, glomerular filtration rate (GFR) estimation by iohexol clearance, and measurement of plasma cardiac troponin I and N-terminal pro-B-type natriuretic peptide (NT-proBNP), plasma and urinary cystatin B, and urinary clusterin and neutrophil gelatinase-associated lipocalin (NGAL). Values were compared between groups, and their association with all-cause mortality explored. Dogs with CKD had significantly lower GFR and higher NT-proBNP, urinary cystatin B, clusterin, and NGAL, compared to controls (P < 0.05). Echocardiographic measurements were similar between dogs with CKD and controls. Median follow-up time was 666 days, during which six dogs with CKD died. Risk of death was associated with increasing age, serum total protein, and normalized left ventricular posterior wall thickness (LVPWDN) and decreasing bodyweight and packed cell volume. Although baseline differences in echocardiographic measurements were not evident between dogs with moderate CKD and controls, the presence of CvRD_K was suggested by the association between LVPWDN and survival.

Effect of prespecified therapy escalation on plasma NT-proBNP concentrations in dogs with stable congestive heart failure due to myxomatous mitral valve disease

Background

Treatment targeted to achieve reduction in N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) improves outcomes in human congestive heart failure (CHF) patients.

Hypothesis

A pre‐specified therapeutic algorithm that increased diuretic or pimobendan usage will reduce plasma NT‐proBNP concentrations in dogs with CHF secondary to myxomatous mitral valve disease (MMVD).

Animals

Twenty‐six dogs with clinically stable CHF secondary to MMVD.

Methods

Prospective, controlled before‐and‐after study. Dogs were examined up to 3 times over 21 days. Treatment was prescribed based on NT‐proBNP as follows: <1500 pmol/L at baseline, no treatment adjustment at any point during the study (group 1); ≥1500 pmol/L and creatinine ≤3.0 mg/dL at baseline or SC visits, treatment escalated according to the algorithm (group 2); ≥1500 pmol/L at baseline, no treatment adjustment (group 3).

Results

N‐terminal pro‐B‐type natriuretic peptide decreased significantly in group 2 (mean change = −1736 pmol/L (95% CI, −804 to −2668), P < .001) but not in groups 1 or 3 (623 pmol/L [–631 to 1877 pmol/L], P = .14 and 685 pmol/L [–304 to 1068 pmol/L], P = .46, respectively). Serum BUN and creatinine did not change significantly between visit 0 and visit 2 in group 1 (median = 23 mg/dL [range 13‐32] versus 19 mg/dL [12‐38], P = .72 and 1.15 mg/dL [0.70‐1.40] versus 0.95 mg/dL [0.70‐1.10], P = .10, respectively) or group 2 (28 mg/dL [18‐87] versus 43.5 mg/dL [21‐160], P = .092 and 1.10 mg/dL [0.90‐2.50] versus 1.55 mg/dL [0.90‐3.30], P = .062, respectively).

Conclusions and Clinical Importance

Use of this treatment escalation algorithm allows effective targeting of treatment for CHF in dogs against an objective criterion.

Sample Size Determination for Evaluation of Time Domain Heart Rate Variability Indices in Canine Lameness

Heart rate variability (HRV) is a physiologic phenomenon that occurs due to changing autonomic tone resulting in variable RR intervals. A reduction in HRV is used as an index of pain in neonatal human patients. Objective measures of pain would be valuable in the evaluation of canine patients and assessment of response to pain management strategies. We hypothesized that dogs with diseases associated with discomfort (osteoarthritis and bone neoplasia) would have reduced HRV compared with normal, healthy dogs. The aim of the study was to calculate the sample size necessary to investigate this hypothesis. Seventeen dogs from the Ryan Veterinary Hospital of the University of Pennsylvania patient population or owned by Ryan Veterinary Hospital of the University of Pennsylvania staff were enrolled in this single-blind, prospective pilot study. A 30 min electrocardiogram (ECG) was obtained from each dog using an ambulatory electrocardiographic monitor. All ECGs were obtained between 10 a.m. and 2 p.m. ECGs were analyzed and time-domain HRV indices computed. Sample size calculations suggest that 207 dogs would be necessary to ascertain if HRV is reduced in dogs experiencing discomfort or pain (50 in the arthritis group, 79 in the bone cancer group, and 78 in the control group).

Treatment of dogs with compensated myxomatous mitral valve disease with spironolactone-a pilot study

OBJECTIVES

Spironolactone improves outcome in dogs with advanced myxomatous mitral valve disease (MMVD). Its efficacy in preclinical MMVD is unknown. The hypothesis was the administration of spironolactone to dogs with compensated MMVD demonstrating risk factors for poorer prognosis will decrease the rate of disease progression. The aim was to provide pilot data to evaluate preliminary effects and sample size calculation for a definitive clinical trial.

ANIMALS

Twenty-five client-owned dogs with MMVD with at least one of the following; left atrial to aortic ratio (LA:Ao) ≥ 1.5, normalized left ventricular internal diameter in diastole ≥ 1.6), N-terminal pro-B-type natriuretic peptide (NT-proBNP) > 550 pmol/L, cardiac troponin I > 0.025 ng/mL.

METHODS

Prospective, single-center, equally randomized, placebo-controlled, double-blinded, parallel grouped pilot study. No dogs were receiving medications for cardiac disease before the enrollment.

RESULTS

Twelve dogs received placebo; 13 received spironolactone. One dog in the spironolactone group died suddenly, 1 developed congestive heart failure, and 2 received suboptimal spironolactone doses. At enrollment, NT-proBNP was significantly higher in the spironolactone group (p=0.005). Left atrial to aortic ratio (p=0.002) and left ventricular internal diameter in diastole (p=0.005) increased over time in the placebo group, but not the spironolactone group; the change did not differ significantly between groups. The change in biomarker concentrations did not differ significantly between groups; there was a tendency toward an increase in NT-proBNP over time in the placebo group. Enrollment of 76 dogs would be necessary to demonstrate a difference in the change in LA:Ao over 6 months between the groups.

CONCLUSIONS

Preliminary results support undertaking a larger clinical trial of treatment of dogs with preclinical MMVD with spironolactone.

Anodal stimulation in two dogs with transvenous permanent bipolar pacemakers

Management of symptomatic bradyarrhythmias such as complete atrioventricular block often involves permanent implantation of a transvenous pacemaker. Both during and after implantation, the operator can telemetrically assess and adjust a variety of electrical parameters associated with the pacemaker function in order to optimize the sensitivity, reliability, and power consumption of the device. Herein, we report an unexpected change in the paced electrocardiographic QRS complex morphology in two dogs undergoing bipolar pacing associated with changes in the pacemaker output amplitude settings first detected during threshold testing. The exclusivity of the electrocardiographic changes solely on pacemaker output settings, consistency between the surface electrocardiogram and ventricular endocardial electrogram, and resolution of this phenomenon when dogs were re-programmed to unipolar pacing is consistent with depolarization of the ventricular myocardium by the anodal electrode of the pacing lead at high pacemaker amplitudes. Anodal stimulation is a potential cause of varying QRS complex morphology witnessed during pacemaker evaluation and interrogation.

Differentiation of Cardiac from Noncardiac Pleural Effusions in Cats using Second-Generation Quantitative and Point-of-Care NT-proBNP Measurements

Background

Pleural effusion is a common cause of dyspnea in cats. N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) measurement, using a first‐generation quantitative ELISA, in plasma and pleural fluid differentiates cardiac from noncardiac causes of pleural effusion.

Hypothesis/Objectives

To determine whether NT‐proBNP measurements using second‐generation quantitative ELISA and point‐of‐care (POC) tests in plasma and pleural fluid distinguish cardiac from noncardiac pleural effusions and how results compare to the first‐generation ELISA.

Animals

Thirty‐eight cats (US cohort) and 40 cats (UK cohort) presenting with cardiogenic or noncardiogenic pleural effusion.

Methods

Prospective cohort study. Twenty‐one and 17 cats in the US cohort, and 22 and 18 cats in the UK cohort were classified as having cardiac or noncardiac pleural effusion, respectively. NT‐proBNP concentrations in paired plasma and pleural fluid samples were measured using second‐generation ELISA and POC assays.

Results

The second‐generation ELISA differentiated cardiac from noncardiac pleural effusion with good diagnostic accuracy (plasma: sensitivity, 95.2%, specificity, 82.4%; pleural fluid: sensitivity, 100%, specificity, 76.5%). NT‐proBNP concentrations were greater in pleural fluid (719 pmol/L (134–1500)) than plasma (678 pmol/L (61–1500), P = 0.003), resulting in different cut‐off values depending on the sample type. The POC test had good sensitivity (95.2%) and specificity (87.5%) when using plasma samples. In pleural fluid samples, the POC test had good sensitivity (100%) but low specificity (64.7%). Diagnostic accuracy was similar between first‐ and second‐generation ELISA assays.

Conclusions and clinical importance

Measurement of NT‐proBNP using a quantitative ELISA in plasma and pleural fluid or POC test in plasma, but not pleural fluid, distinguishes cardiac from noncardiac causes of pleural effusion in cats.

Clinical severity score system in dogs with degenerative mitral valve disease

BACKGROUND

Several risk factors already have been determined for dogs with degenerative mitral valve disease (DMVD). Risk factors often have been considered in isolation and have not always taken into account additional information provided by the history and physical examination (PE).

HYPOTHESIS/OBJECTIVES

Data obtained from history and PE of dogs with DMVD provide prognostic information and can be used for risk stratification.

ANIMALS

Client-owned dogs (n = 244) with DMVD recruited from first opinion practice.

METHODS

Prospective longitudinal follow-up of dogs with DMVD. History and PE data were obtained at 6-month intervals and analyzed with time-dependent Cox models to derive relative risk of cardiac death. Independent hazard ratios were used to derive a clinical severity score (CSS), the prognostic value of which was evaluated by analyzing the median survival times for different risk groups and ROC analysis. Analysis of the progression of CSS over time also was undertaken.

RESULTS

History of cough, exercise intolerance, decreased appetite, breathlessness (difficulty breathing) and syncope with PE findings of heart murmur intensity louder than III/VI and absence of respiratory sinus arrhythmia were independently associated with outcome and allowed development of the CSS. Clinical severity score distinguished groups of dogs with significantly different outcomes.

CONCLUSIONS AND CLINICAL IMPORTANCE

Routinely obtained clinical findings allow risk stratification of dogs with DMVD. Results of ancillary diagnostic tests may be complementary to history and PE findings and always should be interpreted in conjunction with these findings.

The effects of storage conditions on measurements of canine N-terminal pro-B-type natriuretic peptide

OBJECTIVES

The study aims were to assess the temporal stability following storage at room temperature, the effect of up to 4 freeze-thaw cycles and the effect of simulated freezer failure on measurements of canine N-terminal pro-B-type natriuretic peptide (NT-proBNP) in serum and protease-inhibited (PI) plasma.

ANIMALS

Twenty-five blood samples were collected from 16 dogs with myxomatous mitral valve disease.

METHODS

Aliquots of canine serum and PI plasma were stored at room temperature (17-26 °C) for 30 min, 6, 24, 48 and 72 h, respectively. Further aliquots were subjected to between 1 and 4 freeze-thaw cycles. A further aliquot was transferred to storage at 4 °C for 24 h while a paired aliquot remained at -80 °C. All samples were returned to storage at -80 °C until subsequent analysis. N-terminal pro-B-type natriuretic peptide was measured in serum and PI plasma samples using first- and second-generation versions of a commercially-available ELISA. Repeated measures models were used to assess change in NT-proBNP measurements. Wilcoxon signed ranks were used to compare paired measurements.

RESULTS

N-terminal pro-B-type natriuretic peptide concentrations declined over time in all samples stored at room temperature. Of the four situations tested, the rate of decrease was lowest for PI plasma samples measured using the second-generation assay. N-terminal pro-B-type natriuretic peptide is stable in samples subjected to up to 4 freeze-thaw cycles and in previously-frozen samples stored at 4 °C for 24 h.

CONCLUSIONS

Use of the second-generation assay, compared with the first-generation, resulted in significantly higher recovery of NT-proBNP measured in PI plasma stored at room temperature. Transport of serum at room temperature for NT-proBNP measurement is not recommended.

Relationship of plasma N-terminal pro-brain natriuretic peptide concentrations to heart failure classification and cause of respiratory distress in dogs using a 2nd generation ELISA assay

Background

Cardiac biomarkers provide objective data that augments clinical assessment of heart disease (HD).

Hypothesis/Objectives

Determine the utility of plasma N‐terminal pro‐brain natriuretic peptide concentration [NT‐proBNP] measured by a 2nd generation canine ELISA assay to discriminate cardiac from noncardiac respiratory distress and evaluate HD severity.

Animals

Client‐owned dogs (n = 291).

Methods

Multicenter, cross‐sectional, prospective investigation. Medical history, physical examination, echocardiography, and thoracic radiography classified 113 asymptomatic dogs (group 1, n = 39 without HD; group 2, n = 74 with HD), and 178 with respiratory distress (group 3, n = 104 respiratory disease, either with or without concurrent HD; group 4, n = 74 with congestive heart failure [CHF]). HD severity was graded using International Small Animal Cardiac Health Council (ISACHC) and ACVIM Consensus (ACVIM‐HD) schemes without knowledge of [NT‐proBNP] results. Receiver‐operating characteristic curve analysis assessed the capacity of [NT‐proBNP] to discriminate between dogs with cardiac and noncardiac respiratory distress. Multivariate general linear models containing key clinical variables tested associations between [NT‐proBNP] and HD severity.

Results

Plasma [NT‐proBNP] (median; IQR) was higher in CHF dogs (5,110; 2,769–8,466 pmol/L) compared to those with noncardiac respiratory distress (1,287; 672–2,704 pmol/L; P < .0001). A cut‐off >2,447 pmol/L discriminated CHF from noncardiac respiratory distress (81.1% sensitivity; 73.1% specificity; area under curve, 0.84). A multivariate model comprising left atrial to aortic ratio, heart rate, left ventricular diameter, end‐systole, and ACVIM‐HD scheme most accurately associated average plasma [NT‐proBNP] with HD severity.

Conclusions and Clinical Importance

Plasma [NT‐proBNP] was useful for discriminating CHF from noncardiac respiratory distress. Average plasma [NT‐BNP] increased significantly as a function of HD severity using the ACVIM‐HD classification scheme.

Associations between N-terminal procollagen type III, fibrosis and echocardiographic indices in dogs that died due to myxomatous mitral valve disease

OBJECTIVES

To evaluate associations between N-terminal procollagen type III (PIIINP), a serum biomarker of collagen biosynthesis, and myocardial fibrosis in dogs with naturally-occurring myxomatous mitral valve disease (MMVD).

ANIMALS

Twenty-two dogs with echocardiographically-confirmed MMVD were prospectively recruited from a hospital population. All died as a result of MMVD and their hearts were available for post mortem examination.

METHODS

Echocardiographic measurements and serum PIIINP concentrations were obtained from all dogs prior to death or euthanasia. Serum PIIINP concentrations (μg/mL) were measured using a validated commercially available radioimmunoassay. Myocardial tissue samples were collected post mortem and myocardial fibrosis was scored. The average fibrosis score for all cardiac sites in the heart was designated the global fibrosis score (GFS). The average fibrosis score for all papillary muscle sites was designated the papillary fibrosis score (PFS). Univariate and multivariate linear regression analyses were used separately to evaluate associations between GFS and PFS, respectively, and PIIINP and echocardiographic variables.

RESULTS

Left ventricular end-diastolic diameter normalized for body weight (LVEDDN) and PIIINP were weakly independently positively associated with both GFS and PFS. LVEDDN and PIIINP were weakly negatively correlated.

CONCLUSIONS

Both LVEDDN and serum PIIINP increase with increasing fibrosis score, although these relationships were not strong enough to be clinically useful. Although LVEDDN and PIIINP were positively correlated with fibrosis, PIIINP decreased with increasing LVEDDN, suggesting a complex interplay between fibrosis and remodeling in MMVD.

Longitudinal electrocardiographic evaluation of dogs with degenerative mitral valve disease

Background

Increased heart rate (HR) and decreased heart rate variability (HRV) are evident in some dogs with degenerative mitral valve disease (DMVD).

Objectives

Evaluation of the factors influencing HR and HRV (assessed by the vasovagal tonus index; VVTI) and their change over time in dogs with DMVD.

Animals

Client‐owned dogs (n = 257) with DMVD recruited from first opinion practice.

Methods

Prospective longitudinal follow‐up at six‐monthly intervals of dogs with DMVD. Dogs followed up for at least 18 months (n = 102) were grouped according to their outcome as dogs dying/euthanized because of cardiac disease (n = 28; Group 1), noncardiac disease (n = 40; Group 2) and dogs alive (n = 34; Group 3). HR and VVTI were measured on 1‐minute ECG recordings. Repeated measures linear models were constructed to investigate the factors that influence HR and VVTI and their changes over time.

Results

Heart rate and VVTI were affected by disease severity and were different in Cavaliers compared to other breeds. Group 1 and Group 2 dogs underwent an increase in HR and decrease in VVTI, evident at least 18 months before death. Group 1 had a further decrease in VVTI followed by an increase in HR approximately 1 year and 6 months before death, respectively.

Conclusions and Clinical Importance

Dogs with DMVD have an increase in HR and decrease in HRV over a year before death, with greater changes in those dogs dying/euthanized because of cardiac disease. Both HR and VVTI can potentially be regarded as biomarkers for all‐cause mortality.

Associations among serum N-terminal procollagen type III concentration, urinary aldosterone-to-creatinine ratio, and ventricular remodeling in dogs with myxomatous mitral valve disease

OBJECTIVE

To assess relationships among serum N-terminal procollagen type III concentration, urinary aldosterone-to-creatinine concentration ratio (UAC), and clinical variables in dogs with myxomatous mitral valve disease (MMVD) and healthy dogs.

ANIMALS

162 dogs with MMVD and 24 healthy control dogs of comparable age and body weight.

PROCEDURES

Blood and urine samples were collected from each dog. Dogs with MMVD underwent echocardiography and ECG. Ventricular diameter measurements were normalized for body weight. Serum N-terminal procollagen type III and urinary aldosterone concentrations were measured via radioimmunoassay. Each dog was examined on 1 to 3 occasions. Examinations were repeated at approximately 6-month intervals.

RESULTS

Serum N-terminal procollagen type III concentration decreased with increasing severity of MMVD and was negatively associated with age and left ventricular end-diastolic and end-systolic diameters. The UAC increased with prior percentage change in left ventricular end-diastolic diameter per month, subsequent percentage change in left ventricular end-systolic diameter per month, and treatment with diuretics and was negatively associated with age. Both UAC and serum N-terminal procollagen type III concentration were higher in Cavalier King Charles Spaniels than in other breeds when other measured variables were controlled for.

CONCLUSIONS AND CLINICAL RELEVANCE

In dogs with MMVD, echocardiographic indicators of left ventricular remodeling appeared to be associated with a decrease in serum concentration of a marker of collagen type III turnover and an increase in urinary aldosterone concentration.

Relationships between heart rate and age, bodyweight and breed in 10,849 dogs

OBJECTIVES

To evaluate relationships between heart rate and clinical variables in healthy dogs and dogs examined at a referral hospital.

METHODS

Clinical data were extracted from the electronic patient records of a first opinion group (5000 healthy dogs) and a referral hospital (5849 dogs). Univariable and multi-variable general linear models were used to assess associations between heart rate and clinical characteristics. Separate multi-variable models were constructed for first opinion and referral populations.

RESULTS

In healthy dogs, heart rate was negatively associated with bodyweight (P<0.001) but was higher in Chihuahuas. The mean difference in heart rate between a 5 and 55 kg dog was 10.5 beats per minute. In dogs presenting to a referral hospital, heart rate was negatively associated with bodyweight (P<0.001) and the following breeds; border collie, golden retriever, Labrador retriever, springer spaniel and West Highland white terrier and positively associated with age, admitting service (emergency and critical care, emergency first opinion and cardiology) and the following breeds; Cavalier King Charles spaniel, Staffordshire bull terrier and Yorkshire terrier.

CLINICAL SIGNIFICANCE

Bodyweight, age, breed and disease status all influence heart rate in dogs, although these factors account for a relatively small proportion of the overall variability in heart rate.

The combined prognostic potential of serum high-sensitivity cardiac troponin I and N-terminal pro-B-type natriuretic peptide concentrations in dogs with degenerative mitral valve disease

BACKGROUND

Identification of factors associated with decreased survival in dogs with degenerative mitral valve disease (DMVD) will allow more accurate prognosis. N-terminal pro-B-type natriuretic peptide (NT-proBNP) is negatively associated with survival in dogs with DMVD. In human patients, multimarker strategies provide superior risk stratification compared with single markers.

HYPOTHESIS

High-sensitivity cardiac troponin I (hscTnI) and other clinical variables will be associated with survival time in dogs with DMVD. Measuring hscTnI and NT-proBNP in combination will be prognostically superior to measurement of either marker alone. The rate of change of these markers will vary according to cause of death.

ANIMALS

Client-owned dogs (n = 202) with DMVD of varying severity and age-matched healthy control dogs (n = 30) recruited from first opinion private practice.

METHODS

Prospective cohort study relating clinical variables at enrollment in dogs with DMVD to survival time (all-cause, cardiac, and noncardiac mortality). Multivariable Cox regression analysis was used to identify factors associated with survival. Measurements were obtained approximately every 6 months. Repeated measures models were constructed to assess changes over time.

RESULTS

hscTnI, LVEDDN, heart rate, and age were independently associated with decreased survival time (all-cause mortality). Survival times were shortest in dogs in which both serum hscTnI and NT-proBNP were increased. hscTnI and NT-proBNP increased more rapidly in dogs that died of cardiac disease.

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum hscTnI has prognostic value in dogs with DMVD. Measurement of NT-proBNP and hscTnI is prognostically superior to measuring either alone. Serial measurement strategies provide additional prognostic information.

Gerbode defect associated with blunt trauma in a dog

A 6 year-old Labrador retriever was presented after being struck by a car. A ventricular arrhythmia, attributed to myocardial trauma, developed 12 h post-trauma. Echocardiography revealed lesions consistent with a subaortic paramembranous ventricular septal defect (VSD) with shunting of blood from the left ventricle to the right atrium (Gerbode defect). A right-to-left shunting atrial septal defect (ASD) was visualised. Pleural and peritoneal effusions developed within 48 h. Fifteen days post-trauma flow across the ASD was left-to-right while left-to-right shunting across the VSD persisted. No cavitary effusions were detected at 15 days post-trauma or subsequently.