Cardiac Troponin I in the Normal Dog and Cat

Atipamezole Reverses Cardiovascular Changes Induced by High-Dose Medetomidine in Cats Undergoing Sedation for Semen Collection

This study aimed at describing the change in echocardiographic variables after high-dose medetomidine and the reversal with atipamezole in six cats undergoing sedation for semen collection. Further cardiac Troponin I (cTnI) concentration and the effect of repeated sedation were assessed. Echocardiography was performed before and 20 min after sedation with 0.1 mg/kg medetomidine intramuscularly (IM) for urethral catheterisation. Prior to epididymectomy, S-ketamine was administered intravenously. Twenty minutes after reversal with 0.5 mg/kg atipamezole IM, the third echocardiography was performed. Sedation with medetomidine and reversal with atipamezole was repeated on day 7, 14, 21 and 28. Heart rate (HR) and rhythm were monitored throughout all sedations. On day 0 and 28 cTnI concentrations were measured before and after the procedure. After normality testing, the values were compared over time. The administration of medetomidine led to a marked reduction in HR, cardiac output and ventricular systolic function and a significant increase in left ventricular dimensions. Rhythm abnormalities, such as ventricular premature complexes and idioventricular rhythm, could be observed. The administration of atipamezole completely reversed sedation and the changes in haemodynamic variables. No significant increase in cTnI concentrations could be detected, although two out of six cats showed values above the reference range.

Effects of a 28-day feeding trial of grain-containing versus pulse-based diets on cardiac function, taurine levels and digestibility in domestic dogs

In 2018, the US Food and Drug Administration reported a link between canine dilated cardiomyopathy (DCM) and grain-free diets. Evidence to support a link has emerged, but the specific ingredients responsible and the role of taurine or other causative factors remain unclear. We hypothesized dogs fed pulse-based, grain-free diets for 28 days will show decreased macronutrient digestibility, increased fecal bile acid excretion, and reduced plasma cystine, cysteine, methionine and taurine, causing sub-clinical cardiac or blood changes indicative of early DCM. Three diets were formulated using white rice flour (grain), whole lentil (grain-free), or wrinkled pea (grain-free) and compared to the pre-trial phase on a commercial grain-based diet. After 28 days of feeding each diet, the wrinkled pea diet impaired stroke volume and cardiac output, increased end-systolic ventricular diameter and increased plasma N-Terminal Pro-B-type Natriuretic Peptide (NT-ProBNP), albeit in a sub-clinical manner. Digestibility of some macronutrients and sulphur-containing amino acids, excluding taurine, also decreased with pulse-based compared to grain-based diets, likely due to higher fiber levels. Plasma taurine levels were unchanged; however, plasma methionine was significantly lower after feeding all test diets compared to the commercial diet. Overall, DCM-like changes observed with the wrinkled pea diet, but not lentil diet, after only 4 weeks in a breed not known to be susceptible support a link between pea-based diets and canine nutritionally-mediated DCM.

Ala vestibuloplasty improves cardiopulmonary and activity-related parameters in brachycephalic cats

OBJECTIVE

To evaluate the effects of ala vestibuloplasty on cardiopulmonary and lifestyle-related parameters in brachycephalic (BC) cats.

STUDY DESIGN

Prospective cohort.

ANIMALS

Client-owned BC cats (n = 19).

METHODS

Cats were assessed preoperatively by airway computed tomography (CT), endoscopy, contrast echocardiography, cardiac biomarkers, and structured owner questionnaire. Ala vestibuloplasty was performed bilaterally, and blood values, imaging, and owner questionnaire responses were re-evaluated 8-20 weeks postoperatively.

RESULTS

Cats were presented for predominantly respiratory clinical signs attributable to brachycephaly. Preoperatively, all cats had stenotic nares, prolonged normalized pulmonary transit time (nPTT) (mean 5.43 ± 1.10 s), and a hyperattenuating pulmonary pattern. No complications occurred following surgery. Postoperatively, nPTT (mean 3.89 ± 0.74 s, p < .001) and frequencies of sneezing (p = .002), snoring (p = .006), open-mouth breathing (p = .0004), and nasal discharge (p = .019) were decreased. Cats exhibited increased activity (p = .005), less frequent dyspnea during activity (p < .001), longer duration of activity before becoming dyspneic (p = .002), faster recovery from activity (p < .001), and decreased respiratory noise (p < .001). Median questionnaire scores improved from preoperative to postoperative (p < .001).

CONCLUSION

Anatomic, echocardiographic, and CT changes were common in this cohort of clinically affected BC cats. Pulmonary blood flow and respiratory function were improved after surgery.

CLINICAL SIGNIFICANCE

Stenotic nares are the predominant airway abnormality in BC cats. Ala vestibuloplasty is a safe procedure that improves cardiac and CT abnormalities and respiratory and other clinical signs in BC cats.

Biomarkers in the Diagnosis of Heart Failure in Dogs

Every doctor, one way or another, is faced with the problem of chronic heart failure (CHF) in animals [1]. Over 3 million dogs suffer from some form of acquired heart disease. In recent years, biomarkers, mainly cardiac troponin and natriuretic peptides, have become the main source of information for both diagnosis and monitoring of the human heart. Today, the need for diagnostics based on blood samples has become evident also when working with dogs and cats.

Research-Relevant Clinical Pathology Resources: Emphasis on Mice, Rats, Rabbits, Dogs, Minipigs, and Non-Human Primates

Clinical pathology testing for investigative or biomedical research and for preclinical toxicity and safety assessment in laboratory animals is a distinct specialty requiring an understanding of species specific and other influential variables on results and interpretation. This review of clinical pathology principles and testing recommendations in laboratory animal species aims to provide a useful resource for researchers, veterinary specialists, toxicologists, and clinical or anatomic pathologists.

Effect of administering dexmedetomidine with or without atropine on cardiac troponin I level in isoflurane-anesthetized dogs

We aimed to determine whether dexmedetomidine administration with or without atropine increases cardiac troponin I (cTnI) level in healthy dogs. We hypothesized that 10 µg/kg dexmedetomidine + atropine increases the cTnI level, whereas 5 µg/kg dexmedetomidine + atropine does not. Eighteen healthy, pet dogs that underwent an orthopedic surgery or ovariohysterectomy were included in this study. The dogs were randomly assigned to atropine (0.02 mg/kg)–dexmedetomidine (10 µg/kg), saline–dexmedetomidine (10 µg/kg), and atropine (0.02 mg/kg)–dexmedetomidine (5 µg/kg) groups. Each dog was premedicated with atropine or saline intramuscularly (IM). After 10 min, they were IM injected with dexmedetomidine (10 or 5 µg/kg)–morphine (0.5 mg/kg)–midazolam (0.2 mg/kg). Following this, anesthesia was induced after 10 min with propofol and maintained with isoflurane in 100% oxygen. The median plasma cTnI level at 6, 12 and 24 hr after premedication was significantly higher than that at baseline. The cTnI level in the atropine–dexmedetomidine (10 µg/kg) group was significantly higher than that in the saline–dexmedetomidine (10 µg/kg) and atropine–dexmedetomidine (5 µg/kg) groups at 6 and 12 hr after premedication. The cTnI level returned to normal within 72 hr after premedication in all groups. The administration of atropine in combination with 10 µg/kg dexmedetomidine increased the cTnI level, indicating subclinical myocardial damage.

Clinical and pathological findings in rabbits with cardiovascular disease: 59 cases (2001-2018)

OBJECTIVE

To determine epidemiological features of cardiovascular disease in rabbits examined at a veterinary teaching hospital and characterize clinical and pathological findings.

ANIMALS

59 rabbits.

PROCEDURES

Medical records from 2001 to 2018 were reviewed, and data were collected. Echocardiographic images and histologic diagnoses were reviewed.

RESULTS

The prevalence of cardiovascular disease was 2.6% (59/2,249). Clinical signs related to cardiac disease included heart murmur (n = 25 rabbits), arrhythmia (22), tachypnea or dyspnea (13), hyporexia or anorexia (13), and muscle wasting (9). Radiographic (n = 39) abnormalities included cardiomegaly (19) and peritoneal (12) and pleural (11) effusion. Common echocardiographic (n = 37) diagnoses included degenerative valve disease (15), dilated cardiomyopathy (7), unclassified cardiomyopathy (4), restrictive cardiomyopathy (3), and hypertrophic cardiomyopathy (2). On ECG (n = 19), supraventricular arrhythmias (16) were more common than ventricular arrhythmias (12). Thirty-five necropsy reports were available, and diagnoses included cardiomyopathy (n = 14), myocarditis (10), and arteriosclerosis (9). Medical management (n = 20) included a wide range of drugs and dosages with few adverse effects. Survival times (n = 36 rabbits) ranged from 1 to 2,353 days with a median cardiac disease-specific survival time of 306 days.

CONCLUSIONS AND CLINICAL RELEVANCE

The findings provided information on the prevalence of cardiovascular disease in rabbits and survival times for affected rabbits. Right-sided, left-sided, and biventricular congestive heart failure occurred equally. Median survival time was lower than that reported for other species. Further research on the diagnosis and treatment of cardiovascular disease in rabbits is needed.

Effects of Controlled Generator Fume Emissions on the Levels of Troponin I, C-Reactive Protein and Oxidative Stress Markers in Dogs: Exploring Air Pollution-Induced Cardiovascular Disease in a Low-Resource Country

Exhaust fumes from petrol/diesel-powered electric generators contribute significantly to air pollution in many developing countries, constituting health hazards to both humans and animals. This study evaluated the serum concentrations of Troponin I (TnI), C-reactive protein (CRP) and serum levels/activities of oxidative stress markers: catalase (CAT), reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO) and superoxide dismutase (SOD) in dogs experimentally exposed to graded levels of petrol generator exhaust fume (PGEF). Sixteen (16) healthy and adult male Basenji dogs were randomly assigned into four groups (A-D). Group A was the unexposed control while groups B, C and D were exposed to PGEF for 1, 2 and 3 h per day, respectively, for 90 days. Repeated analysis were performed at the baseline, and every thirty days, for a total of 90 days. There was a significant interaction (p < 0.05) between the effects of PGEF exposure level (in h/day) and duration of exposure (in months) on all the tested serum parameters. There was a significant main effect (p < 0.05) for PGEF exposure level on the serum parameters. As the level of PGEF exposure was increased, the serum concentrations of TnI, CRP, CAT, MDA and NO increased, GSH decreased, whereas SOD activity increased by day 30 but declined at the end. Moreover, there was a significant simple main effect (p < 0.05) for duration of PGEF exposure. All the parameters increased as the duration of PGEF exposure was increased to 90 days except GSH concentration which decreased, whereas SOD activity increased initially but declined at the end of the study. Thus, there was increased serum concentrations of TnI, CRP and increased oxidative stress in the PGEF-exposed dogs. These findings are instructive and could be grounds for further studies on air pollutants-induced cardiovascular disease given the widespread use of electricity generators in many low-resource countries.

Clinical-pathological and immunohistochemical evaluations of cardiac lesions in cats with chronic kidney disease

ABSTRACT: Chronic kidney disease (CKD) is characterized by irreversible morphostructural lesions that can progressively evolve to chronic renal insufficiency and kidney failure. It is known that the heart and kidneys are closely related, and that communication between these organs occurs through a variety of pathways; subtle physiological changes in one of them are compensated by the other. Histopathological cardiac evaluation through routine staining presents a limitation to identify specific or discreet lesions in the cardiomyocytes. This study aimed to evaluate serum troponin levels in cats with CKD, associated with clinical and pathological findings, as well as to correlate the morphostructural cardiac lesions to determine their distribution through macroscopic and histological assessments and anti-cardiac troponin C (cTnC) immunohistochemistry (IHC). To this end, 20 cats (18 diagnosed with CKD and two controls) were selected. Anti-human cTnC IHC was conducted after necropsy and separation in eight regions of each collected heart. Heart fragments from two cats without CKD were used as controls. The anti-human cTnC antibody is useful in detecting cardiac lesions and has shown decreased expression in cardiomyocytes of cats with CKD. Serum troponin was above the reference values in 11/18 (61.11%) animals and decreased expression for the cTnC antibody was observed in individual cardiomyocytes in 9/18 (50%) animals. It was verified that the number of regions with decreased expression for the cTnC antibody in cardiomyocytes is significantly correlated with serum troponin. The anti-human cTnC antibody has been found effective in detecting cardiac lesions and has shown decreased expression in the cardiomyocytes of cats with CKD. Correlation was observed between increased serum cTnI and loss of immunoreactivity at anti-cTnC antibody IHC in cats with CKD, which proves damage to cardiomyocytes secondary to kidney disease.

Clinical presentation, cardiovascular findings, etiology, and outcome of myocarditis in dogs: 64 cases with presumptive antemortem diagnosis (26 confirmed postmortem) and 137 cases with postmortem diagnosis only (2004-2017)

INTRODUCTION

This study describes presentation, cardiovascular abnormalities, etiology, and outcome of canine myocarditis in geographic areas not endemic for Trypanosoma or Leishmania.

ANIMALS

Sixty-four (presumed antemortem diagnosis) and 137 (postmortem diagnosis only) client-owned dogs at two tertiary care facilities were included.

MATERIALS AND METHODS

Medical records of dogs with clinical or histopathological diagnosis of myocarditis were reviewed retrospectively.

RESULTS

Common examination findings in dogs with a presumed antemortem diagnosis included fever (21%) and heart murmur (19%). Median cardiac troponin I was 12.2 ng/mL (range: 0.2-808.0 ng/mL), and troponin exceeded 1.0 ng/mL in 26 of 29 (90%) dogs. Ventricular ectopy was the most common arrhythmia (54%), whereas decreased left ventricular systolic function was the most common echocardiographic abnormality (56%). An infectious etiology was diagnosed in 35 of 64 (55%) dogs. Confirmed infectious etiologies included bacterial sepsis (n = 9) or extension of endocarditis (3), toxoplasmosis or neosporosis (3), parvovirus (2), and one case each of bartonellosis, trypanosomiasis, leptospirosis, and dirofilariasis. Median survival time was 4 days (range: 0-828 days) for all dogs vs. 82 days for dogs who survived at least 2 weeks after diagnosis. Presence of pericardial effusion or azotemia was a significant predictor of non-survival. The most common inflammatory infiltrate on histopathology was neutrophilic (47%), and 20 of 137 (14.5%) dogs had concurrent bacterial endocarditis on postmortem.

CONCLUSIONS

Bacterial infection was the most common confirmed etiology of myocarditis in this study. Prognosis for canine myocarditis is guarded and similar to that reported for infective endocarditis. Criteria for the antemortem diagnosis of canine myocarditis are suggested.

Cats with thermal burn injuries from California wildfires show echocardiographic evidence of myocardial thickening and intracardiac thrombi

Recent increases in the prevalence and severity of wildfires in some regions have resulted in an increased frequency of veterinary burn patients. Few studies exist regarding diagnostics and management of burn wounds in veterinary patients and current knowledge is extrapolated from human literature and research models. Post-burn cardiac injury is a common finding and predictor of mortality in human patients and echocardiography is an important tool in monitoring response to therapy and predicting outcome. We describe the notable findings from cats naturally exposed to California wildfires in 2017 and 2018. Domestic cats (n = 51) sustaining burn injuries from the Tubbs (2017) and Camp (2018) wildfires were prospectively enrolled and serial echocardiograms and cardiac troponin I evaluations were performed. Echocardiograms of affected cats revealed a high prevalence of myocardial thickening (18/51) and spontaneous echocardiographic contrast and thrombi formation (16/51). Forty-two cats survived to discharge and 6 died or were euthanized due to a possible cardiac cause. For the first time, we describe cardiovascular and coagulation effects of thermal burn and smoke inhalation in cats. Further studies in veterinary burn victims are warranted and serve as a translational research opportunity for uncovering novel disease mechanisms and therapies.

Increased Plasma Cardiac Troponin I in Live-Stranded Cetaceans: Correlation with Pathological Findings of Acute Cardiac Injury

Capture myopathy (CM), is a syndrome that occurs as the result of the stress during and after capture, handling, restraint, and transport of wild animals. Although CM has been described for many species of cetaceans, characterization of the acute cardiac injury - an important component of this syndrome - are still scarce. In this study, we firstly estimated a normal range for cardiac troponin I (cTnI) on cetaceans. Here, through biochemical analysis (especially of cTnI) and histopathological, histochemical, and immunohistochemical correlations with decreased troponin immunolabelling, we studied the cardiac injury in live-stranded cetaceans. Nine cetaceans which stranded alive on the Canary Islands (January 2016 - June 2019) were included in this study. Sampled individuals presented elevated values of plasma cTnI, which were correlated to histopathological lesions comprised of vascular changes and acute degenerative lesions. Immunohistochemically, injured cardiomyocytes showed a decreased intrafibrillar troponin immunoreaction. This is the first attempt to establish a normal baseline range for cTnI in cetaceans, and the first study comparing plasma biomarkers values with histopathological and immunohistochemical findings. This approach allowed us to demonstrate the degree of cardiac damage as a result of injury, consistent with ischemia-reperfusion lesions. The knowledge gained here could improve decision-making procedures during stressful situations, mainly in live-strandings, handling, and rehabilitation, thereby reducing the mortality of cetaceans.

Capture Myopathy and Stress Cardiomyopathy in a Live-Stranded Risso's Dolphin (Grampus griseus) in Rehabilitation

Simple Summary

Free-living cetaceans are threatened, daily, by a wide variety of stressful situations. An example is provided by live-stranding, in which a cetacean is alive on the beach or in shallow water, and unable to free itself and resume its normal activity. This is the first case of capture myopathy and stress cardiomyopathy in a live-stranded juvenile male Risso’s dolphin (Grampus griseus) with subsequent rehabilitation attempted. Valuable use of blood samples, and finally necropsy assessments, advances our understanding about the pathology common in live-stranded cetaceans.

Abstract

Capture myopathy (CM) is described in wild animals as a metabolic syndrome resulting from the extreme stress suffered during and after capture, handling, restraint, and transport. Although CM has been characterized in many species of cetaceans, descriptions of cardiac injury—an important component of this syndrome, and, according to previous authors, comparable to the existing human pathology so-called stress cardiomyopathy (SCMP)—are still rare. Therefore, the main aim of this report is to illustrate, for the first time, the biochemical analysis, and gross, histopathological, histochemical and immunohistochemical features of CM, and more specifically of the SCMP involved in this syndrome, caused by the live-stranding and consequent rehabilitation attempt, for a certain period of time, in a juvenile male Risso’s dolphin (Grampus griseus). The animal presented elevated values of creatine kinase, cardiac troponin I and blood urea nitrogen, with some variations during the rehabilitation period. Histologically, we detected vascular changes and acute degenerative lesions analogous to the ones observed in humans with SCMP. We consider this study to be an important contribution to the study of cetaceans since it could help in decision-making and treatment procedures during live-strandings and improve conservation efforts by reducing the mortality of these animals.

Skeletal and Cardiac Rhabdomyolysis in a Live-Stranded Neonatal Bryde's Whale With Fetal Distress

The main objective of wildlife forensic investigation is to recognize pathologic changes and cause of death. Even though it may not always be possible to determine the specific illness and/or etiology, the description and subsequent interpretation of the injuries provide an invaluable understanding of pathology in cetacean post-mortem investigations. Although pathological studies have been previously reported in various cetacean species, such descriptions of the infraorder Mysticeti remain rare. A live-stranded neonatal Bryde's whale (Balaenoptera edeni) which subsequently died soon after the stranding, was assessed by physical exam, blood examination, gross necropsy evaluation, histopathology, and immunohistochemistry. It presented with elevated serum levels of creatine kinase, cardiac troponin I, urea, and creatinine. Microscopically, we observed keratin spicules (squamous epithelial cells) and areas of atelectasis in the lungs. Acute degeneration in the myocytes and cardiomyocytes were comparable to the findings previously described in cases of capture myopathy in live-stranded cetaceans. Immunohistochemistry biomarkers such as myoglobin, fibrinogen, and troponin were analyzed. Skeletal and myocardial damage has been documented in several cetacean species. However, this is the first reported case of skeletal and cardiac rhabdomyolysis associated with live-stranding in a newborn Bryde's whale that suffered from fetal distress.

Holter monitoring demonstrates that ventricular arrhythmias are common in cats with decompensated and compensated hypertrophic cardiomyopathy

Arrhythmias can complicate cardiac disease in cats and are a potential cause of sudden death. The aim of this study was to evaluate the presence and nature of cardiac arrhythmias, and the potential correlation between plasma serum troponin I (cTnI) concentrations and the presence or severity of arrhythmias in cats with decompensated (dHCM) and compensated hypertrophic cardiomyopathy (cHCM). Forty one client-owned cats were studied: 16 with cHCM, 15 with dHCM and 10 healthy control cats. Physical examination, echocardiography, cTnI and 24-h Holter recordings were obtained in all cats and thoracic radiographs in cats with dHCM. Cats in both HCM groups were followed for 1 year after their initial Holter examination. The median (range) number of ventricular premature complexes (VPCs) over 24h was 867 (1-35,160) in cats with dHCM, 431 (0-18,919) in cats with cHCM and 2 (0-13) in healthy control cats. The median number of episodes of ventricular tachycardia (VTach) was 0 (0-1497) in dHCM and 0.5 (0-91) in cats with cHCM. The number of VPCs, VTach episodes and heart rate was not different between the HCM groups. Plasma serum troponin I was highest in the cats with dHCM, but there was no correlation between cTnI concentration and the number of arrhythmias. Thirteen of 31 cats with HCM died, but an association with the presence and complexity of ventricular arrhythmias was not observed. Compared to healthy cats, ventricular arrhythmias were common in cats with cHCM and dHCM, but neither presence nor complexity of arrhythmias could be linked to prognosis.

Cardiac troponin I in dogs anaesthetized with propofol and sevoflurane: the influence of medetomidine premedication and inspired oxygen fraction

OBJECTIVE

To investigate changes in serum cardiac troponin I (cTnI) concentrations in dogs in which medetomidine was used for sedation or for premedication prior to anaesthesia with propofol and sevoflurane.

STUDY DESIGN

Prospective clinical study.

ANIMALS

A total of 66 client-owned dogs.

METHODS

The dogs were sedated with medetomidine (0.04 mg kg^-1) intravenously (IV) (group M; n = 20) and left to breath room air or anaesthetized with propofol (6.5 ± 0.76 mg kg^-1 IV) and sevoflurane (4.5% vaporizer setting) in oxygen (group P + S; n = 20) or with medetomidine (0.04 mg kg^-1 IV), propofol (1.92 ± 0.63 mg kg^-1) and sevoflurane (3% vaporizer setting) in oxygen (group M + P + S; n = 26), respectively. After 35 minutes, medetomidine was antagonized with atipamezole (0.1 mg kg^-1 intramuscularly). Blood samples for serum cTnI determination were taken before sedation or anaesthesia, 6 and 12 hours and 4 days thereafter. Serum cTnI concentrations were measured with the Architect STAT Troponin-I assay.

RESULTS

Before sedation or anaesthesia, cTnI concentrations were above the detection limit in 22 out of 66 (33%) of dogs. Compared to basal values, cTnI concentrations significantly increased at 6 and 12 hours in all groups and at day 4 in group M. There were no differences in cTnI concentration between groups at baseline, at 6 hours and at 4 days. At 12 hours, cTnI concentrations were significantly higher in groups M and P + S, respectively, compared to group M + P + S.

CONCLUSIONS AND CLINICAL RELEVANCE

Oxygenation during anaesthesia and reduction of propofol and sevoflurane dose due to the sparing effects of medetomidine might have played a role in alleviation of myocardial hypoxic injury as indicated by the less severe and short-lived increase of cTnI in the M + P + S group.

Diagnostic utility of cardiac troponin I in cats with hypertrophic cardiomyopathy

Background

Cardiac troponin I (cTnI) is useful for assessing hypertrophic cardiomyopathy (HCM) in cats.

Objective

To measure plasma cTnI concentrations in healthy cats and evaluate the clinical utility of cTnI in determining the severity of HCM.

Animals

Clinically healthy cats (n = 88) and cats with HCM (n = 93).

Methods

Multicenter prospective study. Cats with HCM, including hypertrophic obstructive cardiomyopathy at various stages, were diagnosed using echocardiography. Plasma cTnI concentrations were analyzed by a commercial laboratory. Receiver‐operating characteristic curve analysis was used to evaluate the accuracy of plasma cTnI concentrations to detect HCM.

Results

The median cTnI concentration was 0.027 ng/mL (interquartile range, 0.012‐0.048 ng/mL) in healthy cats. Concentrations were significantly higher in diseased cats than in healthy controls, and concentrations were significantly higher in cats with heart failure than in asymptomatic cats. A plasma cTnI concentration of 0.163 ng/mL had a sensitivity of 62.0% and specificity of 100% when used to distinguish normal cats from asymptomatic HCM cats without left atrial dilatation. A cutoff of 0.234 ng/mL had high sensitivity (95.0%) and specificity (77.8%) for assessing heart failure. The areas under the receiver‐operating characteristic curves were 0.85 and 0.93, respectively.

Conclusions and Clinical Importance

Increased cTnI concentrations reflect the severity of HCM. If other causes of cardiac injury are ruled out, plasma cTnI concentration may be useful for predicting the severity of HCM in cats.

Transient Myocardial Thickening in Cats Associated with Heart Failure

Background

Cats with hypertrophic cardiomyopathy (HCM) and congestive heart failure (CHF) can have resolution of both left ventricular hypertrophy and CHF.

Objectives

To describe the clinical characteristics of cats with transient myocardial thickening (TMT) and CHF compared with a control population of cats without resolution of HCM.

Animals

A total of 21 cats with TMT, 21 cats with HCM.

Methods

Retrospective study. Clinical records at 4 veterinary centers were searched for TMT cases and a control group of cats with HCM and CHF. TMT was defined as initial maximal left ventricular wall thickness (LVWT) ≥6 mm with left‐sided CHF, with subsequent resolution of CHF, reduction in left atrium/aorta (LA/Ao), and LVWT<5.5 mm. HCM was defined as persistent LVWT ≥6 mm.

Results

Cats with TMT were younger (2 [0.4–11.4] years) than cats with HCM (8 [1.6–14] years) (P < 0.0001), and antecedent events were more common (15/21 versus 6/21, respectively) (P = 0.01). In cats with TMT, LVWT normalized from 6.8 [6.0–9.7] mm to 4.8 [2.8–5.3] mm and LA/Ao decreased from 1.8 [1.6–2.3] to 1.45 [1.2–1.7] after a mean interval of 3.3 (95% CI: 1.8–4.7) months. CHF recurred in 1 of 21 TMT and 15 of 21 cats with HCM. Cardiac treatment was discontinued in 20 of 21 cats with TMT and 0 of 21 HCM cats. All cats with TMT survived, whereas 8 of 19 cats with HCM died during the study period.

Conclusions and Clinical Importance

TMT occurs in younger cats, and antecedent events are common. The prognosis is better in cats with CHF associated with TMT than HCM.

Plasma N-Terminal Probrain Natriuretic Peptide, Vascular Endothelial Growth Factor, and Cardiac Troponin I as Novel Biomarkers of Hypertensive Disease and Target Organ Damage in Cats

Background

In the absence of ocular target organ damage (ocular‐TOD), diagnosis of hypertension is challenging in cats. Biomarkers would provide additional support for the diagnosis of hypertension.

Hypothesis

Vascular endothelial growth factor (VEGF), N‐terminal probrain natriuretic peptide (NT‐proBNP), cardiac troponin I (cTnI), and urine protein‐to‐creatinine ratio (UPC) are predictors of systemic hypertension, will be increased in cats with hypertension with or without ocular‐TOD, and will decrease with antihypertensive treatment.

Methods

Plasma VEGF, NT‐proBNP, and cTnI concentrations and UPC were determined in healthy geriatric cats, normotensive cats with chronic kidney disease (CKD), hypertensive cats with evidence of hypertensive retinopathy (HT‐ocular‐TOD), and hypertensive cats without hypertensive ocular‐TOD (HT‐noTOD). Comparisons among groups were performed. Multivariable binary logistic regression models were built to identify independent biomarkers of hypertension and ocular‐TOD. Receiver operator characteristic (ROC) curves were drawn to assess clinical use.

Results

Cats with HT‐ocular‐TOD had significantly higher VEGF than all other groups (P < .05) and significantly higher NT‐proBNP than healthy cats (P < .001). Healthy cats had significantly lower cTnI than all other groups (P < .05). No differences were found among groups for UPC (P = .08). Cardiac troponin I and VEGF were independent predictors of hypertension (P < .05), but none of the biomarkers were independent predictors of ocular‐TOD. N‐terminal probrain natriuretic peptide concentrations decreased with antihypertensive treatment (P < .001). The ROC curves indicated that none of the biomarkers met the criteria to function as diagnostic tests for the diagnosis of hypertension or associated ocular‐TOD.

Conclusions and Clinical Significance

Despite statistical significance and changes with ocular‐TOD, antihypertensive treatment, or both, VEGF, NT‐proBNP, and cTnI did not function as useful diagnostic tests for hypertension. Persistently increased systolic blood pressure (SBP) measurements in combination with fundoscopy remains the preferred method for diagnosis of feline hypertension.

Extraneuronal pathology in a canine model of CLN2 neuronal ceroid lipofuscinosis after intracerebroventricular gene therapy that delays neurological disease progression

CLN2 neuronal ceroid lipofuscinosis is a hereditary lysosomal storage disease with primarily neurological signs that results from mutations in TPP1, which encodes the lysosomal enzyme tripeptidyl peptidase-1 (TPP1). Studies using a canine model for this disorder demonstrated that delivery of TPP1 enzyme to the cerebrospinal fluid (CSF) by intracerebroventricular administration of an AAV-TPP1 vector resulted in substantial delays in the onset and progression of neurological signs and prolongation of life span. We hypothesized that the treatment may not deliver therapeutic levels of this protein to tissues outside the central nervous system that also require TPP1 for normal lysosomal function. To test this hypothesis, dogs treated with CSF administration of AAV-TPP1 were evaluated for the development of non-neuronal pathology. Affected treated dogs exhibited progressive cardiac pathology reflected by elevated plasma cardiac troponin-1, impaired cardiac function and development of histopathological myocardial lesions. Progressive increases in the plasma activity levels of alanine aminotransferase and creatine kinase indicated development of pathology in the liver and muscles. The treatment also did not prevent disease-related accumulation of lysosomal storage bodies in the heart or liver. These studies indicate that optimal treatment outcomes for CLN2 disease may require delivery of TPP1 systemically as well as directly to the central nervous system.

Bartonella-associated inflammatory cardiomyopathy in a dog

A 6-year-old, male, mongrel dog was presented for acute onset of dyspnea and cough. At admission, the dog was cachectic and severely depressed. The electrocardiogram showed a sinus rhythm conducted with left bundle truncular branch block and interrupted by frequent multiform ventricular ectopic beats organized in allorhythmias. Thoracic radiographs revealed a marked cardiomegaly with perihilar edema, whereas transthoracic echocardiography revealed a dilated cardiomyopathy with segmental dyskinesis. Furosemide, enalapril, pimobendan, and mexiletine were prescribed, and a Holter was scheduled after resolution of congestive heart failure. Three days later, the dog died suddenly during sleep. Histopathology revealed diffuse myocyte hypertrophy with multifocal hemorrhages, alternating to areas of severe replacement fibrosis and lymphoplasmocytic infiltrates. Immunohystochemistry stains were strongly positive for T-lymphocyte infiltration (CD3) and weakly positive for B-lymphocytes (CD79). Polymerase chain reaction was positive for Bartonella spp. Based on these results, a post-mortem diagnosis of bacterial inflammatory cardiomyopathy was made.

Cloning and Sequencing of Equine Cardiac Troponin I and Confirmation of Its Usefulness as a Target Analyte for Commercial Troponin I Analyzers

The analysis of cardiac troponin I (cTnI) in the diagnosis of myocardial injury in domestic animals is gaining popularity. In this study, equine cTnI was sequenced and compared with previously characterized cTnI from other species. A 6-amino-acid N-terminal deletion unique to the horse was identified. This deletion was outside the epitope region of cTnI recognized by most commercial immunoassays and did not affect the ability of a commercial analyzer system to detect recombinant equine cTnI. No function could be ascribed to the deleted portion. These data support the use of commercial analyzers in measuring equine cTnI.

The diagnostic value of two commercially available human cTnI assays in goat kids with myocarditis

BACKGROUND

Cardiac troponin I (cTnI) is a peripheral blood marker for myocardial damage. Because of the unavailability of goat-specific cTnI assays human cTnI assays may be validated for detection of myocarditis in goat kids.

OBJECTIVES

The purpose of the study was to evaluate 2 commercially available human cTnI assays in goat kids with myocardial damage, and to determine the cTnI expression in cardiac muscle.

MATERIALS AND METHODS

Plasma cTnI concentrations were measured in healthy goat kids (n = 7) and goat kids with myocardial damage (n = 8) using the Beckman Coulter Access Accu TnI and the Biomérieux Vidas Ultra. The results were correlated with gross necropsy and histopathologic findings, and cTnI immunhistochemistry in cardiac tissue.

RESULTS

Macro- and microscopic findings confirmed myocardial damage in the myocarditis group. Mean plasma cTnI concentration was significantly higher in the myocarditis group than in the healthy control group (104.82 vs 0.02 ng/mL). The overall mean plasma cTnI concentration measured by Biomérieux Vidas Ultra (61.75 ng/mL, 95% CI: 19.55-103.95) was comparable to the mean measured by Beckman Coulter Access Accu TnI (50.08 ng/mL, 95% CI: 24.11-76.06), and cTnI concentrations measured by these assays were highly correlated (r = .977) with a -6.2% bias. Both assays were precise and accurate.

CONCLUSION

The human-specific Beckman Coulter Access Accu TnI and the Biomérieux Vidas Ultra can be used for diagnostic confirmation of myocardial damage in caprine medicine.

Cardiac Troponins in Dogs and Cats

Cardiac troponins are sensitive and specific markers of myocardial injury. The troponin concentration can be thought of as a quantitative measure of the degree of injury sustained by the heart, however, it provides no information on the cause of injury or the mechanism of troponin release. Conventionally, the cardiac troponins have been used for diagnosis of acute myocardial infarction in humans and have become the gold standard biomarkers for this indication. They have become increasingly recognized as an objective measure of cardiomyocyte status in both cardiac and noncardiac disease, supplying additional information to that provided by echocardiography and ECG. Injury to cardiomyocytes can occur through a variety of mechanisms with subsequent release of troponins. Independent of the underlying disease or the mechanism of troponin release, the presence of myocardial injury is associated with an increased risk of death. As increasingly sensitive assays are introduced, the frequent occurrence of myocardial injury is becoming apparent, and our understanding of its causes and importance is constantly evolving. Presently troponins are valuable for detecting a subgroup of patients with higher risk of death. Future research is needed to clarify whether troponins can serve as monitoring tools guiding treatment, whether administering more aggressive treatment to patients with evidence of myocardial injury is beneficial, and whether normalizing of troponin concentrations in patients presenting with evidence of myocardial injury is associated with reduced risk of death.

Avaliação dos valores de troponina I, eletrocardiograma e ecocardiograma em felinos sedados com cetamina e midazolam, suplementados ou não com oxigênio

Lesões no miocárdio, causadas por baixa perfusão e oxigenação cardíaca, podem ser ocasionadas por fármacos anestésicos, como a cetamina. Essas lesões podem ser identificadas por meio de biomarcadores específicos e, dentre estes, destaca-se a troponina I. O objetivo deste estudo foi avaliar as alterações cardiovasculares com base nos valores de troponina I (TnI), eletrocardiograma (ECG) e ecocardiograma em gatos sedados com cetamina e midazolam, suplementados ou não com oxigênio. Utilizaram-se 12 gatos machos, hígidos, nos quais se avaliaram os valores de troponina I, eletro e ecocardiografia, frequência cardíaca (FC) e pressão arterial sistólica (PAS) no momento basal (M0). Na sequência, os animais foram sedados com a associação de 10mg.kg-1 de cetamina e 0,5mg.kg-1 de midazolam pela via intramuscular. Decorridos aproximadamente 10 minutos, os animais foram alocados aleatoriamente em dois grupos: com e sem suplementação de oxigênio via máscara facial (GCO e GSO, respectivamente), sendo submetidos novamente aos exames citados. Foram coletadas amostras sanguíneas, para dosagem de TnI em seis, 12 e 24 horas após a administração dos agentes anestésicos. Não foram observadas alterações significativas na FC, na PAS e no ECG após a administração dos tratamentos em ambos os grupos. Os valores médios de TnI elevaram-se significativamente em T6 quando comparados ao basal em ambos os grupos, com médias de 0,507±0,335ng/mL no GSO e 0,777±0,505ng/mL no GCO. Na ecocardiografia, o débito cardíaco (DC) reduziu em M1 em ambos os grupos, quando comparados aos valores basais, sendo M0 0,472±0,115 e M1 0,234±0,08 no GSO e M0 0,356±0,095 e M1 0,222±0,09 no GCO, expressos em L/min. Conclui-se que a administração de cetamina e midazolam em gatos hígidos não promove alterações eletrocardiográficas, aumenta os valores de troponina I, com pico de seis horas após a administração, reduz o débito cardíaco, e que a suplementação de oxigênio 100% via máscara facial não atenua tais alterações.

Clinical and histopathological features of myocarditis in dogs with visceral leishmaniasis

Visceral leishmaniasis (VL) is a cosmopolitan parasitic zoonosis that can promote myocarditis and heart rate changes in canine and human hosts. Thus, histopathological aspects of the myocardium and clinical, hematological, biochemical, radiological and electrocardiographic data were evaluated in a group of 36 dogs naturally infected with VL (VLG) and compared to data from 15 non-infected dogs (CG=Control Group). A prevalence of asymptomatic dogs was present in the CG (100%) and polysymptomatic dogs in the VLG (66%). In addition, two dogs in the VLG demonstrated systolic murmurs in the mitral valve region: one with a II/VI intensity and the other with a III/VI intensity. The mean values of RBC, hemoglobin and hematocrit were lower in dogs in VLG and were associated with higher values of total protein, total leukocytes, neutrophils, creatine kinase overall (CK) and the CK-MB fraction (CK-MB). The absence of radiographic changes was accompanied by a predominance of respiratory sinus arrhythmia associated with episodes of migratory pacemaker and sinus arrest in dogs in VLG (75%), sinus rhythm in dogs in CG (60%) and decreased P wave amplitude in VLG electrocardiography. Mononuclear cell infiltration was detected in the myocardium of 77,8% of dogs in GVL and classified primarily as mild multifocal lymphohistioplasmacytic. Amastigotes were detected in only one dog, which did not allow the association between myocarditis and parasitism, although the myocardial lesions that were found constitute irrefutable evidence of myocarditis in the VLG dogs, accompanied by lenient electrocardiographic changes compared to CG.

CREATINAFOSFOQUINASE-ISOENZIMA MB MASSA (CK-MB MASSA) E TROPONINA I (cTnI) EM CÃES (<italic>Canis familiaris</italic>)

<title>Resumo</title><p>Os marcadores cardíacos, sobretudo a CK-MB massa e a cTnI, tem demonstrado um papel essencial seja em cardiologia clínica ou cirúrgica veterinária e humana, permitindo um diagnóstico mais preciso e acurado nas lesões miocárdicas. O objetivo deste trabalho foi mensurar os marcadores cardíacos em tela na Medicina Veterinária, aprimorar sua utilização e obter informações sobre estes métodos laboratoriais não invasivos que permitem o monitoramento da integridade da célula miocárdica. A quantificação dos parâmetros foi feita do soro de cães saudáveis atendidos na rotina do setor de Clínica Médica de Pequenos Animais do Hospital Veterinário da Universidade Estadual do Norte Fluminense Darcy Ribeiro. O kit de ensaio imunométrico por quimioluminescência turbo (IMMULITE Turbo, Siemens®) humano mostrou-se eficaz na avaliação na espécie canina, tanto para CK-MB massa quanto cTnI. Além disso, os valores encontrados para CK-MB massa e cTnI contribuirão significativamente para a rotina clínica ou para os trabalhos experimentais em cães.</p>

Myocarditis in dogs: etiology, clinical and histopathological features (11 cases: 2007-2013)

Background

Myocarditis is a disease caused by numerous etiological factors and characterized by a non-specific course. The only method allowing for precise characterization of inflammatory changes is the histopathological examination of heart muscle specimens. The study was conducted on heart muscle preparations from 11 dogs with ante-mortem diagnosis of cardiac disease. Animals presented with a poor response to an applied treatment or had suspected sudden cardiac death. The heart specimens were taken post-mortem, preserved and stained with haematoxylin and eosin. Subsequently, the presence and intensity of changes, i.e. inflammatory infiltration, the amount of connective tissue and features of cardiomyocyte degeneration were estimated. The specimens from dogs suspected of having a myocarditis of bacteriological etiology underwent additional bacteriological and immunohistochemical examination.

Results

The examination revealed an inflammatory infiltration of variable intensity combined with the degenerative changes in all dogs. There were vegetative and abnormal cystic forms of Borrelia burgdorferi sensu lato in 6 dogs. A Staphylococcus aureus infection was confirmed in one dog and an acute coronary syndrome with neutrophil infiltration was revealed in another one.

Conclusions

Although the clinical pattern in patients with myocarditis is diverse, the definitive morphological diagnosis is made based on the histopathological examination. This examination can lead to a better understanding of the pathogenesis of the disease. To the best of our knowledge, this is the first description of myocarditis combined with the presence of spore forms of Borrelia burgdorferi sensu lato in the heart specimens of dogs.

Electronic supplementary material

The online version of this article (doi:10.1186/s13620-014-0028-8) contains supplementary material, which is available to authorized users.

Surgical management of a traumatic dislocation of the sternum in an English bulldog

A nine-year-old English bulldog presented with an acute history of dyspnoea, tachycardia and discomfort localising to the ventral thorax following a fall down the stairs that morning. After the dog was stabilised, thoracic radiographs revealed a luxation of the third and fourth sternebrae with dorsal displacement of the caudal segment. The sternum was reduced and stabilised with a contoured 12-hole 3 · 5-mm dynamic compression plate applied to the ventral surface of the sternum. The dog's initial recovery was rapid, cardiorespiratory parameters returning to normal in the first 24 hours. For 2 weeks postoperatively the dog exhibited difficulty in rising from a prone position. After this time there was a full recovery. Clinical examination at 8 months postoperatively did not reveal any abnormalities. Telephone follow-up was performed at 18 months and no complications or cardiorespiratory compromise were reported. To the authors' knowledge, this is the first reported case of a traumatic dislocation of the sternum and its management in the dog.

Serum Cardiac Troponin I concentrations in cats with anaemia - a preliminary, single-centre observational study

OBJECTIVES

A range of cardiovascular abnormalities have been associated with anaemia. However, it remains unclear whether anaemia is associated with cardiac myocyte damage in cats. The aim of this study was to assess if cats with anaemia have an increased prevalence of cardiac myocyte damage, as assessed by serum concentrations of cardiac troponin I, compared to non-anaemic, ill cats.

METHODS

Serum cardiac troponin I concentrations were measured in 18 anaemic cats and in 31 non-anaemic, ill cats with non-primary cardiac, non-renal and non-primary haematological disorders.

RESULTS

The serum cardiac troponin I concentrations in the anaemic group (0·43 ng/mL) were significantly higher (P=0·0002) than in the non-anaemic ill group (0·04 ng/mL). Using a cut-off of less than 0·16 ng/mL, 12 of the 18 anaemic cats had an increased serum cardiac troponin I concentration, which was significantly higher (P=0·005) than the non-anaemic ill cats (7 of 31 cats).

CLINICAL SIGNIFICANCE

Serum cardiac troponin I concentrations were higher in cats with anaemia in this study. Further studies are required to establish whether the anaemia or other confounding factors is the cause of the increased serum cardiac troponin I concentrations.

Influence of the cardiac glycoside digoxin on cardiac troponin I, acid-base and electrolyte balance, and haematobiochemical profiles in healthy donkeys (Equus asinus)

BACKGROUND

The effect of digoxin administration on the serum concentration of the cardiac troponin I (cTnI) has not been reported to date in equidae. This study was therefore designed to evaluate the effect of digoxin on cardiac cell damage in donkeys (Equus asinus) as assessed by cTnI, acid-base and electrolyte balance and haematobiochemical profiles. Ten clinically healthy donkeys were given an IV infusion of digoxin at a dose of 14 μg/kg. Blood samples were collected from the donkeys up through 72 h post-injection.

RESULTS

Three of the donkeys exhibited increased heart and respiratory rates post-injection. In the other seven animals, the heart and respiratory rates were lower 4 h post-injection. The serum digoxin concentration increased significantly at many time points after injection. The serum concentration of cTnI did not differ significantly between pre- and post-injection. An increase in blood pH was noted at 3 h after digoxin injection. There were also increases in PO2 and in oxygen saturation. Decreases in PCO2 at 2 to 48 h post-injection as well as a decrease in blood lactate at 4 h post-injection were observed. The serum concentration of glucose remained significantly elevated at all-time points after digoxin injection.

CONCLUSIONS

It is concluded that administration of digoxin to healthy donkeys (14 μg/kg) did not result in elevations of serum cTnI concentration, signs of digoxin intoxication, ECG abnormalities and did not increase serum concentrations of blood urea nitrogen and creatinine.

Blood cardiac troponin in toxic myocardial injury: archetype of a translational safety biomarker

A translational safety biomarker for toxic myocardial injury is needed in drug discovery and development. This need reflects the increasing recognition of occurrence of cardiotoxicities, prior lack of preclinical blood biomarkers for toxic cardiac injury, introduction of troponin as a biomarker, and regulatory and industry drivers. Cardiac troponin is considered the gold-standard biomarker in humans for cardiac injury due to ischemic injury and drug toxicity. It has been demonstrated to correlate highly with histopathological extent of injury, degree of impairment of cardiac function, and prognosis. Numerous studies have now clearly demonstrated that both cardiac troponin T and cardiac troponin I are sensitive and specific biomarkers of cardiac injury in laboratory animals. Their use is highly recommended for incorporation into preclinical drug-safety studies, especially whenever there is any history of cardiac effect in prior studies with a compound of the same or similar chemical or pharmacological class. The main caveats with respect to cross-species use of specific cardiac troponin assays are the need for species-specific validation, definition of cut-offs based on relevant assessments of imprecision and reference ranges or concurrent controls, and knowledge of the species-dependent kinetics of release into, and clearance from, the blood. Future development of high-sensitivity assays should determine whether minimal increases below a threshold concentration of troponin might reflect reversible myocardial effects.

Cardiac biomarkers in hyperthyroid cats

Background

Hyperthyroidism has substantial effects on the circulatory system. The cardiac biomarkers NT‐proBNP and troponin I (cTNI) have proven useful in identifying cats with myocardial disease but have not been extensively investigated in hyperthyroidism.

Hypothesis

Plasma NT‐proBNP and cTNI concentrations are higher in cats with primary myocardial disease than in cats with hyperthyroidism and higher in cats with hyperthyroidism than in healthy control cats.

Animals

Twenty‐three hyperthyroid cats, 17 cats with subclinical hypertrophic cardiomyopathy (HCM), and 19 euthyroid, normotensive healthy cats ≥8 years of age. Fourteen of the hyperthyroid cats were re‐evaluated 3 months after administration of radioiodine (¹³¹I).

Methods

Complete history, physical examination, complete blood count, serum biochemistries, urinalysis, blood pressure measurement, serum T4 concentration, plasma concentrations of NT‐proBNP and cTNI, and echocardiogram were obtained prospectively from each cat.

Results

Hyperthyroid cats and cats with HCM had plasma NT‐proBNP and cTNI concentrations that were significantly higher than those of healthy cats, but there was no significant difference between hyperthyroid cats and cats with HCM with respect to the concentration of either biomarker. In hyperthyroid cats that were re‐evaluated 3 months after ¹³¹I treatment, plasma NT‐proBNP and cTNI concentrations as well as ventricular wall thickness had decreased significantly.

Conclusions and Clinical Importance

Although there may be a role for NT‐proBNP in monitoring the cardiac response to treatment of hyperthyroidism, neither NT‐proBNP nor cTNI distinguish hypertrophy associated with hyperthyroidism from primary HCM. Therefore, the thyroid status of older cats should be ascertained before interpreting NT‐proBNP and cTNI concentrations.

Evaluation of a high-sensitivity assay for measurement of canine and feline serum cardiac troponin I

BACKGROUND

Cardiac troponins are established as the gold standard biomarkers for acute cardiac injury. As even small elevations of cardiac troponins have prognostic relevance in people, it is important to investigate the performance of sensitive assays for use in veterinary medicine.

OBJECTIVES

The aim of this study was to evaluate analytical and overlap performance of a high-sensitivity cardiac troponin I (cTnI) assay, the ADVIA Centaur CP TnI-Ultra assay, in dogs and cats.

METHODS

Serum samples from dogs and cats with cardiac disease or arrhythmias, along with samples of purified canine free cTnI and complexed cTnI, T, and C (cTnI-T-C) were used in the assay validation study. Intra- and inter-assay variation, linearity under dilution, spike-and-recovery analysis, and detection limit were investigated to assess analytical performance. Overlap performance was evaluated based on the ability of the assay to discriminate between healthy animals and animals with cardiac disease or arrhythmias.

RESULTS

Intra-assay variation of cTnI in canine and feline serum ranged from 3.9 to 6.4% and from 4.0 to 4.8%, respectively. Inter-assay variation ranged from 2.7 to 4.7% and from 4.0 to 7.8%, respectively. The assay demonstrated acceptable linearity under dilution within a clinically relevant range of cTnI concentrations. Spike-and-recovery analysis showed excessive recovery in the range 150.7%-242.0% for free cTnI and 121.1-196.3% for complexed cTnI-T-C, partly due to a matrix effect. Overlap performance was acceptable as animals with cardiac disease or arrhythmias (n = 45 dogs, n = 53 cats) had significantly higher cTnI concentrations than healthy controls (P < .0001).

CONCLUSIONS

The results confirm the ADVIA Centaur CP TnI-Ultra assay as a valuable tool for assessing cTnI and thus myocardial injury in dogs and cats.

Cardiac biomarker changes in camels (Camelus dromedarius) secondary to road transportation

OBJECTIVES

Little is known about cardiac biomarkers in camels despite their extensive use as draft animals. This study was designed to establish reference ranges for the cardiac biomarkers cardiac troponin I (cTnI) and creatine kinase myocardial b fraction (CK-MB) in healthy camels and to investigate their changes in response to road transportation.

ANIMALS

Twenty-five healthy camels transported for a 5 h round-trip journey.

METHODS

None of the camels had evidence of cardiac abnormalities on cardiac auscultation, echocardiography or electrocardiography. Three blood samples were obtained from each camel: 24 h before transportation (T0), within 2 h after unloading (T1) and 24 h after transportation (T2).

RESULTS

The mean cTnI concentration in the camels was 0.032 ± 0.023 ng/mL. All the camels had resting cTnI concentrations of <0.08 ng/mL. At T1, the cTnI concentration was significantly higher (P < 0.001) in all 25 camels compared to values at T0. The CK-MB concentration in the camels was 0.19 ± 0.05 ng/mL. All the camels had resting CK-MB concentrations of <0.33 ng/mL. At T1, the CK-MB concentration was higher in 3/25 camels compared to values at both T0 and T2. Concerning the hematobiochemical variables, significant increases were detected at T1 in total white blood cells, total protein, globulin, magnesium and phosphorus. Cardiac troponin I, CK-MB and all the hematobiochemical parameters had returned to their pre-transport values at T2.

CONCLUSIONS

5 h road transportation might have transient adverse effects on the cardiac muscle of healthy camels.

The cardiac biomarkers troponin I and CK-MB in nonpregnant and pregnant goats, goats with normal birth, goats with prolonged birth, and goats with pregnancy toxemia

This study was designed to establish the reference range for the cardiac biomarkers cardiac troponin I (cTnI) and creatine kinase myocardial band (CK-MB) in nonpregnant and pregnant goats, goats with normal birth, goats with prolonged birth associated with dystocia, and goats with pregnancy toxemia. Fifty-seven does, categorized into three groups (G1 to G3), were used. These groups were comprised of 20 healthy does (G1), 19 does with prolonged birth (G2), and 18 does with pregnancy toxemia (G3). Six blood samples (T0 to T5) were collected from G1. The first blood sample (T0) was taken before insemination, the second (T1) at the first trimester, the third (T2) at the second trimester, the fourth (T3) at the last trimester, the fifth (T4) within 12 h of parturition, and the sixth blood sample (T5) was taken 10 days after parturition. A sample of blood was obtained from G2 and G3 upon admission to the hospital. At T0 to T3, no cTnI was detected in any of the 20 does in G1. At parturition (T4), seven of the 20 goats (35%) exhibited slightly elevated cTnI concentrations (range, 0.01 to 0.04 ng/mL). Ten days after parturition (T5), cTnI was not detected in any of the 20 goats. In 10 of the 19 goats (53%) with prolonged birth (G2), the cTnI was significantly elevated to a mean value of 0.094 ± 0.155 ng/mL, with a maximum value of 0.61 ng/mL. In 16 of the 18 goats (89%) with pregnancy toxemia (G3), the cTnI was significantly elevated to a value of 0.852 ± 1.472 ng/mL, with a maximum value of 5.219 ng/mL. Comparing the values of CK-MB in G1 (T0 to T5), G2 and G3 revealed nonsignificant differences. Only a slight elevation in the CK-MB levels in goats with prolonged birth (G2) was noted. We concluded that in healthy does, the cardiac biomarker cTnI is not elevated during normal pregnancy. The serum cTnI concentration may be elevated in a number of goats at normal vaginal or cesarean delivery. Finally, cTnI is significantly elevated in does with pregnancy toxemia and could be used as a prognostic indicator in such cases. The cardiac biomarker CK-MB is not a good indicator of parturition stress in does. Serum cTnI is elevated in goats with pregnancy toxemia, indicating some degree of cardiac dysfunction.

Cardiac troponin I concentrations in normal dogs and cats using a bedside analyzer

OBJECTIVE

To develop reference ranges for cardiac troponin I (cTnI) in normal dogs and cats using the Biosite Triage Meter((R)).

BACKGROUND

Reference ranges for cTnI in dogs and cats have not yet been reported for this inexpensive bedside analyzer.

METHODS

Purified free canine cTnI was diluted to 5 known concentrations to assess linearity and recovery. Interassay and intraassay precision were evaluated using 3 dilutions obtained from a dog with an elevated cTnI concentration. EDTA plasma was obtained from 55 normal dogs and 58 normal cats for analysis of cTnI.

RESULTS

Measured values of purified cTnI closely matched calculated concentrations (r(2)=0.997) and recovery ranged from 107-164%. Intraassay precision was 2.76+/-1.20% and interassay precision was 8.50+/-4.19%. The dogs were 4.8+/-3.1 years and 24.4+/-11.2kg (27 Mc, 19 Fs, 5 M, 4 F). The cats were 4.9+/-2.8 years and 5.1+/-1.19kg (36 Mc, 22 Fs). The median and range (5th and 95th percentile) of cTnI for dogs were <0.05ng/mL (<0.05-0.12). The median cTnI for cats was <0.05ng/mL, as was the range, because only 3 cats (the upper 5% of the population) had detectable cTnI concentrations. The lower limit of detection for this assay is 0.05ng/mL.

CONCLUSIONS

This study provides reference ranges for cTnI in dogs and cats using the Triage Meter((R)), an affordable bedside analyzer. The availability of reference ranges for this machine may increase clinical use and research of this marker in veterinary medicine.

Embolised mesothelial cells in a tracheobronchial lymph node associated with idiopathic chylopericardium in a dog

A 5·5-year-old male castrated Bernese mountain dog presented with respiratory difficulties and was diagnosed with haemorrhagic pericardial effusion which transformed into chylopericardium. Thoracic duct ligation and subtotal pericardiectomy in combination with biopsy of an enlarged tracheobronchial lymph node were performed. Multiple clusters of mesothelial cell emboli were observed in the subcapsular sinus of the lymph node. No causative agent for the pericardial effusion could be identified, suggesting that this is a case of mesothelial cell embolisation associated with idiopathic -chylopericardium in a dog.

Increased plasma cardiac troponin I concentration in lambs with myocarditis

BACKGROUND

Cardiac troponin I (cTnI) is a blood biomarker of myocardial injury. A human cTnI assay may be useful for measuring cTnI concentrations in lambs with naturally occurring myocarditis.

OBJECTIVE

The aims of this study were to evaluate the utility of a commercially available human chemiluminescent microparticle cTnI immunoassay for measuring plasma cTnI concentrations in lambs with naturally occurring myocarditis from infection with foot and mouth disease virus (FMDV), and to determine cTnI expression in cardiac muscle of affected lambs.

METHODS

Ten lambs with myocarditis and 10 clinically healthy lambs (control group) were included. Clinical signs, gross and histologic necropsy findings, and immunoreactivity for cTnI in cardiac tissue were evaluated. Plasma cTnI concentration was determined using the commercial human immunoassay system.

RESULTS

All lambs with myocarditis died within 1 day of clinical signs. Infection with FMDV was confirmed by PCR analysis. Gross cardiac lesions were evident and histologic examination revealed myocarditis. Immunoreactivity for cTnI was absent in cardiac myocytes that were degenerative or necrotic, but was strong in cardiac myocytes from unaffected areas of the myocardium and in all cardiac myocytes of healthy lambs. The geometric mean plasma concentrations of cTnI for lambs in the myocarditis and control groups were 146.78 μg/L (95% confidence interval [CI], 61.90-348.06) and 0.013 μg/L (95% CI, 0.010-0.017), respectively (t-value 19.27; P < .0001).

CONCLUSIONS

A commercial human cTnI assay may be used to detect plasma cTnI concentrations in sheep, and cTnI may be used as a blood-based biomarker of myocarditis in this species.

Caracterização clínica e laboratorial de cães naturalmente infectados com Trypanosoma cruzi no semiárido nordestino

Objetivou-se, com este estudo, evidenciar os sinais clínicos e laboratoriais desta enfermidade para auxiliar na caracterização da doença de forma natural na área semi-árida da região nordeste. Foram avaliados 10 cães positivos para Trypanosoma cruzi, identificados mediante análises sorológicas de reação de imunofluorescência indireta (RIFI) e enzyme linked immunosorbent assay (ELISA); análise molecular pela Reação em Cadeia Polimerase (PCR), microscopia direta e hemocultura. Os cães chagásicos foram submetidos à avaliação física, verificação da pressão arterial, exames eletrocardiográficos, radiográficos, hematológicos (eritrograma e leucograma) e bioquímicos (ureia, creatinina, ALT, AST, PT, albumina, globulina, CK, CK-MB e cTnI). O exame físico e os valores das pressões arteriais dos cães apresentaram dentro dos parâmetros de normalidade, enquanto que na eletrocardiografia observou-se FC normal com ritmo sinusal, com exceção de um cão, que apresentou taquicardia sinusal (168 bat/min). No ECG de oito cães houve aumento da duração de P (47±6,5ms) sugestivo de aumento atrial, não confirmado radiograficamente. Foi observado supradesnivelamento do segmento ST em um cão. Nos resultados hematológicos constatou-se trombocitopenia (187,4x10³ ±137,2x10³) e anemia (5,0x10(6) ±1,39x10(6)/uL). Os valores médios da hemoglobina (11±2,7g/dL) e do hematócrito (34±10,5%) estavam abaixo dos limites de normalidade. A série branca apresentou-se dentro dos limites de normalidade, com exceção da eosinofilia observada em três cães. Individualmente, registrou-se em dois cães, leucocitose, linfocitose e neutrofilia. Na avaliação bioquímica, registrou-se hiperproteinemia (7,2±0,9g/dL), hipoalbuminemia (2,2±0,4g/dL), hiperglobulinemia (5,1±1,0g/dL) e aumento da CK (196±171U/L). Não houve alteração nas enzimas ALT e AST. A isoenzima CK-MB e o cTnI alteraram somente em três cães. Os cães infectados naturalmente no semiárido nordestino apresentam características relacionáveis à forma crônica indeterminada, ou seja, cães assintomáticos. A identificação dos cães infectados naturalmente sem características patognomônicas da doença de Chagas ressalta a importância desta enfermidade no processo diagnóstico com as demais que manifestam perfis inespecíficos associados ou não às doenças cardiovasculares.

Elimination half-life of intravenously administered equine cardiac troponin I in healthy ponies

REASONS FOR PERFORMING STUDY

To date, no information is available on the true biological elimination half-life (T(1/2) ) of cardiac troponin I (cTnI) in the equine species. Such data are required to better evaluate the optimal time to acquire the cTnI sample following acute myocardial injury.

OBJECTIVE

To determine the T(1/2) of equine cTnI.

METHODS

Four healthy ponies received i.v. injections of recombinant equine cTnI. Plasma cTnI concentrations were measured with a point-of-care cTnI analyser at multiple time points after injection. Standard pharmacokinetic analysis was performed to establish the T(1/2) of cTnI.

RESULTS

The average T(1/2) of cTnI was determined to be 0.47 h using a single rate elimination model.

CONCLUSION

The elimination of recombinant equine cTnI following i.v. administration is very rapid. Establishing the T(1/2 ) of troponin provides critical information in understanding the clinical application of this cardiac biomarker in equine practice.

Measurement of cardiac troponin I utilizing a point of care analyzer in healthy alpacas

BACKGROUND

Myocardial disease in camelids is poorly characterized. Nutritional (selenium deficiency) and toxic (ionophore toxicity) myocardial disease have been reported in camelids. Diagnosis and management of these and other myocardial diseases might be enhanced by evaluating cardiac troponin I (cTnI) concentrations. No information about cTnI reference intervals in camelids is currently available.

HYPOTHESIS/OBJECTIVES

(A) To determine cTnI concentrations obtained using a point of care i-STAT(®)1 analyzer (Heska Corporation) in healthy alpacas; (B) to compare alpaca cTnI concentrations between heparinized whole blood and plasma samples and between 2 different storage conditions (4 °C for 24 h or -80 °C for 30 days); (C) to examine assay reproducibility using the i-STAT(®)1.

ANIMALS, MATERIALS AND METHODS

23 healthy alpacas were evaluated. Blood and plasma samples were analyzed by the i-STAT(®)1 within 1 h of collection. Aliquots of plasma were stored at either 4 °C for 24 h or -80 °C for 30 days, and then analyzed. Assay reproducibility was determined by comparing 2 plasma or whole blood cTnI concentrations measured on the same sample over a 10 min period.

RESULTS

Analyzer-specific plasma cTnI concentrations in clinically normal alpacas had a median of <0.02 ng/mL (range: <0.02 ng/mL to 0.07 ng/mL). Plasma and whole blood concentrations showed good agreement. Storage did not affect cTnI concentrations (p > 0.75). Plasma cTnI concentrations had coefficient of repeatability of 0.02 ng/mL.

CONCLUSIONS

The i-STAT(®)1 can measure cTnI in alpacas on both plasma and whole blood and provides similar values for both samples. Storage at 4 °C for 24 h or -80 °C for 30 days does not affect estimates of plasma cTnI. Evaluation of cTnI might be of value in assessing cardiac disease in this species.