Evaluation of the Audicor Acoustic Cardiography Device as a Diagnostic Tool in Horses with Mitral or Aortic Valve Insufficiency.

Mitral and aortic valve insufficiencies have been commonly reported in horses. The objective of this study was to establish the use of acoustic cardiography (Audicor®) in horses with aortic (AI) or mitral valve insufficiency (MI). A total of 17 healthy horses, 18 horses with AI, and 28 horses with MI were prospectively included. None of the horses was in heart failure. Echocardiography and Audicor® analyses were conducted. Electromechanical activating time (EMAT), rate-corrected EMATc, left ventricular systolic time (LVST), rate-corrected LVSTc, and intensity and persistence of the third and fourth heart sound (S3, S4) were reported by Audicor®. Graphical analysis of the three-dimensional (3D) phonocardiogram served to visually detect murmurs. Audicor® snapshot variables were compared between groups using one-way ANOVA followed by Tukey's multiple-comparisons test. The association between Audicor® snapshot variables and the corresponding echocardiographic variables was investigated by linear regression and Bland-Altman analyses. Heart murmurs were not displayed on Audicor® phonocardiograms. No significant differences were found between Audicor® variables obtained in clinically healthy horses and horses with valvular insufficiency. The Audicor® device is unable to detect heart murmurs in horses. Audicor® variables representing cardiac function are not markedly altered, and their association with corresponding echocardiographic variables is poor in horses with valvular insufficiency that are not in heart failure.

Focused cardiac ultrasound examination in the emergency and critical care horse: Training for non-specialist veterinarians and evaluation of proficiency.

BACKGROUND: Focused cardiac ultrasound examination (FoCUS) is rapidly emerging for point-of-care cardiac assessment using hand-carried ultrasound (HCU) devices. A specific FoCUS protocol for horses and adequate training guidelines currently are not available. HYPOTHESIS: To gain knowledge about the training necessary to become proficient in performing FoCUS using a HCU device. ANIMALS: Three healthy Warmblood horses were used for practical training of veterinarians and veterinary students in equine focused cardiac ultrasound (eFoCUS). METHODS: Prospective educational study. An eFoCUS protocol and 1-day training course were developed. Pre- and post-course written tests were administered to participants to evaluate proficiency in knowledge of echocardiography and echocardiographic pathology. A post-course practical examination involved performing eFoCUS and storage of representative images. Images were evaluated using an image quality score and compared between participants with some practical experience and participants with no practical experience. RESULTS: Participants' knowledge of echocardiography increased significantly. Recognition of echocardiographic pathology pre-course ranged from 40% to 90% (mean score, 65.7%) and post-course from 85% to 100% (mean score, 92%). Eighteen of 21 participants were proficient in performing eFoCUS with a median image quality score of 79% (range, 42%-95%). Image quality did not differ between participants with some practical experience compared to participants with no experience. CONCLUSIONS AND CLINICAL IMPORTANCE: Veterinarians and veterinary students independent of previous experience can become proficient in performing eFoCUS after completion of a 1-day training course.

Atrial fibrillatory rate as predictor of recurrence of atrial fibrillation in horses treated medically or with electrical cardioversion.

BACKGROUND: The recurrence rate of atrial fibrillation (AF) in horses after cardioversion to sinus rhythm (SR) is relatively high. Atrial fibrillatory rate (AFR) derived from surface ECG is considered a biomarker for electrical remodelling and could potentially be used for the prediction of successful AF cardioversion and AF recurrence. OBJECTIVES: Evaluate if AFR was associated with successful treatment and could predict AF recurrence in horses. STUDY DESIGN: Retrospective multicentre study. METHODS: Electrocardiograms (ECG) from horses with persistent AF admitted for cardioversion with either medical treatment (quinidine) or transvenous electrical cardioversion (TVEC) were included. Bipolar surface ECG recordings were analysed by spatiotemporal cancellation of QRST complexes and calculation of AFR from the remaining atrial signal. Kaplan-Meier survival curve and Cox regression analyses were performed to assess the relationship between AFR and the risk of AF recurrence. RESULTS: Of the 195 horses included, 74 received quinidine treatment and 121 were treated with TVEC. Ten horses did not cardiovert to SR after quinidine treatment and AFR was higher in these, compared with the horses that successfully cardioverted to SR (median [interquartile range]), (383 [367-422] vs 351 [332-389] fibrillations per minute (fpm), P < .01). Within the first 180 days following AF cardioversion, 12% of the quinidine and 34% of TVEC horses had AF recurrence. For the horses successfully cardioverted with TVEC, AFR above 380 fpm was significantly associated with AF recurrence (hazard ratio = 2.4, 95% confidence interval 1.2-4.8, P = .01). MAIN LIMITATIONS: The treatment groups were different and not randomly allocated, therefore the two treatments cannot be compared. Medical records and the follow-up strategy varied between the centres. CONCLUSIONS: High AFR is associated with failure of quinidine cardioversion and AF recurrence after successful TVEC. As a noninvasive marker that can be retrieved from surface ECG, AFR can be clinically useful in predicting the probability of responding to quinidine treatment as well as maintaining SR after electrical cardioversion.

Heart rate variability analysis in horses for the diagnosis of arrhythmias.

Heart rate variability (HRV) analysis has been performed on ECG-derived data sets for more than 170 years but is currently undergoing a rapid evolution, thanks to the expansion of the human and veterinary medical technology sector. Traditional HRV analysis was initially performed to identify changes in vago-sympathetic balance, while the most recent focus has expanded to include the use of complex computer algorithms, neural networks and machine learning technology to identify cardiac arrhythmias, particularly atrial fibrillation (AF). Some of these techniques have recently been translated for use in the field of equine cardiology, with particular focus on improving the diagnosis of arrhythmias both at rest and during exercise. This review focuses on understanding the basic HRV variables and important factors to consider when collecting data for use in HRV analysis. In addition, the use of HRV analysis for the diagnosis of arrhythmias is discussed from human, small animal and equine perspectives. Finally, the future of HRV analysis is briefly introduced, including an overview of future developments in this rapidly expanding and exciting field.

Echocardiographic assessment of left ventricular size and systolic function in Warmblood horses using linear measurements, area-based indices, and volume estimates: A retrospective database analysis.

BACKGROUND: Echocardiographic assessment of left ventricular (LV) size and function using area-based indices and volumetric estimates is not well established in horses. OBJECTIVE: To report reference intervals and measurement variability for uni-, 2-, and 3-dimensional echocardiographic indices of LV size and systolic function in Warmblood horses and to provide proof of concept for allometric scaling of variables to body weight. Unidimensional indices were to be compared to area-based indices and LV volume estimates to establish their clinical use. ANIMALS: Thirty healthy Warmblood horses and 70 Warmblood horses with a primary diagnosis of mitral regurgitation or aortic regurgitation. METHODS: Echocardiographic indices of LV size and systolic function were measured using an existing echocardiography database. Weight-related variables were scaled to body weight (BWT). Reference intervals and measurement variability were calculated, the influence of valvular regurgitation on LV size and function was investigated and agreement between different variables for detection of reduced, normal, and increased LV size and systolic function was assessed. RESULTS: Reference values for healthy Warmblood horses were reported. Measurement variability was sufficiently low for clinical use of all variables. Allometric scaling was effective to correct diastolic LV dimensions and cardiac output for differences in BWT. Various echocardiographic indices resulted in different conclusions regarding identification of LV enlargement and systolic dysfunction in healthy horses and horses with valvular regurgitation. CONCLUSIONS AND CLINICAL IMPORTANCE: Echocardiographic assessment of LV size and systolic function should include joint assessment of multiple uni- and multidimensional indices. Area-based or volumetric indices that reflect LV long-axis motion should be included.

Diagnostic value of noninvasive pulse pressure measurements in Warmblood horses with aortic regurgitation.

BACKGROUND: Noninvasive blood pressures (NIBP) and pulse pressures (PP) have not been published in horses with aortic and mitral regurgitation (AR or MR). OBJECTIVES: To investigate NIBP and PP in healthy Warmblood horses and horses with AR and MR and propose PP cutoffs to identify and stage AR severity. ANIMALS: Seventy-three Warmblood horses (healthy, 10; AR, 31; MR, 32). METHODS: Retrospective study. All horses had NIBP and an echocardiogram recorded. Cases were categorized based on severity of regurgitation. Pulse pressures were compared among healthy, MR, and AR groups and among AR severity groups. Cutoffs were determined by receiver operating characteristic curve analyses. RESULTS: Horses with AR had higher PP than horses with MR (mean difference [95% confidence interval (CI)], +17 [9-26] mm Hg, P < .001) and controls (+17 [5-30] mm Hg; P =.004). Horses with severe AR had higher PP compared those with mild (+38 [20-54] mm Hg; P < 0.001) and moderate AR (+33 [18-47] mm Hg; P < .001). The PP cutoffs to distinguish AR from MR and controls were 38 mm Hg (sensitivity [Sn], 100%; specificity [Sp], 19%) for maximal Sn and 61 mm Hg (Sn, 43%; Sp, 100%) for maximal Sp. The PP cutoffs to distinguish severe AR from mild and moderate AR were 57 mm Hg (Sn, 100%; Sp, 70%) for maximal Sn and 77 mm Hg (Sn, 75%; Sp, 100%) for maximal Sp. CONCLUSIONS AND CLINICAL IMPORTANCE: Horses with AR have increased PP. Noninvasive PP measurements interpreted with provided cutoffs may aid clinicians in diagnosing and staging severity of AR in horses.

Equine Echocardiography.

This article provides an overview on the principles of transthoracic echocardiography in horses. Indications for echocardiography, equipment, and technical considerations are discussed and a systematic approach for a complete echocardiographic examination in horses is described. Methods for assessment of chamber dimensions, allometric scaling of measurements, assessment of systolic and diastolic ventricular function, assessment of atrial function, hemodynamic assessment, and evaluation of valvular regurgitation are explained, focusing on traditional 2-dimensional (2D), motion-mode, and Doppler echocardiographic methods. Selected applications of newer echocardiographic methods, such as tissue Doppler imaging and 2D speckle tracking are also described.

The use of heart rate variability analysis to detect arrhythmias in horses undergoing a standard treadmill exercise test.

BACKGROUND: Little is known about normal heart rate variability (HRV) in horses during exercise. It can be difficult to separate premature beats from normal beat-to-beat variation at higher heart rates. OBJECTIVES: The aim was to quantify HRV in healthy horses during a high-speed treadmill-standardized exercise test (HSET) and to compare with the HRV in horses observed to have arrhythmias during exercise. ANIMALS: Thirteen healthy horses (Group H), 30 horses with arrhythmias (Group A), and 11 horses with poor performance but no observed arrhythmias (Group O). METHODS: Prospective, observational study. All horses performed a HSET with simultaneous electrocardiograph (ECG) recorded. The ECGs were corrected for artifacts, and arrhythmias noted. Percent instantaneous beat-to-beat cycle length variation (% R-R variation) was calculated, and HRV analyses were performed on trot, canter, and recovery segments. RESULTS: Group H showed between -4.4 and +3.8% R-R variation during trot and between -6.1 and +5.4% R-R variation during the canter phase of the HSET. Group A had significantly larger maximum and 1st percentile R-R shortening and lengthening compared with Group H and Group O during the recovery phase where most arrhythmias were observed. During recovery, a cutoff of 6% maximum % R-R shortening predicted the presence of arrhythmia with 88% sensitivity and 97% specificity and likelihood ratio of 26. CONCLUSIONS AND CLINICAL IMPORTANCE: Healthy horses have little instantaneous R-R variation during exercise. If a cardiac cycle shortens more than 6% from the previous cycle during the recovery phase, this R-R interval is likely to represent an arrhythmic event.

PGA (polyglycolic acid)-P4HB (poly-4-hydroxybutyrate)-Based Bioengineered Valves in the Rat Aortic Circulation.

BACKGROUND AND AIM OF THE STUDY: Bioengineered living autologous valves with remodeling and growth capacity represent a promising concept for future cardiac and venous valve repair. A meticulous understanding of the mechanisms involved in recellularization and remodeling is essential for the safe and efficient clinical translation of this technology. In this context, the first investigations of bioengineered vascular grafts in immune-incompetent or transgenic rodents represented an important step. However, the in-vivo assessment of bioengineered synthetic scaffold-based (biodegradable) valve replacements in rodent models has not been achieved to date. METHODS: Miniaturized monocuspid PGA (polyglycolic acid)-P4HB (poly-4-hydroxybutyrate)-based valves were created, incorporated into metallic stents (length 2.0 mm, diameter 1.1 mm) and introduced into catheter-based implantation devices. Wistar outbred rats (n = 8) underwent a laparotomy, abdominal aorta arteriotomy and valve delivery into the abdominal aorta. Valve placement and function were evaluated following deployment using ultrasound (Doppler- and M-mode). Explanted tissues were analyzed both macroscopically and histopathologically. RESULTS: No significant physiological or hemodynamic changes were observed, including heart rate, pressure gradients, velocity values and cardiac output before and after valve implantation. The cross-sectional area at the level of the stented valve was reduced by 22%. Valvular leaflet oscillation was observed in two animals, and thrombus formation in the stent was observed in one animal. Histological evaluation revealed cellular infiltration within 3 h in vivo, and no signs of thrombus deposition on the valvular surface. CONCLUSIONS: This study demonstrated the technical feasibility of the transcatheter implantation of bioengineered stented miniaturized valves into the infrarenal rat aorta, without affecting the animal's physiological and hemodynamic variables and with valvular oscillation in part of the implants. These results could serve as a basis for the implementation of a chronic rat in-vivo model for mechanistic studies in bioengineered valvular tissues under systemic hemodynamic conditions. Video 1: 2D ultrasonographic projection revealing graft's leaflet oscillation.

Assessment of method reliability and determination of reference intervals for rotational thromboelastometry in horses.

OBJECTIVES: To assess the measurement reliability of rotational thromboelastometry (ROTEM) measurements in horses, establish reference intervals for healthy horses, and evaluate the relationship between ROTEM variables, hematologic variables, and standard coagulation tests. DESIGN: Prospective observational study. SETTING: University teaching hospital. ANIMALS: Fifty healthy and 10 diseased adult horses. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Blood was sampled from 10 healthy and 10 diseased horses and samples were repeatedly analyzed to evaluate measurement reliability of various ROTEM variables. Four different ROTEM assays (ie, EXTEM, INTEM, FIBTEM, and APTEM) were run simultaneously under standardized conditions. The device-related, operator-related, and day-to-day variability for the majority of ROTEM variables was very low to low, as indicated by a coefficient of variation (CV) of < 15%. Most of test-retest variability of ROTEM variables appeared to be device-related. Blood samples from 50 clinically healthy horses were used to establish reference intervals for ROTEM variables. Multiple stepwise regression analyses identified associations of different ROTEM variables with hematocrit, total protein concentration, fibrinogen concentration, platelet count, prothrombin time, activated partial thromboplastin time, and thrombin time. CONCLUSIONS: ROTEM is a feasible method to evaluate coagulation in horses. Its measurement reliability is acceptable, but device-related measurement variability has to be considered. Reference intervals are presented, but the influence of hematocrit, platelet count, and fibrinogen concentration may need to be taken into account when interpreting individual test results.

Validation of the Accutrend Plus point-of-care triglyceride analyzer in horses, ponies, and donkeys.

OBJECTIVE: To assess the accuracy and reliability of a point-of-care (POC) triglyceride analyzer and to establish reference intervals for blood ([TRIG]POC/WB ) and plasma triglyceride concentrations ([TRIG]POC/PL ) in horses, ponies, and donkeys. DESIGN: Prospective study. SETTING: University teaching hospital. ANIMALS: 120 adult healthy equids (78 horses and ponies, 42 donkeys) and 79 equids suffering from hypertriglyceridemia (73 horses and ponies, 6 donkeys). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: [TRIG]POC/WB and [TRIG]POC/PL were measured using a POC analyzer and plasma triglyceride concentrations were measured using a standard laboratory assay ([TRIG]LAB/PL ). Reference intervals were determined. Test accuracy was assessed by Bland-Altman comparison of POC measurements with standard laboratory measurements and by evaluating linearity of dilutional series. Test reliability was assessed by repeated serial measurements. [TRIG]POC/WB and [TRIG]POC/PL were below the analytic range of the POC assay (<0.8 mmol/L [<70 mg/dL]) in healthy horses and ponies, whereas the reference intervals were 0.82-3.14 mmol/L (73-278 mg/dL) and 0.87-3.02 mmol/L (77-267 mg/dL), respectively, in donkeys. The POC analyzer systematically overestimated triglyceride concentrations when compared to a standard laboratory assay. The difference between [TRIG]POC/WB and [TRIG]POC/PL was small and clinically negligible. The coefficient of variation of repeated measures performed on the POC analyzer was below 10% for [TRIG]POC/WB and [TRIG]POC/PL , both in horses and donkeys and at all concentration ranges. CONCLUSIONS: The POC analyzer allows accurate and reliable measurement of [TRIG]POC/WB and [TRIG]POC/PL in horses, ponies, and donkeys in clinical settings. Assay-specific reference intervals should be determined for diagnosis and clinical monitoring of hypertriglyceridemia in equids.

Hemodynamic Assessment of a Murine Heterotopic Biventricularly Loaded Cardiac Transplant in vivo Model.

BACKGROUND: Heterotopic heart transplantation (HHT) in rodent animal models represents an important technique enabling studies on organ transplantation immunology and pharmaceutical development. Recent investigations used nonworking HHT designs, with the left ventricle (LV) bypassed in the anastomosis system. In spite of their principal success, the lack of orthogonal ventricular filling leads to myocardial atrophy. However, when focusing on the cellular and molecular mechanisms involved in the in vivo remodeling of the myocardium or cell-based cardiovascular implants, a nonworking model is suboptimal as it lacks the native-analogous hemodynamic and metabolic situation. Here we present the hemodynamic and electrical assessment of a biventricularly loaded murine HHT method without the need for a combined heart-lung transplantation approach. METHODS: Heterotopic transplantations (n = 13) were performed on C57BL/6J-(H-2b) inbred mice (n = 13 donors, n = 13 recipients) by creating end-to-side anastomoses between the donors' cranial vena cava (CrVC) and the recipients' abdominal caudal vena cava (CVC), between the donors' ascending aorta and the recipients' abdominal aorta (aAo), and between the grafts' pulmonary trunk and the left atrium. After transplantation, a hemodynamic assessment using echocardiography (including 2D speckle tracking analysis) and electrocardiography was performed. RESULTS: The loaded HHT procedure in the mice was performed with an overall success rate of 61%. In 3 of the remaining 5 cases, only atrial function was restored. The median duration of the entire surgical procedure for the recipient animal was 190 (IQR 180-250) min. The mean heart rate in the loaded HHT group was 355 ± 6 bpm in comparison to the control group with an in situ heart rate of 418 ± 61 bpm. A native-like closing and opening pattern of the aortic and mitral valves (visible on both 2D and M-mode images) was observed, confirming a native-analogous loading of the LV. Pulsed-wave Doppler provided visualization of the flow across the region of anastomoses between the pulmonary trunk and the left atrium, reaching a mean maximum velocity of 382 ± 12 mm/s. Exemplary 2D speckle tracking analysis of the LV free wall and interventricular septum revealed some differences in vector directions in one animal when compared to the orthotopic native heart, indicating an asynchronous movement of the LV. CONCLUSIONS: These results demonstrate the technical (micro)surgical feasibility of a fully loaded HHT procedure in the murine model without using a combined heart-lung transplantation approach. The acute hemodynamic performance of the HHT grafts approximated the native orthotopic situation. This model may open up new options for the investigation of cellular and molecular questions in the murine cardiovascular in vivo system in the near future.

The use of dexmedetomidine continuous rate infusion for horses undergoing transvenous electrical cardioversion--A case series.

Five horses were presented for treatment of atrial fibrillation by transvenous electrical cardioversion (TVEC). A dexmedetomidine infusion was administered for sedation during positioning of the cardioversion catheters, and continued during general anesthesia. Shocks were applied until return to sinus rhythm. Dexmedetomidine infusion provided excellent conditions for TVEC catheter placement and procedure.

Utilisation d'une perfusion continue de dexmedetomidine lors de cardioversion électrique transveineuse chez le cheval: une série de cas. Cinq chevaux présentant une fibrillation atriale ont été traités par cardioversion éléctrique transveineuse (TVEC). Pour le positionnement des cathéters de cardioversion, les chevaux ont reçu une perfusion de dexmédétomidine, poursuivie pendant l'anesthésie générale. Les chocs éléctriques sont répétés jusqu'au retour en rythme sinusal. La perfusion de dexmédétomidine a fourni d'excellentes conditions pour le positionnement des cathéters et la procédure de TVEC.(Traduit par les auteurs).

Evaluation of the non-calibrated pulse contour cardiac output monitor FloTrac/Vigileo against thermodilution in standing horses.

OBJECTIVE: To evaluate the non-calibrated, minimally invasive cardiac output (CO) monitor FloTrac/Vigileo (FloTrac) against thermodilution (TD) CO in standing horses. STUDY DESIGN: Prospective, experimental trial. ANIMALS: Nine adult horses weighing a median (range) of 535 (470-602) kg. METHODS: Catheters were placed in the right atrium, pulmonary artery and carotid artery under local anaesthesia. CO was measured 147 times by TD and FloTrac and indexed to body weight. Changes in CO were achieved with romifidine or xylazine and dobutamine constant rate infusions. Bland-Altman analysis, concordance and polar plot analysis were used to assess agreement and ability to track changes in CO. RESULTS: Mean ± standard deviation COTD of 48 ± 16 mL kg(-1) minute(-1) (range: 19-93 mL kg(-1) minute(-1) ) and mean COF loTrac of 9 ± 3 mL kg(-1) minute(-1) (range: 5-21 mL kg(-1) minute(-1) ) were measured. Low agreement with a large mean bias of 39 mL kg(-1) minute(-1) and wide limits of agreement of 8-70 mL kg(-1) minute(-1) were found. The percentage error of 108% and precision of TD of ± 18% resulted in an estimated precision of FloTrac of ± 106%. Comparison of changes in COF loTrac with changes in COTD gave a concordance rate of 52% in the four-quadrant plot, and a mean polar angle of -11° with radial limits of agreement of ± 61 ° in the polar plot. Mean arterial pressure (MAP) and COF loTrac were positively correlated (r = 0.5, p < 0.0001). No correlation of MAP with COTD was observed. CONCLUSIONS AND CLINICAL RELEVANCE: The FloTrac system, originally designed for use in humans, neither measured absolute CO in standing horses accurately nor tracked relative changes in CO measured by TD correctly. The false dependence of COF loTrac on arterial blood pressure further discourages the use of this technique in horses.

Plasma atrial/A-type natriuretic peptide (ANP) concentration in horses with various heart diseases.

OBJECTIVE: Plasma atrial/A-type natriuretic peptide concentration (CpANP) was measured in horses presenting with various heart diseases to assess its potential diagnostic value. ANIMALS: Fifteen healthy horses (Group 1) and 60 horses with various heart diseases associated with normal chamber size and function (Group 2, n = 24), associated with abnormal left atrial (LA) size and/or function but normal left ventricle (LV) (Group 3, n = 19), or associated with both abnormal LA and LV size and/or function (Group 4, n = 17). METHODS: CpANP was measured by a commercially available radioimmunoassay. Echocardiographic measurements were compared between groups by one-way ANOVA and Holm-Sidak post-hoc test. Receiver operating characteristics (ROC) analyses were performed to identify the best cut-offs to distinguish between groups. Relations between echocardiographic measurements and biomarker concentrations were assessed with backward stepwise multiple linear regression. RESULTS: CpANP increased from Group 1 to 4 and was significantly higher in horses with heart disease than in controls. CpANP was associated with maximum LA area and LV fractional area change. The ROC analyses showed good specificity but poor sensitivity to distinguish between healthy horses and horses with heart disease overall, and between healthy horses and horses with altered left-sided chamber dimensions and/or function. CONCLUSION: CpANP is increased in horses with heart disease associated with altered left-sided chamber dimensions and/or function. However, its diagnostic value is compromised by poor sensitivity.

The use of strain, strain rate, and displacement by 2D speckle tracking for assessment of systolic left ventricular function in goats: applicability and influence of general anesthesia.

BACKGROUND: Assessment of left ventricular (LV) systolic function can be achieved by conventional echocardiographic methods, but quantification of contractility, regional myocardial function, and ventricular synchrony is challenging. The goal of this study was to investigate the applicability of two-dimensional speckle tracking (2DST) to characterize segmental and global wall motion for assessment of LV function and LV synchrony in healthy goats. We aimed to describe the techniques, report normal values of a variety of 2DST indices, and determine the influence of general anesthesia. METHODS: Prospective study on 22 healthy female Saanen goats (3.7 ± 1.1 y, 60.2 ± 10.5 kg [mean ± SD]). All goats underwent two transthoracic echocardiographic examinations, the first standing and unsedated and the second 7.4 ± 3.5 days later during isoflurane anesthesia and positioned in sternal recumbency. Data analyses were performed offline, blinded, and in random order. Left ventricular longitudinal, radial and circumferential strain and strain rate as well as longitudinal and radial displacement were measured using 2DST methods. Summary statistics were generated and differences of 2DST variables between myocardial segments and treatments (i.e., awake vs. anesthetized) were assessed statistically (alpha level=0.05). RESULTS: Echocardiographic analyses by 2DST were feasible in all goats and at both time points. Longitudinal systolic strain, strain rate and displacement followed a gradient from apex to base. Absolute systolic strain was generally lower and strain rate was higher in awake goats compared to anesthetized goats. Circumferential and radial indices did not consistently follow a segmental pattern. Generally, peak strain occurred later in anesthetized goats compared to awake goats. General anesthesia did not significantly influence LV synchrony. CONCLUSIONS: 2SDT is a valid method for non-invasive characterization of LV wall motion in awake and anesthetized goats. The results of this study add to the understanding of LV mechanical function, aid in the diagnosis of global and segmental LV systolic dysfunction, and will be useful for future cardiovascular studies in this species. However, effects of anesthesia and species-specific characteristics should be considered when goats are used as animal models for human disease.

Serum antibodies and DNA indicate a high prevalence of equine papillomavirus 2 (EcPV2) among horses in Switzerland.

BACKGROUND: The DNA of equine papillomavirus type 2 (EcPV2) is consistently found in equine papillomas and squamous cell carcinomas, indicating a causal association of EcPV2 in the pathogenesis of these tumours; however, little is known about the prevalence of this virus. HYPOTHESIS/OBJECTIVES: The aim of this study was to determine the geno- and seroprevalence of EcPV2 in clinically healthy horses in Switzerland. ANIMALS: Fifty horses presented to the equine department of the university clinic, displaying no skin or mucous membrane lesions or severe signs of other diseases, were sampled. METHODS: Cytobrush samples from the penis or vulva and serum samples were collected. To determine the genoprevalence of EcPV2, DNA was extracted from cytobrush samples and tested for viral DNA with a PCR assay amplifying a 338 bp fragment of the E7/E1 region of the viral genome. Seroprevalence was tested using an enzyme-linked immunosorbent assay aimed to detect antibodies against the major capsid protein (L1) of EcPV2. RESULTS: In five of 50 horses (10%), EcPV2-specific DNA was amplified but no antibodies could be detected, whereas in 14 of 50 horses (28%), antibodies against EcPV2 but no DNA were demonstrated. Both antibodies and viral DNA were detected in four of 50 horses (8%). Neither antibodies nor viral DNA were found in 27 of 50 horses (54%). CONCLUSIONS AND CLINICAL IMPORTANCE: The seroprevalence suggests that EcPV2 is prevalent in the Swiss equine population, while the genoprevalence indicates that currently ongoing infections are less common. The discrepancy between geno- and seroprevalence probably indicates different stages of infection in the tested cohort.

Evaluation of a continuous glucose monitoring system compared with an in-house standard laboratory assay and a handheld point-of-care glucometer in critically ill neonatal foals.

OBJECTIVE: To evaluate the applicability and accuracy of a continuous glucose monitoring system (CGMS) in critically ill foals by comparing the performance of the CGMS, a point-of-care (POC) glucometer, and an in-house standard laboratory assay (SLA). DESIGN: Prospective study. SETTING: University teaching hospital. ANIMALS: Seven critically ill neonatal foals requiring intensive care. INTERVENTIONS: Foals were instrumented with a CGMS that measured interstitial glucose concentration every 5 minutes for the duration of 15-79 hours. Capillary and venous blood samples were taken every 4-6 hours for POC and SLA measurements, respectively. MEASUREMENTS AND MAIN RESULTS: Bland-Altman analysis showed a mean bias (95% limits of agreement) of -0.1 (-3.9 to 3.5) mmol/L for comparison of CGMS versus SLA, 0.06 (-3.9 to 4.0) mmol/L for comparison of CGMS versus POC glucometer, and -0.16 (-1.8 to 1.5) mmol/L for comparison of POC glucometer versus SLA. Percent agreement and weighted kappa for classification in hypoglycemia, normoglycemia, and hyperglycemia were 68.4% and 0.296 for CGMS versus SLA, 72.4% and 0.442 for CGMS versus POC glucometer, and 80.7% and 0.568 for POC glucometer versus SLA. CONCLUSIONS: The CGMS may be helpful for monitoring a trend in interstitial glucose concentration in critically ill neonatal foals. However, considering the wide limits of agreement between methods, the CGMS should only be used as an adjunctive device to other, more accurate and readily available methods that are able to detect acute changes in glucose concentration. Its use is further limited by the relatively high costs of the sensors, the mandatory 2-hour initialization period, and the difficulties of keeping the transducer in place in an active foal. The POC glucometer used in this study is easy to use and proved to be sufficiently accurate for repeated, stall-sided glucose monitoring in neonatal foals.

Atrial natriuretic peptide and cardiac troponin I concentrations in healthy Warmblood horses and in Warmblood horses with mitral regurgitation at rest and after exercise.

OBJECTIVE: Atrial natriuretic peptide (ANP) and cardiac troponin I (cTnI) serve as biomarkers for increased cardiac pressure/volume loading and for myocardial stress or damage. The objective was to describe the time course of plasma ANP concentrations (CpANP) and plasma cTnI concentrations (CpcTnI) in horses with mitral regurgitation (MR) compared to healthy horses at rest and after exercise, and to describe the relationship of CpANP with cardiac dimensions and intracardiac pressures. ANIMALS: 15 healthy Warmblood horses and 7 Warmblood horses with MR. METHODS: Cardiac dimensions at rest were measured using echocardiography. All horses underwent standardized treadmill exercise. Biomarker concentrations and intracardiac pressures were measured at rest and after exercise. Hypotheses were tested using statistical methods. The level of significance was P < 0.05. RESULTS: Horses with MR showed increased left atrial (LA) and left ventricular (LV) dimensions but similar exercise capacity compared to healthy horses. Pulmonary capillary wedge pressures (PCWP) and CpANP increased with exercise. Horses with MR had higher PCWP and higher CpANP at rest and after exercise compared to healthy horses, with the maximum difference in CpANP reached 10 min after exercise. CpANP was significantly related to PCWP and - although inconsistently and only in healthy horses - to echocardiographic indices of LA and LV size and function. CpcTnI was low throughout the study in both groups. CONCLUSIONS: CpANP is increased in horses with MR and is related to LA pressures and to left heart dimensions. MR is not necessarily associated with exercise intolerance and exercise-induced myocardial stress or damage.