Echocardiography is a diagnostic imaging technique used to assess the heart's structure and function in horses. It utilizes ultrasound waves to create detailed images of the heart, allowing veterinarians to evaluate cardiac anatomy, blood flow, and heart motion. Echocardiography is instrumental in diagnosing various cardiac conditions, such as valvular disorders, congenital heart defects, and myocardial diseases in equine patients. The procedure provides valuable information on heart size, wall thickness, and chamber dimensions. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, applications, and clinical implications of echocardiography in equine cardiology.
Maas LT, Louie EW, Finno CJ, Donnelly CG, Stern JA, Hill AE, Morgan JM.Cardiac arrhythmias are common in horses, but their clinical relevance remains controversial. Objective: To describe prevalence and identify risk factors for arrhythmias that may warrant additional screening in a sedentary mixed-breed population of horses. Methods: Prospective cross-sectional. Methods: Ninety-four clinically healthy, university-owned, sedentary horses underwent 24-h ambulatory electrocardiograms and echocardiograms. Potential risk factors were recorded for all horses. Affected individuals were defined as those with >1 supraventricular premature complex/h or with any ventric...
Wang T, Meng J, Peng X, Huang J, Huang Y, Yuan X, Li X, Yang X, Chang X, Zeng Y, Yao X.Yili horses, a versatile breed from Xinjiang, China, are renowned for their racing abilities. However, studies on the links between cardiac morphology, function, and metabolic profiles with performance are limited. This study combined echocardiographic, transcriptomic, and metabolomic analyses to explore these relationships in high-level, average, and untrained Yili horses. Echocardiographic assessments revealed increased left ventricular mass in trained horses, with significant differences in intraventricular septal thickness and left ventricular end-diastolic diameter. RNA sequencing identif...
Schneider MJ, Piotrowski IL, Junge HK, van Steenkiste G, Vernemmen I, van Loon G, Schwarzwald CC.Left atrial mechanical dysfunction is common in horses following the treatment of atrial fibrillation (AF). This study aimed to evaluate the use of an acoustic cardiography monitor (Audicor) in quantifying cardiac mechanical and hemodynamic function in horses with AF before and after treatment and to correlate these findings with echocardiographic measures. Twenty-eight horses with AF and successful transvenous electrical cardioversion were included. Audicor recordings with concomitant echocardiographic examinations were performed one day before, one day after, and two to seven days after card...
van Spijk JN, Junge HK, Eberhardt C, Wolf N, Vogt D, Zscherpe P, Herger E, Straub M, Schwarzwald CC.Echocardiographic evaluation of right heart (RH) size and function in horses is challenging and relies on subjective assessment. Objective: Evaluate inter- and intra-rater agreement of subjective assessment of RH size, RH function, and the presence of pulmonary hypertension (PHT) in horses. Assess subjective RH changes with and without PHT and the influence of observer experience. Methods: Healthy horses (n = 30) and horses with Doppler measurements suggesting the presence or absence of PHT (n = 30 each). Methods: Nine standard echocardiographic recordings were analyzed by experienced ...
Ibrahim L, Vernemmen I, Buschmann E, van Loon G, Cornillie P.The interatrial septum morphology, shaped by the septum primum and secundum fusion, results in the formation of the fossa ovalis (FO) and its limbus. Incomplete fusion can lead to a patent foramen ovale (PFO), while complete fusion may produce septal ridges and pouches (SPs), with SPs in humans linked to ischemic stroke and atrial arrhythmias. In horses, atrial tachycardia and fibrillation often originate near the FO. This study examines adult equine interatrial septum morphology to enhance understanding the region and guide electrophysiological interventions for equine cardiac arrhythmias. Po...
Fernandes T, Uberti B, Robin M.Utrasonographic measurements of the abdominal viscera and the heart in growing Arabian foals have not been described. Objective: To establish normal intervals for ultrasonographic measurements of cardiac indices and abdominal viscera in growing Arabian foals from birth to 1 year of age. Methods: Prospective longitudinal descriptive study. Methods: Ultrasonographic images were captured from 15 foals every 3 months from 1 week to 1 year of age. During each examination, at least three images were obtained at each location and measurements were obtained using standardised ultrasonographic approa...
Vernemmen I, Demeyere M, Van Steenkiste G, Buschmann E, Decloedt A, van Loon G.Ultrasonographic guidance of catheter-based interventions in horses is based primarily on transthoracic echocardiography (TTE). Intracardiac echocardiography (ICE) has the potential to provide detailed imaging of specific cardiac regions. Insight and training in echocardiographic guidance can be acquired using an echocardiography simulator. Objective: Use an echocardiography simulator for horses to determine specific ICE views for catheter-based interventions and validate these in live horses. Methods: Six adult healthy experimental horses. Methods: Observational study. An echocardiographic ph...
Wang T, Meng J, Wang J, Ren W, Yang X, Adina W, Bao Y, Zeng Y, Yao X.The purpose of this study was to explore the relationship between blood lipid levels and the differences in cardiac structure and function of trained and untrained Yili horses as related to exercise performance. We utilized quantitative lipidomics technology to elucidate how the differences in lipid compounds in the blood influenced performance outcomes. Sixteen 18-month-old Yili horses were selected, ten of which received a 15-week training regimen, and six were kept as untrained controls. Cardiac structure and function were assessed by echocardiography, while plasma lipid metabolites were de...
Roustaei A, Masoudifard M, Azari O, Keshipour H, Koohestani O.The effects of dexmedetomidine (DEX), as a sedative drug, on echocardiographic measurements have been investigated in many species but not in horses. Therefore, this study aimed to evaluate the echocardiographic and clinical effects of two sedative doses of DEX in healthy horses. Six female crossbred horses weighted 250-330 kg underwent echocardiography before and after sedation by intravenous administration of a low dose of 3.5 μg/kg (LD) and a high dose of 7 μg/kg (HD) of DEX. A significant increase (p≤ 0.05) was observed in the diameters of the pulmonary artery and the left atrium measu...
Shroff K, Stefanovski D, Reef VB, Kraus MS, Solis CN.Information about congestive heart failure (CHF) treatment in the horse is limited. Torsemide, an oral loop diuretic, is increasingly used in humans, dogs, and cats with CHF. Torsemide is well absorbed and induces diuresis in healthy horses, and its use in a horse with CHF has been reported. This retrospective descriptive study aimed to describe the use of torsemide in equids with CHF. Methods: 12 equids (10 horses, 1 miniature donkey, and 1 mule). Methods: Horses presented to a referral practice with clinical signs of congestive heart failure. Diagnosis was confirmed with echocardiography. Tr...
Mendoza FJ, Buzon-Cuevas A, Aguilera-Aguilera R, Gonzalez-De Cara CA, De Las Heras A, Perez-Ecija A.Systemic inflammatory response syndrome (SIRS) in donkeys is observed to be secondary to colic, diarrhea or pleuropneumonia, among other disorders. Horses with SIRS develop secondary disturbances such as hyperlipemia, laminitis, disseminated intravascular coagulopathy, and hemodynamic and cardiac derangements, which impair their prognosis and increase the mortality rate. In donkeys, no information is available on the effect of experimentally induced endotoxemia in the cardiovascular system. Acute experimental endotoxemia was induced by lipopolysaccharide (LPS) infusion in six healthy adult non...
Santosuosso E, Léguillette R, Shoemaker S, Baumwart R, Temple S, Hemmerling K, Kell T, Bayly W.Fitness assessment of horses remains challenging. Heart rate variability (HRV) can be used to monitor human athlete's training, but its value is unknown in horses. Objective: The linear domain HRV variables are affected by fitness. Methods: Twelve healthy untrained thoroughbreds were randomly split into a training group (6 weeks of incremental racetrack training) and a control group (no training). Methods: Linear domain HRV variables were analyzed (high frequency [HF], low frequency [LF], their normalized units [Hf, Lf], root mean square of successive differences between beats [RMSSD], Poinc...
Calewaert A, Palarea-Albaladejo J, Coultous R, Capewell P, Hanks E, Decloedt A, van Loon G.MicroRNA (miRNA) has previously been used as a biomarker for cardiac disease in humans and dogs, however, studies in horses are not yet available. Objective: To determine if adult horses with moderate or severe mitral valve regurgitation have a different serum miRNA expression profile compared to healthy controls. Methods: Retrospective cross-sectional. Methods: Serum samples from 77 adult horses with moderate or severe mitral valve regurgitation and 77 healthy control horses were analysed using a commercial cardiac disease-specific miRNA panel previously used in dogs. Results: The commercial ...
Caivano D, Cicogna M, Orvieto S, Spitale D, Porciello F.A 16-year-old horse, 400 kg, male, Quarter horse gelding was examined for a cardiac murmur that had not been previously heard. Physical examination revealed a regularly irregular pulse and a grade III/VI, decrescendo, diastolic murmur with a point of maximum intensity over the left heart base. Base-apex standard electrocardiographic examination at rest showed sinus rhythm with second-degree atrio-ventricular blocks. Echocardiography identified the presence of four aortic valve cusps, two equal larger and two unequal smaller cusps. Color flow Doppler examination showed a diastolic regurgitant j...
Vernemmen I, Buschmann E, Demeyere M, Verhaeghe LM, Van Steenkiste G, Decloedt A, van Loon G.Improved characterization of arrhythmias is based on minimally invasive catheterizations. However, these catheterizations have been poorly explored in horses because apart from 3-dimensional (3D) mapping systems, continuous guidance of the catheter's position with adequate detail is difficult using current imaging modalities. Objective: Position multiple electrophysiology catheters simultaneously at predetermined strategical positions in the heart using transthoracic echocardiographic guidance. Methods: Eight adult healthy horses. Methods: Observational study. Two electrophysiological studies ...
Vernemmen I, Buschmann E, Van Steenkiste G, Demeyere M, Verhaeghe LM, De Somer F, Devreese KMJ, Schauvliege S, Decloedt A, van Loon G.Cardiac catheterizations in horses are mainly performed in the right heart, as access to the left heart traditionally requires an arterial approach. Transseptal puncture (TSP) has been adapted for horses but data on follow-up and closure of the iatrogenic atrial septal defect (iASD) are lacking. Objective: To perform TSP and assess postoperative complications and iASD closure over a minimum of 4 weeks. Methods: Eleven healthy adult horses. Methods: Transseptal puncture was performed under general anesthesia. Serum cardiac troponin I concentrations were measured before and after puncture. Wee...
Shokrollahi S, Mohammadi R, Sarrafzadeh-Rezaei F, Jalilzadeh-Amin G, Hashemi-Asl SM.The aim of this study was to compare the sedative and cardiovascular effects of the combination of xylazine-acepromazine versus xylazine-pregabalin - in horses. Four healthy crossbred horses were included in the study and assigned to two treatments. In treatment I (T1), the animals received xylazine hydrochloride (1.00 mg kg) in combination with acepromazine maleate (0.05 mg kg) intravenously. In treatment II (T2), the animals received intragastric administration of pregabalin (4.00 mg kg) followed by xylazine hydrochloride (1.00 mg kg) intravenously after 60 min. Head height above ground (HHA...
Ramos GV, Santos MM, Gava FN, de Lacerda-Neto JC.The effects of conditioning on cardiac function in young horses is still unknown. For this reason, this study evaluated the left ventricular (LV) function of young horses by echocardiography after six weeks of conditioning. Fourteen untrained young purebred Arabian horses were evaluated at rest and after a stress test (ST) before and after a six-week conditioning program. There was an increase in V4 (p < 0.001) after conditioning, as well as a reduction in both heart rate (HR) at rest and peak HR during the ST (p < 0.001). There was also a reduction in internal diameter, along with an in...
Vernemmen I, Van Steenkiste G, Buschmann E, Cornelis K, Schauvliege S, Ibrahim L, Decloedt A, van Loon G.Radiofrequency ablation has been successfully applied to treat right atrial arrhythmias in horses. Ablation of left-sided arrhythmias requires a retrograde transarterial approach which is complicated. In human medicine, the left atrium is accessed through transseptal puncture (TSP) of the fossa ovalis (FO) using a caudal approach via the femoral vein. Objective: To develop a zero fluoroscopy TSP technique for horses using a jugular vein (cranial) and transhepatic (caudal) approach. Methods: In vivo experimental study. Methods: Transseptal puncture was performed in 18 horses admitted for euthan...
Piotrowski IL, Junge HK, Schwarzwald CC.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...
Naseri A, Akyuz E, Turgut K, Guzelbektes H, Sen I.The term "sepsis-induced cardiomyopathy" (SIC) is used to describe transient cardiac dysfunction in septic patients. However, there is no universally accepted definition of SIC; a reduction in left ventricular ejection fraction (LVEF) is often used. In addition to systolic dysfunction, diastolic dysfunction is now recognized as an essential component of SIC. It can be emphasized that previous animal experiments played an essential role in revealing SIC and hemodynamic instability in sepsis and septic shock. The diagnostic and prognostic capabilities of echocardiography for the assessment of SI...
Chompoosan C, Pongthaisong P, Kenchaiwong W, Pontaema T, Lerdweeraphon W.Pregnancy affects maternal hemodynamics. The changes in autonomic nervous system activity for hemodynamics adaptation in pregnant horses are still unclear. Thus, this study aimed to examine the effect of pregnancy on electrocardiographic, vasovagal tonus index, and echocardiographic variables in horses. Unassigned: A total of 23 Thai native crossbred mares without any cardiac abnormalities were included in this study. The animals were assigned into two groups, a non-pregnant mare group (n =12) and a pregnant mare group (n = 11). Electrocardiogram recordings (paper speed = 25 mm/s and calibrati...
Heun F, Niebuhr T, Gutierrez Bautista A, Wiedmann F, Verhaar N, Kästner S, Feige K, Schmidt C.A two-year-old donkey presented with recurrent syncope. Electrocardiography revealed periods without any atrioventricular conduction and without any ventricular escape rhythm with a duration of up to one minute. Finally, atrioventricular conduction resumed spontaneously with a preceding ventricular escape beat. Laboratory tests and echocardiography identified no reversible cause. The diagnosis of a paroxysmal atrioventricular block (PAVB) was made. Therefore, a single-chamber cardiac pacemaker was implanted under general anesthesia. The device was programmed in the VVI mode to prevent further ...
Kis J, Rózsa L, Husvéth F, Mezőszentgyörgyi D, Kovács S, Bakos Z, Zsolnai A, Anton I.The g.66493737C/T polymorphism of the myostatin gene (MSTN) majorly influences muscle fiber composition and best race distance of Thoroughbreds. Thus, a better understanding of this process may lead to superior genetic exploitation for maximizing Thoroughbred athletic potential. Our objective is to investigate whether myostatin genotypes are associated with muscular development and cardiac variables of Thoroughbreds. Echocardiography and muscular ultrasonography were performed on three groups having C/C, C/T, and T/T genotypes, respectively. Each group consisted of 22 animals. Homogeneity of v...
Carstensen H, Nissen SD, Saljic A, Hesselkilde EM, van Hunnik A, Hohl M, Sattler SM, Fløgstad C, Hopster-Iversen C, Verheule S, Böhm M, Schotten U....Atrial fibrillation (AF) is more prevalent in athletes, and currently, the mechanisms are not fully understood. Atrial fibrillation inducibility and stability was investigated in trained and untrained Standardbred racehorses. The horses underwent echocardiography for evaluation of atrial size. High-density mapping during AF was performed, and the presence of structural remodeling, as well as the expression of inflammatory and pro-inflammatory markers in the atria, was studied. Atrial fibrillation sustained significantly longer after tachypacing in the trained horses, whereas no difference in A...
Cruz-Aleixo AS, de Oliveira KC, de Oliveira Ferreira LV, Cedeo Quevedo DA, Cruz RKS, Tsunemi MH, Chiacchio SB, Lourenço MLG.Clinical, electrocardiographic and echocardiographic parameters in Pega donkeys are scarce in the literature; hence, this study was performed to describe the echocardiographic and electrocardiographic measurements in Pega breed donkeys. The objectives of this study were to describe and illustrate the clinical, electrocardiographic, and echocardiographic parameters in Pega donkeys used for reproduction. Fifty Pega breed donkeys were evaluated, with an average age of 3.4 years and with 20 males and 30 females. In each animal, the electrocardiographic examination at rest was performed using the T...
Marzok M, Kandeel M, Babiker H, Alkhodair KM, Farag A, Ibrahim H, El-Ashker M, Alghuwainem Y, El-Khodery S.The purpose of this study was to provide a systematic meta-analysis on echocardiographic measurements in normal Thoroughbred and Standardbred horses. The current systematic meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). All the available published papers on the reference values of echocardiographic assessment via M-mode echocardiography were searched, and fifteen studies were finally selected for analysis. In both fixed and random effect, the confidence interval (CI) for the interventricular septum (IVS) was 2.8-3.1 and 4.7-7.5; for the ...
Nissen SD, Saljic A, Kjeldsen ST, Jespersen T, Hopster-Iversen C, Buhl R.Second-degree atrioventricular (AV) block is the most common cardiac arrhythmia in horses, affecting 40-90% depending on breed. Usually, the AV blocks occur while the horses are resting and disappear upon exercise and are, therefore, considered to be uneventful for horses. However, if the AV blocks occur frequently, this may result in syncope and collapse. Identifying the cause of second-degree AV block is difficult and often subscribed to high vagal tone. In this report, we present an eight-year-old Quarter horse with a high burden of second-degree AV blocks and multiple collapses. The clinic...
Vitale V, Vezzosi T, Di Franco C, Briganti A, Tognetti R, Conte G, Bucchioni E, Sgorbini M.For the echocardiographic examination horses should not be sedated unless absolutely necessary because this alters cardiac dimensions and indices of function. However, some horses do not tolerate the echocardiographic procedure and require sedation to conduct the examination safely and obtain good quality images. The objective of this study was to evaluate whether the concurrent infusion of dobutamine in horses sedated with romifidine counteracts the cardiovascular changes observed with sedation alone. Twelve healthy untrained Standardbred mares were used. Three echocardiographic examinations ...
Reef VB, Bonagura J, Buhl R, McGurrin MK, Schwarzwald CC, van Loon G, Young LE.Murmurs and arrhythmias are commonly detected in equine athletes. Assessing the relevance of these cardiovascular abnormalities in the performance horse can be challenging. Determining the impact of a cardiovascular disorder on performance, life expectancy, horse and rider or driver safety relative to the owner's future expectations is paramount. A comprehensive assessment of the cardiovascular abnormality detected is essential to determine its severity and achieve these aims. This consensus statement presents a general approach to the assessment of cardiovascular abnormalities, followed by a ...
Brown DJ, Rush JE, MacGregor J, Ross JN, Brewer B, Rand WM.A novel method for quantitative echocardiographic interpretations is introduced based on the calculation of ratio indices in which each raw M-mode measurement is divided by the aortic root dimension (Ao). "Aorta-based" indices were calculated with the animal's measured aortic root dimension (Ao(m)) as the length standard. Conversely, "weight-based" indices employed an idealized estimate of aortic dimension (Ao(w)) with a weighted least squares linear regression against the cube root of body weight (Ao(w) = kW(1/3)). Use of these indices circumvented undesirable statistical characteristics inhe...
Schwarzwald CC.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...
De Clercq D, van Loon G, Tavernier R, Duchateau L, Deprez P.In humans, atrial fibrillation (AF) induces electrical, contractile, and structural remodeling leading to AF stabilization. Little is known about AF-induced atrial remodeling in horses. Objective: Induced AF produces rapid atrial electrical and contractile remodeling in horses. Methods: Six horses, 5 animals completed the study. Methods: Each horse was instrumented with a pulse generator and pacemaker to maintain AF by burst pacing and to study atrial and ventricular electrophysiology (AF cycle length [AFCL], AF duration, and atrial/ventricular effective refractory period [AERP/VERP] at differ...
Buhl R, Ersbøll AK, Eriksen L, Koch J.To evaluate changes over time in echocardiographic measurements in young Standardbred racehorses undergoing training and racing and determine whether there was any relationship between cardiac dimensions and racing performance. Methods: Longitudinal observational study. Methods: 103 horses. Methods: 2-dimensional and M-mode echocardiography was performed 4 times at 6-month intervals. Results: Significant cardiac enlargement took place during the study period as indicated by increases in left ventricular internal diameter in diastole (LVIDd), estimated left ventricular muscle mass (LV mass), an...
Long KJ, Bonagura JD, Darke PG.Eighteen echocardiographic images useful for diagnostic imaging, M-mode echocardiography, and Doppler echocardiography of the equine heart were standardised by relating the position of the axial beam to various intracardiac landmarks. The transducer orientation required for each image was recorded in 14 adult horses by describing the degree of sector rotation and the orientation of the axial beam relative to the thorax. Repeatable images could be obtained within narrow limits of angulation and rotation for 14 of the 18 standardised images evaluated. Twenty-seven National Hunt horses were subse...
Young LE, Rogers K, Wood JL.Cardiac morphology in human athletes is known to differ, depending on the sports-specific endurance component of their events, whereas anecdotes abound about superlative athletes with large hearts. As the heart determines stroke volume and maximum O(2) uptake in mammals, we undertook a study to test the hypothesis that the morphology of the equine heart would differ between trained horses, depending on race type, and that left ventricular size would be greatest in elite performers. Echocardiography was performed in 482 race-fit Thoroughbreds engaged in either flat (1,000-2,500 m) or jump racin...
Schwarzwald CC, Schober KE, Bonagura JD.To assess the feasibility, describe the techniques, and determine the reliability of transthoracic echocardiography for characterization of left atrial (LA) size and LA mechanical function in horses. Methods: 6 healthy adult horses. Methods: Repeated echocardiographic examinations were performed independently by 2 observers in standing, unsedated horses by use of 2-dimensional echocardiography, pulsed-wave flow Doppler, and tissue Doppler imaging (TDI) techniques. Test reliability was determined by estimating measurement variability, within-day interobserver variability, and between-day inter-...
Richard EA, Fortier GD, Pitel PH, Dupuis MC, Valette JP, Art T, Denoix JM, Lekeux PM, Erck EV.The objectives of this study were to determine the prevalence of sub-clinical diseases in poorly-performing Standardbred horses, compare their physiological response to exercise with control horses, and identify predictive parameters of poor-performance. Fifty horses underwent thorough clinical and ancillary examinations, including haematological and biochemical evaluation, Doppler echocardiography, standardised exercise tests (SETs) on both treadmill and racetrack, treadmill video-endoscopy and collection of respiratory fluids. Most of the poorly-performing horses exhibited many concomitant d...
Buhl R, Ersbøll AK.To assess whether physical training induces cardiac hypertrophy and valvular regurgitation in maturing Standardbred trotters and to establish a prediction model for the size of the left ventricle. Methods: Longitudinal observational study. Methods: 53 Standardbred trotters. Methods: Each horse underwent 2-D, M-mode, and color flow Doppler echocardiography at 5.5 years of age; previously, each horse had been examined at 2, 2.5, 3, and 3.5 (time of maturity) years of age. Horses were or were not in training or racing for variable periods during the entire assessment period; data for a given hors...
Young LE.Guided M-mode echocardiography was performed in seven 2-year-old Thoroughbreds before commencement of commercial flat-race training, and 18 weeks later, when all horses were either racing regularly (5 horses), or at racing fitness (2 horses). M-mode echocardiography was performed using a 2.5 MHz annular phased array ultrasound transducer and a Vingmed 800 Supervision echocardiograph. Images were obtained from the right hemithorax; a short axis view of the left ventricle (LV) at the level of the chordae tendinae was used to position the M-mode cursor. The following variables were measured: left...
Buhl R, Meldgaard C, Barbesgaard L.Electrocardiographic reference values of clinically normal horses during exercise are a prerequisite when evaluating horses with poor performance or horses presented with cardiac abnormalities (e.g. valvular regurgitation). No published studies have reported cardiac rhythms of clinically normal showjumping horses. Objective: To demonstrate the feasibility of obtaining exercise electrocardiogram (ECG) in normal horses during showjumping and also to document the prevalence and frequency of arrhythmias in association with exercise. Methods: Thirty-four healthy showjumping horses aged 4-13 years (...
Schwarzwald CC, Schober KE, Bonagura JD.Noninvasive assessment of left ventricular (LV) function is incompletely studied in horses. Objective: The goals of this study were to investigate the feasibility, techniques, and reliability of tissue Doppler imaging (TDI) for characterization of LV radial wall motion in healthy horses. Methods: Three Standardbreds, 3 Thoroughbreds; age 8-14 years; body weight 517-606 kg. Methods: Repeated echocardiographic examinations were performed by 2 observers in unsedated horses using TDI. Test reliability was determined by estimating measurement variability, within-day interobserver variability, and b...
Nath LC, Anderson GA, Hinchcliff KW, Savage CJ.To measure the cardiac troponin I (cTnI) concentration in horses and determine whether it could be used in the diagnosis of myocardial disease, as well as determining the association between cTnI and survival. Methods: Prospective, observational study. Methods: Physical examination, echocardiography, telemetric electrocardiography and postmortem were used to diagnose cardiac disease. Diagnoses were grouped as myocardial disease, structural heart disease or lone arrhythmia. Blood samples were collected at admission for cTnI analysis and the results were compared with those for 18 healthy horses...
Marr CM, Reef VB, Brazil TJ, Thomas WP, Knottenbelt DC, Kelly DF, Baker JR, Reimer JM, Maxson AD, Crowhurst JS.This report describes the history, clinical, electrocardiographic and echocardiographic findings, treatment, outcome and post-mortem findings in seven horses with aorto-cardiac fistula. Affected horses included 5 stallions, one gelding and one mare; 2 each of the Thoroughbred, Arabian and Standardbred breeds and one Thoroughbred-cross with a mean +/- s.d. age of 12 +/- 4 years, range 6-18 years. The presenting signs were acute distress (four horses), exercise intolerance (two horses) and the lesion was detected during a routine examination in one horse. Five horses had monomorphic ventricular ...
Patteson MW, Gibbs C, Wotton PR, Cripps PJ.Cardiac dimensions and indices of cardiac function were measured in 29 clinically normal adult Thoroughbreds (TB) which performed minimal exercise using guided M-mode and two-dimensional (2-D) echocardiography, from a variety of image planes and measurement methods, and standardised imaging planes based on intracardiac anatomical landmarks. The different methods of measuring these variables were compared. The variables which were considered to be most valuable for quantitative echocardiography were measured in a further 9 horses. Comparable measurements of cardiac dimensions can be obtained fr...
Barbesgaard L, Buhl R, Meldgaard C.Exercise-associated arrhythmias are important differentials when evaluating poor performance sport horses. However, most studies of arrhythmias have been conducted in racehorses and therefore there is a paucity of knowledge concerning the prevalence and significance of exercise-associated arrhythmias in riding horses. Objective: The objective of this study was to examine the prevalence of arrhythmias, particularly supraventricular premature complex (SVPCs) and ventricular premature complex (VPCs), associated with exercise in normal performing dressage horses. Methods: In total, 21 normal perfo...
Schwarzwald CC, Schober KE, Bonagura JD.Atrial contractile dysfunction occurs in some species after conversion of atrial fibrillation (AF) to normal sinus rhythm (NSR) but has not been reported in horses with naturally occurring AF. Objective: Transthoracic echocardiography allows detection of left atrial (LA) mechanical dysfunction in horses after conversion of AF to NSR. Methods: Five Standardbreds with AF and 6 healthy Standardbreds of similar age, weight, and athletic condition were included in this study. Methods: Four horses were treated pharmacologically (quinidine), and 1 horse was treated by means of transvenous electrical ...
Hall TL, Magdesian KG, Kittleson MD.Literature available regarding congenital cardiac defects in foals is limited to reports of individual cases or small case series. Objective: To describe the clinical, echocardiographic, and necropsy findings and breed predilection of congenital cardiac defects in neonatal foals. Methods: Eighteen foals < 15 days of age with 1 or more congenital cardiac defects. Methods: Medical records of foals diagnosed with congenital cardiac defects at the William R. Pritchard Veterinary Medical Teaching Hospital were reviewed. Data collected included history, signalment, clinical signs, laboratory data, d...
Decloedt A, Verheyen T, Sys S, De Clercq D, van Loon G.The quantification of equine left ventricular (LV) function is generally limited to short-axis M-mode measurements. However, LV deformation is 3-dimensional (3D) and consists of longitudinal shortening, circumferential shortening, and radial thickening. In human medicine, longitudinal motion is the best marker of subtle myocardial dysfunction. Objective: To evaluate the feasibility and reliability of 2-dimensional speckle tracking (2DST) for quantifying equine LV longitudinal function. Methods: Ten healthy untrained trotter horses; 9.6 ± 4.4 years; 509 ± 58 kg. Methods: Prospective study. Re...
Zucca E, Ferrucci F, Croci C, Di Fabio V, Zaninelli M, Ferro E.The aim of this study was to obtain echocardiographic measurements and establish reference ranges for 14 parameters in Standardbred racehorses in training. Background: Several studies have been published about cardiac measurements in Thoroughbreds, Standardbreds, National Hunt horses, Warmbloods and ponies; however, not all parameters have been published for the Standardbred trotter in training. Methods: Thirty normal Standardbred racehorses in training were assessed by two-dimensional echocardiography (2-D) and M-mode echocardiography using standardized imaging planes. Mean values, standard d...
Berthoud D, Schwarzwald CC.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. Methods: Thirty healthy Warmblood horses and 70 Warmblood...
Schwarzwald CC, Schober KE, Berli AS, Bonagura JD.Noninvasive assessment of left-ventricular (LV) function is clinically relevant, but is incompletely studied in horses. Objective: To document the feasibility, describe the techniques, and determine the reliability of 2D speckle tracking (2DST) for characterization of LV radial and circumferential wall motion in horses. Methods: Three Standardbreds, 3 Thoroughbreds; age 8-14 years; body weight 517-606 kg. Methods: Observational study. Repeated 2-dimensional echocardiographic examinations were performed in unsedated horses by 2 observers and subsequently analyzed by 2DST. Test reliability was d...
Schefer KD, Bitschnau C, Weishaupt MA, Schwarzwald CC.Stress echocardiography is used to diagnose myocardial dysfunction in horses, but current methods are not well standardized. The influence of heart rate (HR) on measurements is largely unknown. Objective: To investigate the use of 2-dimensional echocardiography (2DE), anatomical M-mode (AMM), tissue Doppler imaging (TDI), and 2D speckle tracking (2DST) at rest and after exercise for quantification of regional and global left-ventricular (LV) function. Methods: Five athletic Warmblood horses; 11.6+/-3.6 years; 529+/-48 kg. Methods: Prospective study. Three separate echocardiographic examination...
Grenacher PA, Schwarzwald CC.To study the applicability of anatomical M-mode (AMM) for assessment of left ventricular (LV) size and function in horses, evaluate agreement with conventional M-mode (CMM), determine reliability, and establish reference intervals for AMM measurements. Methods: 98 horses; 13.1 +/- 5.6 years; 538 +/- 78 kg. Methods: Two-dimensional and M-mode recordings were analyzed retrospectively. Standard LV dimensions and indices of LV function, including time intervals, were measured in CMM and compared with AMM studies in long-axis (lx) and short-axis (sx) views. Results: The percentages of measureable c...
De Clercq D, Decloedt A, Sys SU, Verheyen T, Van Der Vekens N, van Loon G.Atrial fibrillation (AF) cycle length (CL) and atrial size have been used in humans to characterize electrical and structural remodeling to predict outcome of cardioversion of AF and risk for AF recurrence (rAF). Objective: Atrial fibrillation cycle length can be determined in horses with AF, and AFCL and atrial size are related to risk for rAF. Methods: Eighteen horses with naturally occurring AF that were successfully converted to sinus rhythm (SR) by transvenous electrical cardioversion (TVEC). Methods: Prospective study. Horses with severe valvular regurgitation, left atrial enlargement, o...
Slater JD, Herrtage ME.Echocardiographic examinations were performed on 41 clinically normal small ponies, large ponies and horses. Using standardised two-dimensional (2-D) echocardiographic images to guide M-mode studies, the interventricular septal thickness, left ventricular internal dimension and left ventricular wall in systole and diastole, and aortic diameter in diastole were measured. Normal values for these echocardiographic dimensions were obtained across a wide range of bodyweights. Although there was a trend for echocardiographic dimensions to increase with bodyweight across the whole range of animals ex...
Trachsel DS, Schwarzwald CC, Bitschnau C, Grenacher B, Weishaupt MA.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. Methods: 15 healthy Warmblood horses and 7 Warmblood horses with MR. Methods: Cardiac dimensions at rest were measured us...
van Loon G, Van Steenkiste G, Vera L, Decloedt A.Minimally-invasive catheter-based interventional cardiology is a mainstay for the diagnosis and treatment of arrhythmias in human medicine. Very accurate imaging using fluoroscopy, CT and MRI is essential during interventional cardiology procedures. Because these imaging techniques are either not possible or provide too little anatomical detail in horses, echocardiography is currently the best technique to visualize catheters in horses. Over the past decades, catheter-based techniques have been applied to induce arrhythmias using pacing and to perform arrhythmia research using electrophysiolog...
Linton RA, Young LE, Marlin DJ, Blissitt KJ, Brearley JC, Jonas MM, O'Brien TK, Linton NW, Band DM, Hollingworth C, Jones RS.To assess the suitability of lithium dilution as a method for measuring cardiac output in anesthetized horses, compared with thermodilution and transesophageal Doppler echocardiography. Methods: 6 horses (3 Thoroughbreds, 3 crossbreeds). Methods: Cardiac output was measured in 6 anesthetized horses as lithium dilution cardiac output (LiDCO), thermodilution cardiac output (TDCO), and transesophageal Doppler echocardiographic cardiac output (DopplerCO). For the LiDCO measurements, lithium chloride was administered i.v., and cardiac output was derived from the arterial lithium dilution curve. Sod...
