The equine cardiovascular system, particularly the heart, is fundamental to maintaining the health and performance of horses. The heart is responsible for pumping oxygenated blood throughout the body, supporting vital functions and physical activity. In horses, the heart's structure and function are adapted to meet the demands of both rest and exertion, with notable features such as a large cardiac output and efficient blood circulation. Conditions affecting the equine heart, such as arrhythmias, valvular diseases, and myocardial disorders, can significantly impact a horse's well-being and athletic capability. This page aggregates peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and pathophysiology of the equine heart, as well as diagnostic and therapeutic approaches to managing cardiac health in horses.
Manohar M.1. Left ventricular (LV) myocardial O2 extraction was studied in five healthy ponies which had catheters implanted in the great cardiac vein and main pulmonary artery 15-30 days before the study. The abdominal aorta was percutaneously catheterized to sample arterial blood. 2. In addition, phasic LV and aortic pressures, LV dP/dtmax and rate-pressure product were also studied; dP/dtmax is the maximal rate of rise of the left ventricular pressure during the isovolumic phase, and is considered an index of myocardial contractility. Measurements were made at rest (control) and during adenosine infu...
Art T, Lekeux P.A preliminary study attempted to assess the influence of atmospheric conditions on the breathing pattern of ponies. The respiratory airflow, tidal volume, breathing frequency, minute volume, total pulmonary resistance and heart rate of five ponies (257 +/- 9 kg and three to five years old) were measured by a standardised procedure. Data were collected at rest, during a nine minute period of treadmill exercise and during a five minute recovery period. The ambient temperature (degrees C) and relative humidity (%) were recorded at the time of each investigation and the respiratory parameters were...
Dedrick P, Reef VB, Sweeney RW, Morris DD.Using echocardiography, mitral valve bacterial endocarditis was diagnosed in a yearling Thoroughbred filly with a history of periodic fever and intermittent hind limb lameness. Streptococcus sp were isolated from blood, and the filly was treated with penicillin, resulting in a bacteriologic cure. Severe mitral regurgitation developed secondary to scarring of the valve, which resulted in the filly's death. A poor prognosis usually is indicated in horses with bacterial endocarditis, as bacteriologic cures are infrequent and severe valvular insufficiency often develops.
King JM, Flint TJ, Anderson WI.A newly described congenital heart anomaly, the incomplete subaortic stenotic ring was detected at necropsy in four dogs, one cat, one cow, one horse, one sheep and one pig. These structures were grossly and histologically similar to complete subaortic stenotic rings, being composed of variably dense interlacing bands and sheets of fibrous connective tissue. In all nine cases, their presence at necropsy was considered an incidental finding.
MacDonald AA, Fowden AL, Silver M, Ousey J, Rossdale PD.Hearts from 24 foals were studied; 10 were from foetuses ranging in gestational age from 230 to 322 days and 14 were from newborn and young foals aged between birth and 17 days. The foramen ovale and associated vena caval and atrial structures were examined by scanning electron microscopy. Additional observations were made by light and transmission electron microscopy. A tube-like flap of tissue was observed, extending from the aperture in the caudal vena cava to the lumen of the left atrium. In the younger foetuses, the distal end of this tube was covered with a thread-like network of tissue....
Machida N, Yasuda J, Too K.A morphometric study of hearts in 81 equine foetuses, ranging in age from 190 to 330 days of foetal age, and in 26 newborn foals is reported. The mean weight, external dimensions, ventricular wall thickness and circumference of the atrio-ventricular orifice were measured. Features of the main associated vessels of the heart were also recorded. All cardiac measurements of foetuses increased linearly throughout the latter half of pregnancy and were highly correlated with foetal age. This linear growth pattern was also found in the parameters of the associated arterial trunks. The ratio of the ri...
Bertone JJ.Six standing awake adult horses were instrumented for measurement of mean arterial, central venous, and pulmonary arterial blood pressures (mm of Hg), thermodilution cardiac output (ml/kg/min), and pulmonary arterial blood temperature (C). Total peripheral resistance was calculated from these values. Base-line data were accumulated, and a single dose of hydralazine HCl (0.5 mg/kg) was administered IV. Horses were monitored for 420 minutes after hydralazine administration. Mean arterial and central venous blood pressures did not change from the base-line values. Cardiac output and heart rate we...
Weber JM, Dobson GP, Parkhouse WS, Wheeldon D, Harman JC, Snow DH, Hochachka PW.This study characterizes the effects of exercise on the cardiac output (Q) and the metabolic rate (VO2) of trained Thoroughbred racehorses. Heart rate, Q, and arteriovenous (a-v)O2 difference were measured at rest and at three levels of submaximal treadmill exercise (1.6 m/s walk and 3-4 m/s trot at 6% incline, and 6.5 m/s horizontal canter). Heart rate and (a-v)O2 difference were also measured during maximal exercise (12.5 m/s gallop, 5% incline) to obtain an estimate of maximum O2 uptake (VO2max). The walk, trot, and canter represented 25, 45, and 55% VO2max. Mean heart rate went from 48.9 (...
Bertone JJ, Paull KS, Wingfield WE, Boon JA.M-mode echocardiographic structures, and cardiac function indices, PCV, and total plasma protein values were determined for 34 endurance equine athletes before (base line) and after (after race) a 161-km endurance competition and were compared. The PCV (base-line mean, 37%; after-race mean, 46%) and total plasma protein value (base-line mean, 6.9 g/dl; after-race mean, 7.5 g/dl) increased. Compared with base-line echocardiography, after-race echocardiography indicated an increase in heart rate, as determined from the simultaneous ECG recorded on the echocardiograph (base-line mean, 41 beats/mi...
Clark ES, Reef VB, Sweeney CR, Lichtensteiger C.Aortic insufficiency was suspected in a thin 1-year-old colt with a grade IV/V decrescendo holodiastolic murmur and a bounding arterial pulse. Echocardiographic findings (diastolic fluttering of the septal leaflet of the mitral valve, left ventricular volume overload, and incomplete aortic valve closure) were diagnostic for aortic valve insufficiency. Moderately thick fibrotic aortic valve leaflets were found at necropsy. Fenestrations were found in the aortic and pulmonic valve cusps. Congenital valvular disease may have led to aortic valvular insufficiency in this horse.
Rugh KS, Garner HE, Hatfield DG, Miramonti JR.The response of coronary collaterals in nine ponies subjected to repeated reversible occlusions (2 min duration, 30 min interval) of the left anterior descending coronary artery was studied at rest. Each pony was instrumented with a Doppler flowmeter and hydraulic cuff occluder around the left anterior descending coronary artery, left ventricular subendocardial sonomicrometers, and a left ventricular micromanometer. Initial occlusions increased end diastolic myocardial segment length by 3% and decreased segment systolic shortening, stroke work, and velocity of shortening by 103%, 95%, and 79% ...
Reef VB.Mitral valvular insufficiency associated with ruptured chordae tendineae was diagnosed in 3 foals with signs of congestive heart failure, which were believed to be secondary to the development of pulmonary hypertension associated with the valvular insufficiency. The septal leaflet of the mitral valve was affected in all 3 foals, and foal 2 also had ruptured chordae tendineae associated with the caudal mitral valve leaflet. Bacterial endocarditis and myocardial necrosis were associated with the ruptured chordae tendineae in foals 3 and 2, respectively. Idiopathic rupture was considered in foal ...
Reef VB, Mann PC, Orsini PG.M-mode, 2-dimensional, and contrast echocardiographic studies were used to detect tricuspid atresia in 2 foals. M-mode echocardiographic findings included a small right ventricle, large left ventricle, large mitral valve excursion, large left atrium (foal 2), dropout of the cranial aspect of the aortic root, and a thick band of echoes in the tricuspid valve region. These findings were confirmed by 2-dimensional echocardiography. In addition, a large right atrium, persistent foramen ovale, ventricular septal defect, and large mitral valve apparatus were imaged. One foal also had a thick right a...
Baker D, Kreeger J.An expansile, yellow, soft mass was observed in the free wall of the right ventricle of a 3-year-old, male, Morgan, horse at necropsy. The mass was composed of well differentiated adipocytes in solid sheets or infiltrating between muscle fibers with associated myofiber degeneration. The mass was interpreted to be an infiltrative lipoma of the heart.
Reef VB, Spencer P.Echocardiographic evaluation of 23 horses with aortic insufficiency was performed, using M-mode (n = 23) and 2-dimensional real-time echocardiography (n = 14 of 23). Echocardiograms were evaluated for abnormalities of aortic and mitral valves and alterations in motion of these valves. Changes in left ventricular chamber size and function, as well as aortic root size, were evaluated. The presence of other cardiac disease was also evaluated. Horses with aortic insufficiency had significant increases (P less than 0.01) in mean values of left ventricular chamber size, aortic root diameter, and sho...
Rugh KS, Garner HE, Sprouse RF, Hatfield DG.Systemic arterial hypertension is associated with equine laminitis, a disease precipitated by gross over-ingestion of carbohydrates. We examined the hearts from nine chronically hypertensive (161 +/- 11/99 +/- 6 mmHg) laminitic ponies and nine normotensive (128 +/- 2/76 +/- 3 mmHg) ponies postmortem for signs of left ventricular hypertrophy. The hypertensive ponies had hearts which were significantly larger (7.77 +/- 0.26 g/kg bodyweight (BW) vs. 5.67 +/- 0.22 g/kg BW), as well as increased combined left ventricle and septum weight (4.99 +/- 0.21 g/kg BW vs. 3.67 +/- 0.20 g/kg BW) and left ven...
von Segesser L, Jornod N, Faidutti B.The risk of repeat sternotomy is higher than that of the initial sternotomy, especially if the pericardial sac was left open at the first intervention. In 200 consecutive patients with a pericardial defect after open heart operations, the pericardium was closed with a glutaraldehyde-preserved equine pericardial patch. Precardiac adhesions at reoperation were assessed in four groups of patients on a scale of 6, ranging from 0 (no adhesions) to 5 (calcified or ossified adhesions). Group I comprised 13 patients in whom the pericardium was left open at the first operation and an equine pericardial...
Wilson RB, Haffner JC.Right atrioventricular atresia with a ventricular septal defect, a rare congenital cardiac anomaly of either animals or man, was diagnosed in a one week old Arabian foal. The foal had been weak and cyanotic since birth, sometimes becoming dyspneic when stressed. Necropsy revealed a dilated and hypertrophied left ventricle with the right ventricle being small. The right atrioventricular valve was absent. The right and left ventricles communicated via a septal defect which was located immediately adjacent to the aortic valve.
Kiryu K, Nakamura T, Kaneko M, Oikawa M, Yoshihara T.Twenty thoroughbred race horses were selected for postmortem cardiopathological study of sudden cardiac death; ten of the twenty horses died suddenly. In order to define accurately the morphological changes observed in these ten hearts, ten other thoroughbred race horses considered to have normal hearts were selected as a control group and studied by postmortem coronary angiography. Of the ten horses that died suddenly, eight were witnessed to have died either during or shortly after training or racing. The death was instantaneous except in one horse, which showed ventricular tachycardia and d...
Freestone JF, Thomas WP, Carlson GP, Brumbaugh GW.Pericarditis and pericardial effusion are considered to occur rarely in the horse. The clinical and laboratory features of idiopathic pericarditis with effusion diagnosed in 10 horses over a seven-year period were reviewed. Consistent physical findings included tachycardia, ventral oedema, jugular venous distention and diminished heart sounds. Electrocardiographic features included diminished voltages and electrical alternans, and the effusion was identified by echocardiography in the six horses in which it was performed. Pericardiocentesis relieved clinical signs in nine horses. Laboratory an...
Moore EN, Spear JF.We tested the multiple-wavelet hypothesis by studying the initiation and maintenance of atrial fibrillation in normal mules, horses, cows, calves, and goats. Persistence of atrial fibrillation in animals with a large atrial mass was compared with results in adult goats and calves having a smaller atrial mass. Atrial stimulation in clinically normal cows, mules, calves, and goats was accomplished using an intra-atrial stimulating catheter with rapid atrial pacing (30/s). Once initiated, atrial fibrillation persisted for 95,120,125 min, 3 days, and 8 weeks in five adult cows, respectively. In co...
Meijler FL, van der Tweel I.Atrial fibrillation is one of the most common cardiac arrhythmias in humans. It also occurs quite frequently in dogs and horses. Comparative study of this arrhythmia may contribute to better understanding of the pathophysiological mechanisms involved. In this study, we present a quantitative analysis of atrial fibrillation in humans, dogs, horses, and in a kangaroo, making use of histograms and serial autocorrelograms of the ventricular rhythm with and without digitalis medication. Increase in the size of the animal and thus in the size of the heart is accompanied by a decrease in ventricular ...
Thomas WP, Madigan JE, Backus KQ, Powell WE.Cardiopulmonary function was studied in 10 full-term healthy foals from birth to 14 days of age. Systemic and pulmonary haemodynamics were recorded in lateral recumbency via indwelling aortic and pulmonary artery catheters. Mean body weight increased from 45.4 +/- 2.4 kg on Day 1 to 70.6 +/- 6.1 kg on Day 14. All foals had a continuous murmur of patent ductus arteriosus for 3-6 days. From Day 1 (12 h old) to Day 14, heart rate increased (89 +/- 4 to 95 +/- 5/min), mean aortic pressure increased (87.7 +/- 1.9 to 100.3 +/- 3.2 mmHg), mean pulmonary artery pressure decreased (38.6 +/- 4.6 to 27.4...
Van Der Vekens N, van Dievoet MA, De Puydt H, Decloedt A, Ven S, De Clercq D, Deprez P, van Loon G.Although cardiac troponin T (cTnT) assays have been used to detect myocardial damage in horses, a cTnT assay has not been analytically validated, to our knowledge. The aims of this study were to estimate the precision of a high-sensitivity cTnT assay in horses and determine the effect of hemolysis on the measured cTnT concentration. Serum samples from horses were mixed in 3 different pools. Pool 1 consisted of samples from 3 healthy horses, pool 2 from 6 horses with heart failure or atypical myopathy, and pool 3 from 10 horses with atypical myopathy. The within- and between-run coefficients of...
Echigoya Y, Sato T, Itou T, Endo H, Sakai T.To elucidate the molecular properties of the equine glycolytic enzymes equine M(1) (eM(1)) and M(2) (eM(2))-pyruvate kinase (PK), mRNAs were isolated from thoroughbred horse skeletal muscle and hair roots, respectively. The full-length eM(1) and eM(2)-PK cDNAs consist of 2,320 and 2,376 bp, respectively, containing a 1596 bp open reading frame. The cDNAs were mapped to equine chromosome 1, and the equine pyruvate kinase M (PKM) gene consists of twelve exons. Exon 9 of eM(1)-PK and exon 10 of eM(2)-PK were further investigated in five equine species. Out of 55 amino acids encoded by exon 9 in e...
Meijler FL, van der Tweel I.Atrial fibrillation is one of the most common cardiac arrhythmias in humans. It also occurs quite frequently in dogs and horses. Comparative study of this arrhythmia may contribute to better understanding of the pathophysiological mechanisms involved. In this study, we present a quantitative analysis of atrial fibrillation in humans, dogs, horses, and in a kangaroo, making use of histograms and serial autocorrelograms of the ventricular rhythm with and without digitalis medication. Increase in the size of the animal and thus in the size of the heart is accompanied by a decrease in ventricular ...
Arosio P, Gatti G, Bolognesi M.Various precipitating agents were examined in order to crystallize horse heart and spleen ferritins. Cadmium sulfate induced the crystallization of the spleen ferritin, while 2-methyl-2,4-pentanediol and poly(ethylene glycol) only induced that of the heart ferritin. Isoelectric focusing analysis showed that the crystals grown from cadmium sulfate contained only the more acidic isoferritins, and those grown from methyl pentanediol only the less acidic isoferritins. Heart ferritin crystallizes in a cubic space group, as previously reported for spleen ferritin crystals grown from cadmium sulfate....
Vörös K, Holmes JR, Gibbs C.This study was designed to evaluate the accuracy of two-dimensional echocardiography (2DE) in determining the left ventricular volume (LVV) of the horse in vitro. After examining the shape of the left ventricular silicon rubber casts of four equine hearts, two modified Simpson's rule methods (Model A and Model B) as combinations of conical shapes and one biplane area-length method as a single cone (Model C) were chosen for volume calculations. One long axis and three short axis planes were used for linear and area 2DE measurements, respectively. The ventricular length (L) was calculated from t...
Hillidge CJ, Lees P.Cardiac output in the horse was measured before and at predetermined times during 2-hour periods of thiopentone-halothane and thiopentone-diethyl ether anaesthesia. Left ventricular stroke volume was decreased to a similar extent during anaesthesia with each volatile agent, but a greater reduction in cardiac output occurred during halothane anaesthesia. This finding reflected the differing effects of halothane and ether on heart rate, a slight bradycardia occurring with the former agent while ether produced a small degree of tachycardia. The latter effect was attributed to enhanced sympathoadr...
Hughes SB, Quan M, Guthrie A, Schulman M.The insulin-like growth factor system (insulin-like growth factor 1, insulin-like growth factor 2, insulin-like growth factor 1 receptor, insulin-like growth factor 2 receptor and six insulin-like growth factor-binding proteins) and insulin are essential to muscle metabolism and most aspects of male and female reproduction. Insulin-like growth factor and insulin play important roles in the regulation of cell growth, differentiation and the maintenance of cell differentiation in mammals. In order to better understand the local factors that regulate equine physiology, such as muscle metabolism a...
Marr CM.Respiratory and cardiac diseases are common in older horses. Advancing age is a specific risk factor for cardiac murmurs and these are more likely in males and small horses. Airway inflammation is the most common respiratory diagnosis. Recurrent airway obstruction can lead to irreversible structural change and bronchiectasis; with chronic hypoxia, right heart dysfunction and failure can develop. Valvular heart disease most often affects the aortic and/or the mitral valve. Management of comorbidity is an essential element of the therapeutic approach to cardiac and respiratory disease in older e...
Ruíz-López P, Cuypers C, Schauvliege S.This retrospective study investigated the effect of a xylazine infusion on heart rate; mean arterial pressure; blood gases; anesthetic and dobutamine requirements; recovery quality and duration; percentage of death/survival; and days to die/discharge in horses after colic surgery under partial intravenous anesthesia with isoflurane and lidocaine infusion. Anesthetic records of equine colic surgery were reviewed from similar periods in 2020-2021 and 2021-2022. In both groups, after sedation with xylazine 0.7 mg/kg intravenously (IV) and induction with ketamine 2.2 mg/kg and midazolam 0.06 mg/kg...
The study aimed to assess Apgar scores and collect data on clinical, hemato-biochemical, and venous blood gas parameters in seven mules during their first 48 hours of life. Apgar scores, heart rate (HR), respiratory rate (RR), body temperature (BT), body weight (BW), time to achieve sternal recumbency, stand, nurse, and pass meconium were recorded. Blood samples were collected at birth (T0), 6 (T6), 12 (T12), 24 (T24), 48 (T48) hours of life. Data distribution was verified and differences in laboratory parameters over time assessed. One foal had an Apgar score of 6/8, thus excluded from the st...
Fritz SA, Hall JO.Ionophores are a class of polyether antibiotics that are commonly used as anticoccidial agents and growth promotants in ruminant diets. Ionophores transport ions across lipid membranes and down concentration gradients, which results in mitochondrial destruction, reduced cellular energy production, and ultimately cell death. Cardiomyocytes are the primary target in equine patients when exposed to toxic concentrations and the clinical disease syndrome is related to myocardial damage. Animals can survive acute exposures but can have permanent heart damage that may result in acute death at future ...
Diaz AEC, Herfindal L, Andersen HL, Fossen T.Parsley fern, , is a common fern in arctic-alpine regions, and even though this species has been known since ancient times and has been presumed to cause the poisoning of horses, its natural products have not previously been investigated. Here, we characterise 15 natural products isolated from the aerial parts of , including the previously undescribed compound 3-malonyl pteroside D. The structure determinations were based on several advanced 1D and 2D NMR spectroscopic techniques, Circular Dichroism spectroscopy and high-resolution mass spectrometry. The pteroside derivatives exhibited selecti...
Dufourni A, Buschmann E, Vernemmen I, Van Steenkiste G, van Loon G, Decloedt A.Echocardiographic measurements are important prognostic indicators but might be influenced by heart rate and blood pressure. This is particularly important when comparing repeated examinations. Objective: To determine the effect of physiological stress at mildly increased heart rates and pharmacological challenge using IV administration of N-butylscopolammonium bromide and metamizol sodium on heart rate, blood pressure, and echocardiographic measurements. Methods: Twenty healthy Warmblood horses. Methods: Randomized crossover study. Horses were examined echocardiographically by 2-dimensional, ...
Kutara K, Kadekaru S, Hisaeda K, Sugimoto K, Ono T, Inoue Y, Nakamura S, Yoshitake R, Ohzawa E, Goto A, Iwata E, Shibano K, Une Y, Kitagawa H.The necropsy of a 2-day-old Noma horse that died of weakness showed an enlarged cardiac base and a narrow cardiac apex, suggesting cardiac malformation. The excised heart underwent imaging to investigate its luminal structure. On three-dimensional magnetic resonance imaging, the right atrium and right ventricle were discontinuous. The right atrium communicated with the left atrium and the left ventricle communicated with the right ventricle. The lumen narrowed near the pulmonary artery valve. Since the same findings were observed on gross examination, the foal was diagnosed with tricuspid atre...
Hermange T, Ruault B, Couroucé A.The aim of this study is to describe clinical data associated with acorn intoxication and to find variables associated with survival. Data from horses presented at CISCO-ONIRIS from 2011 to 2018 with a diagnosis of acorn intoxication were included. Diagnosis was based on the following: season, the presence of acorns in the environment, clinical and hemato-biochemical parameters suggestive of a digestive/renal disease, the co-morbidity of companion animals, and post-mortem findings. Statistical analysis was completed using Student's t-test for mean comparisons and a Chi-square test for group co...
Paranjape VV, Knych HK, Berghaus LJ, Cathcart J, Giancola S, Craig H, James C, Saksena S, Reed RA.Matrix type transdermal buprenorphine patches have not been investigated in horses and may provide an effective means of providing continuous pain control for extended period and eliminating venous catheterization. Unassigned: Assessment of the physiological variables (heart rate, respiratory rate, body temperature) and thermal nociceptive threshold testing, and describing the pharmacokinetic profile of transdermal buprenorphine matrix-type patch (20 μg h and 40 μg h dosing) in healthy adult horses. Unassigned: Randomised experimental study with a Latin-square design. Unassigned: Six adu...
Mozo Vives B, Mainguy-Seers S, Lavoie JP.Salbutamol and hyoscine butylbromide (HBB) are commonly used bronchodilators in horses with severe asthma (SA). Objective: To compare the bronchodilation potency, duration, and adverse effects of salbutamol and HBB in SA. Methods: Six horses in exacerbation of SA. Methods: The effects of inhaled salbutamol (1000 μg) and HBB (150 mg, IV) were compared in a randomized, blinded, crossover experiment. Lung function, intestinal borborygmi and heart rate were assessed before and sequentially until 180 minutes after drug administration, and analyzed with 2-way repeated-measures ANOVA and Dunne...
Massie S, Bayly W, Ohmura H, Takahashi Y, Mukai K, Léguillette R.Comparatively little is known regarding the initial cardiorespiratory response of young racehorses to training. The objectives were to compare physiological parameters before and after introductory training and determine whether young Thoroughbreds show endoscopic signs of exercise-induced pulmonary hemorrhage (EIPH). Ten Thoroughbreds (20-23 months) underwent 12-weeks of introductory training, including weekly speed sessions. Two 600 m high-speed exercise tests (HSET) were performed following weeks 4 and 12 while wearing a validated ergospirometry facemask. Peak oxygen consumption (V̇Opk...
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...
Pontaema T, Pongthaisong P, Kenchaiwong W, Chompoosan C, Lerdweeraphon W.Vasovagal tonus index (VVTI) serves as a straightforward assessment tool for autonomic function during both physiological and pathological conditions, including pregnancy, in horses. Obtaining VVTI through a modified base apex lead system could be a practical and comfortable solution. In this study, we assessed VVTI in horses with respect to training status and electrocardiographic measurements utilizing a novel modified base apex lead technique. Unassigned: A total of 12 Thai native crossbred horses and 12 Arabian horses, all free of cardiac abnormalities, were enrolled in the study. Animals ...
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 ...
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...
Foreman JH, Tennent-Brown BS, Oyama MA, Sisson DD.Cardiac troponin-I (cTnI) is a highly sensitive and specific marker of myocardial injury detectable in plasma by immunoassay techniques. Inclusion criteria over a 3-year period required a diagnosis of cardiac disease accompanied by electrocardiographic (ECG) and cardiac ultrasound examinations (n = 23) in adult horses (≥2 years of age). A second group of normal adult ponies (n = 12) was studied as a reference group. Heparinized jugular venous blood samples were collected and centrifuged within 30 min, and the plasma was separated and frozen at -70 °C for subsequent batched cTnI analysis. Th...
Navas de Solis C, Ramseyer A, Stefanovski D, Haughan J, Solomon CJ, Kirsch K.Exercising arrhythmias are common in horses participating in eventing competitions. Heart rate variability (HRV) and a specific measure of the degree of heart rate fluctuation (Detrended Fluctuation Analysis alpha1; DFA-α1) are proposed as exercise intensity and fatigue markers. Objective: (1) To describe exercising arrhythmias and DFA-α1 values during 2-4* level eventing cross-country competitions in horses from two European countries; (2) to identify associations between exercising arrhythmias, DFA-α1 and competition results and (3) to evaluate whether markers of the intensity of exercise...
Kazama T, Hector RC, Hess AM, Rezende ML.To determine the cardiopulmonary effects of oral trazodone before isoflurane anesthesia in systemically healthy horses. Unassigned: 12 horses donated for euthanasia (from August 2022 through June 2023) due to conditions unrelated to the cardiovascular system were included in this prospective, randomized, controlled trial. Horses were assigned to receive oral trazodone (6 mg/kg; n = 7) or corn syrup (n = 5) 1 hour before xylazine (1 mg/kg, IV) sedation, ketamine (2.2 mg/kg, IV) and propofol (0.7 mg/kg, IV) induction, and anesthetic maintenance with inhaled isoflurane (target 1.6% expired) for 7...
Wonghanchao T, Sanigavatee K, Poochipakorn C, Huangsaksri O, Chanda M.Changes in resting heart rate (HR) and HR variability (HRV) are utilised to assess training effects in horses. However, limited research has examined how these variables reflect training effects during exercise sessions and recovery periods, particularly in horses of different ages. This study investigated how HR and HRV changed during exercise sessions and recovery periods in untrained adult horses (UAHs; = 9) and geriatric horses (UGHs; = 9). HR and HRV were measured before and during a 54 min exercise bout over a 12-week training programme. Mixed-effects model with Greenhouse-Geisser corr...
Wienhold S, Bär L, Ringleb Z, Zirpel V, Gomolla A, Denk BF, Volkmer N, Gaertner RJ, Klink ESC, Pruessner JC.In any therapeutic setting, the outcome depends in part on the therapeutic alliance, characterized by mutual understanding, empathy and trust among the participants. This also manifests through physiological synchronization (PS) processes involving breathing, heart and brain. This study examined the dynamics of heart rate variability (HRV) synchronization patterns during horse-assisted therapy. We explored the correlations between the therapist's horse preference, levels of early life adversity (ELA), and PS relationships within and across dyads of participants, therapists, and therapy horses....
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, Yang X, Ren W, Meng J, Yao X, Chu H, Yao R, Zhai M, Zeng Y.Training not only enhances the athletic performance of horses but also improves cardiac structure and function, strengthens cardiovascular adaptability, and reduces the risk of cardiovascular diseases. However, the consequences of training on equine cardiac structure and function remain unclear. This study investigated the morphological, functional, genetic, and metabolic changes in the hearts of Yili horses divided into three groups: high athletic performance (agility group, AG), low athletic performance (ordinary group, OG), and untrained (untrained group, UN). The results showed remodeling ...
