Electrocardiography (ECG) in horses is a diagnostic tool used to assess the electrical activity of the heart. It involves recording the electrical impulses that govern heartbeats, providing insights into cardiac function and rhythm. This non-invasive method is useful for identifying arrhythmias, conduction disturbances, and other cardiac abnormalities in equine patients. Electrocardiography can be performed at rest or during exercise to evaluate cardiac performance under different physiological conditions. This page compiles peer-reviewed research studies and scholarly articles that explore the methodology, interpretation, and clinical applications of electrocardiography in equine health.
Schwarzwald C.Heart murmurs and arrhythmias are common in horses. Assessment of their clinical relevance concerning health, performance, safety and longevity of sports horses is of highest importance. A comprehensive cardiovascular examination is crucial for diagnosis and assessment of the severity of disease. Recently, an expert panel of the American College of Veterinary Internal Medicine (ACVIM) and the European College of Equine Internal Medicine (ECEIM) developed a consensus statement containing recommendations for sports horses with heart disease. This article summarizes the most relevant recommendati...
Broux B, De Clercq D, Decloedt A, Van Der Vekens N, Verheyen T, Ven S, Pardon B, van Loon G.The electrocardiographic differentiation between atrial (APDs) and ventricular (VPDs) premature depolarizations is important. P wave prematurity and normal QRS and T wave morphology generally are used as discriminating criteria for APDs. Objective: The aim of this study was to determine whether P, Q, R, S, and T wave amplitude, PQ interval, QRS and P wave duration and P and T wave morphology differ between APDs and sinus beats. To determine the relationship between the RR coupling interval and the change in S wave amplitude between sinus beats and APDs. Methods: Case-control study. From a modi...
Pedersen PJ, Karlsson M, Flethøj M, Trachsel DS, Kanters JK, Klaerke DA, Buhl R.Quantitative measurements of cardiac repolarization, defined as the electrocardiographic QT interval, have important diagnostic implications in humans, as irregularities can trigger potentially fatal ventricular tachyarrhythmia. In both humans and horses, cardiac repolarization is influenced to some extent by heart rate, age, body weight (BW), sex, autonomic tone, and environment. In horses, there is substantial inter-breed variation in size and training, and the aims of this study were therefore to determine the best model describing the QT to RR relationship in breeds of various athletic hor...
Kjöllerström HJ, do Mar Oom M, Chowdhary BP, Raudsepp T.The Sorraia, a critically endangered indigenous Iberian horse breed, is characterized by low genetic variability, high rate of inbreeding, bad sperm quality and subfertility. Here, we studied 11 phenotypically normal but subfertile Sorraia stallions by karyotyping, sex chromosome sperm-FISH and molecular analysis of FKBP6 - a susceptibility locus for impaired acrosome reaction (IAR). The stallions had normal sperm concentration (>300 million cells/ml), but the numbers of progressively motile sperm (21%) and morphologically normal sperm (28%) were invariably low. All stallions had a normal 6...
Lanata A, Guidi A, Baragli P, Paradiso R, Valenza G, Scilingo EP.This study reports on the implementation of a novel system to detect and reduce movement artifact (MA) contribution in electrocardiogram (ECG) recordings acquired from horses in free movement conditions. The system comprises both integrated textile electrodes for ECG acquisition and one triaxial accelerometer for movement monitoring. Here, ECG and physical activity are continuously acquired from seven horses through the wearable system and a model that integrates cardiovascular and movement information to estimate the MA contribution is implemented. Moreover, in this study we propose a new alg...
Broux B, De Clercq D, Decloedt A, De Baere S, Devreese M, Van Der Vekens N, Ven S, Croubels S, van Loon G.Arrhythmias are common in horses. Some, such as frequent atrial or ventricular premature beats, may require long-term anti-arrhythmic therapy. In humans and small animals, sotalol hydrochloride (STL) is often used for chronic oral anti-arrhythmic therapy. STL prolongs repolarization and the effective refractory period in all cardiac tissues. No information on STL pharmacokinetics or pharmacodynamics in horses is available and the aim of this study was to evaluate the pharmacokinetics of intravenously (IV) and orally (PO) administered STL and the effects on surface electrocardiogram and left ve...
Aleman M, Davis E, Williams DC, Madigan JE, Smith F, Guedes A.An intravenous (IV) overdose of pentobarbital sodium is the most commonly used method of euthanasia in veterinary medicine. However, this compound is not available in many countries or rural areas resulting in usage of alternative methods such as intrathecal lidocaine administration after IV anesthesia. Its safety and efficacy as a method of euthanasia have not been investigated in the horse. Objective: To investigate changes in mean arterial blood pressure and electrical activity of the cerebral cortex, brainstem, and heart during intrathecal administration of lidocaine. Our hypothesis was th...
Cuervo-Arango J, Aguilar JJ, Vettorazzi ML, MartÃnez-Bovà R.The present study characterizes the relationship between the levels of eCG, ovarian morphology, resumption of cyclicity, and fertility in postaborted embryo transfer recipient mares. A total of 32 pregnant recipient mares carrying a male fetus were aborted at approximately 65 days of gestation by single transcervical administration of cloprostenol. In addition, 25 gestation age-matched mares were used as nonaborted controls. The concentration of progesterone, but not of eCG, differed significantly between controls and aborted mares 48 hours after abortion. Of treated mares, 84.4% (27 of 32) ex...
Decloedt A, de Clercq D, Ven S, van der Vekens N, Chiers K, van Loon G.Endomyocardial biopsies could be a valuable tool in equine cardiology for diagnosing myocardial disease, which is probably underdiagnosed in horses because of lack of specific diagnostic measures and limitations of currently available diagnostic methods. Objective: To describe a technique for serial right atrial and right ventricular endomyocardial biopsy in standing horses using a percutaneous approach through the jugular vein. Methods: Prospective study. Methods: Biopsy was performed in 10 healthy standing horses sedated with detomidine, under continuous electrocardiography monitoring. A 10 ...
Hiraga A, Sugano S.Since the first recording of electrocardiograms (ECGs) of a horse in Japan was carried out in 1944, studies on ECGs have been performed intensively. During the early stages of research from the 1950s to 1960s, leads to use for ECG recording were evaluated using several different approaches including unipolar leads, bipolar limb leads, and bipolar chest leads. Based on these studies, the AB lead, which is oriented along the long axis of the heart, became the standard reference method in Japan. Electrodes of the AB lead are placed on the upper 1/4th point along a straight line between the wither...
Aleman M, Williams DC, Guedes A, Madigan JE.An overdose of pentobarbital sodium administered i.v. is the most commonly used method of euthanasia in veterinary medicine. Determining death after the infusion relies on the observation of physical variables. However, it is unknown when cortical electrical activity and brainstem function are lost in a sequence of events before death. Objective: To examine changes in the electrical activity of the cerebral cortex and brainstem during an overdose of pentobarbital sodium solution for euthanasia. Our testing hypothesis is that isoelectric pattern of the brain in support of brain death occurs bef...
Decloedt A, de Clercq D, van der Vekens N, Verheyen T, Ven S, van Loon G.Shortening of atrial fibrillation cycle length (AFCL) is a marker of atrial electrical remodelling due to atrial fibrillation (AF). Objective: To investigate the effect of administration of detomidine on AFCL measured invasively from an intra-atrial electrogram (AFCLEGM) and noninvasively by tissue Doppler imaging (AFCLTDI). We hypothesised that detomidine would have no effect on AFCL but would improve the ease of TDI measurements and facilitate noninvasive AFCL determination. Methods: Prospective clinical study. Methods: Measurements were performed before and after i.v. administration of 7.5â...
Hesselkilde EZ, Almind ME, Petersen J, Flethøj M, Præstegaard KF, Buhl R.Despite increased focus on cardiac arrhythmias in horses, the nature and prevalence is still poorly described. Case reports suggest that arrhythmias occurring secondary to systemic disease are seen more commonly in the clinic than arrhythmias caused by cardiac disease. The aim of this study was to investigate the prevalence of arrhythmias in colic horses referred for hospital treatment. Associations between electrolyte disturbances and arrhythmias were also investigated. Results: Heart rate was 37.4 ± 3.7 bpm in the control group, and 51.6 ± 11.8 bpm, in the colic group, which was ...
Pedersen PJ, Moeller SB, Flethøj M, Kanters JK, Buhl R, Klaerke DA.Irregularities in cardiac repolarization are known to predispose for arrhythmias and sudden cardiac death in humans. The QT interval is a quantitative measurement of repolarization, and clinically, the QTc (QT interval corrected for heart rate) and Tpeak to Tend intervals (TpTe) are used as repolarization markers. To support the use of these markers in horses, we sought to describe the possible influence of the environment, time of day, day-to-day effects, T wave conformation, age, body weight (BW), and horse-to-horse variation on repolarization measurements. Methods: 12 Warmblood geldings, ag...
Tzelos T, Blissitt KJ, Clutton RE.To determine whether preoperative electrocardiographic measurements linked to sympathetic nervous activity could be used to predict recovery quality after general anaesthesia in horses. Methods: Prospective, clinical study. Methods: Eighteen adult client-owned horses. Methods: The electrocardiogram (ECG) was recorded presurgery in horses under three standard conditions: stabled unattended; with a groom whilst being led along a standard course; alone in the induction box. After surgery, each animal's recovery quality was scored by eight experienced anaesthetists or technicians using Donaldson's...
Slack J, Boston RC, Soma LR, Reef VB.Cardiac arrhythmias are a recognised but poorly characterised problem in the Standardbred racehorse. Frequency data could aid the development of cardiac arrhythmia screening programmes. Objective: To characterise the occurrence of cardiac arrhythmias in Standardbreds prior to racing and in the late post race period using a handheld, noncontinuous recording device. Methods: Prospective, observational study, convenience sampling. Methods: Noncontinuous electrocardiographic recordings were obtained over a 12 week period from Standardbred horses competing at a single racetrack. Electrocardiograms ...
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 ...
Uhlendorf F, Gehlen H, Stadler P.The aim of the study was to extend the range of the electrocardiographic examination in horses, evaluating the practicability of special electrocardiographic techniques (exercise- and Holter-ECG) and comparing these with more common techniques (resting-ECG) in equine medicine. Methods: Electrocardiographic examination (resting-ECG for 1 minute, exercise-ECG and Holter-ECG) was performed in 20 horses without any clinical or echocardiographic findings and in 80 patients with abnormal findings (valvular regurgitation and/or atrial fibrillation). Results: In comparison with the resting-ECG, the ex...
Peters ST, Hopkins A, Stewart S, Slack J, de Solis CN.To describe the clinical findings and management of myocardial injury secondary to blunt thoracic trauma and rib fracture in an adult horse. Methods: A 6-year-old Warmblood gelding presented for treatment of blunt thoracic trauma. Sonographic examination of the thorax revealed a complete, mildly comminuted fracture of the left 5th rib with a fragment overlying the left atrium and coronary artery, hemothorax, and subjective left ventricular dyskinesis. Evidence of myocardial injury included atrial fibrillation, ventricular ectopy, and increased plasma cardiac troponin I concentration. The rib f...
Decloedt A, Verheyen T, Van Der Vekens N, Sys S, De Clercq D, van Loon G.Atrial fibrillation (AF) causes atrial electrical and contractile remodelling in horses. The aim of this study was to quantify left atrial (LA) contractile function and its time course of recovery after cardioversion of naturally-occurring AF in horses. The study population included 42 AF horses which were successfully treated using transvenous electrical cardioversion TVEC (n=39) or quinidine sulfate (n=3), with trivial or mild mitral regurgitation present in 25 horses. Thirty-seven healthy horses were used as controls. AF duration was estimated based on the history and previous examinations....
Kaese S, Frommeyer G, Verheule S, van Loon G, Gehrmann J, Breithardt G, Eckardt L.The most frequently used animal species in experimental cardiac electrophysiology are mice, rabbits, and dogs. Murine and human electrocardiograms (ECGs) show salient differences, including the occurrence of a pronounced J-wave and a less distinctive T-wave in the murine ECG. Mouse models can resemble human cardiac arrhythmias, although mice differ from human in cardiac electrophysiology. Thus, arrhythmia mechanisms in mice may differ from those in humans and should be transferred to the human situation with caution. Further relevant cardiovascular animal models are rabbits, dogs, and minipigs...
Pedersen PJ, Kanters JK, Buhl R, Klaerke DA.Cardiac repolarization, measured as QT and Tpeak to Tend (TpTe) intervals on the ECG, is important, as irregularities caused by diseases, ventricular hypertrophy, drugs and genetic defects can trigger arrhythmias which predispose human patients to syncope and sudden cardiac death. In horses, repolarization is not well described and therefore QT analysis cannot yet be used diagnostically. Therefore, we sought to describe reference values for the normal QT and TpTe intervals in Standardbreds and to determine the best method for heart rate (HR) correction. Methods: 30 Standardbreds. Methods: QT a...
Buhl R, Andersen LO, Karlshøj M, Kanters JK.The objective of this prospective field study was to investigate whether commonly used criteria for clinical death occurred at the same time as cardiac death, as determined by electrocardiography. Specific ECG changes during euthanasia were also studied. Twenty-nine horses were euthanized with pentobarbital at two different dose rates and 15 of the 29 horses also received detomidine hydrochloride for sedation. ECG was recorded prior to and during euthanasia. Time to collapse, cessation of reflexes, heart sounds and asystole were recorded. ECG recordings were used to calculate RR intervals, PQ ...
Verheyen T, Decloedt A, van der Vekens N, Sys S, De Clercq D, van Loon G.Atrial fibrillation (AF) is the most important dysrhythmia affecting performance in horses and has been associated with incoordination, collapse and sudden death. Limited information is available on ventricular response during exercise in horses with lone AF. Objective: To investigate ventricular response in horses with lone AF during a standardised lungeing exercise test. Methods: A modified base-apex electrocardiogram was recorded at rest and during a standardised lungeing exercise test from 43 horses diagnosed with lone AF. During the test horses walked for 7 min, trotted for 10 min, ca...
Nath LC, Anderson GA, Hinchcliff KW, Savage CJ.To determine whether there is evidence of myocardial injury in horses with acute abdominal disease. Methods: Prospective case series. Methods: 18 healthy horses and 69 horses with acute abdominal disease. Methods: 18 healthy horses had been admitted to the hospital for investigation and were assigned to group 1. Horses examined for acute abdominal disease were assigned to 3 groups: strangulating obstruction, nonstrangulating obstruction, or inflammatory disease (groups 2, 3, and 4, respectively). Heart rate, Hct, and blood lactate and cardiac troponin I (cTnI) concentrations were measured at i...
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...
Buhl R, Hesselkilde EM, Carstensen H, Hopster-Iversen C, van Loon G, Decloedt A, Van Steenkiste G, Marr CM, Reef VB, Schwarzwald CC, Mitchell KJ....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. Objective: Evaluate if AFR was associated with successful treatment and could predict AF recurrence in horses. Methods: Retrospective multicentre study. Methods: Electrocardiograms (ECG) from horses with persistent AF admitted for cardioversion with either medical treatmen...
Nath LC, Forbes G, Elliott AD, Tomren V, Ryan A, Franklin SH.AliveCor is a smartphone electrocardiography device (iECG) providing automated heart rate (HR) and rhythm determination. Atrial fibrillation (AF) in horses often is paroxysmal and rapid ECG acquisition is needed for diagnostic confirmation. iECGs were collected post-race from 15 horses with AF and 64 horses in sinus rhythm (SR). Results of manual assessment were compared to 3 commercial algorithms for HR and rhythm. Agreement between manually derived HR (HRM ) and HR derived by the AliveECG Vet (HRVET ) and Kardia version-1 (KV1 HR) and Kardia advanced (KADV HR) algorithms was quantified by th...
Epstein V.Hyperkalaemia affected the equine myocardium. The minimum plasma potassium concentration required to induce electrocardiographic changes was 6.2 mmol/litre and severe cardiotoxic effects were observed at levels of 8.0 to 10.1 mmol/litre in this experimental situation. The most consistent sign of hyperkalaemia was broadening and flattening of the P wave, which was generally associated with a change in T waves in the chest lead from negative to positive. The more pronounced the hyperkalaemia, the less pronounced the P wave and the more peaked positive the T wave. Severe hyperkalaemia was associa...
Schauvliege S, van Loon G, De Clercq D, Devisscher L, Deprez P, Gasthuys F.To examine the influence of direct current shock application in anaesthetized horses with atrial fibrillation (AF) and to study the effects of cardioversion to sinus rhythm (SR). Methods: Prospective clinical study. Methods: Eight horses successfully treated for AF (transvenous electrical cardioversion after amiodarone pre-treatment). Methods: Cardioversion catheters and a pacing catheter were placed under sedation [detomidine 10 microg kg(-1) intravenously (IV)]. After additional sedation (5-10 microg kg(-1) detomidine, 0.1 mg kg(-1) methadone IV), anaesthesia was induced with ketamine, 2.2 m...
Dyson DH, Pascoe PJ.A controlled study of the cardiovascular responses in horses anesthetized with acepromazine (0.05 mg/kg of body weight, IV), guaifenesin (100 mg/kg, IV), thiamylal (5.0 mg/kg, IV), and halothane in O2 (1.2 to 1.4% end-expired concentration) was performed to determine whether hypotension could be prevented by use of various treatments. Six horses were given 5 treatments in a randomized sequence: no treatment (control), methoxamine (0.04 mg/kg, IV), lactated Ringer solution (20.0 ml/kg, IV), 7.5% hypertonic saline solution (4.0 ml/kg, IV), or constant infusion of dobutamine (5.0 mg/kg/min, IV) d...
Nath LC, Anderson GA, Hinchcliff KW, Savage CJ.To determine whether there is evidence of myocardial injury in horses with acute abdominal disease. Methods: Prospective case series. Methods: 18 healthy horses and 69 horses with acute abdominal disease. Methods: 18 healthy horses had been admitted to the hospital for investigation and were assigned to group 1. Horses examined for acute abdominal disease were assigned to 3 groups: strangulating obstruction, nonstrangulating obstruction, or inflammatory disease (groups 2, 3, and 4, respectively). Heart rate, Hct, and blood lactate and cardiac troponin I (cTnI) concentrations were measured at i...
Kenchaiwong W, Sangpo P, Kusol A, Pontaema T, Lerdweeraphon W.Improper attachment of the grounding lead is one of the artifacts and causes difficulty in interpretation of ECG. This study aimed to examine the effects of the position of a ground electrode on electrocardiographic (ECG) parameters in horses. Unassigned: Sixteen Arabian horses without any cardiac problems were included in this study. The animals were divided into two groups, the base-apex lead method 1 (BA1 method) and the base-apex lead method 2 (BA2 method) with the reposition of the ground limb electrode to the xiphoid. ECG recordings (paper speed=25 mm/s and calibration=10 mm/mV) were per...
Mitten LA.Exercise intolerance, due to cardiovascular disease in horses, may be caused by cardiac arrhythmias, valvular regurgitation, congenital abnormalities, myocardial dysfunction, pericardial disease, and vascular thrombosis. The most common cardiovascular cause of exercise intolerance in horses is atrial fibrillation. Cardiovascular abnormalities such as cardiac arrhythmias or murmurs, however, are common in athletic horses and are not always associated with exercise intolerance. Use of an electrocardiography (during rest and exercise) and echocardiography may be necessary to better determine the ...
Trachsel DS, Calloe K, J Rgensen E, Lunddahl CS, Pedersen PJ, Kanters JRK, Klaerke DA, Buhl R.To determine whether administration of trimethoprim-sulfadiazine (TMS), detomidine (DET), or TMS plus DET would be associated with changes in ECG repolarization parameters in horses. Methods: 9 healthy adult horses. Methods: Each horse received 4 treatments in a blinded, randomized, crossover study design as follows: TMS, 16 to 24 mg/kg, IV; DET, 0.015 to 0.02 mg/kg, IV; TMS plus DET; and saline (0.9% NaCl) solution. Surface ECG traces were obtained over 24 hours, and repolarization parameters were measured at predefined time points after each treatment and compared with a 2-way ANOVA for repe...
Van Steenkiste G, De Clercq D, Vera L, Decloedt A, van Loon G.Atrial tachycardia including focal atrial tachycardia and macroreentrant atrial tachycardia (atrial flutter), are occasionally found in horses. Diagnosis, treatment and follow-up of these arrhythmias has been inadequately described. Objective: To describe the findings on surface electrocardiography (ECG), intra-atrial electrogram recording and tissue Doppler imaging (TDI), the response to treatment by transvenous electrical cardioversion (TVEC), and TDI follow-up, of sustained atrial tachycardia in horses. Methods: Case series. Methods: Records from horses with sustained atrial tachycardia tre...
Buschmann E, Van Steenkiste G, Vernemmen I, Demeyere M, Schauvliege S, Decloedt A, van Loon G.Sustained atrial tachycardia at an atrial rate of 191/min on the surface ECG was detected in a 6-year-old Warmblood mare. The vectorcardiogram obtained from a 12-lead ECG suggested a caudo-dorsal right atrial origin of the arrhythmia. Impedance-based three-dimensional electro-anatomical mapping, using the EnSite™ Precision Cardiac Mapping System revealed a clockwise macro-reentry around a line of conduction block in the caudomedial right atrium. Ten radiofrequency applications were applied to isolate the caudal vena cava myocardial sleeves at a power of 35 W and mean contact force of 14 ...
Buschmann E, Van Steenkiste G, Vernemmen I, Demeyere M, Schauvliege S, Decloedt A, van Loon G.Myocardial sleeves of the caudal vena cava are the predilection site for atrial tachycardia (AT) in horses. Caudal vena cava isolation guided by the ablation index, a lesion quality marker incorporating power, duration and contact force, might improve outcome. Objective: Describe the feasibility and outcome of caudal vena cava isolation using ablation index-guided radiofrequency catheter ablation (RFCA) to treat AT in horses. Methods: Ten horses with sustained AT. Methods: Records from 10 horses with sustained AT treated by three-dimensional electro-anatomical mapping and ablation index-guided...
Rose RJ, Davis PE.Electrocardiograms were reocrded from 153 racehorses and 10 Olympic three-day-event horses. The horses were then grouped into those presented for routine examination, those in which there was a complaint of poor performance, those going to the Montreal Olympics, and those with upper respiratory tract abnormalities. When the ECGs of the four groups were compared on the basis of detection of abnormality, it was found that 93.2% of the poor performance group showed abnormalities of various types. The routine examination group showed 21.1% of horses with abnormal ECGs, and over half of these have ...
Zucca E, Ferrucci F, Di Fabio V, Croci C, Ferro E.The research examines the use of Holter monitoring combined with treadmill exercise to better understand and diagnose cardiac arrhythmias in racehorses. This technology provides a comprehensive view of the horse’s […]
Matsui K, Sugano S, Amada A.Changes of the heart rate and ECG to twitching were examined using 5 Thoroughbred foals at various ages and their mares. The effect of the heart rate decrease to twitching was significantly greater in the foals than in the mares. The decreased heart rate in the foals continued during and after the twitching. Changes of the T wave in the A-B lead ECG shown as enhancement of the negative ingredient of the T wave were observed both in the foals and in the mares, accompanied by a decrease in the heart rate during and/or after the twitching. Two out of the five foals showed second-degree A-V block ...
Yamaya Y, Kubo K, Amada A, Sato K.The atrioventricular (AV) conductive functions were investigated before and after the pharmacological autonomic nervous blockade (PAB) through the electrophysiological study on six horses (AV block group) in which the dropped beats occurred more frequently (over 200 beats/24 hr) and on five horses (control group) in which the dropped beats occurred sporadically (under 200 beats/24 hr) or in which the arrhythmias were not recognized at all on the long-term electrocardiogram. As a result, AV conductivity, conduction time and refractoriness in the AV block group were lower, longer and higher, res...
Schwarzwald C.Heart murmurs and arrhythmias are common in horses. Assessment of their clinical relevance concerning health, performance, safety and longevity of sports horses is of highest importance. A comprehensive cardiovascular examination is crucial for diagnosis and assessment of the severity of disease. Recently, an expert panel of the American College of Veterinary Internal Medicine (ACVIM) and the European College of Equine Internal Medicine (ECEIM) developed a consensus statement containing recommendations for sports horses with heart disease. This article summarizes the most relevant recommendati...
Ali M, Musa MM, Alfadul S, Al-Sobayel K.A trial was conducted to check effect of adding gum Arabic (GA) instead of egg yolk (EY) as a cryoprotectant for stallion sperm. Two experiments were designed; experiment I tested adding 3 levels of nonheated GA (i.e., 3, 6 and 9 g/100 mL diluents) in HF-20 extender. However, in experiment II the same levels were tested except that GA was heated at 80 °C for 60 min. HF-20 containing 10% of EY was used as control. In experiment I, sperm frozen in HF-20 containing nonheated GA exhibited lower percentages of motile sperm, progressively motile sperm and sperm with intact plasma membranes, vit...
Doonan GR, Brown CM, Mullaney TP, Brooks DB, Ulmanis EG, Slanker MR.Several hundred Michigan horses were accidentally exposed to varying levels of monensin. Severity of effects was proportional to the level of feed contamination; sudden death resulted on at least two premises. Acute signs of cardiovascular impairment occurred on one premises having received feed containing over 200 grams of monensin per tonne. Gross and histological postmortem lesions consisted of acute myocardial necrosis. Although only circumstantially confirmed, investigations led to the suspicion that the source of poisoning was a ration formulation error in a feedmill in southwestern Onta...
Reef VB.Arrhythmias detected on prepurchase examination should be confirmed with an ECG. Exercising ECG determines if the arrhythmia is overdriven during exercise or is a safety concern. An echocardiogram is needed in all horses with a grade 3/6 or louder mid to late systolic, holosystolic, or pansystolic murmur or any holodiastolic decrescendo murmur to identify the cardiac abnormality and its hemodynamic impact. Most horses with arrhythmias and murmurs have a normal performance career and life expectancy and are insurable. Risks for sudden death and congestive heart failure associated with the commo...
Holmes JR, Alps BJ.The paper describes the changes in P, QRS and T vector orientations in the H plane in the aberrant beats in cases of partial atrioventricular block and premature atrial and ventricular systoles. The sites of possible atrial ectopic foci are discussed in relation to the anatomy of the atrial chambers and the orientation of the P vectors associated with atrial ectopic beats.
Kruger K, Stegmann GF, Becker PJ.To characterize the cardiorespiratory and electrocardiographic effects of the combined administration of phenylbutazone and romifidine. Methods: Prospective four-period, four-treatment, blinded, randomized, crossover trial. Methods: Five, healthy, mixed breed horses. Methods: Prior to treatment administration, a catheter was introduced into the intra-thoracic cranial vena cava via the jugular vein and a subcutaneously located carotid artery was catheterised. All treatments were administered intravenously (IV) and consisted of saline placebo (PLC), phenylbutazone (PBZ, 4.4 mg kg(-1) ) romifidin...
