Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Cardiovascular Health
Cardiovascular health in horses encompasses the study of the heart and blood vessels, focusing on their structure, function, and associated disorders. The equine cardiovascular system is responsible for the circulation of blood, delivering oxygen and nutrients to tissues, and removing waste products. Research in this area includes the examination of cardiac anatomy, the electrophysiology of the heart, and common cardiovascular conditions such as arrhythmias, valvular diseases, and heart murmurs. Diagnostic tools such as echocardiography, electrocardiography, and cardiac biomarkers are utilized to assess cardiovascular function and detect abnormalities. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological mechanisms, diagnostic approaches, and therapeutic strategies related to cardiovascular health in horses.
Comparative examination of percussional and echocardiographic determination of the cardiac dullness area in healthy horses. Since percussion started to be a method forgotten and not trusted by many practitioners, the aim of the study was to demonstrate whether this procedure could deliver exact data if done accurately and by a practised examiner. The trial presented here included 31 healthy warm-blooded horses. Percussion of the area of cardiac dullness and then echocardiographic imaging of the same region were performed. To obtain the relevant measurement points, the 4th and 5th intercostal spaces (ICS) were used on the left and the 4th ICS on the right side. On the left side, the dorsal border of cardiac dullness...
Acute training in racing horses at two different levels of effort: A haemorheological analysis. During acute exercise several significant cardiovascular alterations take place, along with possible physiopathological consequences, such as Exercise Inducted Pulmonary Haemorrhage (EIPH). Given the relevance of blood rheology in the determination of flow resistance and its supposed participation in the stated events, the present paper focuses on the analysis of modifications in haematocrit, blood viscosity and erythrocyte deformability in Thoroughbred horses caused by two different levels of effort (6 to 9 m/s and 13 to 16 m/s), in the same track they train in and with their own jockeys. The...
Effects of an adapted intravenous amiodarone treatment protocol in horses with atrial fibrillation. Good results have been obtained with a human amiodarone (AD) i.v. protocol in horses with chronic atrial fibrillation (AF) and a pharmacokinetic study is required for a specific i.v. amiodarone treatment protocol for horses. Objective: To study the efficacy of this pharmacokinetic based i.v. AD protocol in horses with chronic AF. Methods: Six horses with chronic AF were treated with an adapted AD infusion protocol. The protocol consisted of 2 phases with a loading dose followed by a maintenance infusion. In the first phase, horses received an infusion of 6.52 mg AD/kg bwt/h for 1 h followed by...
Physiology of equine performance and associated tests of function. This review addresses the physiology of performance horses in the context of functional tests aimed at assisting clinicians in the search for explanations of the individual's limitations, actual or perceived as below expectation. The intention is to assist clinicians who are faced frequently by owners or trainers seeking explanations for poor performance; and for research workers as a basis on which to proceed in their search for new methodologies, particularly those that can be applied in the field as for treadmill exercise. The review sets out fundamental physiological pathways, the entailme...
Echocardiographic evidence of left atrial mechanical dysfunction after conversion of atrial fibrillation to sinus rhythm in 5 horses. 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 ...
The cardiopulmonary effects of dobutamine and norepinephrine in isoflurane-anesthetized foals. To evaluate the cardiovascular effects of norepinephrine (NE) and dobutamine (DB) in isoflurane-anesthetized foals. Methods: Prospective laboratory study. Methods: Norepinephrine (0.05, 0.10, 0.20, and 0.40 microg kg(-1) minute(-1)) and dobutamine (2.5, 5.0, and 10 microg kg(-1) minute(-1)) were alternately administered to seven healthy, 1- to 2-week-old isoflurane-anesthetized foals. Arterial and pulmonary arterial blood pressure, right atrial pressure, pulmonary artery occlusion pressure, heart rate, body temperature, cardiac output, arterial and mixed venous blood pH, partial pressure of ca...
Effect of butorphanol administration on cardiovascular parameters in isoflurane-anesthetized horses – a retrospective clinical evaluation. To determine cardiovascular responses to administration of butorphanol in isoflurane-anesthetized horses. Methods: Retrospective evaluation of anesthetic records. Methods: Seventy-six horses anesthetized for a variety of clinical surgical procedures. Methods: Anesthetic records of clinical equine patients anesthetized between January 1999 and December 2003 were searched. The records were reviewed for horses in which anesthesia was induced with ketamine and a benzodiazepine and maintained with isoflurane, and horses that received butorphanol intraoperatively. Exclusion criteria included horses ...
Cardiovascular effects of enoximone in isoflurane anaesthetized ponies. Enoximone is a phosphodiesterase III inhibitor frequently used to improve cardiac output (CO) in man. As the use of enoximone has not been reported in horses, the effects of this inodilator were examined in isoflurane anaesthetized ponies. Methods: Prospective, randomised, experimental study. Methods: Six healthy ponies, weighing 286 (212-367) +/- 52 kg, aged 5.0 +/- 1.6 years (4-6.5). Methods: After sedation with romifidine [80 microg kg(-1) intravenously (IV)], general anaesthesia was induced with midazolam (0.06 mg kg(-1) IV) and ketamine (2.2 mg kg(-1) IV) and maintained with isoflurane in...
Effects of Rho-kinase and Src protein tyrosine kinase inhibition on agonist-induced vasoconstriction of arteries and veins of the equine laminar dermis. To determine the effects of inhibition of Rho-kinase or Src-family protein tyrosine kinases (srcPTK) on agonist-induced contractile responses in equine laminar arteries and veins. Methods: Laminar arteries and veins obtained from 13 adult mixed-breed horses. Methods: Laminar vessels were mounted on myographs and exposed to phenylephrine (PE), 5-hydroxytryptamine (5-HT), prostaglandin F(2) (PGF(2)), and endothelin-1 (ET-1) with or without the Rho-kinase inhibitor Y-27632 (10 microM), srcPTK inhibitor PP2 (10 microM), or a negative control analogue for PP2 (PP3; 10 microM). Results: Responses to...
Relationship between hair elements and severity of atrioventricular block in horses. The aim of this study was to investigate the relationships between the mean concentrations of trace elements and the severity of the second-degree atrioventricular (AV) block in the mane hair of horses. Electrocardiographs of horses were continually recorded for 6 h using a holter cardiac monitor to determine dropped ventricular beats (DVBs) which can be used as an indicator of the severity of the AV block. Mane hair Ca, Cu, Mg, and Zn concentrations were measured by the particle-induced X-ray emission method. The Zn/Cu ratio and Ca concentration in mane hair were significantly and positively ...
Myocardial fibrosis in a horse with polymorphic ventricular tachycardia observed during general anesthesia. Ventricular dysrhythmias are more commonly associated with myocardial disease than are supraventricular dysrhythmias. Management of arrhythmias under general anesthesia is difficult because of the dysrhythmogenic effects of the anesthetic drugs. This report describes a severe ventricular dysrhythmia observed in a pony under general anesthesia, with a severe and old myocardial fibrosis found on postmortem examination. Fibrose du myocarde chez un cheval présentant de la tachycardie ventriculaire polymorphe observée au cours d’une anesthésie générale. Les dysrythmies ventriculaires sont pl...
Effect of voltage-gated and capacitative calcium entry blockade on agonist-induced constriction of equine laminar blood vessels. To characterize the relative contributions of voltage-gated and capacitative Ca(2+) entry to agonist-induced contractions of equine laminar arteries and veins. Methods: 16 adult mixed-breed horses. Methods: Laminar arteries and veins were isolated and mounted on small vessel myographs for the measurement of isometric tension. Concentration-response curves were obtained for the vasoconstrictor agonists phenylephrine, 5-hydroxytryptamine (5-HT), prostaglandin F(2) (PGF(2)), and endothelin-1 (ET-1) either in the absence of extracellular Ca(2+) or in the presence of the voltage-gated Ca(2+) channe...
Methods and reliability of echocardiographic assessment of left atrial size and mechanical function in horses. 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-...
Comparison of ketamine and S(+)-ketamine, with romifidine and diazepam, for total intravenous anesthesia in horses. To compare the quality of induction and recovery, degree of muscle relaxation, clinically apparent potency and cardiopulmonary effects of racemic ketamine or S(+)-ketamine when used for total intravenous anesthesia in horses. Methods: Prospective randomized clinical trial Methods: Sixteen healthy stallions (323 +/- 99 kg), with a mean age of 6.2 years, undergoing castration. Methods: Horses were pre-medicated with romifidine IV, 15 minutes before induction of anesthesia. Each animal was then randomly allocated to receive either diazepam and ketamine (DK) or diazepam and S(+)-ketamine (DKS) at ...
Heart rate response to therapeutic riding in children with cerebral palsy: an exploratory study. The study was designed to document the heart rate response to therapeutic riding in children with cerebral palsy having mild-to-severe disability. Methods: Participants consisted of eight youth riders with cerebral palsy, divided into two groups: ambulatory and wheelchair dependent. The riders received continuous digital heart rate monitoring during 10 weekly 20-minute therapeutic horseback riding sessions. Results: The averaged resting, median, and peak heart rate values, as well as the peak percentage heart rate reserve values, were significantly higher in the wheelchair-dependent group. Con...
Cardiovascular effects of acute pulmonary obstruction in horses with recurrent airway obstruction. Recurrent airway obstruction (RAO) is common in horses. Although pulmonary artery (PA) pressure increases during RAO, cardiac function in horses with RAO has received limited attention. Objective: The purpose of this study was to noninvasively determine the cardiovascular effects of acute pulmonary obstruction (APO) in horses with RAO and their reversibility. Methods: Five geldings with RAO, inducible by exposure to moldy hay, were studied. Methods: Pulmonary mechanics, echocardiography, serum troponin I concentrations, arterial blood gases, and hematocrit were obtained before and after 7 days...
Effects of a specific endothelin-1A antagonist on exercise-induced pulmonary haemorrhage (EIPH) in thoroughbred horses. During high intensity exercise, the very high pulmonary artery pressure (Ppa) experienced by Thoroughbred horses is considered a major factor in the aetiology of exercise-induced pulmonary haemorrhage (EIPH). Recently, endothelin-1 (ET-1), a potent vasoconstrictive hormone, has been found to increase Ppa in horses at rest via binding to its ET-1A receptor subtype. In addition, plasma concentrations of ET-1 are increased in horses during and after high intensity exercise. Objective: If ET-1 increases Ppa during exercise in the horse, administration of a specific ET-1A antagonist would decrease ...
Right ventricular pressure dynamics and stress echocardiography in pharmacological and exercise stress testing. There is interest in using pharmacological stress testing (PST) as a substitute for exercise stress testing (EST) to evaluate cardiac function in horses. Objective: To compare the effect of PST and EST on right ventricular pressure dynamics and stress echocardiography. Methods: Five horses completed a PST and EST in a randomised crossover design. High fidelity pressure transducers were placed in the right ventricle. Continuous pressure signals were digitally collected and stored, and dP/dtmax, dP/dtmin and tau calculated from these measurements. ECGs were recorded continuously for 20 h. Echoca...
Effects of chronic acetazolamide administration on fluid flux from the pulmonary vasculature at rest and during exercise in horses. Horses develop high pulmonary pressures during exercise, which force fluid out of pulmonary capillaries. Specific airway diseases in horses, especially those associated with hypoxaemia, hypercapnoea and acidosis may influence pulmonary haemodynamics and pulmonary interstitial fluid equilibrium. Objective: This study was designed to determine fluid flux (J(V-A) l/min) across the lung in exercising horses treated chronically with acetazolamide. Methods: Six horses were exercised on a treadmill until fatigue without (Con) and with chronic carbonic anhydrase (CA) inhibition (AczTr) and associated ...
Effect of repeated exercise and recovery on heart rate variability in elite trotting horses during high intensity interval training. Interval training is a commonly used training method for trotting horses. In addition, trainers are provided with efficient and inexpensive heart rate monitor devices for the management of training. Objective: Since the high frequency (HF) frequency peak (fHF) of heart rate variability (HRV) corresponds to the breathing frequency in combination with stride frequency during trotting, it is hypothesised that modifications of breathing and stride frequencies induced by repeated exercise could be detected from fHF. Methods: RR interval time series of 7 trotting horses were recorded during an inter...
A comparison of cross-country recovery rates at CCI 2* with and without steeplechase competitions. Short format 3-day events were introduced in 2004. Anecdotal reports suggested that horses were more tired on completion of the cross-country phase of short format events when compared with horses completing the cross-country phase of long format competitions, despite the absence of Phases A, B and C. Objective: To compare the physiological parameters and haematological parameters of horses that had completed the cross-country phase of a short format (SF) and a long format (LF) CCI 2* competition. Methods: During a CCI 2* competition 69 competitors took part in the short format and 74 in the l...
Heart rate variability in trotters during different training periods. Endurance training induces changes in autonomic nervous system functions. High intensity training includes the risk of overtraining, in man and horse. Heart rate variability (HRV) is a noninvasive measurement of the autonomic regulation of the heart rate, which is quick and easy to measure with modern telemetric technology. Objective: Since HRV is affected by changes in the autonomic nervous system, it might be an early stage indicator of poor recovery from a previous bout of exercise or overreaching or overtraining in horses in general. Methods: The aim of the study was to monitor recovery an...
Effect of light exercise on valvular regurgitation in standardbred trotters. Although valvular regurgitation is diagnosed frequently by colour Doppler echocardiography in racehorses at rest, there is currently no information about the effect of exercise on valvular regurgitation. Objective: To investigate the effect of light exercise on valvular regurgitation in a population of trotters. Methods: Standardbred trotters (n = 73) were examined by resting auscultation and echocardiography, of which 50 fullfilled the criteria of the study. Of these, 4 had reduced performance according to the trainers and were not included in the statistical analyses. Horses that showed valv...
Nitric oxide synthase inhibition in thoroughbred horses augments O2 extraction at rest and submaximal exercise, but not during short-term maximal exercise. Work is required to establish the role of endogenous nitric oxide (NO) in metabolism of resting and exercising horses. Objective: To examine the effects of NO synthase inhibition on O2 extraction and anaerobic metabolism at rest, and during submaximal and maximal exertion. Methods: Placebo and NO synthase inhibition (with Nomega-nitro-L-arginine methyl ester [L-NAME] administered at 20 mg/kg bwt i.v.) studies were performed in random order, 7 days apart on 7 healthy, exercise-trained Thoroughbred horses at rest and during incremental exercise leading to 120 sec of maximal exertion at 14 m/sec ...
Effect of detraining on cardiorespiratory variables in young thoroughbred horses. Thoroughbred racehorses often experience interruptions to their training. Identifying the effects of these changes and how they alter athletic performance might provide an insight on to how to prevent these changes from occurring. Objective: Training and detraining young Thoroughbreds alters their aerobic capacities with correlated changes in circulatory capacities; if horses remained spontaneously active in a pasture during their detraining period, their decreases in aerobic capacity during detraining would be reduced. Methods: We trained 6 Thoroughbred yearlings for 6 months using a conventi...
Haematological and respiratory gas changes in horses and mules exercised at altitude (3800 m). Despite the common use of equids as visitors to high altitude mountainous environments, there are a paucity of carefully orchestrated scientific approaches. Further, again as a function of a common perceived advantage of mules over horses in these similar environments there are needs for controlled comparisons between these 2 equids. Objective: To measure haematological and respiratory function in horses and mules at low altitude (225 m), at rest and post exercise. In addition the rate and magnitude of these changes were followed over a 13 day period at high altitude (3800 m) to contrast accli...
The effect of adrenergic suppression induced by guanabenz administration on exercising thoroughbred horses. Adrenergic activity accompanies intense exercise and mediates physiological and metabolic responses to exercise. Guanabenz, an antihypertensive drug marketed for human usage, depresses brain vasomotor and cardioaccelerator centres, blocks peripherally adrenergic neurons and is reportedly used as a calming agent in horses but little is known of its effects in the species. Objective: To determine if guanabenz induces measurable signs of adrenergic suppression on fit Thoroughbred horses undergoing intense exercise. Methods: In a random crossover design, 12 exercise conditioned Thoroughbred horses...
The physiological responses to simulated race tests on a track and on a treadmill in standardbred trotters. It is unclear to what extent the physiological response to a standardised treadmill exercise test simulating racing conditions resembles the circulatory and metabolic response observed after a simulated race on a track. Objective: To compare the physiological responses of a standardised treadmill exercise test used to simulate racing conditions and a simulated race performed on a track on the same Standardbred trotting horses, all in racing condition. Methods: Six Standardbred trotters in racing condition performed a standardised inclined treadmill exercise test protocol simulating racing cond...
