Rupture of the biceps tendon in a Thoroughbred steeplechase horse.
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Animals↗
Biomedical subjects
V B Reef
Publications and source records attributed to V B Reef.
Right ventricular pressure dynamics during exercise: relationship to stress echocardiography.
Thorough evaluation of myocardial function remains difficult to evaluate under exercising conditions. This study described right ventricular (RV) pressure dynamics during and immediately following exercise. Nine Thoroughbreds without evidence of cardiac disease completed treadmill exercise at 110% of the speed necessary to elicit VO2max while RV pressures were recorded. RV pressure dynamics were calculated at rest, maximal speed and at 10 s intervals for 2 min after exercise. Stress echocardiography was performed at rest and within 120 s after exercise. Mean dP/dtmax and dP/dtmin values were significantly greater at maximal speed and up to 30 s immediately postexercise than at rest and all time points from 60 to 120 s postexercise. Mean dP/dtmax and dP/dtmin were not significantly different from resting values after 60 s postexercise. Tau (the time constant for ventricular relaxation) decreased significantly with exercise, but was not significantly different from rest at time points from 60 to 120 s following exercise. Mean % fractional shortening (FS) increased postexercise; however, the coefficient of variability was large. Wall motion indices also showed large variability postexercise. These temporal changes in normal horses suggest that exercising RV pressure dynamics may provide a better estimation of cardiac function during exercise than postexercise stress echocardiography.
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Aortic root disease in four horses.
Clinical findings in 4 horses with aortic root disease are described. Three of the horses had aneurysms of the right aortic sinus, and in 2 of the 3, the aneurysm ruptured, creating a fistula between the aorta and right ventricle. One of these horses had had a murmur since birth, and the aortic sinus aneurysm may have been a congenital anomaly. In a second horse, the aneurysm may have been an acquired condition that developed secondary to chronic aortic regurgitation. Another horse had a large subendocardial hematoma associated with dissection of blood from the aorta to the interventricular septum because of a tear in the aortic root near the right aortic sinus. Ventricular ectopy and signs of abdominal pain were the most common initial signs in these horses.
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Superficial digital flexor tendon healing: ultrasonographic evaluation of therapies.
Until recently, it was difficult to critically evaluate tendon healing in vivo. Superficial digital flexor tendon injuries were considered healed when the injured tendon was cold, non-painful, adequate time had passed for tendon healing to occur, and no recurrence of the injury was detected when the horse returned to athletic work. This article discusses how ultrasonography has revolutionized the diagnosis, treatment, and management of tendon injuries.
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Stress echocardiography and its role in performance assessment.
Stress echocardiography in the horse is in its infancy, and investigations need to continue to determine the significance and mechanism of postexercise echocardiographic abnormalities detected in horses. This work should be coupled with investigations on the exercise-induced changes in cardiac isoenzymes, cTnI, arterial oxygen content, and cardiac rhythm that may occur concurrently. With continued investigations into the cardiovascular problems that occur in the exercising horse, the sport horse veterinarian should be better able to accurately diagnose and treat problems causing poor performance in the horse.
Animals↗
Causes of poor performance of horses during training, racing, or showing: 348 cases (1992-1996).
OBJECTIVE: To determine results for horses undergoing a high-speed treadmill examination, including videoendoscopy of the pharynx and larynx before and during exercise, echocardiography before and after exercise, and electrocardiography before, during, and after exercise, because of poor performance. DESIGN: Retrospective study. ANIMALS: 348 horses. RESULTS: A definitive diagnosis was obtained for 256 (73.5%) horses. One hundred forty-eight horses had dynamic obstruction of the airway during exercise, 33 had clinically important cardiac arrhythmias alone, 22 had a combination of dynamic airway obstruction and clinically important cardiac arrhythmias, 19 had poor cardiac fractional shortening immediately after exercise, 10 had exertional rhabdomyolyis, 15 had clinically apparent lameness, and 9 had other disorders. Thirty-nine of the horses with dynamic obstruction of the airway during exercise had multiple airway abnormalities. Fifty-three horses also had subclinical myopathy CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a complete evaluation, including a high-speed treadmill examination, should be conducted in horses with poor performance, regardless or whether horses do or do not have a history of abnormal respiratory noises and particularly if the horses have grade-II or -III left laryngeal hemiplegia.
Airway Obstruction↗
Pericarditis in horses: 18 cases (1986-1995).
OBJECTIVE: To determine clinical signs of pericarditis in horses and to determine whether there were any relationships among clinical signs, echocardiographic findings, treatment, and outcome. DESIGN: Retrospective study. ANIMALS: 18 horses. RESULTS: Physical examination was performed on 16 horses. Cardiovascular abnormalities included tachycardia (n = 16), pericardial friction rub (10), venous distention (7), murmur (7), muffled heart sounds (6), weak arterial pulse (6), jugular pulse (6), and edema (5). Twelve horses also had respiratory abnormalities; the most common was dull lung sounds, ventrally, suggestive of pleural effusion (10). Echocardiography was the most important tool for diagnosis of pericarditis. Detection of clinical signs of right-sided heart failure was significantly associated with severe accumulation of pericardial effusion and with detection of cardiac compromise. Severe accumulation of pericardial effusion was also significantly associated with echocardiographic detection of cardiac compromise. Pericarditis was idiopathic in 6 horses, and bacterial in 5. Five horses had nonseptic pericarditis associated with bacterial respiratory disease, and 2 had nonseptic pericarditis associated with viral respiratory disease. Fourteen of the 18 horses were treated specifically for pericarditis; 10 received antimicrobials and 6 with suspected immune-mediated pericarditis received corticosteroids. Pericardial drainage and lavage were performed on 6 horses in which pericardial effusion or fibrin accumulation was compromising cardiac function. Pericarditis resolved in all 14 horses that were treated, and all 14 returned to their prior intended use. CLINICAL IMPLICATIONS: With early detection of disease and aggressive treatment, the prognosis for horses with pericarditis is good.
Adrenal Cortex Hormones↗
Severe mitral regurgitation in horses: clinical, echocardiographic and pathological findings.
Forty-three horses with mitral regurgitation (MR) and congestive heart failure were examined, using M-mode, 2-dimensional real-time and Doppler echocardiography. There was no breed or sex predisposition when compared to the general hospital population. The mean +/- s.d. age of affected horses was 7.6 +/- 8.1 years. Horses with MR and congestive heart failure had significant increases in mean values for left ventricular chamber size, left atrial size and heart rate and significant decreases in interventricular septal and left ventricular free wall thickness. Significant increases in pulmonary artery diameter were detected compared to aortic diameter. Mean values for fractional shortening were not significantly different from normal. All horses had a Grade 3-6/6 holosystolic or pansystolic murmur with its point of maximal intensity in the mitral to aortic valve area. Atrial fibrillation was found at presentation in 24 horses with MR and congestive heart failure. One horse presented with atrial tachycardia and subsequently developed atrial fibrillation. Seven horses had ventricular premature contractions. Exercise intolerance (n = 34), respiratory signs (n = 31), and fever (n = 21) were the most common presenting signs. Thickening of the left atrioventricular valve leaflets, endocarditis, flail valve leaflets, rupture of a chorda tendineae, and mitral valve prolapse were detected echocardiographically. Doppler echocardiography confirmed the presence of a large systolic regurgitant jet in the left atrium in all horses in which it was used, and in many horses, concurrent tricuspid and pulmonary regurgitation was detected. All horses died or were subjected to euthanasia due to the severity of their MR and/or lack of response to therapy. Post mortem examinations were performed in 35 horses and confirmed the echocardiographic findings. The echocardiographic detection of a flail mitral valve leaflet was significantly associated with the detection of a ruptured chorda tendineae at post mortem examination. There was a significant association between echocardiographic detection of a dilated pulmonary artery and its presence at post mortem examination. M-mode, 2-dimensional real-time, and Doppler echocardiography should be used to accurately characterise the valvular abnormalities and assess the severity of mitral regurgitation. Pulmonary artery dilatation, an echocardiographic indication of severe pulmonary hypertension, should be considered a grave prognostic indicator and may indicate impending pulmonary artery rupture.
Animals↗
Bacterial endocarditis in horses: ten cases (1984-1995).
A retrospective study of 10 horses with bacterial endocarditis was performed in order to describe the echocardiographic findings in horses with bacterial endocarditis, in conjunction with clinical signs and post mortem findings, and to evaluate the usefulness and the formulation of a prognosis. Echocardiographic and post mortem examinations were performed in 7 horses. Post mortem examination alone was performed in 2 horses and echocardiographic examination alone performed in one horse. No breed or sex predilection was obvious. Mean age +/- s.d. was 2.12 +/- 3.32 years. Predominant clinical signs and abnormal clinical pathology data were fever, cardiac murmur, tachycardia, tachypnoea, hyperfibrinogenaemia, anaemia and leucocytosis. Pasteurella/Actinobacillus spp. and Streptococcus spp. were most commonly cultured. Vegetative lesions were found most frequently on the mitral valve and secondarily on the aortic valve. The location and number of lesions identified with echocardiography in the horses accurately described the lesions found on post mortem examination. Medical treatment was attempted in 50% of the horses. Serial echocardiography was used to assess the response to treatment in 2 horses. All horses with vegetative lesions of the mitral and/or aortic valve died or were subjected to euthanasia due to the severity of their cardiac disease. Both horses with tricuspid valve endocarditis were cured of the infection, one horse returned to racing after antimicrobial therapy and the other was subjected to euthanasia due to severe laminitis.
Animals↗
Streptococcal fibrinous pericarditis and peritonitis in a Vietnamese pot-bellied pig.
An 8-month-old female Vietnamese pot-bellied pig was examined because of a 48-hour history of anorexia and signs of depression. Hypothermia, dehydration, pronounced respiratory effort, and muffled heart sounds were detected. Abdominal ultrasonography revealed ascites and hepatic congestion. Echocardiography revealed pericardial effusion and fibrinous pericarditis. Ultrasound-guided pericardiocentesis was diagnostic and therapeutic. Cytologic examination of pericardial and peritoneal fluid revealed degenerated neutrophils and intra-and extracellular gram-positive cocci. On microbial culture of pericardial and peritoneal fluid specimens, moderate growth of a beta-hemolytic Streptococcus sp of group G was observed. After initial treatment corrected hypothermia and dehydration, the pig was treated with sulfadiazine/sulfamerazine/sulfamethazine and oxytetracycline for 30 days. Echocardiographic examination 3 months after the initial examination revealed resolution of the pericardial effusion and fibrinous pericarditis.
Animals↗
Concordance of ultrasonographic and physical findings in cattle with an umbilical mass or suspected to have infection of the umbilical cord remnants: 32 cases (1987-1989).
Medical records of 32 cattle treated for umbilical abnormalities that had undergone ultrasonographic examination of the umbilicus followed by umbilical resection or postmortem examination were reviewed. Thirty of the cattle were between 6 and 240 days old (mean, 73 days); the remaining 2 cattle were a 3-year-old bull and a 5-year-old cow. Thirty (94%) animals had external evidence of infection associated with the umbilicus. Two calves did not have external signs of infection; 1 had an abscess of the urachus and the other was found to be normal. Two-dimensional real-time ultrasonography was used to identify abnormal umbilical cord remnants. Ultrasonographic results were most reliable for the urachus, and the urachus was the most commonly affected internal umbilical cord remnant. Statistical agreement between ultrasonographic and physical (surgical or postmortem) findings was good to excellent for all umbilical structures. Intra-abdominal adhesions were found at surgery in 47% of animals with umbilical abnormalities; however, adhesions were not detected ultrasonographically.
Abdominal Muscles↗
Physiological valvular regurgitation in clinically normal young racehorses: prevalence and two-dimensional colour flow Doppler echocardiographic characteristics.
Colour flow Doppler echocardiographic examinations were performed on 15 horses; 10 Thoroughbreds and 5 Standardbreds; 9 mares, 5 geldings and 1 stallion; mean +/- s.d. 3.4 +/- 1.1 years. Cardiac murmurs were audible in 12 horses (80%), but these had characteristics consistent with functional murmurs in all horses. A standardised two-dimensional (2-D) and M-mode echocardiographic examination was unremarkable in all horses except that aortic valve prolapse was identified in 3 horses, tricuspid valve prolapse in 2 horses and mitral valve prolapse was present in one horse. Colour flow Doppler echocardiography revealed laminar antegrade flow in most sites but variance was noted in the right ventricular outflow tract in some horses. Small regurgitant jets associated with the aortic valve were seen in 12 horses (80%), with the tricuspid valve in 7 horses (46%), with the pulmonary valve in 4 horses (26%) and the mitral valve in 4 horses (26%). It was concluded that with colour flow Doppler echocardiography, as in other species, small regurgitant jets could be detected in many normal horses.
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Heart murmurs in horses: determining their significance with echocardiography.
Physiological flow murmurs occur frequently in horses and may be difficult to distinguish from murmurs associated with underlying cardiac disease. The significance of heart murmurs auscultated in horses is often difficult to determine if the horse is not exhibiting any clinical signs or if the signs, such as poor performance, are nonspecific. A complete echocardiographic examination (M-mode, 2-dimensional (2-D) and Doppler) provides an objective assessment of the severity of the horse's underlying cardiac disease. Valvular regurgitation and ventricular septal defects (VSDs) occur frequently and may impair performance, result in the horse's premature demise or have no apparent effect on the horse's life expectancy or performance capabilities. The echocardiographic findings that are used to formulate a prognosis for longevity and performance in horses with valvular regurgitation include the abnormalities detected on the valve leaflets, degree of cardiac chamber enlargement, severity of the resultant volume overload, size of the regurgitant jet, and relative relationship of jet size to chamber size. The echocardiographic findings that are used to formulate a prognosis for horses with VSDs are the number, size and location of the defect(s), degree of left ventricular volume overload, maximal velocity and direction of shunt flow through the defect and the presence and severity of concurrent valvulus regurgitation. Knowledge of the natural progression of the common types of cardiovascular disease in horses, coupled with the echocardiographic findings, clinical history and owner's or trainer's expectations can help the veterinarian form an accurate prognosis for life and performance in horses with heart murmurs.
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Evaluation of ventricular septal defects in horses using two-dimensional and Doppler echocardiography.
Ventricular septal defects (VSDs) were diagnosed in 27 horses; in 26 affected horses systolic murmurs were detected over both sides of the chest. Holodiastolic decrescendo murmurs were also detected in 5 horses. Standardbreds and Arabian horses were over-represented, while Thoroughbred horses were under-represented, when compared to the hospital population (P < 0.0001). Five horses had previously raced successfully, one 2-year-old was training successfully and close to racing, and 4 horses had competed successfully in other types of competition. Eleven horses had a history of exercise intolerance or poor performance, 5 horses were stunted and 3 horses were in congestive heart failure at the time of presentation. The VSD murmur was detected as an incidental finding in 14 horses. Membranous VSD were most commonly detected (in 23/27 affected horses) and were typically found underneath the septal leaflet of the tricuspid valve and the right and/or noncoronary leaflet of the aortic valve. Muscular VSDs were much less common and were located in any portion of the muscular septum. The VSDs ranged in size from 1-4.6 cm (maximal diameter) in affected horses. A left to right shunt through the VSD was detected in 26/27 affected horses with Doppler echocardiography. The peak velocity of shunt flow detected through the VSD was 0-5.8 m/s. The interventricular pressure gradients estimated from the peak shunt velocity obtained with Doppler echocardiography were 0-135 mmHg. Right ventricular pressures estimated with Doppler echocardiography were 15-84 mmHg, similar to invasively obtained measurements of right ventricular pressure in 80% of horses in which right sided cardiac catheterisation was performed (n = 5). Left ventricular and left atrial volume overload was detected in the majority (23/27) of horses. Right atrial and right ventricular volume overload was severe in 3 horses with muscular VSDs, mild in 1 horse with a perimembranous VSD, and mild in 2 horses with membranous VSDs. Concurrent left ventricular dysfunction was detected in 2 horses. Aortic valve prolapse was seen in 7 horses associated with the membranous location of the VSD; 6 of these horses had very mild (1+) or mild (2+) aortic regurgitation. Severe (4+) aortic regurgitation was present in one horse, severe mitral regurgitation in 2 horses, severe tricuspid regurgitation in 3 horses, and severe pulmonary regurgitation was detected in 2 horses. Mitral valve prolapse, tricuspid valve dysplasia, a flail aortic valve leaflet, and a bicuspid pulmonary valve were additional findings detected in one horse each. Post mortem examinations were performed in 8 horses which confirmed the echocardiographic findings. Sixteen out of 27 horses had a history of racing or competing successfully either before or after the diagnosis of the VSD. Two horses were useful pleasure horses, 3 horses presented in congestive heart failure, 1 horse developed signs of congestive heart failure, 2 horses were lost to follow-up and 2 are still alive but are small and stunted. The successful racehorses usually had a membranous VSD that measured < or = 2.5 cm in its largest diameter and a peak velocity of shunt flow through the VSD of > or = 4 m/s. Two-dimensional (2-D) and Doppler echocardiography is useful in assessing the haemodynamic significance of VSDs in horses and can be used to help formulate a prognosis for life and performance.
Animals↗
Sonographic findings in horses with mediastinal lymphosarcoma: 13 cases (1985-1992).
Sonographic findings correlated with necropsy findings in 8 of 9 horses in which the cranial portion of the mediastinum was evaluated by use of both methods. Cranial mediastinal masses were imaged as multilobular and homogeneously hypoechoic; a complex echogenic pattern was observed with necrosis within the mass. Pleural effusion was a common finding in horses with mediastinal lymphosarcoma. Cytologic evaluation of pleural fluid samples was useful in diagnosis of lymphosarcoma in 10 of 12 horses that had thoracentesis. Sonographic examination of the thorax and cranial portion of the mediastinum can aid in the diagnosis of mediastinal lymphosarcoma in horses. Such examination should be performed in horses with clinical signs of cranial vena cava obstruction in which pleural effusion is detected, or when thoracic lymphosarcoma is suspected.
Animals↗
Hydrops amnii in a mare.
A multiparous pregnant Welsh Pony mare was examined because of anorexia, dyspnea, and a large abdomen. Ultrasonography of the uterus revealed an excessive amount of amniotic fluid surrounding the fetus. Transabdominal ultrasonography permitted differentiation of hydrops amnii from hydrops allantois. The mare aborted a 7-month-old fetus with brachygnathia and a large, edematous umbilical cord. Hydrops amnii, an excessive accumulation of amniotic fluid in the amniotic cavity, is most commonly reported in cattle and sheep.
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Three-dimensional sonographic imaging of the equine superficial digital flexor tendon.
In a feasability study, a technique for constructing 3-dimensional sonographic images of the superficial digital flexor tendon (SDFT) was established in 6 clinically normal horses and applied to 7 horses with injured SDFT. Two-dimensional B-mode sonographic images were recorded on videotape as the sonographic transducer was manually moved along the palmar aspect of the metacarpal region. Selected videofields were digitized, and 3-dimensional images were constructed, using a computer work station and dedicated software program. The 3-dimensional images were of high quality and presented qualitative clinical information in unique fashion. Indication of the extent of SDFT injuries was excellent. Such 3-dimensional images would be especially useful in explaining to owners and trainers the importance of the injury to their horse and would have a role in monitoring tendon healing and in the assessment of various treatments.
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