Mary M. Durando

Cardiac troponin I concentrations in horses with colic

OBJECTIVE To determine prevalence of myocardial injury in horses with colic on the basis of high concentrations of cardiac troponin I (cTnI), frequency of cardiac arrhythmias within the first 24 to 48 hours after hospital admission or surgery because of colic, and associations between high cTnI concentrations and cardiac arrhythmias, clinical course, and outcome (survival to discharge from hospital vs nonsurvival [death or euthanasia]). DESIGN Prospective observational study. ANIMALS 111 horses with colic. PROCEDURES Blood was drawn at admission and 12 and 24 hours after admission if horses were treated medically or 12 and 24 hours after surgery if treated surgically. A 24-hour ambulatory ECG was recorded beginning the morning after admission in medically treated cases or after surgery and evaluated for arrhythmias. Clinical and clinicopathologic data and outcome were obtained. Associations between cTnI concentrations and other variables were determined. RESULTS An abnormal cTnI concentration (≥ 0.10 ng/mL) at admission was significantly associated with the occurrence of ventricular arrhythmias, outcome, and surgical treatment. CONCLUSIONS AND CLINICAL RELEVANCE The data suggested that horses with colic and high cTnI concentrations at admission were more likely to have ventricular arrhythmias and have a less favorable prognosis for recovery. High cTnI concentrations in horses with colic were suggestive of myocardial damage.

Clinical techniques for diagnosing cardiovascular abnormalities in performance horses

Abstract Horses are frequently evaluated at referral institutions for poor exercise performance. Although the musculoskeletal and respiratory systems are more common causes of reduced athletic ability, the cardiovascular system is also an important cause, and horses with cardiac disease often present with a vague complaint of exercise intolerance. Determination of the contribution of cardiovascular abnormalities to decreased athletic ability may be difficult, as horses have a high percentage of murmurs and dysrhythmias that may not influence performance. However, they also may have paroxysmal or exercise-induced dysfunction that decreases cardiac output, and thus performance. Although resting examinations (physical exam and auscultation, electrocardiography, and echocardiography) will detect overt cardiac disease, and are an important part of the exam, an exercise test is crucial in the detection of exercise-induced dysfunction. The high-speed treadmill has revolutionized our ability to evaluate these horses. Exercising electrocardiography is used to evaluate heart rhythm during exercise, while functional evaluation with echocardiography is restricted to the immediate post-exercise period. In the future, measurement of exercising ventricular pressure dynamics and cardiac output may provide useful information in selected cases.

Comparison of echocardiographic measurements in elite and nonelite Arabian endurance horses

OBJECTIVE To determine whether echocardiographic variables differed between successful (elite) and less successful (nonelite) Arabian endurance horses. ANIMALS 34 Arabian horses that competed in endurance racing. PROCEDURES Horses were assigned to either an elite or nonelite group on the basis of results of a previous competition, and a standardized echocardiographic examination was performed on each horse within 1 to 4 weeks after that competition. Multivariable logistic regression with backward stepwise elimination was used to create a prediction model for the determination of horse status (elite or nonelite) as a function of the measured echocardiographic variables. RESULTS The elite and nonelite groups consisted of 23 and 11 horses, respectively. One horse in the nonelite group had a frequent ventricular dysrhythmia that could have negatively affected its performance and riders safety, whereas none of the horses in the elite group had remarkable cardiac abnormalities. The left ventricular internal diameter during systole and diastole and left ventricular mass and stroke volume were significantly greater for horses in the elite group, compared with those for horses in the nonelite group. The final logistic regression model correctly predicted the horse status for all of the horses in the elite group and 8 of 11 horses in the nonelite group. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that heart size was significantly associated with performance for Arabian endurance horses in a manner similar to findings for Thoroughbred and Standardbred racehorses in active competition.

The Effects of Equine Assisted Activities Therapy on Plasma Cortisol and Oxytocin Concentrations and Heart Rate Variability in Horses and Measures of Symptoms of Post-Traumatic Stress Disorder in Veterans

&NA; With the increase in the number of horses being used in Equine‐Assisted Activities and Therapies (EAAT) programs and with the increasing concern for animal welfare, it is important to understand the impact of such interventions on the stress level and quality of life for the horses involved. The purpose of the present pilot study was to test the hypothesis that participation in EAAT would acutely alter physiological markers of stress and well‐being, including plasma cortisol, plasma oxytocin, and heart rate variability (HRV), in horses and that symptoms of posttraumatic stress disorder (PTSD) would be reduced after five sessions of EAAT in veterans who had previously been diagnosed with PTSD. Nine healthy geldings, of various breeds, ages 10–23 years, conditioned and experienced as therapeutic riding horses, were selected to participate in the study. Of these, seven were selected at random to wear electrocardiogram units, and all nine were used for blood sampling to measure plasma cortisol and oxytocin. Each horse was randomly assigned to partner with a veteran for five EAAT sessions, 1 hour in duration. A standing control was conducted on a later date on which horses did not participate in EAAT. Measurement after 5 days of EAAT was conducted immediately after the end of the last session on day 5 using the Brief Symptom Inventory and the PCL‐5 (a 20 item self‐report measure of the Diagnostic and Statistical Manual of Mental Disorders ‐ 5 for symptoms of PTSD). Two way repeated measure analysis of variance showed no significant day by time interactions for plasma cortisol (P = .821) or oxytocin (P = .861). There was a significant day by time interaction (P = .006) for heart rate (HR); where on day 1, HR (bpm) was significantly lower during the interaction with the veterans. There were no significant differences in HRV variables. Posttherapy measures in PTSD symptoms in veterans were significantly reduced except for interpersonal sensitivity (P = .08) and phobic anxiety (P = .17). There was an effect of EAAT on HR which was significantly reduced on day 2 during the actual EAAT session. Equine‐Assisted Activities and Therapies had no effect on respiration rate and systolic or diastolic blood pressure in veterans involved in five sessions of EAAT, lasting 60 minutes in duration over the course of 5 days. Stress levels, as demonstrated by plasma cortisol concentrations and HRV, did not change in horses involved in EAAT sessions with veterans who had been previously diagnosed with PTSD. Furthermore, the horses used in this study did not demonstrate increased levels of well‐being as demonstrated by the lack of change in plasma oxytocin concentrations after EAAT sessions. Symptoms of PTSD did change significantly in the veterans who participated in this study.