Electrocardiographic parameters of the American Miniature Horse: influence of age and sex

Santarosa, Bianca Paola; Lourenço, Maria Lúcia Gomes; Dantas, Gabriela Nascimento; Ulian, Carla Maria Vela; Heckler, Marta Cristina Thomas; Sudano, Mateus José; Gonçalves, Roberto Calderón; Chiacchio, Simone Biagio

doi:10.1590/s0100-736x2016000600015

Cited by 3 publications

(6 citation statements)

References 22 publications

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“…In mares, the duration of PR and QT intervals were inversely proportional to the HR, with higher values at 210 days of gestation and shorter at 30 days. Unlike this study, pregnant mares of the American Miniature Horse breed had shown no difference in relation to non-pregnant mares for the duration of these segments, in none of the 7 derivations, however, as already exposed, these animals presented themselves at the beginning of pregnancy [25].…”

Section: Discussioncontrasting

confidence: 83%

“…The negative T wave showed distinct values between the mare in the postpartum period (21 days) and in the middle third of gestation (210 days). These ECG parameters also showed no difference between pregnant and nonpregnant mares of the same breed studied [25].…”

Section: Discussionmentioning

confidence: 59%

“…The electrocardiography (ECG), with HR assessment and wave morphology [19], can assist in complete cardiac evaluation of pregnant mares and newborn foals [4], however, it is necessary to use the reference values for the miniature breeds, in addition to the age range and reproductive condition [6,7,14,24,25].…”

Section: Introductionmentioning

confidence: 99%

“…Several studies had been carried out in relation to ECG and other clinical parameters in foals, such as Thoroughbred [5,20,28] and Ponies [10]. However, there are no descriptions of clinical parameters and ECG of AMH neonatal foals, despite the study that evaluated 17 foals aged 15 days to 10 months [25].…”

Section: Introductionmentioning

confidence: 99%

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Electrocardiographic Aspects of Singleton Pregnancy and Neonatal Period in American Miniature Horse Breed

Gama

Campos

Teixeira

et al. 2021

Acta Scientiae. Vet.

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Background: During pregnancy, cardiovascular adaptations occur in order to meet maternal demands and adequate support for fetal development, but they are still unclear in the equine species, especially in the American Miniature horse breed. The main hemodynamic changes that occur during pregnancy are increased heart rate, cardiac output, and blood volume. It is necessary to use the reference values for the miniature breeds, in addition to the age range and reproductive condition, so the objective of this study was to evaluate the effect of pregnancy on electrocardiographic (ECG) parameters in mares and also of age in newborns foals of American Miniature horse breed. Materials, Methods & Results: Ten American Miniature Horse mares, between 7 and 19 years old (12.14 ± 4.05 years), 116.85 ± 24.09 kg of body weight were used in the experiment. All these mares were pluriparous, with 5.9 ± 3.5 of births, minimum of 2, and maximum of 12 foaling times. They were maintained in common social group in an indoor house stable with straw bed, with access to an outdoor paddock for several h per day. Twice a day they were fed with hay. Mineral supplements and water were available ad libitum. The ECG were obtained in 10 pregnant mares and in 10 neonates. All females were examined at a representative time of each trimester of pregnancy, at 30, 210, 300 days before and 21 days after delivery. Neonates were examined on different times: first 24 h after delivery, weekly on the 7th, 14th, 21st, 28th and 35th days of age. The ECG parameters considered were the heart rate and rhythm, duration and intervals (P, PR, QRS, QT, T) and amplitude (P, R, S, T) of ECG waves. The mean of pregnancy duration was 319.4 ± 4.97 days. Heart Rate (HR) varied between 51 to 59 bpm during pregnancy and 56 bpm on the 21st day after delivery. Comparing the clinical parameters of pregnant mares, non-pregnant mares and foal a difference was found for HR, Respiration Rate (RR) and Temperature (P = 0.001). All ECG parameters of pregnant, non-pregnant and foal mares showed a significant difference (P = 0.0001), except for the amplitude of the P1, P2 and R waves, which was similar for the 3 groups. The mean values of HR and amplitude of the positive T wave were higher in foals when compared to pregnant and non-pregnant mares, which in turn did not differ from each other. The mean duration of the P wave, PR segment, QRS complex, QT segment and T wave were the same among mares and greater than in foals. Comparing pregnant and non-pregnant mares, there was a difference in only 3 parameters: duration of the QTc segment, amplitude of the S wave and negative T wave. The non-pregnant mares had a longer duration of the QTc segment and a greater amplitude of the negative T wave, while the foals had a greater amplitude of the S wave.Discussion: Although this study did not measure HR at delivery time, it is worth to consider the action of the parasympathetic autonomic nervous system close to delivery, which reduces the HR of mares. This is because at delivery, sympathetic-adrenal activation should be avoided since the increase in sympathetic tone can cause uterine atony via B2 receptors. For this reason, it has been shown that, during physiological birth, horses are under parasympathetic control, and stress response mechanisms are not activated. It was conclude that the morphometry of the waves, intervals and ECG complexes, during the evolution of the reproductive state, the electrocardiographic aspects were generally associated with heart rate (PR and QT intervals). As for neonates, there was a discrepancy among the most of ECG parameters when compared to the adult female, regardless of reproductive status, clarifying the importance of ECG patterns not only for the breed, but also for the age group.

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Section: Discussioncontrasting

confidence: 83%

Section: Discussionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Electrocardiographic Aspects of Singleton Pregnancy and Neonatal Period in American Miniature Horse Breed

Gama

Campos

Teixeira

et al. 2021

Acta Scientiae. Vet.

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show abstract

“…The effect of age was not considered in this study, since most horses were of similar age (7-11 years). A recent study on 203 horses of the American Miniature Horse breed revealed that QT intervals were shorter in foals than in other age groups, suggesting that with a smaller heart size the ventricular conduction velocity is slower (34). To prove the effect of age on the QT interval, horses of all age groups should be presented in the study, including foals, yearlings, adults, and elderly horses.…”

Section: Resultsmentioning

confidence: 99%

Normal QT interval in Ukrainian Riding Horses at rest and during exercise

Popadiuk¹,

Holopura²

2020

Medycyna Weterynaryjna

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Measurement of the main parameter of cardiac repolarization, namely QT interval, has a very high diagnostic value in human medicine, since its irregularities may indicate severe life-threatening ventricular tachyarrhythmias. The QT interval may vary not only with heart rate, age, sex, and autonomic tone, but also with horse breeds. Therefore, the description of its reference values for a specific breed is of great importance. The Ukrainian Riding Horse was bred as a show jumping, dressage and three-day eventing breed on the basis of Hanoverian, Thoroughbred and Trakehner stallions and local mares, as well as Hungarian Furioso, Gidran Arab and Nonius mares. Twenty-three horses of the Ukrainian riding breed were included in the study: 8 geldings, 8 mares, and 7 stallions aged 3-11 years. The electrodes for ECG recording were placed according to an adapted base-apex system. The ECG was registered during rest, exercise, and recovery periods. QT intervals were measured from resting to peak exercise levels on the traces of the 2nd lead and plotted against RR intervals. The piecewise regression model was fitted to the data plot. The values of Slope1, Slope2, and RRbend were compared to those of other breeds. The QT/RR relationship was relatively described by the piecewise linear regression model for all sexes (0.95 < r2 < 0.97). The sex of horses of the Ukrainian riding breed had a significant effect on the model. In terms of Slope1, Slope2, and RRbend values, Ukrainian riding horses are closest to Warmbloods, Standardbreds, and Thoroughbreds. The QT interval in horses should be corrected for breed and sex.

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The state of the cardiovascular system in normal and obese ponies according to the results of cardiographic studies

Borovkov,

Borovkova

2023

J. Vet. Med. Biotechnol. Biosafety

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Horses and ponies have physiological peculiarities in their cardiovascular system in comparison with other species as well as among themselves. Electrocardiogram (ECG) studies in ponies help to elucidate the peculiarities of cardiovascular system functioning, to establish reference values for parameters and to perform early diagnosis of arrhythmias. Arrhythmias, or irregular heart rhythms, can significantly affect the health of horses. Regular ECG screening can help detect early signs of cardiovascular disease such as myocarditis, valvular disease and congenital heart defects. Since horses and ponies come in different breeds, each with unique cardiovascular characteristics, this study aims to establish normative electrocardiogram parameters for ponies to allow for more accurate interpretation of electrocardiographic data. The study involved 18 ponies, aged 4–9 years, in a relatively calm state. Nine animals formed the control group and nine with signs of obesity formed the study group. All animals underwent a general clinical examination using widely accepted methods. Electrocardiographic studies were performed using the BeeW recorder, a state-of-the-art miniature electrocardiograph that allows registration, analysis and interpretation of electrocardiograms over the Internet using an Android tablet, smartphone or laptop. The study showed that the average heart rate (HR) for all ponies was 44.6 ± 2.1 bpm. No cases of sinus bradycardia with HR below 24 bpm were observed. Thirteen animals (72.2%) had HR in the range of 24–42 bpm, while five animals (27.8%) had sinus tachycardia. ECG findings showed positive P waves in 10 animals (55.5%) and negative P waves in 8 (44.5%). Positive T waves were observed in 5 animals (27.8%), while 13 (72.2%) had negative T waves. The QRS complex was predominantly a qR pattern with variations including QR, Qr, and qRS. In addition, two animals had sinus tachycardia and two had atrioventricular block

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Electrocardiographic parameters of the American Miniature Horse: influence of age and sex

Cited by 3 publications

References 22 publications

Electrocardiographic Aspects of Singleton Pregnancy and Neonatal Period in American Miniature Horse Breed

Electrocardiographic Aspects of Singleton Pregnancy and Neonatal Period in American Miniature Horse Breed

Normal QT interval in Ukrainian Riding Horses at rest and during exercise

The state of the cardiovascular system in normal and obese ponies according to the results of cardiographic studies

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