Avaliação do ritmo cardíaco em cães da raça Boxer saudáveis pela eletrocardiografia contínua (Holter)

Nogueira, Raírys Cravo; Muzzi, Ruthnéa Aparecida Lázaro; Herrera, Dolores; Falco, I.; Cavalcanti, Guilherme Albuquerque de Oliveira

doi:10.1590/s0102-09352006000100021

Cited by 4 publications

(5 citation statements)

References 7 publications

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“…It is known that the T 3 hormone plays a stimulating role in the synthesis of structural cardiac proteins, such as voltage-dependent potassium channels, β1-adrenergic receptors, sodium/potassium ATPase, among others [4], justifying the intense impact of untreated hypothyroidism on the cardiac system [3,24]. Thus, the cardiovascular system is strongly influenced by ANS [16], since, in an episode of an imbalance between sympathetic and parasympathetic ANS, that is dysautonomia [12], it would result in cardiac changes, such as arrhythmias, sinoatrial blocks [6], dilated cardiomyopathies [3] and even risk of tissue necrosis, due to abnormalities in the myocardial microarchitecture [13]. Signs of pause, arrhythmia, and blocks were observed on the dog's electrocardiography (Figure 1B-1E), representing cardiac risks and, therefore, requiring monitoring of the cardiac condition for detailed investigation [6].…”

Section: Discussionmentioning

confidence: 99%

“…Considering that the Holter monitoring exam is a simple and non-invasive tool that helps the veterinarians to understand cardiac autonomic modulation [6,14,16,17], it is recommended to use this exam in the clinical routine in cases of hypothyroidism for monitoring the cardiac risk and the ANS imbalance. Additionally, studies with other drugs for the treatment of hypothyroidism, such as liothyronine sodium, deserve to be investigated regarding the effects on the cardiac and autonomic systems, due to the lack of data.…”

Section: Discussionmentioning

confidence: 99%

“…To assess the impact of untreated and treated hypothyroidism on ANS, an HRV analysis was performed by Holter monitoring [24]. This method is considered the most complete to assess cardiac rhythm and the presence of abnormal complexes, verifying the autonomic condition [14,16,17,22]. Therefore, two Holter monitoring exams were performed, being one before treatment and the other after five months of levothyroxine therapy.…”

Section: Casementioning

confidence: 99%

“…As the heart is under constant influence from the autonomic nervous system (ANS), its modulation can be assessed by heart rate variability (HRV) [14,16,17,22]. For this, the Holter exam for 24 h is the most complete method for assessing cardiac rhythm [15][16][17], being commonly used in hypothyroidism human [5,11,23,24], due to the risk of arrhythmias and dysautonomia. However, reports in dogs are scarce [6,13,15].…”

Section: Introductionmentioning

confidence: 99%

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Minimum Dose of Levothyroxine Restored the Autonomic Balance on a Dalmatian Female Dog with Primary Hypothyroidism

Costa

Waller

Rocha

et al. 2020

Acta Scientiae. Vet.

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Background: Hypothyroidism is an endocrine disease that leads to a reduction in the hormones thyroxine (T3) and triiodothyronine (T4), which therapy with levothyroxine restores the clinical signs related to the metabolic rate. Due to the influence of thyroid hormones on the heart, which is under the constant influence of the autonomic nervous system (ANS), dogs with hypothyroidism can develop bradycardia, arrhythmia, and dysautonomia. Heart rate variability (HRV) assesses autonomic modulation by the Holter method, which is scarce in dogs. We aimed to report the cardiac and autonomic effects of the primary hypothyroidism untreated and treated with levothyroxine in a canine case by Holter monitoring.Case: A 7-year-old female Dalmatian, weighing 36 kg, was referred for clinical evaluation due to apathy, weight gain, low hair quality, and lethargy. On physical examination, alopecic lesions on the hind limbs and tail, as well as bradycardia with a heart rate (HR) of 40-50 beats per minute (bpm) were observed, in addition to a 3/6 mitral murmur and 2/6 tricuspid murmur. Given the suspicion of thyroid gland disorder, the blood hormonal measurement revealed an increase in thyroid-stimulating hormone (TSH; 0.65 ng/mL) and a decrease in free T4 (0.11 ng/mL) and total T4 (0.44 ng/mL), confirming primary hypothyroidism. Therapy was started with a minimum dose of levothyroxine (0.913 mg, every 12 h), which clinical signs were restored in five months of treatment, with weight loss, hair growth, and active behavior. To assess the impact of untreated and treated hypothyroidism on the patient’s ANS, a Holter monitoring exam was performed for 24 h before and after therapy. Before treatment, the average HR was 75 bpm, and the HR<50 bpm occurred during 05 h 20 min 36 s. Still, 320 pause events (>2.0s), 1st-degree atrioventricular blocks (AVB), six ventricular ectopias events, and 2nd-degree sinoatrial block (SAB) were also observed. The ANS parasympathetic tone was significantly stimulated, highlighting bradycardia, arrhythmia, and dysautonomia. After five months of treatment with levothyroxine, the average HR was 89 bpm, and the HR<50 bpm occurred during 02 h 06 min 13 s. No ventricular pauses, blocks, or ectopias were observed, showing the stimulation of sympathetic tonus, which restored HR and ANS balance. Still, it was observed that the minimum levothyroxine dose corrected cardiac changes by increasing the low frequency (LF), decreasing the high frequency (HF), and, consequently, increasing the LF/HF ratio, normalizing the frequency conditions in HRV.Discussion: In the frequency index, HF indicates the vagal activity, whereas LF indicates both systems with parasympathetic predominance. Before treatment, the dog had a low LF/HF ratio (0.46), indicating dysautonomia with parasympathetic stimulation. After therapy, the conditions of bradycardia and functional cardiac capacity were corrected, restoring ANS, due to the serum recovery of thyroid hormones. This study reported the cardiac and autonomic effects of primary hypothyroidism untreated and treated with levothyroxine on a dog, that had intense bradycardia and abnormal stimulation of the parasympathetic tone, associated with episodes of 1st-degree AVB, ventricular ectopias, and 2nd-degree SAB. After therapy with a minimum dose of levothyroxine, there was a decrease in parasympathetic activity and an increase in sympathetic stimulus, correcting cardiac changes, and restoring the balance of ANS. As it is a simple, non-invasive, and safe tool that helps the clinician to understand cardiac autonomic modulation, it is recommended to adopt the Holter monitoring exam in cases of hypothyroidism cases to assess sympathetic-vagal balance and check potential cardiac risks.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Casementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Minimum Dose of Levothyroxine Restored the Autonomic Balance on a Dalmatian Female Dog with Primary Hypothyroidism

Costa

Waller

Rocha

et al. 2020

Acta Scientiae. Vet.

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“…Infelizmente, o eletrocardiograma (ECG) realizado durante o exame físico tem limitada habilidade em detectar muitas arritmias, pois é realizado em repouso e por curto período de tempo (Miller et al, 1999;Cote e Ettinger, 2005). Dessa forma, o eletrocardiograma ambulatorial por longo período (ou monitorização Holter) consiste no teste não invasivo ideal para demonstrar e quantificar a freqüência e a complexidade de arritmias por longos períodos (Sisson et al, 1999;Nogueira et al, 2006). Assim, a monitorização eletrocardiográfica ambulatorial (MEA) por 24 horas confirmou a ocorrência universal de extra-sístoles ventriculares (EV) e detectou taquicardia ventricular não sustentada (TVNS) em cerca de 40% dos pacientes humanos com CMD (Dec e Valentin, 1994); em cães, poucos são os trabalhos com MEA, sendo a maioria em Boxers e Dobermans.…”

Section: Introductionunclassified

Monitorização eletrocardiográfica ambulatorial por 24-horas em cães com cardiomiopatia dilatada idiopática

Yamaki

Soares

Pereira

et al. 2007

Arq. Bras. Med. Vet. Zootec.

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RESUMOCaracterizou-se monitorização eletrocardiográfica ambulatorial por 24 horas (ou monitorização Holter) em cães com cardiomiopatia dilatada idiopática, visando principalmente à detecção de arritmias ventriculares não detectadas pela eletrocardiografia convencional (de repouso). Para tanto, avaliaram-se 40 pacientes com diagnóstico de cardiomiopatia dilatada idiopática, por meio de exame físico e mensuração indireta da pressão arterial, além de exames eletrocardiográfico, ecocardiográfico, radiográfico de tórax e da monitorização Holter. Extra-sístoles ventriculares foram detectadas, por monitorização Holter, em 97,5% dos animais e taquicardia ventricular, em 45%. Não houve correlação entre o número de extra-sístoles ventriculares e a fração de encurtamento. Considerando as manifestações clínicas, apenas houve associação entre presença de taquicardia ventricular e histórico de síncopes. Conclui-se que a incidência de arritmias ventriculares em cães com cardiomiopatia dilatada idiopática é bastante alta, sendo a taquicardia ventricular relativamente freqüente, ocorrendo mais sob a forma não sustentada. Palavras

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Avaliação por eletrocardiografia contínua (holter) em cães da raça Pastor Alemão praticantes de atividade física regular

Cavalcanti¹,

Nogueira²,

Sampaio³

et al. 2009

Arq. Bras. Med. Vet. Zootec.

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Avaliação do ritmo cardíaco em cães da raça Boxer saudáveis pela eletrocardiografia contínua (Holter)

Abstract: Avaliação do ritmo cardíaco em cães da raça Boxer saudáveis pela eletrocardiografia contínua (Holter) [Evaluation

Cited by 4 publications

References 7 publications

Minimum Dose of Levothyroxine Restored the Autonomic Balance on a Dalmatian Female Dog with Primary Hypothyroidism

Minimum Dose of Levothyroxine Restored the Autonomic Balance on a Dalmatian Female Dog with Primary Hypothyroidism

Monitorização eletrocardiográfica ambulatorial por 24-horas em cães com cardiomiopatia dilatada idiopática

Avaliação por eletrocardiografia contínua (holter) em cães da raça Pastor Alemão praticantes de atividade física regular

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