Correction of QT values to allow for increases in heart rate in conscious Beagle dogs in toxicology assessment

Tattersall, Marshall Leslie; Dymond, Michael; Hammond, Tim; Valentin, Jean‐Pierre

doi:10.1016/j.vascn.2005.02.005

Cited by 62 publications

(31 citation statements)

References 21 publications

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“…Different studies in dogs have shown that baseline uncorrected QT values are within the physiological range at similar heart rates (HR) suggesting that QTi are being measured accurately. This is consistent with emerging data showing that the accuracy of ECG parameter measurement in dogs is highly reproducible between and within individuals and is independent of the number of cycles measured (Hamlin et al 2004;Tattersall et al, 2006).…”

Section: Introductionsupporting

confidence: 91%

“…Sex hormones are suspected to play a key role in this process. These findings were contradicted by the results of another study, although this should be interpreted with caution since the animals were not sexually mature at the initiation of some of these studies (Tattersall et al, 2006). Perhaps these notions deserve more attention since castration is a common practice in dogs and this influence has not been yet studied.…”

Section: Baslinementioning

confidence: 88%

“…Methods of QTc assessment 3. References window (usually less than 3 h) thus excluding any major influence of nycthemeral QT or HR variation (Tattersall et al, 2006).…”

Section: Measurement Of the Qt Intervalmentioning

confidence: 99%

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Tomenendalova J: How to approach the QT interval in dogs - the state of the heart: a review

Agudelo¹,

Scheer²,

Tomenendálová³

2011

Vet. Med. - Czech

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ABSTRACT:The QT interval has been the objective of exhaustive attention in the past and also in recent times. A number of conditions, congenital and acquired, can have a direct effect on cardiac repolarization. Also drug regulatory agencies have showed increasing interest in the topic because certain drugs can prolong the QT interval to a level that produces ventricular arrhythmias. The dog is a species that shares some similarities with the human electrical system and has been used in human and veterinary research. We here present the current recommendations for QT measurement in dogs for use in clinical and experimental practice.

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Section: Introductionsupporting

confidence: 91%

Section: Baslinementioning

confidence: 88%

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Tomenendalova J: How to approach the QT interval in dogs - the state of the heart: a review

Agudelo¹,

Scheer²,

Tomenendálová³

2011

Vet. Med. - Czech

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“…Formulae for calculating corrected QT interval (QTc) have been available since 1920 (Bazett 1920, Fridericia 1920) and various alternative methods have been studied, mainly in toxicology researches (Spier et al 2001, Davey 2002, Tattersall et al 2006, Ollerstam et al 2007). In medicine, the Bazett correction is worldwide employed due to its simplicity and reliable data.…”

Section: Introductionmentioning

confidence: 99%

QT interval in healthy dogs: which method of correcting the QT interval in dogs is appropriate for use in small animal clinics?

Oliveira

Muzzi

et al. 2014

Pesq. Vet. Bras.

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Pesq. Vet. Bras. 34(5):469-472, maio 2014 469 RESUMO.-[Intervalo QT em cães hígidos: qual método de correção para o intervalo QT é mais apropriado na clínica de pequenos animais?] O intervalo QT do eletrocardiograma (ECG) é influenciado por variações da frequência cardíaca (FC), o que pode levar a erros na interpretação de sua duração. Considerando que as alterações na duração do intervalo QT refletem anormalidades da repolarização ventricular, as quais predispõem a ocorrência de arritmias, esta variável deve ser devidamente avaliada. O objetivo deste trabalho foi determinar qual método de correção do intervalo QT é mais adequado para os cães, considerando-se diferentes intervalos de FC normais. Cães adultos saudáveis, de diferentes raças (n=130; Pastor Alemão, Boxer, Pit Bull Terrier e Poodle) foram submetidos ao exame eletrocardiográfico, no qual se determinaram os intervalos QT a partir da derivação bipolar II e foram corrigidos os efeitos da FC por meio da aplicação de três fórmulas, envolvendo regressão quadrática, cúbica ou linear. Os valores do QT corrigido (QTc) obtidos utilizando as diversas fór-mulas foram significativamente diferentes (ρ<0,05), sendo os derivados da equação QTcV = QT + 0,087 (1-RR), os mais consistentes (regressão linear). The electrocardiography (ECG) QT interval is influenced by fluctuations in heart rate (HR) what may lead to misinterpretation of its length. Considering that alterations in QT interval length reflect abnormalities of the ventricular repolarisation which predispose to occurrence of arrhythmias, this variable must be properly evaluated. The aim of this work is to determine which method of correcting the QT interval is the most appropriate for dogs regarding different ranges of normal HR (different breeds). Healthy adult dogs (n=130; German Shepherd, Boxer, Pit Bull Terrier, and Poodle) were submitted to ECG examination and QT intervals were determined in triplicates from the bipolar limb II lead and corrected for the effects of HR through the application of three published formulae involving quadratic, cubic or linear regression. The mean corrected QT values (QTc) obtained using the diverse formulae were significantly different (ρ<0.05), while those derived according to the equation QTcV = QT + 0.087(1-RR) were the most consistent (linear regression). QTcV values were strongly correlated (r=0.83) with the QT interval and showed a coefficient of variation of 8.37% and a 95% confidence interval of 0.22-0.23 s. Owing to its simplicity and reliability, the QTcV was considered the most appropriate to be used for the correction of QT interval in dogs. intervalo de confiança de 95% de 0,22-0,23s. Devido à confiabilidade dos dados, o QTcV foi considerado o mais apropriado para ser utilizado para a correção do intervalo QT em cães, além de ser um método de fácil execução.

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“…The maximum ST-segment deviation never exceeded 1mm (or 0.1mV), as also observed by Levine and Bristol (21). The inversion of T wave polarity in serial ECG is not considered normal (22). These transitory T-wave alterations may indicate a myocardial disease and might occur in the absence of a clinically detectable heart disease.…”

Section: Time (T) Groupsmentioning

confidence: 99%

Cardiac evaluation after experimental intoxication by Amorimia rigida (Malpighiaceae) extracts in rabbits

Borboleta¹,

Ef²,

Oliveira³

et al. 2012

J. Venom. Anim. Toxins incl. Trop. Dis

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Clinical and laboratory changes were evaluated in rabbits after intoxication by Amorimia rigida, a plant that causes sudden death. Nine New Zealand male rabbits, averaging 3.54 kg, were categorized into three groups (n = 3) and received, for eight consecutive days, the equivalent of 30 g/kg dry matter of A. rigida water-soluble (SG) and water-insoluble (IG) extracts via nasoesophageal route. The control group received water. There were no alterations in creatine kinase enzyme (CK), CK myocardial fraction (CKMB) or troponine I (cTnI). None of the animals had clinical or electrocardiographic (conventional and Holter) alterations. There were progressive decreases in the left ventricular ejection fraction and systolic fractional shortening. Doppler echocardiography alterations suggested a systolic dysfunction in the SG and IG groups and diastolic dysfunction in IG group. It was concluded that the soluble and insoluble extracts of A. rigida cause deficit of cardiac function.Key words: toxic plant, Amorimia rigida, cardiac muscle profile, electrocardiography, echocardiography, rabbit. Original PaPer The Journal of Venomous Animals and Toxins including Tropical Diseases ISSN 1678-9199 | 2012 | volume 18 | issue 3 | pages 295-305 INTRODUCTIONThe genus Amorimia (Malpighiaceae) contains one of the 10 most important toxic plants in South America (1), best known of which is Amorimia rigida (Mascagnia rigida), well distributed in Minas Gerais state (Brazil), mainly in the northern and northeastern regions, where it is popularly known as "salsa-rosa" or "suma-roxa". It belongs to a group that causes acute intoxication that may provoke death preceded or not by a short period of clinical signs (2).After A. rigida intake, animals may show apathy, anorexia, rigid walking, prolonged recumbence, muscle tremors and death, among other clinical signs. Significant alterations have not been found at necropsy of animals intoxicated by A. rigida. Multifocal infiltrate of lymphocytes in the myocardium associated with edema and congestion of myocytes was found in the histological exams (3).Studies are necessary to elucidate which physiopathological mechanisms are involved in A. rigida intoxication that leads to sudden death. In spite of the existence of some reports of mortality in the absence of cardiac lesions, it is suggested that the main action of this plant in the heart may be due to its phytochemical characteristics that might affect cardiac function within a period insufficient to produce alterations detectable by optical microscopy (4).To the best of our knowledge, no previous study has concurrently evaluated continuous electrocardiography (Holter), Doppler echocardiography and the cardiac muscle biochemical profile in animals after the intake of A. rigida. Thus, the present work aimed to ascertain the influence of this plant on the cardiac system using the rabbit as the experimental model. MATERIALS AND METHODS Animal AssaysNine six-month-old white New Zealand male rabbits weighing an average of 3.54 kg were used. Firstl...

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Correction of QT values to allow for increases in heart rate in conscious Beagle dogs in toxicology assessment

Cited by 62 publications

References 21 publications

Tomenendalova J: How to approach the QT interval in dogs - the state of the heart: a review

Tomenendalova J: How to approach the QT interval in dogs - the state of the heart: a review

QT interval in healthy dogs: which method of correcting the QT interval in dogs is appropriate for use in small animal clinics?

Cardiac evaluation after experimental intoxication by Amorimia rigida (Malpighiaceae) extracts in rabbits

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