Esta pesquisa foi suportada por uma concessão do United Cidadãos de Investigação em Epilepsia (CURE) para SLB.

<p class="jove_title"&gt; 1. Materiais para Construção</p&gt;<ol&gt;<li&gt; Um cateter da veia jugular é construído a partir de uma peça (100 mm) da PE-50 tubos de polietileno, chanfrada em uma extremidade, e depois preenchido com solução salina com heparina (50 U de heparina / ml salina).</li&gt;<li&gt; A gravação do ECG eletrodos são construídos a partir de dois comprimentos de 100 mm de fio de prata isolados (30AWG). Uma extremidade de ambos os fios é despojado e soldada a um microconector, eo isolamento é torcido para formar um terceiro fio que é usado como terra. Cinco milímetros de isolamento é retirado da extremidade distal dos fios e descartados.</li&gt;</ol&gt;<p class="jove_title"&gt; 2. Implantação do cateter da veia jugular</p&gt;<ol&gt;<li&gt; Anesthetize o animal pela administração de uretano, ip (1,2 g / kg).</li&gt;<li&gt; Verifique regularmente (intervalos de 10 min) profundidade da anestesia através da avaliação da resposta retirada pedal e / ou reflexos oculares. Se necessário, complementar a anestesia.</li&gt;<li&gt; Depois que o animal está no plano adequado de anestesia, raspar o lado direito do pescoço da clavícula até o queixo.</li&gt;<li&gt; Faça uma incisão longitudinal (10-15 mm) na pele acima da artéria carótida e abrir a incisão.</li&gt;<li&gt; Usando técnicas de dissecção romba, espalhar o músculo subjacente para localizar e isolar a veia jugular direita.</li&gt;<li&gt; Coloque dois pedaços de seda cirúrgica (# 2) sob a veia jugular, e posicione a sutura da porção mais rostral e caudal da incisão. Amarrar a ligadura rostral interromper o fluxo através da veia.</li&gt;<li&gt; Recolha a ligadura caudal para levantar o navio fora do tecido subjacente e fazer um pequeno corte. Em seguida, insira a extremidade chanfrada da heparina cateter preenchido PE-50 (50 U / ml salina) de polietileno (100 mm de comprimento), e avançar a ponta cerca de 8 mm ao nível do átrio direito.</li&gt;<li&gt; A fim de garantir o cateter, amarrar a ligadura caudal em torno de ambos navio e cateter. Finalmente, feche a ferida com clips ou ferida ou sutura.</li&gt;<li&gt; Durante a implantação do cateter, a extremidade exposta ou é presa com uma pinça hemostática ou conectado para evitar o refluxo de sangue antes de apego a uma bomba de infusão.</li&gt;</ol&gt;<p class="jove_title"&gt; 3. Implantação de eletrodos CG</p&gt;<ol&gt;<li&gt; Coloque o animal em suas costas e raspar o peito.</li&gt;<li&gt; Para a colocação dos eletrodos, fazer duas incisões longitudinais (≈ 10 mm), um no canto superior direito e um nos quadrantes inferior esquerdo do peito, ea pele sobrejacente livre para expor os músculos do tórax.</li&gt;<li&gt; Suture um dos expostos de 5 mm pontas dos eletrodos de prata-wire para os músculos do tórax em cada uma das áreas expostas, e coloque o eletrodo terra por via subcutânea.</li&gt;<li&gt; Feche a incisões com grampos de sutura e ligue o microconector para o dispositivo de gravação.</li&gt;<li&gt; Envolva o animal frouxamente em uma toalha para manter a temperatura corporal durante o procedimento.</li&gt;</ol&gt;<p class="jove_title"&gt; 4. Gravação de ECG</p&gt;<ol&gt;<liGravações&gt; são feitas usando um Powerlab Aquisição de Dados do Sistema e Macintosh computador ou hardware similar / software (amplificado, 50X; filtrado, 1000-1000 Hz).</li&gt;<li&gt; Depois de um período de equilíbrio 20-30 min, o registro ECG durante 20 min.</li&gt;</ol&gt;<p class="jove_title"&gt; 5. Indução de arritmias ventriculares</p&gt;<ol&gt;<li&gt; Coloque o cateter da veia jugular a uma seringa remoto colocado em uma bomba de infusão programável.</li&gt;<li&gt; Iniciar a infusão aconitina a uma taxa para fornecer uma dose constante de 5 ug / kg / min durante 7 minutos.</li&gt;<li&gt; Após a fibrilação ventricular ou o fim do período de infusão, eutanásia do animal usando um procedimento aprovado.</li&gt;</ol&gt;<p class="jove_title"&gt; 6. Análise do ECG</p&gt;<ol&gt;<li&gt; O intervalo QT representa a duração total da atividade elétrica ventricular. Fig. 1 mostra um modelo de registro ECG ea duração do intervalo QT. Calcule o tempo médio entre o início da onda Q e terminação da onda T para todos os batimentos cardíacos gravados ao longo de um intervalo de cinco minutos obtida durante o período de gravação de 20 min.</li&gt;<li&gt; Para corrigir o intervalo QT para as diferenças na freqüência cardíaca (QTc), use a fórmula de Bazett, QTc = QT / (RR)<sup&gt; ½</sup&gt;, Onde RR é o intervalo médio entre os batimentos. O intervalo RR é calculada como a duração entre sucessivas ondas Q obtidos durante o período analisado.</li&gt;<li&gt; A dispersão QT (QTd) é calculado subtraindo-se o QT mínima do QT máxima registrada para cada animal.</li&gt;</ol&gt;<p class="jove_title"&gt; 7. Análise da variabilidade da freqüência cardíaca</p&gt;<ol<liProgramas&gt; Software (ie LabChart 7, ADInstruments, Inc.) que analisam a variabilidade nos intervalos RR obtidos durante o período de análise são usados ​​para o cálculo automatizado de variância temporal e / ou espectral da frequência cardíaca.</li</ol&gt;<p class="jove_title"&gt; 8. Análise da susceptibilidade a arritmias ventriculares</p&gt;<ol<li&gt; Calcular a latência do início da infusão aconitina à contração ventricular prematura primeiro (PVC, fig. 2, Painel 1), taquicardia ventricular (VT, Fig, 2, Painel 2) e fibrilação ventricular (VF, Fig. 2. Painel 3 ).</li</ol&gt;<p class="jove_title"&gt; 9. Resultados representante</p&gt;<p class="jove_content"&gt; Figura. 3 ilustra uma medida da VFC no domínio espectral (root mean squared do desvio padrão do intervalo RR, RMSSD) em ratos controle e em animais que foram submetidos SE uma semana antes do teste. Esta medida da VFC, o que representa mudanças no controle parassimpático da função cardíaca<sup&gt; 26</sup&gt;, É significativamente diminuída em animais após estado de mal epiléptico. Fig. 4 mostra que tanto o intervalo QT corrigido (QTc, Painel A) e dispersão do QT (QTd, Painel B) são significativamente aumentados de duas semanas após SE<sup&gt; 27</sup&gt;. Tomados em conjunto, esses dados prevêem que SE aumenta o risco de arritmias ventriculares. Esta previsão é confirmada pelos resultados que os períodos de infusão aconitina necessário para levar a arritmias experimental (PVC, VT, VF) observado nestes estudos foram significativamente menores nos animais após SE (Fig. 5)<sup&gt; 27</sup&gt;.</p&gt;<p class="jove_content"<img src="/files/ftp_upload/2726/2726fig1.jpg" alt="figure 1" /<br /<strong&gt; Figura 1.</strong&gt; Modelo de gravação ECG de um batimento cardíaco normal, mostrando P, QRS e ondas T. O intervalo QT é calculado como o tempo entre as linhas tracejadas.</p&gt;<p class="jove_content"<img src="/files/ftp_upload/2726/2726fig2.jpg" alt="figure 2" /<br /<strong&gt; Figura 2. Painel 1)</strong&gt; Contrações ventriculares prematuras (PVC) são isolados contracções dos ventrículos (B) que ocorrem entre batimentos cardíacos normais (A). Gravações de PVC são caracterizadas pela ausência de ondas P e T.<strong&gt; Painel 2</strong&gt; A taquicardia ventricular (VT) é uma série de contrações ventriculares múltiplas (C) que ocorrem sem batimentos cardíacos intervir normal (A).<strong&gt; Painel 3</strong&gt; A fibrilação ventricular (FV) é a falta de ritmo perceptível e nenhuma associação entre QRS e as ondas P (D).</p&gt;<p class="jove_content"<img src="/files/ftp_upload/2726/2726fig3.jpg" alt="figure 3" /<br /<strong&gt; Figura 3.</strong&gt; O root mean squared do desvio padrão (RMSSD; ms) dos intervalos entre os batimentos cardíacos observados em ratos controle e em animais submetidos a status epilepticus (SE) 1 semana antes do teste. ** P &lt;0,01 comparado ao controle.</p&gt;<p class="jove_content"<img src="/files/ftp_upload/2726/2726fig4.jpg" alt="figure 4" /<br /<strong&gt; Figura 4.</strong&gt; A média do intervalo QT corrigido (Painel A) e dispersão do QT (Painel B) calculado a partir de gravações de ECG obtidos de animais controle (Cont) e de ratos submetidos a estado de mal epiléptico (SE) duas semanas antes do teste. * P &lt;0,05 em comparação com Cont. (Metcalf, et al. Am. J. Physiol. Coração e Circ, 2009, Am Soc Physiol, usada com permissão do<sup&gt; 27</sup&gt;).</p&gt;<p class="jove_content"<img src="/files/ftp_upload/2726/2726fig5.jpg" alt="figure 5" /<br /<strong&gt; Figura 5.</strong&gt; As latências (s) entre o início da infusão aconitina ea primeira contração ventricular prematura (PVC), taquicardia ventricular (VT) e fibrilação ventricular (VF) em animais controle (Cont) e ratos submetidos a estado de mal epiléptico (SE) duas semanas antes do teste. * P &lt;0,05, ** p &lt;0,01 em comparação com Cont. (Metcalf, et al. Am. J. Physiol. Coração e Circ, 2009, Am Soc Physiol, usada com permissão do<sup&gt; 27</sup&gt;).</p&gt;

<ol>
	<li>Chugh, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Determinants+of+prolonged+QT+interval+and+their+contribution+to+sudden+death+risk+in+coronary+artery+disease:+The+Oregon+sudden+unexpected+death+study.">Determinants of prolonged QT interval and their contribution to sudden death risk in coronary artery disease: The Oregon sudden unexpected death study.</a> Circulation. 119, 663-670 (2009).</li><li>Darbar, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensitivity+and+specificity+of+QTc+dispersion+for+identification+of+risk+of+cardiac+death+in+patients+with+peripheral+vascular+disease.">Sensitivity and specificity of QTc dispersion for identification of risk of cardiac death in patients with peripheral vascular disease.</a> BMJ. 312, 874-878 (1996).</li><li>Bruyne, M. C. d. e. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=QTc+dispersion+predicts+cardiac+mortality+in+the+elderly:+The+Rotterdam+study.">QTc dispersion predicts cardiac mortality in the elderly: The Rotterdam study.</a> Circulation. 97, 467-472 (1998).</li><li>Malik, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heart+rate+variability:+standards+of+measurement,+physiological+interpretation,+and+clinical+use.">Heart rate variability: standards of measurement, physiological interpretation, and clinical use.</a> Circulation. 93, 1043-1065 (1996).</li><li>Grippo, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+susceptibility+to+ventricular+arrhythmias+in+a+rodent+model+of+experimental+depression.">Increased susceptibility to ventricular arrhythmias in a rodent model of experimental depression.</a> Am. J. Physiol. 286, H619-H626 (2004).</li><li>Li, M., Wang, J., Xie, H. H., Shen, F. M., Su, D. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+susceptibility+of+ventricular+arrhythmia+to+aconitine+in+conscious+hypertensive+rats.">The susceptibility of ventricular arrhythmia to aconitine in conscious hypertensive rats.</a> Acta. 28, 211-215 (2007).</li><li>Beig, M. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Voluntary+exercise+does+not+affect+stress-induced+tachycardia,+but+improves+resistance+to+cardiac+arrhythmias+in+rats.">Voluntary exercise does not affect stress-induced tachycardia, but improves resistance to cardiac arrhythmias in rats.</a> Clin. Exp. Pharm. Physiol. , (2010).</li><li>Hazari, M. S., Haykai-Coates, N., Winsett, D. W., Costa, D. L., Farraj, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+single+exposure+to+particulate+or+gaseous+ari+pollution+increases+the+risk+of+aconitine-induced+cardiac+arrhythmia+in+hypertensive+rats.">A single exposure to particulate or gaseous ari pollution increases the risk of aconitine-induced cardiac arrhythmia in hypertensive rats.</a> Toxicol. Sci. 112, 532-542 (2009).</li><li>Amran, M. S., Hashimoto, K., Homma, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+sodium-calcium+exchange+inhibitors,+KB-R7943+and+SEA0400,+on+aconitine-induced+arrhythmias+in+guinea+pigs+in+vivo,+in+vitro,+and+in+computer+simulation+studies.">Effects of sodium-calcium exchange inhibitors, KB-R7943 and SEA0400, on aconitine-induced arrhythmias in guinea pigs in vivo, in vitro, and in computer simulation studies.</a> J. Pharmacol. Exp. Ther. 310, 83-89 (2004).</li><li>Klekot, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Antiarrhythmic+activity+of+a+membrane-protecting+agent+Sal'magin+in+rats+with+aconitine-induced+arrhythmias.">Antiarrhythmic activity of a membrane-protecting agent Sal'magin in rats with aconitine-induced arrhythmias.</a> Bull. Exp. Biol. Med. 142, 209-211 (2006).</li><li>Lowenstein, D. H., Alldredge, B. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Status+Epilepticus.">Status Epilepticus.</a> New England J. Med. 338, 970-976 (1998).</li><li>Walker, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Status+epilepticus:+an+evidence+based+guide.">Status epilepticus: an evidence based guide.</a> BMJ. 331, 673-677 (2005).</li><li>Shorvon, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Status epilepticus: its clinical features and treatment in children and adults. , (1994).</li><li>Boggs, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemodynamic+monitoring+prior+to+and+at+the+time+of+death+in+status+epilepticus.">Hemodynamic monitoring prior to and at the time of death in status epilepticus.</a> Epilepsy Res. 31, 199-209 (1998).</li><li>Walton, N. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systemic+effects+of+generalized+convulsive+status+epilepticus.">Systemic effects of generalized convulsive status epilepticus.</a> Epilepsia. 34, S54-S58 (1993).</li><li>Boggs, J. G., Painter, J. A., DeLorenzo, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+electrocardiographic+changes+in+status+epilepticus.">Analysis of electrocardiographic changes in status epilepticus.</a> Epilepsy Res. 14, 87-94 (1993).</li><li>Painter, J. A., Shiel, F. O., DeLorenzo, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cardiac+pathology+findings+in+status+epilepticus.">Cardiac pathology findings in status epilepticus.</a> Epilepsia. 34, 30-30 (1993).</li><li>Lathers, C. M., Schraeder, P. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+pharmacology:+drugs+as+a+benefit+and/or+risk+in+sudden+unexpected+death+in+epilepsy.">Clinical pharmacology: drugs as a benefit and/or risk in sudden unexpected death in epilepsy.</a> J. Clin. Pharmacol. 42, 123-126 (2002).</li><li>Dashieff, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sudden+unexpected+death+in+epilepsy:+a+series+from+an+epilepsy+surgery+program+and+specualtion+of+the+relationship+to+sudden+cardiac+death.">Sudden unexpected death in epilepsy: a series from an epilepsy surgery program and specualtion of the relationship to sudden cardiac death.</a> J. Clin. Neurophysiol. 8, 216-222 (1991).</li><li>Tigaran, P. -. C. o. d. r. e. a., Dalager-Pedersen, S., Baandrup, S., Dam, U., M, ., Vesterby-Charles, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sudden+unexpected+death+in+epilepsy:+is+death+by+seizures+a+cardiac+event.">Sudden unexpected death in epilepsy: is death by seizures a cardiac event.</a> Am. J. Forensic Med. Pathol. 26, 99-105 (2005).</li><li>Leung, H., Kwan, P., Elger, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Finding+the+missing+link+between+ictal+bradyarrhythmia,+ictal+asystole,+and+sudden+unexpected+death+in+epilepsy.">Finding the missing link between ictal bradyarrhythmia, ictal asystole, and sudden unexpected death in epilepsy.</a> Epilepsy and Behavior. 9, 19-30 (2006).</li><li>Nei, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=EEG+and+ECG+in+sudden+unexplained+death+in+epilepsy.">EEG and ECG in sudden unexplained death in epilepsy.</a> Epilepsia. 45, 338-345 (2004).</li><li>Dudek, F. E., Clark, S., Williams, P. A., Grabenstatter, H. L., Pitkanen, A., Schwartzkroin, P. A., Moshe, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Models of Seizures and Epilepsy. , 415-432 (2006).</li><li>Turski, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Limbic+seizures+produced+by+pilocarpine+in+rats:+behavioral+electroencephalographic,+and+neuropathological+study.">Limbic seizures produced by pilocarpine in rats: behavioral electroencephalographic, and neuropathological study.</a> Behav. Brain Res. 9, 315-335 (1989).</li><li>Kulkarni, S. K., George, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lithium-pilocarpine+neurotoxicity:+a+potential+model+of+status+epilepticus.">Lithium-pilocarpine neurotoxicity: a potential model of status epilepticus.</a> Methods Find. Exp. Clin. Pharamacol. 17, 551-567 (1995).</li><li>Stein, P. K., Bosner, M. S., Kleiger, R. E., Conger, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hart+rate+variability:+a+measure+of+cardiac+autonomic+tone.">Hart rate variability: a measure of cardiac autonomic tone.</a> Am. Heart J. 127, 1376-1381 (1994).</li><li>Metcalf, C. S., Poelzing, S., Little, J. G., Bealer, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Status+epilepticus+induces+cardiac+myofilament+damage+and+increased+susceptibility+to+arrhythmias+in+rat.">Status epilepticus induces cardiac myofilament damage and increased susceptibility to arrhythmias in rat.</a> Am. J. Physiol. 297, H2120-H2127 (2009).</li></ol>

Dois aspectos dos procedimentos descritos são de importância crítica. Em primeiro lugar, a taxa de administração aconitina para o coração deve ser equivalente em animais. Isto requer a colocação consistente das dicas veia jugular cateter em relação ao coração, e ajuste cuidadoso da taxa de infusão. A taxa de entrega aconitina ao coração deve ser igual, a fim de avaliar adequadamente o aparecimento de arritmias ventriculares em relação a susceptibilidade alterada. Se a entrega aconitina varia, então a ...

methods for ecg evaluation of indicators of cardiac risk, and susceptibility to aconitine-induced arrhythmias in rats following status epilepticus

Letais arritmias cardíacas contribuem para a mortalidade em uma série de condições patológicas. Vários parâmetros obtidos a partir de um não-invasiva, eletrocardiograma facilmente obtidos (ECG) são estabelecidas, bem validadas indicadores prognósticos de risco cardíaco em pacientes que sofrem de uma série de cardiomiopatias. Aumento da freqüência cardíaca, diminuição da variabilidade da freqüência cardíaca (VFC), e aumento da duração e da variabilidade da atividade elétrica cardíaca ventricular (intervalo QT) são indicativos de maior risco cardíaco 1-4. Em modelos animais, é importante comparar esses ECG derivados variáveis ​​e susceptibilidade a arritmias induzida experimentalmente. Infusão intravenosa do agente aconitina arritmogênica tem sido amplamente utilizada para avaliar a susceptibilidade a arritmias em uma variedade de condições experimentais, incluindo modelos animais de depressão e hipertensão 5 6, 7 após o exercício e exposição a poluentes atmosféricos 8, bem como a determinação dos antiarrítmicos eficácia dos agentes farmacológicos 9,10. Note-se que a dispersão do intervalo QT em humanos é uma medida da variação do intervalo QT em todo o conjunto completo de cabos de um padrão de 12 derivações ECG. Consequentemente, a medida de dispersão QT do ECG duas derivações em ratos descrita neste protocolo é diferente do que o calculado a partir de registros ECG humano. Isso representa uma limitação na tradução dos dados obtidos de roedores à medicina clínica humana. Estado de mal epiléptico (SE) é uma crise única ou uma série de convulsões recorrentes continuamente com duração superior a 30 min 11,12 11,12, e os resultados na mortalidade em 20% dos casos 13. Muitas pessoas sobrevivem da SE, mas morrer dentro de 30 dias 14,15. O mecanismo (s) desta mortalidade tardia não é totalmente compreendido. Tem sido sugerido que arritmias ventriculares letais contribuir para muitas destas mortes 14-17. Além de SE, os pacientes com crises recorrentes de forma espontânea, epilepsia ou seja, estão em risco de morte súbita prematura e inesperada associada a epilepsia (SUDEP) 18. Tal como acontece com SE, os mecanismos precisos mediação SUDEP não são conhecidos. Tem sido proposto que as anormalidades e arritmias ventriculares resultando uma contribuição significativa 18-22. Para investigar os mecanismos de apreensão relacionados com morte cardíaca, ea eficácia de terapias cardioprotetor, é necessário obter os dois indicadores ECG derivados de risco e avaliar a susceptibilidade a arritmias cardíacas em modelos animais de doenças convulsivas 23-25. Aqui nós descrevemos métodos para o implante de eletrodos ECG na Sprague-Dawley laboratório de ratos (Rattus norvegicus), seguindo SE coleta e análise de gravações de ECG, e indução de arritmias durante a infusão intravenosa de aconitina. Estes procedimentos podem ser usados ​​para determinar diretamente as relações entre ECG derivados medidas de atividade elétrica cardíaca e susceptibilidade a arritmias ventriculares em modelos de ratos de distúrbios convulsivos, ou qualquer patologia associada com maior risco de morte súbita cardíaca.

Watch this Scientific Journal Video about Methods for ECG Evaluation of Indicators of Cardiac Risk, and Susceptibility to Aconitine-induced Arrhythmias in Rats Following Status Epilepticus at JoVE.com

Methods for ECG Evaluation of Indicators of Cardiac Risk, and Susceptibility to Aconitine-induced Arrhythmias in Rats Following Status Epilepticus

Técnicas de medição da atividade elétrica do coração pelo eletrocardiograma (ECG), e análise de fatores de risco cardíaco e susceptibilidade a arritmias após estado de mal epiléptico (SE) no rato são descritos.

Métodos para ECG Avaliação de Indicadores de risco cardíaco e Susceptibilidade à Aconitina arritmias induzidas em ratos após a Estado Epiléptico

Lethal cardiac arrhythmias contribute to mortality in a number of pathological conditions. Several parameters obtained from a 
non-invasive, easily ...

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17.6K visualizações.  University of Utah. Técnicas de medição da atividade elétrica do coração pelo eletrocardiograma (ECG), e análise de fatores de risco cardíaco e susceptibilidade a arritmias após estado de mal epiléptico (SE) no rato são descritos.

Vídeo: Methods for ECG Evaluation of Indicators of Cardiac Risk, and Susceptibility to Aconitine-induced Arrhythmias in Rats Following Status Epilepticus

Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart failure. Here, we describe a detailed surgical procedure for creating pressure overload and cardiac hypertrophy in rats by constriction of the ascending aorta using a small metallic clip. After anesthesia, the trachea is intubated by inserting a cannula through a half way incision made between two cartilage rings of trachea. Then a skin incision is made at the level of the second intercostal space on the left chest wall and muscle layers are cleared to locate the ascending portion of aorta. The ascending aorta is constricted to 50&#8211;60% of its original diameter by application of a small sized titanium clip. Following aortic constriction, the second and third ribs are approximated with prolene sutures. The tracheal cannula is removed once spontaneous breathing was re-established. The animal is allowed to recover on the heating pad by gradually lowering anesthesia. The intensity of pressure overload created by constriction of the ascending aorta is determined by recording the pressure gradient using trans-thoracic two dimensional Doppler-echocardiography. Overall this protocol is useful to study the remodeling events and contractile properties of the heart during the gradual onset and progression from compensated cardiac hypertrophy to heart failure stage.

We describe a stepwise procedure for creating pressure overload and left ventricular hypertrophy in Wistar rats by constriction of the ascending aorta using a small metallic clip. This model is extensively used for studying remodeling changes during cardiac hypertrophy and for identifying and evaluating strategies for regression of such changes.

Aorta ascendente constrição em ratos para a criação de sobrecarga de pressão Cardíaca Hipertrofia Modelo

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart ...

Medicina

Early Detection of Drug-Induced Renal Hemodynamic Dysfunction Using Sonographic Technology in Rats

The kidney normally functions to maintain hemodynamic homeostasis and is a major site of damage caused by drug toxicity. Drug-induced nephrotoxicity is estimated to contribute to 19- 25% of all clinical cases of acute kidney injury (AKI) in critically ill patients. AKI detection has historically relied on metrics such as serum creatinine (sCr) or blood urea nitrogen (BUN) which are demonstrably inadequate in full assessment of nephrotoxicity in the early phase of renal dysfunction. Currently, there is no robust diagnostic method to accurately detect hemodynamic alteration in the early phase of AKI while such alterations might actually precede the rise in serum biomarker levels. Such early detection can help clinicians make an accurate diagnosis and help in in decision making for therapeutic strategy. Rats were treated with Cisplatin to induce AKI. Nephrotoxicity was assessed for six days using high-frequency sonography, sCr measurement and upon histopathology of kidney. Hemodynamic evaluation using 2D and Color-Doppler images were used to serially study nephrotoxicity in rats, using the sonography. Our data showed successful drug-induced kidney injury in adult rats by histological examination. Color-Doppler based sonographic assessment of AKI indicated that resistive-index (RI) and pulsatile-index (PI) were increased in the treatment group; and peak-systolic velocity (mm/s), end-diastolic velocity (mm/s) and velocity-time integral (VTI, mm) were decreased in renal arteries in the same group. Importantly, these hemodynamic changes evaluated by sonography preceded the rise of sCr levels. Sonography-based indices such as RI or PI can thus be useful predictive markers of declining renal function in rodents. From our sonography-based observations in the kidneys of rats that underwent AKI, we showed that these noninvasive hemodynamic measurements may consider as an accurate, sensitive and robust method in detecting early stage kidney dysfunction. This study also underscores the importance of ethical issues associated with animal use in research.

Early stage hemodynamic dysfunction is critical to the development of kidney disease. Yet, detection methodologies are limited. Recent advances in sonography provide a noninvasive, accurate option for early detection of kidney injury. This study outlines a step-by-step, sonographic methodology for detecting kidney dysfunction using a drug-induced nephrotoxicity rat model.

Detecção precoce de Induzida por Medicamentos Renal hemodinâmica Disfunção Usando ultrassonografia Tecnologia em Ratos

The kidney normally functions to maintain hemodynamic homeostasis and is a major site of damage caused by drug toxicity. Drug-induced nephrotoxicity is ...

Cardiac Magnetic Resonance for the Evaluation of Suspected Cardiac Thrombus: Conventional and Emerging Techniques

We present the conventional cardiac magnetic resonance (CMR) protocol for evaluating a suspected thrombus and highlight emerging techniques.&#160;The appearance of a mass on certain magnetic resonance (MR) sequences can help differentiate a thrombus from competing diagnoses such as a tumor. T1 and T2 signal characteristics of a thrombus are related to the evolution of hemoglobin properties. A thrombus typically does not enhance following contrast administration, which also helps differentiation from a tumor. We also highlight the emerging role of T1 mapping in the evaluation of a thrombus, which can add another level of support in diagnosis. Prior to any CMR exam, patient screening and interviews are critical to ensure safety and to optimize patient comfort. Effective communication during the exam between the technologist and the patient promotes proper breath holding technique and higher quality images. Volumetric post processing and structured reporting are helpful to ensure that the radiologist answers the ordering services&#39; question and communicates these results effectively. Optimal pre-MR safety evaluation, CMR exam execution, and post exam processing and reporting allow for delivery of high quality radiological service in the evaluation of a suspected cardiac thrombus.

The goal of this article is to describe how cardiac magnetic resonance can be used for the evaluation and diagnosis of a suspected cardiac thrombus. The method presented will describe data acquisition as well as the pre-procedure and post-procedure protocol.

Ressonância magnética cardíaca para avaliação de suspeita de trombo cardíaco: técnicas convencionais e emergentes

We present the conventional cardiac magnetic resonance (CMR) protocol for evaluating a suspected thrombus and highlight emerging techniques.&#160;The ...

Echocardiographic Assessment of Cardiac Anatomy and Function in Adult Rats

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional imaging to study the cardiac anatomy of the left ventricle and M-mode echo to assess its dimensions. However, this could limit a comprehensive study. Herein, we describe a protocol that allows an assessment of the heart chamber size, left ventricular function (systolic and diastolic) and valvular function. A conventional medical ultrasound machine was used in this protocol and different echo views were obtained through left parasternal, apical and suprasternal windows. In the left parasternal window, the long and short axis were acquired to analyze left chamber dimensions, right ventricle and pulmonary artery dimensions, and mitral, pulmonary and aortic valve function. The apical window allows the measurement of heart chamber dimensions and evaluation of systolic and diastolic parameters. It also allows Doppler assessment with detection and quantification of heart valve disturbances (regurgitation or stenosis). Different segments and walls of the left ventricle are visualized throughout all views. Finally, the ascending aorta, aortic arch, and descending aorta can be imaged through the suprasternal window. A combination of ultrasound imaging, Doppler flow and tissue Doppler assessment have been obtained to study cardiac morphology and function. This represents an important contribution to improve the assessment of cardiac function in adult rats with impact for research using these animal models.

A non-invasive protocol for transthoracic echocardiography assessment of cardiac anatomy and function for adult rats is presented in the current study. The heart valves, all four cardiac chambers and the ascending aorta, aortic arch and descending aorta are studied in detail.

Avaliação ecocardiográfica da anatomia e função cardíaca em ratos adultos

The use of experimental animal models has become crucial in cardiovascular science. Most studies using rodent models are focused on two-dimensional ...

Semi-Minimal Invasive Method to Induce Myocardial Infarction in Rats and the Assessment of Cardiac Function by an Isolated Working Heart System

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily and highly reproducible MI induction procedure is required to obtain further insight and better understanding of the underlying pathological changes. This procedure can also be used to evaluate the effects or potency of new and promising treatments (as drugs or interventions) in acute MI, subsequent remodeling and heart failure (HF). After intubation and pre-operative preparation of the animal, an anesthetic protocol with isoflurane was performed, and the surgical procedure was conducted&#160;quickly. Using a minimally invasive approach, the left anterior descending artery (LAD) was located and occluded by a ligature. The occlusion can be performed acutely for subsequent reperfusion (ischemia/reperfusion injury). Alternatively, the vessel can be ligated permanently to investigate the development of chronic MI, remodeling or HF. Despite common pitfalls, the drop-out rates are minimal. Various treatments such as remote ischemic conditioning can be examined for their cardioprotective potential pre-, peri- and post-operatively. The post-operative recovery was quick as the anesthesia was precisely controlled and the duration of the operation was short. Post-operative analgesia was administered for three days. The minimally invasive procedure reduces the risk of infection and inflammation. Furthermore, it facilitates rapid recovery. The &#8220;working heart&#8221; measurements were performed ex vivo and enabled precise control of preload, afterload and flow. This procedure requires specific equipment and training for adequate performance. This manuscript provides a detailed step-by-step introduction for conducting these measurements.

This article presents an efficient method to perform myocardial ischemia and subsequent chronic reperfusion in rats using a minimally invasive approach. In addition, left ventricular hemodynamic function of rats is assessed by echocardiography and isolated working heart methods.&#160;

Método invasivo semi-mínimo para induzir infarto do miocárdio em ratos e a avaliação da função cardíaca por um sistema cardíaco de trabalho isolado

Myocardial infarction (MI) remains the main contributor to morbidity and mortality worldwide. Therefore, research on this topic is mandatory. An easily ...

Analyzing Long-Term Electrocardiography Recordings to Detect Arrhythmias in Mice

Arrhythmias are common, affecting millions of patients worldwide. Current treatment strategies are associated with significant side effects and remain ineffective in many patients. To improve patient care, novel and innovative therapeutic concepts causally targeting arrhythmia mechanisms are needed. To study the complex pathophysiology of arrhythmias, suitable animal models are necessary, and mice have been proven to be ideal model species to evaluate the genetic impact on arrhythmias, to investigate fundamental molecular and cellular mechanisms, and to identify potential therapeutic targets.
Implantable telemetry devices are among the most powerful tools available to study electrophysiology in mice, allowing continuous ECG recording over a period of several months in freely moving, awake mice. However, due to the huge number of data points (&gt;1 million QRS complexes per day), analysis of telemetry data remains challenging. This article describes a step-by-step approach to analyze ECGs and to detect arrhythmias in long-term telemetry recordings using the software, Ponemah, with its analysis modules, ECG Pro and Data Insights, developed by Data Sciences International (DSI). To analyze basic ECG parameters, such as heart rate, P wave duration, PR interval, QRS interval, or QT duration, an automated attribute analysis was performed using Ponemah to identify P, Q, and T waves within individually adjusted windows around detected R waves. 
Results were then manually reviewed, allowing adjustment of individual annotations. The output from the attribute-based analysis and the pattern recognition analysis was then used by the Data Insights module to detect arrhythmias. This module allows an automatic screening for individually defined arrhythmias within the recording, followed by a manual review of suspected arrhythmia episodes. The article briefly discusses challenges in recording and detecting ECG signals, suggests strategies to improve data quality, and provides representative recordings of arrhythmias detected in mice using the approach described above.

Here we present a step-by-step protocol for a semiautomated approach to analyze murine long-term electrocardiography (ECG) data for basic ECG parameters and common arrhythmias. Data are obtained by implantable telemetry transmitters in living and awake mice and analyzed using Ponemah and its analysis modules.

Analisando gravações de eletrocardiografia de longo prazo para detectar arritmias em camundongos

Arrhythmias are common, affecting millions of patients worldwide. Current treatment strategies are associated with significant side effects and remain ...

Modified Heterotopic Abdominal Heart Transplantation and a Novel Aortic Regurgitation Model in Rats

Over the past 50 years, many researchers have reported heterotopic abdominal heart transplantation in mice and rats, with some variations in the surgical technique. Modifying the transplantation procedure to strengthen the myocardial protection could prolong the ischemia time while preserving the donor&#39;s cardiac function. This technique&#39;s key points are as follows: transecting the donor&#39;s abdominal aorta before harvesting to unload the donor&#39;s heart; perfusing the donor&#39;s coronary arteries with a cold cardioplegic solution; and topical cooling of the donor&#39;s heart during the anastomosis procedure. Consequently, since this procedure prolongs the acceptable ischemia time, beginners can easily perform it and achieve a high success rate.
Moreover, a new aortic regurgitation (AR) model was established in this work using a technique different from the existing one,&#160;which is created by inserting a catheter from the right carotid artery and puncturing the native aortic valve under continuous echocardiographic guidance. A heterotopic abdominal heart transplantation was performed using the novel AR model. In the protocol, after the donor&#39;s heart is harvested, a stiff guidewire is inserted into the donor&#39;s brachiocephalic artery and advanced toward the aortic root. The aortic valve is punctured by pushing the guidewire further even after the resistance is felt, thus inducing AR. It is easier to damage the aortic valve using this method than with the procedure described in the conventional AR model. Additionally, this novel AR model does not contribute to the recipient&#39;s circulation; therefore, this method is expected to produce a more severe AR model than the conventional procedure.

This study demonstrates a reproducible heterotopic abdominal heart transplantation technique in rats that beginners can learn and perform. Additionally, a novel aortic regurgitation model in rats is generated by performing heterotopic abdominal heart transplantation and damaging the donor's aortic valve using a guidewire after harvesting.

Transplante Cardíaco Heterotópico Abdominal Modificado e um Novo Modelo de Regurgitação Aórtica em Ratos

Over the past 50 years, many researchers have reported heterotopic abdominal heart transplantation in mice and rats, with some variations in the surgical ...

Manipulação padronizada de Tuina para osteoartrite do joelho em ratos

Tuina Manipulation to Reduce Inflammation and Cartilage Loss in Knee Osteoarthritis Rats

Clinical trials suggest that Tuina manipulation is effective in treating knee osteoarthritis (KOA), while further studies are required to discover its mechanism. Therefore, the manipulation of animal models of knee osteoarthritis is critical. This protocol provides a standard process for Tuina manipulation on KOA rats and a preliminary exploration of the mechanism of Tuina for KOA. The press and kneading manipulation method (a kind of Tuina manipulation that refers to pressing and kneading the specific area of the body surface) is applied on 5 acupoints around the knee joint of rats. The force and frequency of the manipulation were standardized by finger pressure recordings, and the position of the rat during manipulation is described in detail in the protocol. The effect of manipulation can be measured by pain behavior tests and microscopic findings in synovial and cartilage. KOA rats showed significant improvement in pain behavior. The synovial tissue inflammatory infiltration was reduced in the Tuina group, and the expression of tumor necrosis factor (TNF)-&#945; was significantly lower. Compared to the control group, chondrocyte apoptosis was less in the Tuina group. This study provides a standardized protocol for Tuina manipulation on KOA rats and preliminary proof that the therapeutic effects of Tuina may be related to reducing synovial inflammation and delayed chondrocyte apoptosis.

Autor em destaque: Compreendendo o mecanismo de manipulação da tuina em ratos 

We present a protocol for Tuina manipulation performed on plaster-immobilized-induced knee osteoarthritis rats. Based on the preliminary results, it suggested that the efficacy of the method relied on the reduction of inflammation and cartilage loss.

Manipulação de Tuina para Reduzir a Inflamação e Perda de Cartilagem em Ratos com Osteoartrite de Joelho

Clinical trials suggest that Tuina manipulation is effective in treating knee osteoarthritis (KOA), while further studies are required to discover its ...