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1.
Rev. bras. cir. cardiovasc ; 34(5): 517-524, Sept.-Oct. 2019. tab
Artigo em Inglês | LILACS | ID: biblio-1042055

RESUMO

Abstract Objective: To evaluate the effect of high-dose vitamin C on cardiac reperfusion injury and plasma levels of creatine kinase-muscle/brain (CK-MB), troponin I, and lactate dehydrogenase (LDH) in patients undergoing coronary artery bypass grafting (CABG). Methods: This is a double-blind randomized clinical trial study. Fifty patients (50-80 years old) who had CABG surgery were selected. The intervention group received 5 g of intravenous vitamin C before anesthesia induction and 5 g of vitamin C in cardioplegic solution. The control group received the same amount of placebo (normal saline). Arterial blood samples were taken to determine the serum levels of CK-MB, troponin I, and LDH enzymes. Left ventricular ejection fraction was measured and hemodynamic parameters were recorded at intervals. Results: High doses of vitamin C in the treatment group led to improvement of ventricular function (ejection fraction [EF]) and low Intensive Care Unit (ICU) stay. The cardiac enzymes level in the vitamin C group was lower than in the control group. These changes were not significant between the groups in different time intervals (anesthesia induction, end of bypass, 6 h after surgery, and 24 h after surgery) for CK-MB, LDH, and troponin I. Hemodynamic parameters, hematocrit, potassium, urinary output, blood transfusion, arrhythmia, and inotropic support showed no significant difference between the groups. Conclusion: Vitamin C has significantly improved the patients' ventricular function (EF) 72 h after surgery and reduced the length of ICU stay. No significant changes in cardiac biomarkers, including CK-MB, troponin I, and LDH, were seen over time in each group. IRCT code: IRCT2016053019470N33


Assuntos
Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Ácido Ascórbico/administração & dosagem , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Ponte de Artéria Coronária/métodos , Antioxidantes/administração & dosagem , Arritmias Cardíacas/prevenção & controle , Fatores de Tempo , Biomarcadores/sangue , Traumatismo por Reperfusão Miocárdica/sangue , Método Duplo-Cego , Reprodutibilidade dos Testes , Função Ventricular/efeitos dos fármacos , Resultado do Tratamento , Estatísticas não Paramétricas , Troponina I/sangue , Creatina Quinase Forma BB/sangue , Creatina Quinase Forma MM/sangue , Hemodinâmica/efeitos dos fármacos , Unidades de Terapia Intensiva , L-Lactato Desidrogenase/sangue
2.
Rev. bras. anestesiol ; 67(1): 50-56, Jan.-Feb. 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-843357

RESUMO

Abstract Background and objectives: Hemodynamic response to airway stimuli is a common phenomenon and its management is important to reduce the systemic repercussions. The objective of this study is to compare the efficacy of intravenous magnesium sulfate versus lidocaine on this reflex hemodynamics after laryngoscopy and tracheal intubation. Methods: This single-center, prospective, double-blind, randomized study evaluated 56 patients ASA 1 or 2, aged 18-65 years, scheduled for elective surgeries under general anesthesia with intubation. The patients were allocated into two groups: Group F received 30 mg·kg-1 of magnesium sulphate and Group L, 2 mg·kg-1 of lidocaine, continuous infusion, immediately before the anesthetic induction. Blood pressure (BP), heart rate (HR), and bispectral index (BIS) were measured in both groups at six different times related to administration of the study drugs. Results: In both groups there was an increase in HR and BP after laryngoscopy and intubation, compared to baseline. Group M showed statistically significant increase in the values of systolic and diastolic blood pressure after intubation, which was clinically unimportant. There was no difference in the BIS values between groups. Among patients receiving magnesium sulfate, three (12%) had high blood pressure versus only one among those receiving lidocaine (4%), with no statistical difference. Conclusion: Magnesium sulfate and lidocaine have good efficacy and safety for hemodynamic management in laryngoscopy and intubation.


Resumo Justificativa e objetivos: A resposta hemodinâmica aos estímulos das vias aéreas é um fenômeno comum e seu controle é importante para diminuir as repercussões sistêmicas. O objetivo deste trabalho é comparar os efeitos da administração endovenosa de sulfato de magnésio versus lidocaína na hemodinâmica desse reflexo após a laringoscopia e intubação orotraqueal. Métodos: Este estudo duplamente encoberto, aleatorizado, unicêntrico e prospectivo avaliou 56 pacientes, ASA 1 ou 2, entre 18 e 65 anos, escalados para cirurgias eletivas sob anestesia geral com intubação orotraqueal. Foram alocados em dois grupos, o M recebeu 30 mg·kg-1 de sulfato de magnésio e o L, 2 mg·kg-1 de lidocaína, em infusão contínua, imediatamente antes da indução anestésica. Os valores de pressão arterial (PA), frequência cardíaca (FC) e índice biespectral (BIS) foram aferidos nos dois grupos em seis momentos relacionados com a administração dos fármacos do estudo. Resultados: Em ambos os grupos houve aumento na FC e PA após a laringoscopia e intubação, em relação aos valores basais. No Grupo M observou-se elevação estatisticamente significativa, mas clinicamente pouco importante, nos valores das pressões arteriais sistólica e diastólica após a intubação. Não houve diferença nos valores de BIS entre os grupos. Dos pacientes que receberam o sulfato de magnésio, 3 (12%) apresentaram episódio de hipertensão, ao passo que apenas um dos que receberam lidocaína (4%) apresentou esse sinal, sem diferença estatística. Conclusão: Sulfato de magnésio e a lidocaína apresentam boa eficácia e segurança no controle hemodinâmico à laringoscopia e intubação.


Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Idoso , Adulto Jovem , Hemodinâmica/efeitos dos fármacos , Intubação Intratraqueal/efeitos adversos , Laringoscopia/efeitos adversos , Lidocaína/farmacologia , Sulfato de Magnésio/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Infusões Intravenosas , Método Duplo-Cego , Estudos Prospectivos , Resultado do Tratamento , Procedimentos Cirúrgicos Eletivos , Frequência Cardíaca/efeitos dos fármacos , Lidocaína/administração & dosagem , Sulfato de Magnésio/administração & dosagem , Pessoa de Meia-Idade
3.
Int. braz. j. urol ; 41(3): 466-472, May-June 2015. tab, ilus
Artigo em Inglês | LILACS | ID: lil-755882

RESUMO

ABSTRACTObjectives:

To compare the effects of CO2 insufflation on hemodynamics and oxygen levels and on acid-base level during Robot-Assisted Radical Prostatectomy (RARP) with transperitoneal (TP) versus extra-peritoneal (EP) accesses.

Materials and Methods:

Sixty-two patients were randomly assigned to TP (32) and EP (30) to RARP. Pre-operation data were collected for all patients. Hemodynamic, respiratory and blood acid-base parameters were measured at the moment of induction of anesthesia (T0), after starting CO2 insuffation (T1), and at 60 (T2) and 120 minutes (T3) after insufflation. In all cases, the abdominal pressure was set at 15 mmHg. Complications were reported according to the Clavien-Dindo classification. Student's two–t-test, with a significance level set at p<0.05, was used to compare categorical values between groups. The Mann-Whitney U-test was used to compare the median values of two nonparametric continuous variables.

Results:

The demographic characteristics of the patients in both groups were statistically comparable. Analysis of intra-operative anesthesiologic parameters showed that partial CO2 pressure during EP was significantly higher than during TP, with a consequent decrease in arterial pH. Other parameters analysed were similar in the two groups. Postoperative complications were comparable between groups. The most important limitations of this study were the small size of the patient groups and the impossibility of maintaining standard abdominal pressure throughout the operational phases, despite attempts to regulate it.

Conclusions:

This prospective randomized study demonstrates that, from the anesthesiologic viewpoint, during RARP the TP approach is preferable to EP, because of lower CO2 reabsorption and risk of acidosis.

.


Assuntos
Idoso , Animais , Humanos , Masculino , Pessoa de Meia-Idade , Anestesia por Inalação/métodos , Dióxido de Carbono/metabolismo , Hemodinâmica/efeitos dos fármacos , Prostatectomia/métodos , Neoplasias da Próstata/cirurgia , Procedimentos Cirúrgicos Robóticos/métodos , Gradação de Tumores , Duração da Cirurgia , Estudos Prospectivos , Peritônio/cirurgia , Neoplasias da Próstata/patologia , Reprodutibilidade dos Testes , Fatores de Risco , Estatísticas não Paramétricas , Fatores de Tempo , Resultado do Tratamento
4.
Braz. j. med. biol. res ; 47(8): 646-654, 08/2014. tab, graf
Artigo em Inglês | LILACS | ID: lil-716273

RESUMO

The physiological mechanisms involved in isoproterenol (ISO)-induced chronic heart failure (CHF) are not fully understood. In this study, we investigated local changes in cardiac aldosterone and its synthase in rats with ISO-induced CHF, and evaluated the effects of treatment with recombinant human brain natriuretic peptide (rhBNP). Sprague-Dawley rats were divided into 4 different groups. Fifty rats received subcutaneous ISO injections to induce CHF and the control group (n=10) received equal volumes of saline. After establishing the rat model, 9 CHF rats received no further treatment, rats in the low-dose group (n=8) received 22.5 μg/kg rhBNP and those in the high-dose group (n=8) received 45 μg/kg rhBNP daily for 1 month. Cardiac function was assessed by echocardiographic and hemodynamic analysis. Collagen volume fraction (CVF) was determined. Plasma and myocardial aldosterone concentrations were determined using radioimmunoassay. Myocardial aldosterone synthase (CYP11B2) was detected by quantitative real-time PCR. Cardiac function was significantly lower in the CHF group than in the control group (P<0.01), whereas CVF, plasma and myocardial aldosterone, and CYP11B2 transcription were significantly higher than in the control group (P<0.05). Low and high doses of rhBNP significantly improved hemodynamics (P<0.01) and cardiac function (P<0.05) and reduced CVF, plasma and myocardial aldosterone, and CYP11B2 transcription (P<0.05). There were no significant differences between the rhBNP dose groups (P>0.05). Elevated cardiac aldosterone and upregulation of aldosterone synthase expression were detected in rats with ISO-induced CHF. Administration of rhBNP improved hemodynamics and ventricular remodeling and reduced myocardial fibrosis, possibly by downregulating CYP11B2 transcription and reducing myocardial aldosterone synthesis.


Assuntos
Animais , Humanos , Masculino , Aldosterona/sangue , /metabolismo , Insuficiência Cardíaca/tratamento farmacológico , Miocárdio/metabolismo , Natriuréticos/uso terapêutico , Peptídeo Natriurético Encefálico/uso terapêutico , Aldosterona/genética , Cardiotônicos , Doença Crônica , Colágeno/análise , Modelos Animais de Doenças , Ecocardiografia , Fibrose/etiologia , Insuficiência Cardíaca/induzido quimicamente , Insuficiência Cardíaca/metabolismo , Hemodinâmica/efeitos dos fármacos , Isoproterenol , Assistência de Longa Duração , Miocárdio/patologia , Natriuréticos/administração & dosagem , Peptídeo Natriurético Encefálico/administração & dosagem , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real , Proteínas Recombinantes/uso terapêutico , Transcrição Gênica/efeitos dos fármacos , Remodelação Ventricular/efeitos dos fármacos
5.
Rev. bras. anestesiol ; 64(2): 73-78, Mar-Apr/2014. tab, graf
Artigo em Português | LILACS, SES-SP | ID: lil-711136

RESUMO

Contexto: pacientes de cirurgia cardíaca submetidos a revascularização do miocárdio com circulação extracorpórea. Objetivo: avaliar o efeito hemodinâmico da adição de sufentanil intratecal para anestesia geral. Desenho: estudo prospectivo, randômico e aberto, após aprovação do Comitê de Ética em Pesquisa. Cenário: estudo monocêntrico feito no Instituto Dante Pazzanese de Cardiologia, São Paulo, Brasil. Pacientes: foram submetidos à revascularização eletiva 40 pacientes de ambos os sexos que assinaram o termo de consentimento informado. Critérios de exclusão: doença renal crônica, procedimentos de emergência, reoperações, contraindicação para raquianestesia, fração de ejeção do ventrículo esquerdo inferior a 40%, índice de massa corporal acima de 32 kg/m2 e uso de nitroglicerina. Intervenções: os pacientes foram randomizados para receber (ou não) 1μg/kg de sufentanil intratecal. Anestesia foi induzida e mantida com infusão contínua de sevoflurano e remifentanil. Principais medidas de desfecho: variáveis hemodinâmicas, níveis sanguíneos de troponina I cardíaca, peptídeo natriurético do tipo B, interleucina-6 e fator de necrose tumoral alfa durante e após a cirurgia. Resultados: os pacientes do grupo sufentanil precisaram de menos suporte inotrópico com dopamina, comparados aos do grupo controle (9,5% vs 58%, p = 0,001), e menos aumentos de doses de remifentanil (62% vs 100%, p = 0,004). Os dados hemodinâmicos em oito intervalos de tempo diferentes e os dados bioquímicos não apresentaram diferenças entre os grupos. Conclusões: os pacientes que receberam sufentanil intratecal apresentaram uma estabilidade hemodinâmica ...


Context: Cardiac surgery patients undergoing coronary artery bypass grafting with cardiopulmonary bypass. Objective: Evaluate the effect of adding intrathecal sufentanil to general anesthesia on hemodynamics. Design: Prospective, randomized, not blinded study, after approval by local ethics in Research Committee. Setting: Monocentric study performed at Dante Pazzanese Institute of Cardiology, Sao Paulo, Brazil. Patients: 40 consenting patients undergoing elective coronary artery bypass, both genders. Exclusion criteria: Chronic kidney disease; emergency procedures; reoperations; contraindication to spinal block; left ventricular ejection fraction less than 40%; body mass index above 32 kg/m2 and use of nitroglycerin. Interventions: Patients were randomly assigned to receive intrathecal sufentanil 1 μg/kg or not. Anesthesia induced and maintained with sevoflurane and continuous infusion of remifentanil. Main outcome measures: Hemodynamic variables, blood levels of cardiac troponin I, B-type natriuretic peptide, interleukin-6 and tumor necrosis factor alfa during and after surgery. Results: Patients in sufentanil group required less inotropic support with dopamine when compared to control group (9.5% vs 58%, p = 0.001) and less increases in remifentanil doses (62% vs 100%, p = 0.004). Hemodynamic data at eight different time points and biochemical data showed no differences between groups. Conclusions: Patients receiving intrathecal sufentanil have more hemodynamical stability, as suggested by the reduced inotropic support and fewer adjustments in intravenous opioid doses. .


Contexto: pacientes de cirugía cardíaca sometidos a revascularización miocárdica con circulación extracorpórea. Objetivo: evaluar el efecto hemodinámico de la adición de sufentanilo intratecal para anestesia general. Proyecto: estudio prospectivo, aleatorizado y abierto, con posterior aprobación del Comité de Ética en Investigación. Escenario: estudio monocéntrico realizado en el Instituto Dante Pazzanese de Cardiología, São Paulo, Brasil. Pacientes: cuarenta pacientes de ambos sexos que firmaron el consentimiento informado fueron sometidos a revascularización electiva. Criterios de exclusión: enfermedad renal crónica, procedimientos de urgencia, reintervenciones, contraindicación para la raquianestesia, fracción de eyección del ventrículo izquierdo inferior al 40%, índice de masa corporal por encima de 32 kg/m2 y uso de nitroglicerina. Intervenciones: los pacientes fueron aleatorizados para recibir (o no), 1 µg/kg de sufentanilo intratecal. La anestesia se indujo y se mantuvo con infusión continua de sevoflurano y remifentanilo. Principales medidas de resultados: variables hemodinámicas, niveles sanguíneos de troponina i cardíaca, péptido natriurético del tipo B, interleucina 6 y factor de necrosis tumoral alfa durante y después de la cirugía. Resultados: los pacientes del grupo sufentanilo necesitaron menos soporte inotrópico con dopamina, comparado con el grupo control (9,5 vs. 58%, p = 0,001) y menos aumentos de dosis de remifentanilo (62 vs. 100%, p = 0,004). Los datos hemodinámicos en 8 intervalos de tiempo diferentes y los datos bioquímicos no presentaron diferencias entre los grupos. Conclusiones: los pacientes que recibieron sufentanilo intratecal tuvieron una estabilidad hemodinámica mayor, evidenciada por el soporte ...


Assuntos
Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Analgésicos Opioides/administração & dosagem , Ponte de Artéria Coronária , Sufentanil/administração & dosagem , Ponte de Artéria Coronária/efeitos adversos , Hemodinâmica/efeitos dos fármacos , Injeções Espinhais , Complicações Pós-Operatórias/etiologia , Estudos Prospectivos
6.
Clinics ; 69(5): 308-313, 2014. tab, graf
Artigo em Inglês | LILACS | ID: lil-709611

RESUMO

OBJECTIVE: We aimed to evaluate angiotensin receptor blocker add-on therapy in patients with low cardiac output during decompensated heart failure. METHODS: We selected patients with decompensated heart failure, low cardiac output, dobutamine dependence, and an ejection fraction <0.45 who were receiving an angiotensin-converting enzyme inhibitor. The patients were randomized to losartan or placebo and underwent invasive hemodynamic and B-type natriuretic peptide measurements at baseline and on the seventh day after intervention. ClinicalTrials.gov: NCT01857999. RESULTS: We studied 10 patients in the losartan group and 11 patients in the placebo group. The patient characteristics were as follows: age 52.7 years, ejection fraction 21.3%, dobutamine infusion 8.5 mcg/kg.min, indexed systemic vascular resistance 1918.0 dynes.sec/cm5.m2, cardiac index 2.8 L/min.m2, and B-type natriuretic peptide 1,403 pg/mL. After 7 days of intervention, there was a 37.4% reduction in the B-type natriuretic peptide levels in the losartan group compared with an 11.9% increase in the placebo group (mean difference, -49.1%; 95% confidence interval: -88.1 to -9.8%, p = 0.018). No significant difference was observed in the hemodynamic measurements. CONCLUSION: Short-term add-on therapy with losartan reduced B-type natriuretic peptide levels in patients hospitalized for decompensated severe heart failure and low cardiac output with inotrope dependence. .


Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Bloqueadores do Receptor Tipo 1 de Angiotensina II/uso terapêutico , Antagonistas de Receptores de Angiotensina/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Losartan/uso terapêutico , Peptídeo Natriurético Encefálico/efeitos dos fármacos , Baixo Débito Cardíaco/tratamento farmacológico , Método Duplo-Cego , Dobutamina/sangue , Seguimentos , Hemodinâmica/efeitos dos fármacos , Fatores de Tempo , Resultado do Tratamento
7.
Vertex rev. argent. psiquiatr ; 25(114): 92-8, 2014 Mar-Apr.
Artigo em Espanhol | LILACS, BINACIS | ID: biblio-1176971

RESUMO

OBJECTIVE: To assess if there are changes in brain hemodynamics evaluated by means of transcranial doppler's flow velocity, pulsatile index and cerebral perfusion pressure, between cocaine chronic abusers and healthy volunteers. METHOD: Prospective, case and control, observational study. Sex, age, user history, vital signs and transcranial doppler findings.Statistical analysis was performed by means of normality test, Wilcoxon's test for non parametric samples and T Student test. RESULTS: Fifty-three abusers and 35 healthy volunteers were studied. Statistical differences were found for a diminish in age(p=0.008) and cerebral perfusion pressure in all cerebral arteries (p

Assuntos
Cocaína/farmacologia , Encéfalo/irrigação sanguínea , Hemodinâmica/efeitos dos fármacos , Inibidores da Captação de Dopamina/farmacologia , Transtornos Relacionados ao Uso de Cocaína/fisiopatologia , Adolescente , Adulto , Adulto Jovem , Doença Crônica , Estudos Prospectivos , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
8.
Rev. méd. Chile ; 141(11): 1395-1401, nov. 2013. ilus, tab
Artigo em Espanhol | LILACS | ID: lil-704565

RESUMO

Background: Trauma is an important cause of death among young adults. Aim: To determine the characteristics, treatments and evolution of trauma patients admitted to an intensive care unit (ICU) of a public hospital in Santiago, Chile. Material and Methods: All polytrauma (PT) and severely traumatized (ST) patients admitted to ICU were included. We recorded the type of trauma along with demographic and hemodynamic variables, treatments and complications. The evolution and treatments received by PT and ST patients were compared. Results: We recorded data from 72 patients aged 43 ± 21 years (93% males). Sixty two percent were PT and 24% had penetrating injuries. TBI (Trauma Brain Injury) was the most common trauma. On admission, acute Physiology and Chronic Health Evaluation II (APACHE II) score was 18.7 + 7.3, and Injury Severity Score (ISS) was 32.8 + 20.1. ICU stay was 7.8 + 6 days. Sixty seven per cent of patients required surgery and 58% received blood transfusions. No differences were found between PT and ST. ICU and hospital mortality rates were 15 and 25% respectively. Conclusions: The characteristics and evolution of PT and ST of this series of patients are similar to those described abroad. Mortality was in agreement with ISS and APACHE II scores.


Assuntos
Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Ferimentos e Lesões , APACHE , Transfusão de Sangue , Chile/epidemiologia , Traumatismos Craniocerebrais/epidemiologia , Traumatismos Craniocerebrais/mortalidade , Traumatismos Craniocerebrais/terapia , Hemodinâmica/efeitos dos fármacos , Mortalidade Hospitalar , Hospitalização/estatística & dados numéricos , Hospitais Gerais , Escala de Gravidade do Ferimento , Unidades de Terapia Intensiva , Estudos Prospectivos , Resultado do Tratamento , Ferimentos e Lesões/epidemiologia , Ferimentos e Lesões/mortalidade , Ferimentos e Lesões/terapia
9.
Arq. bras. cardiol ; 90(3): 231-235, mar. 2008. tab
Artigo em Inglês, Português | LILACS | ID: lil-479625

RESUMO

Nos países em que é comercializada, a administração precoce de levosimendana deve ser considerada em pacientes que permanecem sintomáticos e com dispnéia em repouso apesar da terapia inicial, principalmente aqueles com história de insuficiência cardíaca crônica ou em tratamento prolongado com betabloqueadores. Pacientes hipotensos ou com isquemia ativa não são os melhores candidatos para receber infusão de levosimendana e precisam, primeiro, ter esses problemas tratados.


In countries where it is available, early levosimendan infusion can be considered for patients who remain symptomatic with dyspnea at rest despite initial therapy, particularly those with a history of chronic heart failure or chronically treated with beta-blockers. Hypotensive patients or patients with active ischemia are not the best candidates for levosimendan administration and should have these problems addressed first.


Assuntos
Humanos , Cardiotônicos/uso terapêutico , Insuficiência Cardíaca/tratamento farmacológico , Hidrazonas/uso terapêutico , Piridazinas/uso terapêutico , Vasodilatadores/uso terapêutico , Doença Aguda , Antagonistas Adrenérgicos beta/efeitos adversos , Cardiotônicos/administração & dosagem , Cardiotônicos , Hemodinâmica/efeitos dos fármacos , Hidrazonas/administração & dosagem , Hidrazonas , Hipotensão/complicações , Isquemia/complicações , Inibidores de Fosfodiesterase/efeitos adversos , Piridazinas/administração & dosagem , Piridazinas , Síndrome , Vasodilatadores/administração & dosagem , Vasodilatadores
10.
Braz. j. med. biol. res ; 38(6): 967-976, June 2005. ilus, graf
Artigo em Inglês | LILACS | ID: lil-402674

RESUMO

The aim of the present study was to evaluate the effect of amiodarone on mean arterial pressure (MAP), heart rate (HR), baroreflex, Bezold-Jarisch, and peripheral chemoreflex in normotensive and chronic one-kidney, one-clip (1K1C) hypertensive rats (N = 9 to 11 rats in each group). Amiodarone (50 mg/kg, iv) elicited hypotension and bradycardia in normotensive (-10 ± 1 mmHg, -57 ± 6 bpm) and hypertensive rats (-37 ± 7 mmHg, -39 ± 19 bpm). The baroreflex index (deltaHR/deltaMAP) was significantly attenuated by amiodarone in both normotensive (-0.61 ± 0.12 vs -1.47 ± 0.14 bpm/mmHg for reflex bradycardia and -1.15 ± 0.19 vs -2.63 ± 0.26 bpm/mmHg for reflex tachycardia) and hypertensive rats (-0.26 ± 0.05 vs -0.72 ± 0.16 bpm/mmHg for reflex bradycardia and -0.92 ± 0.19 vs -1.51 ± 0.19 bpm/mmHg for reflex tachycardia). The slope of linear regression from deltapulse interval/deltaMAP was attenuated for both reflex bradycardia and tachycardia in normotensive rats (-0.47 ± 0.13 vs -0.94 ± 0.19 ms/mmHg and -0.80 ± 0.13 vs -1.11 ± 0.13 ms/mmHg), but only for reflex bradycardia in hypertensive rats (-0.15 ± 0.02 vs -0.23 ± 0.3 ms/mmHg). In addition, the MAP and HR responses to the Bezold-Jarisch reflex were 20-30 percent smaller in amiodarone-treated normotensive or hypertensive rats. The bradycardic response to peripheral chemoreflex activation with intravenous potassium cyanide was also attenuated by amiodarone in both normotensive (-30 ± 6 vs -49 ± 8 bpm) and hypertensive rats (-34 ± 13 vs -42 ± 10 bpm). On the basis of the well-known electrophysiological effects of amiodarone, the sinus node might be the responsible for the attenuation of the cardiovascular reflexes found in the present study.


Assuntos
Animais , Masculino , Ratos , Amiodarona/farmacologia , Antiarrítmicos/farmacologia , Células Quimiorreceptoras , Hemodinâmica/efeitos dos fármacos , Hipertensão Renal/fisiopatologia , Barorreflexo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Doença Crônica , Eletrofisiologia , Frequência Cardíaca/efeitos dos fármacos , Ratos Wistar
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