Age and Sex Differences in Heart Rate Variability and Vagal Specific Patterns - Baependi Heart Study.

Background: Heart rate variability (HRV) is a noninvasive method for assessing autonomic function. Age, sex, and chronic conditions influence HRV. Objectives: Our aim was to evaluate HRV measures exploring differences by age, sex, and race in a sample from a rural area. Methods: Analytical sample (n = 1,287) included participants from the 2010 to 2016 evaluation period of the Baependi Heart Study, a family-based cohort in Brazil. Participants underwent 24-hour Holter-ECG (Holter) monitoring. To derive population reference values, we restricted our analysis to a 'healthy' subset (i.e. absence of medical comorbidities). A confirmatory analysis was conducted with a subgroup sample that also had HRV derived from a resting ECG 10'-protocol obtained during the same time period. Results: The 'healthy' subset included 543 participants. Mean age was 40 ± 14y, 41% were male, 74% self-referred as white and mean body-mass-index was 24 ± 3kg/m2. Time domain HRV measures showed significant differences by age-decade and by sex. Higher values were observed for males across almost all age-groups. Parasympathetic associated variables (rMSSD and pNN50) showed a U-shaped distribution and reversal increase above 60y. Sympathetic-parasympathetic balance variables (SDNN, SDANN) decreased linearly by age. Race differences were no significant. We compared time domain variables with complete data (Holter and resting ECG) between 'healthy' versus 'unhealthy' groups. Higher HRV values were shown for the 'healthy' subset compared with the 'unhealthy' group. Conclusion: HRV measures vary across age and sex. A U-shaped pattern and a reversal increase in parasympathetic variables may reflect an age-related autonomic dysfunction even in healthy individuals that could be used as a predictor of disease development.

Carotid intima-media thickness and metabolic syndrome in a rural population: Results from the Baependi Heart Study.

BACKGROUND AND AIMS: Carotid intima-media thickness (cIMT) is a strong predictor of cardiovascular events and associated with metabolic syndrome (MetS). MetS is a cluster of cardiovascular risk factors, but the association structure between specific factors and disease development is not well-established in rural populations. We described the association structure between MetS factors and cIMT in a sample from rural Brazil. METHODS: We studied 1937 participants from the Baependi Heart Study who underwent carotid ultrasound exam. We used ATP-III-2001 for MetS definition and linear mixed-effects models, adjusting by the family structure, to assess independent associations between the cardiovascular risk factors which define MetS and cIMT. RESULTS: The sample's mean age was 46 ± 16y, 61% female, 73% white, mean body-mass-index 26±5 kg/m2, mean cIMT 0.53 ± 0.16 mm, with 35% of the sample classified with MetS. As expected, cIMT demonstrated a linear relationship with increasing age, and cIMT higher values were observed for MetS (0.58 ± 0.16 mm) compared to non-MetS (0.49 ± 0.14 mm). Considering models for cIMT with MetS and all of its factors, we found that blood pressure, glucose and obesity were independently associated with cIMT, but not HDL or triglycerides. CONCLUSIONS: cIMT showed a linear relationship with increasing age. Blood pressure, obesity, and glucose were independently associated with cIMT, but not HDL-cholesterol or triglycerides. In a rural population, hypertension, diabetes and obesity play a more important role than lipids in determining cIMT interindividual variability.

Atualização do atendimento do paciente em parada cardiorrespiratória: O que todo clínico deve saber? / Update of medical care in cardiorespiratory arrest: What should every clinician know?

O objetivo deste estudo foi apresentar uma revisão narrativa do atendimento à parada cardiorrespiratória, baseada nas diretrizes mais atuais e, também, uma análise crítica de informações de literatura recente, que vão além das recomendações gerais das diretrizes vigentes. A parada cardiorrespiratória, quando ocorre de forma inesperada, abrupta, em indivíduo que se encontrava estável horas antes do evento, é chamada de morte súbita. Essa condição é a principal causa de óbito extra-hospitalar não traumático e, dentre suas diversas causas, a síndrome coronariana aguda é a mais comum em adultos. Uma vez que a frequência de síndrome coronariana aguda tende a aumentar com o aumento da expectativa de vida e de prevalência de outros fatores de risco na população, a ocorrência de morte súbita também tende a aumentar nesse cenário. No intuito de orientar o atendimento de pacientes em parada cardiorrespiratória, há mais de quatro décadas foram criadas diretrizes internacionais, que evoluíram com o surgimento de novas evidências, especialmente nos últimos 20 anos. Todo médico deve estar preparado para atender uma situação de parada cardiorrespiratória, pois ele pode ser chamado para atender tais casos em diferentes cenários (emergência, unidade de internação ou em ambiente extra-hospitalar). Entretanto, apesar da importância da incorporação de novas evidências nessas diretrizes, mudanças frequentes nas recomendações representam grande desafio para os clínicos se manterem atualizados. Além da dificuldade na atualização permanente, há recomendações feitas pelas diretrizes de sociedades médicas que divergem entre si e são questionadas por especialistas, o que gera dúvida na tomada de decisão do clínico. Conforme pormenorizado neste artigo de atualização, as etapas do algoritmo de Suportes Básico e Avançado de Vida são apresentadas como uma sequência, para facilitar para o socorrista que atua sozinho a oferecer intervenções com impacto na sobrevivência do paciente, devendo priorizar a reanimação cardiopulmonar de qualidade e a desfibrilação precoce, se indicada.

The objective of this study was to present a narrative review of cardiac arrest care based on the most current guidelines, and also a critical analysis of recent literature information that goes beyond the general recommendations of the current guidelines. Cardiac arrest, when occurring unexpectedly, abruptly, in an individual who was stable hours before the event, is called sudden death. This condition is the leading cause of non-traumatic out-of-hospital death and, among its many causes, acute coronary syndrome is the most common in adults. Since the frequency of acute coronary syndrome tends to increase with increasing life expectancy and the prevalence of other risk factors in the population, sudden death also tends to increase in this scenario. In order to guide the care of patients with cardiopulmonary arrest, for over 4 decades, international guidelines have been created and have evolved with the emergence of new evidence, especially in the last 20 years. Every physician should be prepared to deal with a cardiac arrest situation as he or she may be called upon to treat such cases in different scenarios (emergency, inpatient unit or out-of-hospital setting). However, despite the importance of incorporating new evidence into these guidelines, frequent changes to the recommendations pose a major challenge for clinicians to update their knowledge. In addition to the difficulty of constantly updating, there are recommendations made by the guidelines of medical societies that differ from each other and are questioned by specialists, which creates doubt in the process of decision making among clinicians. As detailed in this update article, the stages of the algorithm of Basic and Advanced Life Support are presented in a sequence to help the rescuer who works alone to provide interventions that impact the patient's survival, and prioritize quality cardiopulmonary resuscitation and early defibrillation, if required.

Poor sleep quality and lipid profile in a rural cohort (The Baependi Heart Study).

AIM: To test the association between cardiometabolic risk factors and subjective sleep quality assessed by the Pittsburgh sleep quality index (PSQI), independent of obstructive sleep apnea (OSA) and sleep duration. METHODS: A total of 573 participants from the Baependi Heart Study, a rural cohort from Brazil, completed sleep questionnaires and underwent polygraphy for OSA evaluation. Multivariable linear regression analysis tested the association between cardiovascular risk factors (outcome variables) and sleep quality measured by PSQI, adjusting for OSA and other potential confounders (age, sex, race, salary/wage, education, marital status, alcohol intake, obesity, smoking, hypertension, and sleep duration). RESULTS: The sample mean age was 43 ± 16 years, 66% were female, and mean body mass index (BMI) was 26 ± 5 kg/m2. Only 20% were classified as obese (BMI ≥30). Overall, 50% of participants reported poor sleep quality as defined by a PSQI score ≥5. A high PSQI score was significantly associated with higher very-low-density lipoprotein (VLDL) cholesterol levels (beta = 0.392, p = 0.012) and higher triglyceride levels (beta = 0.017, p = 0.006), even after adjustments, including the apnea-hypopnea index. Further adjustments accounting for marital status, alcohol intake, and medication use did not change these findings. No significant association was observed between PSQI scores and glucose or blood pressure. According to PSQI components, sleep disturbances (beta = 1.976, p = 0.027), sleep medication use (beta = 1.121, p = 0.019), and daytime dysfunction (beta = 1.290, p = 0.024) were significantly associated with higher VLDL serum levels. Only the daytime dysfunction domain of the PSQI components was significantly associated with higher triglyceride levels (beta = 0.066, p = 0.004). CONCLUSION: Poorer lipid profile was independently associated with poor sleep quality, assessed by the PSQI questionnaire, regardless of a normal sleep duration and accounting for OSA and socio-economic status.

Atherosclerosis and inflammation: overview and updates.

The concept that inflammation participates pivotally in the pathogenesis of atherosclerosis and its complications has gained considerable attention, but has not yet entered clinical practice. Experimental work has elucidated molecular and cellular pathways of inflammation that promote atherosclerosis. The recognition of atherogenesis as an active process rather than a cholesterol storage disease or a repository of calcium has highlighted some key inflammatory mechanisms. For example, mononuclear phagocytes contribute to all stages of this disease, illustrating the link between inflammation and atherosclerosis. From a clinical perspective, harnessing inflammation may now help target therapeutics, change guidelines, and enter daily practice. Multiple lines of incontrovertible evidence have proven a causal role for low-density lipoprotein (LDL) cholesterol in atherosclerosis, and we have highly effective tools for lowering LDL, consequently reducing events. Yet, even with intense LDL reduction, events still occur. Inflammation can explain some of this residual risk. An anti-inflammatory intervention has now proven capable of improving outcomes in individuals well treated with LDL-lowering agents. A suite of trials are now pursuing anti-inflammatory therapies in this context. Assessment and treatment of residual inflammatory risk are poised to provide new inroads into preventive cardiology. This brief review aims to explore the potential mechanisms underlying the association of inflammation and atherogenesis, and their clinical consequences.

Association between Obstructive Sleep Apnea and Cardiovascular Risk Factors: Variation by Age, Sex, and Race. The Multi-Ethnic Study of Atherosclerosis.

RATIONALE: The association between obstructive sleep apnea (OSA) and cardiovascular disease (CVD) is complex, bidirectional, and may vary across groups. Understanding which cardiovascular risk factors vary in their relationship to OSA across population groups may improve knowledge of OSA-related CVD susceptibility. OBJECTIVES: To better understand the heterogeneity of associations, we assessed whether associations of OSA with cardiovascular risk factors vary by age, sex, and race/ethnicity. METHODS: We performed cross-sectional analyses of 1,344 Multi-Ethnic Study of Atherosclerosis participants who underwent overnight full polysomnography, assays of fasting blood, and assessments of cardiovascular risk factors. Risk factors considered were blood pressure, glucose/lipid concentrations, white blood cell (WBC) total and subset counts, and cystatin C. The outcome was the apnea-hypopnea index (AHI). Linear regression analyses with tests for interactions were conducted. RESULTS: The sample had a mean age of 68 ± 9 years. Forty-seven percent of the sample was male, and 32% had moderate or severe OSA (AHI, ≥15). Multivariable adjusted analysis showed significant associations between higher AHI with lower high-density lipoprotein cholesterol and higher diastolic blood pressure and neutrophil counts. Significant interactions with demographic factors were observed. Stronger associations were shown between AHI and higher total WBC count (Pint = 0.006) and glucose concentrations (Pint = 0.006) in younger (<65 yr) than in older individuals, higher triglyceride concentrations in men than in women (Pint = 0.006), and higher total WBC (Pint = 0.07) and monocyte counts (Pint = 0.03) in African American individuals than in other racial groups. CONCLUSIONS: In a multiethnic cohort, we found increased levels of cardiovascular risk factors in association with OSA, including elevated neutrophil counts, a marker of inflammation. Furthermore, several associations were stronger in men, younger individuals, and African American individuals, highlighting pathways for CVD risk that may explain heterogeneity in the associations between CVD and OSA across population groups.

Elevations in neutrophils with obstructive sleep apnea: The Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND: Obstructive sleep apnea (OSA) associates with increased risk of cardiovascular diseases (CVD). Immune abnormalities and surges in sympathetic activity accompany OSA and CVD. We hypothesized that OSA associates with leukocytosis partially by abnormalities in autonomic nervous system (ANS) function that would suggest a pathway linking OSA and CVD. METHODS: Participants from the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective cohort of individuals initially without overt CVD, underwent polysomnography and assays for white blood cells (WBC) and subsets. Heart rate (HR) and heart rate variability (HRV), indirect measurements of ANS, were obtained from overnight electrocardiography. A formal statistical mediation analysis tested the indirect effect that mean HR and HRV measures contribute to associations between OSA and leukocytosis. RESULTS: The analytical sample consisted of 1298 participants (54% female), ages 54-93years, 14% with severe OSA (apnea-hypopnea-index, AHI≥30). Severe OSA associated with a higher prevalence of obesity, diabetes, and increased levels of WBC total and subsets. Neutrophil count associated with severe OSA after adjusting for confounders (p=0.017). Mean HR positively associated with OSA indices and neutrophils. A mediation analysis revealed an "indirect" effect of mean HR that explained an estimated 11% of the association between AHI and neutrophils. Overnight hypoxia also associated with neutrophil count (p=0.009), and mean HR explained 14% of the association between neutrophils and hypoxia. CONCLUSIONS: In the MESA cohort, OSA measures associate with elevated neutrophil counts and increases in overnight mean HR. These data link innate immune dysregulation with OSA and provide a potential pathophysiologic pathway between CVD and OSA.

Cardiac rhythm disorders in obstructive sleep apnea.

Obstructive sleep apnea (OSA) is common among patients with cardiac rhythm disorders. OSA may contribute to arrhythmias due to acute mechanisms, such as generation of negative intrathoracic pressure during futile efforts to breath, intermittent hypoxia, and surges in sympathetic activity. In addition, OSA may lead to heart remodeling and increases arrhythmia susceptibility. Atrial distension and remodeling, that has been shown to be associated with OSA, is a well-known anatomical substrate for atrial fibrillation (AF). AF is the arrhythmia most commonly described in patients with OSA. Several observational studies have shown that the treatment of OSA with continuous positive airway pressure (CPAP) reduces recurrence of AF after electrical cardioversion and catheter ablation. There is also evidence that nocturnal hypoxemia, a hallmark of OSA, predicts sudden cardiac death (SCD) independently of well-established cardiovascular risk factors. Among patients with an implantable cardiac defibrillator, those with OSA have a higher risk of receiving treatment for life-threatening arrhythmias. Nocturnal hypoxemia may also increase vagal tone, which increases susceptibility to bradycardic and conduction rhythm disorders that have also been described in patients with OSA. In conclusion, there are several biological pathways linking OSA and increased cardiac arrhythmogenesis propensity. However, the independent association is derived from observational studies and the direction of the association still needs clarification due to the lack of large clinical trials. This review focuses on the current scientific evidence linking OSA to cardiac rhythm disorders and point out future directions.

Associação entre apneia obstrutiva do sono e lesão miocárdica em pacientes com angina refratária

Introdução: A doença arterial coronária (DAC) é a principal causa de mortalidade nos países industrializados e representa cerca de 10% de todos os óbitos no Brasil.1 Num espectro de maior gravidade dos pacientes com DAC crônica, encontram-se aqueles classificados como angina refratária, uma vez que apresentam sintomas aos esforços habituais e mesmo ao repouso, a despeito de otimização da terapêutica clínica e do controle de fatores de risco. No conhecimento e combate aos fatores de risco da DAC, a apneia obstrutiva do sono (AOS) é comum nesta população,2 no entanto, ainda sub diagnosticada e seus potenciais efeitos deletérios no sistema cardiovascular precisam ser esclarecidos. A AOS é caracterizada por episódios recorrentes de obstrução parcial (hipopneias) ou total (apneias) das vias aéreas superiores durante o sono. Estes eventos recorrentes geram hipoxemia intermitente e aumento da estimulação simpática, com consequente aumento da demanda de oxigênio pelo miocárdio durante o sono. No entanto, o papel da AOS em pacientes com angina refratária é desconhecido. Objetivos: Estudo 1: comparar a prevalência de AOS em duas populações de DAC crônica, a de angina refratária, com sintomas limitantes e recorrentes, com a de pacientes com DAC estável. Estudo 2: avaliar a associação entre lesão miocárdica e AOS em pacientes com angina refratária. Material e Métodos..

Background (Paper 1): Refractory angina is a severe form of coronary artery disease (CAD) characterized by persistent angina despite optimal medical therapy. Obstructive sleep apnea (OSA) and depression are common in patients with stable CAD and may contribute to a poor prognosis. Objectives: We hypothesized that OSA and depression are more common and more severe in patients with refractory angina than in patients with stable CAD. Methods...

Postoperative atrial fibrillation after cardiac surgery: who should receive chemoprophylaxis?

To evaluate arrhythmogenic risk factors associated with greater incidence of postoperative atrial fibrillation (POAF) in patients undergoing cardiac surgery (CABG and/or valvular surgery) in order to identify those more prone to the development of this arrhythmia for possible chemoprophylaxis. Sixty-six patients who underwent elective cardiac surgery were assessed. The following risk factors for the development of POAF were correlated: advanced age, valvular heart disease (VHD), left atrial (LA) enlargement, left ventricular dysfunction (LVD), electrolyte imbalance (EI), previous CABG, prior use and withdrawal of beta-blockers (BB) and/or digitalis 24 hours before surgery). The incidence of AF was high (47%) in our study, most frequently on the first postoperative day. Sixty-four percent of the study sample was male, and the mean age was 62 years. Among patients with two or less risk factors for AF, only 24% developed arrhythmia, while the presence of three or more risk factors was associated with increased incidence of postoperative AF (69%), (p = 0.04). Age > 65 years (58% of the patients) was the most prevalent risk factor, followed by LA enlargement in 45% (p = 0.001), and VHD in 38% (p = 0.02). The presence of three or more risk factors increases significantly the incidence of this arrhythmia in the postoperative period after cardiac surgery. Among the primary risk factors are advanced age, left atrial enlargement, and valvular heart disease.

Fibrilação atrial no pós-operatório de cirurgia cardíaca: quem deve receber quimioprofilaxia? / Fibrilación atrial en el postoperatorio de cirugía cardiaca: ¿quién debe recibir quimioprofilaxia? / Postoperative atrial fibrillation after cardiac surgery: who should receive chemoprophylaxis?

Avaliar fatores de risco arritmogênicos associados à maior incidência de fibrilação atrial (FA) no pós-operatório (PO) de cirurgia cardíaca (revascularização miocárdica e/ou cirurgia valvar), com o intuito de selecionar os mais propensos ao desenvolvimento dessa arritmia para possível quimioprofilaxia. Avaliarem-se 66 pacientes submetidos à cirurgia cardíaca eletiva. Correlacionaram-se os principais fatores de risco (idade avançada, doença valvar (DV), aumento atrial esquerdo (AE), disfunção ventricular (DVE), distúrbio eletrolítico (DHE), cirurgia cardíaca prévia (CCP), uso prévio e suspensão de betabloqueador (B-Bloq) e/ou digital 24 horas antes da cirurgia) para o desenvolvimento de FA no PO. A incidência de FA foi elevada (47 por cento) em nossa casuística e mais freqüente no primeiro dia de PO. Dos pacientes pesquisados, 64 por cento eram do sexo masculino com idade média de 62 anos. Entre os pacientes com dois ou menos fatores de risco para FA, apenas 24 por cento desenvolveram a arritmia, enquanto a presença de três ou mais desses fatores esteve associada à sua maior incidência no PO (69 por cento), (p = 0,04). Em ordem de maior freqüência, idade > 65 anos (em 58 por cento dos pacientes) foi o fator de risco mais prevalente, seguido de aumento do AE em 45 por cento (p = 0,001) e DV em 38 por cento (p = 0,02). A presença de três ou mais fatores de risco aumenta consideravelmente a incidência dessa arritmia no PO de cirurgia cardíaca. Entre os principais fatores, destacaram-se idade avançada, aumento do AE e doença valvar.

To evaluate arrhythmogenic risk factors associated with greater incidence of postoperative atrial fibrillation (POAF) in patients undergoing cardiac surgery (CABG and/or valvular surgery) in order to identify those more prone to the development of this arrhythmia for possible chemoprophylaxis. Sixty-six patients who underwent elective cardiac surgery were assessed. The following risk factors for the development of POAF were correlated: advanced age, valvular heart disease (VHD), left atrial (LA) enlargement, left ventricular dysfunction (LVD), electrolyte imbalance (EI), previous CABG, prior use and withdrawal of beta-blockers (BB) and/or digitalis 24 hours before surgery). The incidence of AF was high (47 percent) in our study, most frequently on the first postoperative day. Sixty-four percent of the study sample was male, and the mean age was 62 years. Among patients with two or less risk factors for AF, only 24 percent developed arrhythmia, while the presence of three or more risk factors was associated with increased incidence of postoperative AF (69 percent), (p = 0.04). Age > 65 years (58 percent of the patients) was the most prevalent risk factor, followed by LA enlargement in 45 percent (p = 0.001), and VHD in 38 percent (p = 0.02). The presence of three or more risk factors increases significantly the incidence of this arrhythmia in the postoperative period after cardiac surgery. Among the primary risk factors are advanced age, left atrial enlargement, and valvular heart disease.

Evaluar factores de riesgo arritmogénicos asociados a la mayor incidencia de fibrilación atrial (FA) en el postoperatorio (PO) de cirugía cardiaca (revascularización miocárdica y/o cirugía valvular), con el intuito de seleccionar los más propensos al desarrollo de esa arritmia para posible quimioprofilaxia. Se evaluaron a 66 pacientes sometidos a la cirugía cardiaca electiva. Se correlacionaron los principales factores de riesgo (edad avanzada, enfermedad valvar (DV), aumento atrial izquierdo (AE), disfunción ventricular (DVE), disturbio electrolítico (DHE), cirugía cardiaca previa (CCP), uso previo y suspensión de betabloqueante (B-Bloq) y/o digital 24 horas antes de la cirugía) para el desarrollo de FA en el PO. La incidencia de FA se mostró elevada (47 por ciento) en nuestra casuística y más frecuente al primer día de PO. De todos los pacientes investigados, el 64 por ciento pertenecían al sexo masculino con edad promedio de 62 años. Entre los pacientes con dos o menos factores de riesgo para FA, sólo el 24 por ciento desarrollaron la arritmia, mientras que la presencia de tres o más de esos factores estuvo asociada a su mayor incidencia en el PO (69 por ciento), (p = 0,04). Por orden de mayor frecuencia, edad > 65 años (en el 58 por ciento de los pacientes) resultó el factor de riesgo más prevalente, seguido de aumento del AE en el 45 por ciento (p = 0,001) y DV en el 38 por ciento (p = 0,02). La presencia de tres o más factores de riesgo aumenta considerablemente la incidencia de esa arritmia en el PO de cirugía cardiaca. Entre los principales factores, se destacaron: edad avanzada, aumento de AE y enfermedad valvular.

Padronização da anestesia em suínos para procedimentos cirúrgicos cardiovasculares experimentais / Standardization of anesthesia in swine for experimental cardiovascular surgeries / Estandarización de la anestesia en cerdos para procedimientos quirúrgicos cardiovasculares experimentales

JUSTIFICATIVA E OBJETIVO: Embora sejam os cães os animais mais utilizados em Cirurgia Experimental, nota-se crescente utilização de ovinos, bovinos e suínos como modelos para experimentação científica. Assim, faz-se necessário maior aprendizado de seu tratamento e padronizações básicas para os procedimentos cirúrgicos mais complexos em suínos. O objetivo foi avaliar a sedação e analgesia, obtidas pela injeção intramuscular de midazolam e cetamina e anestesia local com lidocaína a 2 por cento sem vasoconstritor, na realização de traqueostomia, dissecção de artéria e veia femorais. MÉTODO: A freqüência cardíaca e o reflexo córneo-palpebral foram avaliados logo no início da sedação, durante os procedimentos cirúrgicos descritos e após seu término. Foram utilizados oito suínos fornecidos por fazendas locais sem tratamento prévio da raça Large White, com peso de 35 a 42 quilos que receberam injeção intramuscular de 22 mg.kg-1 de cetamina e 0,3 mg.kg-1 de midazolam. RESULTADOS: A abordagem anestésica nesses animais, de difíceis intubação e acesso aos vasos profundos, provou ser segura para sedação e analgesia através do método utilizado: acesso intramuscular. CONCLUSÃO: Obteve-se adequado plano de anestesia para o procedimento proposto.

BACKGROUND AND OBJECTIVES: Although dogs are the animals used more often in Experimental Surgeries, the use of sheep, bovine, and swine as models for scientific experiments has been growing. Thus, further learning on the treatment and basic standardization of more complex surgeries in swine are necessary. The objective of this study was to evaluate sedation and analgesia, obtained by the intramuscular administration of midazolam and ketamine, and local anesthetics with 2 percent lidocaine without vasoconstrictor, in tracheostomy and dissection of femoral artery and vein. METHODS: The heart rate and corneal-palpebral reflex were evaluated at the beginning of sedation, during the surgical procedures, and at the end of those procedures. Eight Large White swine, without prior treatment, weighing 35 to 42 kg were provided by local farms. They received intramuscular injections of 22 mg.kg-1 of ketamine and 0.3 mg.kg-1 of midazolam. RESULTS: The anesthetic approach on those animals, who present both difficult intubation and access to deep vessels, proved to be safe for sedation and analgesia by the method chosen: intramuscular administration. CONCLUSIONS: An adequate plane of anesthesia for the proposed procedure was achieved.

JUSTIFICATIVA Y OBJETIVOS: Aunque los perros sean los animales más a menudo usados en Cirugía Experimental, se nota un aumento en la utilización de los ovinos, bovinos y porcinos como modelo para experimentación científica. De esa forma, se hace necesario aprender más con su tratamiento y estandarizaciones básicas para los procedimientos quirúrgicos más complejos en porcinos. El objetivo fue evaluar la sedación y la analgesia obtenidas por la inyección intramuscular de midazolán y la cetamina y anestesia local con lidocaína a un 2 por ciento sin vasoconstrictor, en la realización de traqueostomía, disección de arteria y vena femorales. MÉTODO: La frecuencia cardíaca y el reflejo córneo-palpebral fueron evaluados inmediatamente al inicio de la sedación, durante los procedimientos quirúrgicos descritos y después en su conclusión. Se utilizaron ocho porcinos que fueron suministrados por haciendas de la región sin tratamiento previo de la raza Large White, con peso de 35 a 42 kilos que recibieron inyección intramuscular de 22 mg.kg-1 de cetamina y 0.3 mg.kg-1 de midazolán. RESULTADOS: El abordaje anestésico en esos animales, de difícil intubación y acceso a los vasos profundos, demostró ser seguro para la sedación y analgesia a través del método utilizado: el acceso intramuscular. CONCLUSIÓN: Se obtuvo un adecuado plan de anestesia para el procedimiento propuesto.

Standardization of anesthesia in swine for experimental cardiovascular surgeries.

BACKGROUND AND OBJECTIVES: Although dogs are the animals used more often in Experimental Surgeries, the use of sheep, bovine, and swine as models for scientific experiments has been growing. Thus, further learning on the treatment and basic standardization of more complex surgeries in swine are necessary. The objective of this study was to evaluate sedation and analgesia, obtained by the intramuscular administration of midazolam and ketamine, and local anesthetics with 2% lidocaine without vasoconstrictor, in tracheostomy and dissection of femoral artery and vein. METHODS: The heart rate and corneal-palpebral reflex were evaluated at the beginning of sedation, during the surgical procedures, and at the end of those procedures. Eight Large White swine, without prior treatment, weighing 35 to 42 kg were provided by local farms. They received intramuscular injections of 22 mg.kg of ketamine and 0.3 mg.kg(-1) of midazolam. RESULTS: The anesthetic approach on those animals, who present both difficult intubation and access to deep vessels, proved to be safe for sedation and analgesia by the method chosen: intramuscular administration. CONCLUSIONS: An adequate plane of anesthesia for the proposed procedure was achieved.

Prevention of atrial fibrillation with moderate doses of amiodarone in the postoperative period of cardiac surgery is safe and effective in patients with high risk for developing this arrhythmia.

OBJECTIVE: To assess if prophylaxis with moderate doses of amiodarone in the postoperative period of cardiac surgery (coronary artery bypass grafting and/or valve surgery), reduces the incidence of atrial fibrillation in patients with high risk for developing this arrhythmia. METHODS: A randomized and prospective clinical study involving 68 patients who underwent elective cardiac surgery. Mean age was 64 years and 59% of participants were males. Patients with three or more risk factors for atrial fibrillation, according to the literature, were randomized into two groups to receive or not prophylaxis with amiodarone in the first postoperative day. The dose administered ranged from 600 mg/day to 900 mg/day, intravenously, on the first postoperative day, followed by 400 mg/day orally until hospital discharge or until completing seven days. The other patients, who presented two or fewer risk factors, were followed up until hospital discharge. All patients were evaluated by means of cardiac and/or electrocardiographic monitoring. RESULTS: In the group treated with amiodarone, 7% of patients presented atrial fibrillation, whereas in the control group 70% of patients developed arrhythmia. Among the non-randomized individuals (with two or fewer risk factors), only 24% presented atrial fibrillation. CONCLUSION: The prophylactic use of amiodarone was effective in the prevention of atrial fibrillation in patients with three or more risk factors for this arrhythmia. This treatment can be useful to reduce stay at the Intensive Care Unit and, consequently, the complications originating from longer hospitalization.

Prevenção de fibrilação atrial com amiodarona em moderada dosagem no pós-operatório de cirurgia cardíaca é segura e eficaz em pacientes de alto risco para desenvolver essa arritmia / Prevention of atrial fibrillation with moderate doses of amiodarone in the postoperative period of cardiac surgery is safe and effective in patients with high risk for developing this arrhythmia

OBJETIVO: Avaliar se a profilaxia com amiodarona em moderada dosagem, no pós-operatório de cirurgia cardíaca (revascularização miocárdica e/ou cirurgia valvar), reduz a incidência de fibrilação atrial em pacientes de alto risco para desenvolver essa arritmia. MÉTODOS: Estudo clínico, randomizado e prospectivo, realizado em 68 pacientes submetidos a cirurgia cardíaca eletiva. A média de idade foi de 64 anos e 59 por cento dos participantes eram do sexo masculino. Os pacientes com três ou mais fatores de risco para fibrilação atrial, de acordo com a literatura, foram randomizados em dois grupos, para receber ou não profilaxia com amiodarona no primeiro dia de pós-operatório. A dose administrada foi de 600 mg/dia a 900 mg/dia, por via intravenosa, no primeiro dia de pós-operatório, seguida de 400 mg/dia por via oral até a alta hospitalar ou até completar sete dias. Os demais pacientes, com dois ou menos fatores de risco, foram seguidos até a alta hospitalar. Todos os pacientes foram observados por monitorização cardíaca e/ou eletrocardiografia. RESULTADOS: No grupo que recebeu amiodarona, 7 por cento dos pacientes apresentaram fibrilação atrial, enquanto no grupo controle 70 por cento desenvolveram a arritmia. Nos indivíduos não-randomizados (com dois ou menos fatores de risco), apenas 24 por cento apresentaram fibrilação atrial. CONCLUSÃO: O uso profilático de amiodarona foi eficaz na prevenção de fibrilação atrial nos pacientes com três ou mais fatores de risco para essa arritmia. Esse tratamento pode ser benéfico na redução da permanência na Unidade de Terapia Intensiva e, conseqüentemente, nas complicações advindas do maior tempo de internação hospitalar.

OBJECTIVE: To assess if prophylaxis with moderate doses of amiodarone in the postoperative period of cardiac surgery (coronary artery bypass grafting and/or valve surgery), reduces the incidence of atrial fibrillation in patients with high risk for developing this arrhythmia. METHODS: A randomized and prospective clinical study involving 68 patients who underwent elective cardiac surgery. Mean age was 64 years and 59 percent of participants were males. Patients with three or more risk factors for atrial fibrillation, according to the literature, were randomized into two groups to receive or not prophylaxis with amiodarone in the first postoperative day. The dose administered ranged from 600 mg/day to 900 mg/day, intravenously, on the first postoperative day, followed by 400 mg/day orally until hospital discharge or until completing seven days. The other patients, who presented two or fewer risk factors, were followed up until hospital discharge. All patients were evaluated by means of cardiac and/or electrocardiographic monitoring. RESULTS: In the group treated with amiodarone, 7 percent of patients presented atrial fibrillation, whereas in the control group 70 percent of patients developed arrhythmia. Among the non-randomized individuals (with two or fewer risk factors), only 24 percent presented atrial fibrillation. CONCLUSION: The prophylactic use of amiodarone was effective in the prevention of atrial fibrillation in patients with three or more risk factors for this arrhythmia. This treatment can be useful to reduce stay at the Intensive Care Unit and, consequently, the complications originating from longer hospitalization.