Atrial fibrillation is the most prevalent form of cardiac arrhythmia. Studies in animal modelshave provided important insights into arrhythmia mechanisms. However, to date, we do not dispose ofanimal models of spontaneous atrial arrhythmia.Thus, we aimed to develop a model of spontaneous atrial arrhythmia in rats and to assesspathophysiological mechanisms of these arrhythmias by using a multidisciplinary approach. We alsoaimed to assess the presence and the extent of inflammation and endothelial dysfunction, incriminatedin atrial fibrillation-related complications such as stroke, in atrial fibrillation patients.The animal study describes the first animal model of spontaneous atrial arrhythmias. We alsoprovide evidence that multiple mechanisms participate in arrhythmia occurrence in this model,particularly autonomic imbalance with relative vagal hyperactivity, left atrial endocardial fibrosis, anddecreased left atrial expression of the Pitx2 gene. In our clinical study, we found high levels ofvascular endothelial growth factor and von Willebrand factor in atrial fibrillation patients compared tosinus rhythm controls. These results suggest specific thromboembolic risk patterns according to theclinical form of arrhythmia and highlight a parallel evolution of atrial fibrillation and endothelialdysfunction. These results add new insights into the understanding of atrial arrhythmias. This new animalmodel could facilitate studies of pathophysiological mechanisms involved in atrial arrhythmias andallow assessment of efficacy and toxicity of therapeutic agents in a setting that faithfully reproducesthe clinical presentation of the arrhythmia

Objectif: Déterminer si l’efficacité de l’amiodarone pour le maintien du rythme sinusal varie selon la fonction systolique ventriculaire gauche. Contexte: Malgré un profil de sécurité établi en insuffisance cardiaque, nous ignorons si l’efficacité de l’amiodarone et son impact sur différentes issues cardiovasculaires sont modulés par la fonction ventriculaire gauche. Méthode: Nous avons effectué une analyse combinée de 3307 patients (âgés de 68,0±0,9 ans ; 31,1% de femmes) recrutés dans les études AFFIRM et AF-CHF qui ont été randomisés au contrôle du rythme par l’amiodarone (N=1107) ou au contrôle de la fréquence cardiaque (N=2200). Résultats: Chez les patients sous amiodarone, la survie sans fibrillation auriculaire était de 84% et de 45% à 1 et 5 ans respectivement, sans égard à la fraction d’éjection ventriculaire gauche (P=0,8754, ajusté). De façon similaire, la proportion moyenne ajustée de temps en fibrillation auriculaire (15,0±1,8%) n’a pas été influencée par la fraction d’éjection (P=0,6094). Durant le suivi, 1963 patients (59,4%) ont requis au moins une hospitalisation, incluant 1401 (42,6%) patients hospitalisés pour cause cardiovasculaire. Les taux ajustés d’hospitalisation pour toutes causes et pour cause cardiovasculaire étaient similaires entre les patients sous amiodarone et ceux dans le groupe de contrôle de la fréquence dans l’ensemble de la population ainsi que dans les sous-groupes de patients avec et sans dysfonction ventriculaire gauche sévère. De façon similaire, les taux ajustés de mortalité globale et cardiovasculaire étaient similaires entre chez les patients sous amiodarone et ceux traités par le contrôle de la fréquence dans l’ensemble de la population ainsi que dans les sous-groupes de patients avec et sans dysfonction ventriculaire gauche sévère. Conclusions: L’efficacité de l’amiodarone pour le maintien du rythme sinusal n’est pas influencée par la fonction ventriculaire gauche. Le contrôle du rythme avec l’amiodarone s’associe à des taux de mortalité et d’hospitalisation comparables au contrôle de la fréquence à la fois chez les patients avec et sans dysfonction ventriculaire gauche sévère. / Objectives: To determine whether amiodarone’s efficacy in maintaining sinus rhythm varies according to left ventricular systolic function. Background: Despite amiodarone’s established safety profile in heart failure, it is unknown whether its impact on cardiovascular outcomes is modulated by ventricular function. Methods: We conducted a pooled analysis of 3307 patients (age 68.0±0.9 years; 31.1% female) enrolled in AFFIRM and AF-CHF trials who were randomized to rhythm control with amiodarone (N=1107) or rate control (N=2200). Results: In amiodarone-treated patients, freedom from recurrent atrial fibrillation was 84% and 45% at 1 and 5 years, respectively, with no differences according to left ventricular function (adjusted P=0.8754). Similarly, the adjusted mean proportion of time in atrial fibrillation (15.0±1.8%) did not vary according to ventricular function (P=0.6094). During follow-up, 1963 (59.4%) patients required at least one hospitalization, with 1401 (42.6%) patients hospitalized for a cardiovascular reason. Adjusted all-cause and cardiovascular hospitalization rates were similar with amiodarone versus rate control in the overall population and in subgroups of patients with and without severe left ventricular dysfunction. Similarly adjusted all-cause and cardiovascular mortality rates were similar with amiodarone versus rate control, overall and in subgroups of patients with and without severe left ventricular dysfunction. Conclusions: Amiodarone’s efficacy in maintaining sinus rhythm and reducing the burden of atrial fibrillation is similar in patients with and without left ventricular dysfunction. Rhythm control with amiodarone was associated with similar mortality and hospitalisation rates when compared to rate control in patients with and without severe left ventricular dysfunction.

Aptikus minimalius PAL simptomus, yra labai svarbūs diagnostiniai, greitai atliekami neinvaziniai tyrimo metodai (kulkšnies-žasto indeksas, nykščio indeksas, ėjimo testas, segmentinių slėgio gradientų matavimas ir kt.). Ambulatorinėje grandyje retai matuojamas kulkšnies-žasto indeksas riboja galimybę nustatyti PAL kiek galima anksčiau, numatyti galimas gyvybiškai svarbių organų kraujagyslines komplikacijas, laiku siųsti pacientą konsultuoti angiochirurgui. Mažai tyrinėtu alternatyvaus neinvazinio impedanso pletizmografijos tyrimu galima nustatyti ne tik periferinių arterijų ligos simptomus, bet vienu metu įvertinti eilę kitų parametrų. Darbo tikslas buvo nustatyti neinvazinio impedanso pletizmografijos metodo efektyvumą kojų arterinei kraujotakai įvertinti ir šį metodą palyginti su kitais neinvaziniais bei invaziniais diagnostikos metodais. Tyrimo metu nustatyta statistiškai reikšminga kulkšnies-žasto indekso bei impedanso pletizmografijos parametrų sąsaja pacientams, sergantiems lėtiniu prieširdžių virpėjimu, lyginant su pacientais neturinčiais šio ritmo sutrikimo, nustatyta impedanso pletizmografijos - bangos viršūnės laiko parametro sąsaja su angiografiškai aptikta kraujagyslės okliuzijos vieta. Pagrindinio impedanso pletizmografijos parametro (bangos viršūnės laiko) specifiškumas yra 96 proc., jautrumas – 73 proc. atsižvelgiant į KŽI pokyčius, o lyginant su angiografija – jautrumas 100 proc., specifiškumas – 50 proc. Taigi, neinvazinis impedanso pletizmografijos... [toliau žr. visą tekstą] / In cases of observing even the slightest PAD symptoms, rapid non-invasive diagnostic test methods become extremely important (the ankle-brachial index, thumb index, walking test, measurement of segmental pressure gradients, etc.). in an outpatient setting , the ankle-brachial index (ABI) is rarely measured, thus limiting the opportu¬nities for the earliest possible detection of PAD, prediction of vascular com¬plications of vital organs, and timely referral of the patient for a con¬sultation with an angiosurgeon. An alternative non-invasive test method of impedance plethysmo¬graphy, which has been little investigated so far, allows both detection of symptoms of peripheral arterial disease and concurrent assessment of a number of other parameters. The aim of the study is to assess the efficiency of a non-invasive method of impedance plethysmography in diagnosing arterial circulation disorders in the legs, and to compare this method with other non-invasive and invasive diagnostic methods of peripheral arterial disease. A significant correlation between the Ankle-Brachial Index and the im¬pedance plethysmography parameters was established in subjects with permanent atrial fibrillation, but not in subjects without this rhythm disorder. During the study, an obvious correlation between the Crest Time in¬ter¬val measured by the impedance plethysmography method and the vas¬¬cular occlusion site shown on angiography was established. Specificity of the impedance plethysmography... [to full text]

Despite major advances in the treatment and prevention of atherosclerosis the last several decades, cardiovascular disease still accounts for the majority of deaths in Sweden. With the population getting older, more obese and with rising numbers of diabetics, the cardiovascular disease burden may increase further in the future. The focus in cardiovascular disease has shifted with time from calcification and narrowing of arteries to the biological processes within the atherosclerotic plaque. C-reactive protein (CRP) has emerged as one of many proteins that reflect a low grade systemic inflammation and is suitable for analysis as it is more stable and easily measured than most other inflammatory markers. Several large prospective studies have shown that CRP is not only an inflammatory marker, but even a predictive marker for cardiovascular disease. C-reactive protein is associated with several other risk factors for cardiovascular disease including obesity and the metabolic syndrome. Our study of twenty healthy men during a two week endurance cross country skiing tour demonstrated a decline in already low baseline CRP levels immediately after the tour and six weeks later. In a study of 200 obese individuals with impaired glucose tolerance randomised to a counselling session at their health care centre or a one month stay at a wellness centre, we found decreased levels of CRP in subjects admitted to the wellness centre. The effect remained at one, but not after three years of follow-up. In a prospective, nested, case-referent study with 308 ischemic strokes, 61 intracerebral haemorrhages and 735 matched referents, CRP was associated with ischemic stroke in both uni- and multivariate analyses. No association was found with intracerebral haemorrhages. When classifying ischemic stroke according to TOAST criteria, CRP was associated with small vessel disease. The CRP 1444 (CC/CT vs. TT) polymorphism was associated with plasma levels of CRP, but neither with ischemic stroke nor with intracerebral haemorrhage. A study on 129 patients with atrial fibrillation was used to evaluate whether inflammation sensitive fibrinolytic variables adjusted for CRP could predict recurrence of atrial fibrillation after electrical cardioversion. In multivariate iv models, lower PAI-1 mass was associated with sinus rhythm even after adjusting for CRP and markers of the metabolic syndrome. In conclusion, lifestyle intervention can be used to reduce CRP levels, but it remains a challenge to maintain this effect. CRP is a marker of ischemic stroke, but there are no significant associations between the CRP1444 polymorphism and any stroke subtype, suggesting that the CRP relationship with ischemic stroke is not causal. The fibrinolytic variable, PAI-1, is associated with the risk of recurrence of atrial fibrillation after electrical cardioversion after adjustment for CRP. Our findings suggest a pathophysiological link between atrial fibrillation and PAI-1, but the relation to inflammation remains unclear.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2009. / Härtill 4 uppsatser.

INTRODUÇÃO: A queda é um fenômeno complexo, altamente prevalente e de alto custo, podendo causar sérias conseqüências inclusive a morte. O idoso com fibrilação atrial se beneficia do uso de anticoagulante. No entanto, a ocorrência de quedas pode restringe o seu uso. Este trabalho objetivou analisar a associação entre a ocorrência de queda e as variáveis obtidas na avaliação clínica e multifatorial em idosos com fibrilação atrial; verificar a freqüência, características e conseqüências das quedas. MÉTODOS: Neste estudo transversal, foram avaliados 107 idosos com 60 anos ou mais com fibrilação atrial crônica do ambulatório de cardiogeriatria do InCor-HCFMUSP. Os participantes foram divididos em dois grupos: (1) sem história de queda no último ano e (2) com história de um ou mais episódios de queda no último ano. Foram submetidos à avaliação que incluiu: dados sóciodemográficos; história da quedas; suas características e conseqüências; questionários de qualidade de vida (BOMFAQ); de nível funcional (HAQ); de risco nutricional (Guigoz); da função psico-cognitiva (Prime MD, Mini-Mental); avaliação do equilíbrio e da mobilidade (escala de Berg, POMA, Timed up & go); avaliação neurológica e de força muscular; avaliação da acuidade visual (tabela de Snellen e teste de Donders) e avaliação auditiva. Todos os dados foram submetidos à análise estatística com teste qui-quadrado ou teste de verossimilhança ou teste exato de Fisher. As médias das variáveis quantitativas foram comparadas com teste t-Student ou teste da soma de postos de Wilcoxon. Os valores de p<0,05 foram considerados estatisticamente significantes. As variáveis significantes na análise univariada foram utilizadas no ajuste do modelo de regressão logística, determinando sensibilidade, especificidade e probabilidade estimada de queda. Resultados: 1) 51,4% (55 idosos) caíram ao menos uma vez no último ano, sendo que as quedas resultaram em lesões corporais em 90% dos casos, 2) não houve diferenças entre os grupos com respeito à idade, sexo, índice de massa corporal, hábitos, riscos nutricionais e atividade física, 2) houve relação significante entre a ocorrência de queda com: a presença de sintomas, como cansaço; o uso de amiodarona; diagnóstico de insuficiência cardíaca CF III e de diabete melito; força muscular; o BOMFAQ (dificuldade de manter o equilíbrio); deficiência auditiva e visual e a escala equilíbrio da POMA A regressão logística das variáveis significantes positivas mostrou as seguintes variáveis independentes: uso de amiodarona, diagnóstico de diabete melito e a queixa de dificuldade de manter equilíbrio no BOMFAQ. O conjunto apresentou sensibilidade de 92,9% e especificidade 44,9%, a razão de chance foi de 5,95 e razão de verossimilhança positivo foi de 5.0. Conclusão:Em um grupo de idosos com FAC capaz de freqüentar ambulatório e relativamente independente, muitos fatores de risco de quedas foram identificados, sendo preditores independentes deste risco, a simples referência de dificuldade em manter o equilíbrio, o diagnóstico de diabete melito e o uso de amiodarona; A ocorrência de quedas com recorrências e conseqüências foi elevada. Nesses pacientes, o questionamento sobre a ocorrência de quedas no último ano e a avaliação do risco de quedas é fundamental diante da decisão em indicar a anticoagulação. / Introduction: Falling is a complex phenomenon, highly prevalent and costly. It may cause serious consequences, including death. Anticoagulation is beneficial for elderly patients with atrial fibrillation. However, falls may limit its use, especially when recurrent. The goals of this study were to evaluate the association between the occurrence of falls and variables derived from clinical and multidisciplinary evaluation of elderly patients with atrial fibrillation, to analyze the prevalence, characteristics and consequences of falls. Methods: This cross-sectional study involved 107 elderly patients older than 60 years of age with chronic atrial fibrillation who were followed in the Geriatric Cardiology Outpatient Clinic of InCor-HCFMUSP. Subjects were divided in two groups: (1) those with no history of falls in the past year, and (2) patients with at least one fall within the previous year. All patients underwent clinical and multifactorial evaluation, which included socio-demographic data, history of falls, their characteristics and consequences, questionnaires on quality of life (BOMFAQ), functional activity (HAQ), nutritional risk (Guigoz), psycho-cognitive function (PRIME MD, Mini-Mental), and the following evaluations: balance and mobility (Berg scale, POMA, Timed up & go), neurologic, muscular strength, and hearing status, and visual acuity (Snellen table and Donders test). Statistical tests employed included chi-square, analysis of likelihood methods, and Fisher exact test, as appropriate. Quantitative variables were compared by t-test or Wilcoxon. A p-value <0.05 was considered statistically significant. Variables statistically significant by univariate analysis were employed in a model of logistic regression to determine sensitivity, specificity, and estimated probability of falls. Results: 1) 51.4% of the patients (55) fell at least once in the preceding year, with 90% of the falls resulting in corporal lesions. 2) There were no difference between the two groups in regard to age, gender, body mass index, habits, nutritional risks, and level of physical activity. 3) There was a significant relationship between the occurrence of fall and the following univariate variables: symptom of fatigue, use of amiodarone, class III heart failure , diabetes, muscular strength, difficulty to maintain balance detected by the BOMFAQ questionnaire, hearing and visual impairment, and POMA balance scale. 4) The risk factors most frequent were hypertension, visual and hearing impairments, and muscular weakness. Logistic regression yielded the following independent variables: use of amiodarone, diabetes, and difficulty to maintain balance by BOMFAQ. These variables together had 92,9% sensitivity and 44,9% specificificity for predicting the occurrence of falls, with a hazard ratio of 5.95 and likelihood methods of 5.0. Conclusion: in a group of relatively independent, elderly patients with chronic atrial fibrillation which were able to visit an out-patient clinic, many risk factors for falls were identified. The multivariate analysis identified as independent risk factors, the use of amiodarone, the diagnosis of diabetes and difficulty in maintaining balance detected by the BOMFAQ questionnaire. The frequency of falls with recurrences and consequences was high. In these patients, it is very important to ask about the occurrence of falls in the last year and to evaluate the risk of falls, considering the decision to prescribe anti-coagulation.

Estima-se que mais de 800.000 cirurgias cardíacas de revascularização do miocárdio por ano são realizadas no mundo. Nesta intervenção terapêutica uma das complicações mais comuns é a fibrilação atrial, que esta intimamente relacionada com aumento de risco de morbidade e mortalidade pós-operatória. Os fatores determinantes desta manifestação podem ser pré, intra e pós-operatórios que possivelmente se relaciona com as proteínas pró-inflamatórias, canais iônicos e sistema renina-angiotensina. Portanto, os polimorfismos nos genes que codificam essas proteínas podem ter importante papel no desenvolvimento da FAPo. O objetivo deste trabalho foi de avaliar a associação entre os polimorfismos dos genes IL6 (G-174C), KCNE5 (C97T) e AGT (A-217G) e a incidência da FAPo e seus efeitos na expressão de RNAm, em apêndice atrial direito e em sangue periférico. Para o estudo foram selecionados 76 indivíduos portadores de insuficiência coronariana obstrutiva com indicação de intervenção cirúrgica de revascularização do miocárdio. Desses, 16 com FAPo, 52 sem FAPo e 8 pacientes foram excluídos por motivo de óbito. Amostras de sangue periférico foram obtidas para análise de parâmetros bioquímicos e para extração de DNA genômico e RNA total, antes e 48 horas após a cirurgia cardíaca. Os polimorfismos de nucleotídeo único (SNP) dos genes da IL-6, KCNE5 e do AGT foram detectados pela PCR-RFLP e confirmados por sequenciamento de DNA. A expressão de RNAm em leucócitos totais de sangue periférico e de tecido foi analisada pela PCR em tempo real, utilizando o gene GAPDH como referência endógena. A freqüência do alelo -174G foi de 75 % no GFA e 69,2% no GC e não foi associada ao desenvolvimento de FAPo. A freqüência do alelo 97T foi de 0% no GFA e 10,8% no GC e não foi associada a menor incidência de FAPo. A freqüência do alelo -217A foi de 12,5% no GFA e 15,9% no GC e também não foi associado ao desenvolvimento de FAPo. A expressão de RNAm da IL-6 em LTSP foi reduzida do pré para o pós-operatório de cirurgia de RM em ambos os grupos e não houve correlação entre a expressão de RNAm da IL-6 em LTSP e apêndice auricular direito. A expressão de RNAm do KCNE5 em LTSP foi reduzida do pré para o pós-operatório de cirurgia de RM, exceto em indivíduos do gênero masculino do GC, sugerindo a influência do gênero na expressão desse gene. Não houve correlação entre a expressão de RNAm do KCNE5 em LTSP e apêndice auricular direito. Não se detectou expressão de RNAm do AGT em LTSP e sua expressão em apêndice auricular direito foi extremamente baixa, portanto não está associada ao desenvolvimento de FAPo. / It is estimated that more than 800,000 heart surgery coronary artery bypass grafting are performed annually in the world. This therapeutic intervention of the most common complication was atrial fibrillation, which is closely related to increased risk of morbidity and postoperative mortality. The determining factors of this event can be pre, intra and postoperative possibly relates to the pro-inflammatory proteins, ion channels and renin-angiotensin system. Therefore, polymorphisms in the genes encoding these proteins may play an important role in the development of PoAF. The objective of this study was to evaluate the association between polymorphisms of IL6 gene (G-174C), KCNE5 (C97T) and AGT (A-217G) and the incidence of PoAF and its effects on mRNA expression in right atrial appendage and peripheral blood. For the study we selected 76 individuals with obstructive coronary artery disease with indication for surgical myocardial revascularization. Of these, 16 with PoAF, 52 without PoAF and 8 patients were excluded because of death. Blood samples were obtained for biochemical analysis and extraction of genomic DNA and total RNA before and 48 hours after cardiac surgery. The single nucleotide polymorphisms (SNPs) of IL-6, KCNE5 and AGT were detected by PCR-RFLP and confirmed by DNA sequencing. mRNA expression in total leukocytes in peripheral blood and tissue were analyzed by real-time PCR, using GAPDH gene as endogenous reference. The frequency of-174G allele was 75% in the GFA and 69.2% in GC and was not associated with the development of FAPO. The 97T allele frequency was 0% in GFA and 10.8% in GC and was not associated with a lower incidence of PoAF. The frequency of allele-217A was 12.5% in the GFA and 15.9% in GC and was not associated with the development of PoAF. The mRNA expression of IL-6 on LTSP was reduced from preoperative to the postoperative period of CABG in both groups and no correlation between mRNA expression of IL-6 on LTSP and right atrial appendage. The mRNA expression of KCNE5 LTSP was reduced in the pre and postoperative CABG, except among males in the CG, suggesting the influence of gender on expression of this gene. There was no correlation between the expression of mRNA KCNE5 in LTSP and right auricular appendage. There was no mRNA expression of AGT in LTSP and its expression in right atrial appendage was extremely low, so it is associated with the development of PoFA.

Orientador: Domingo Marcolino Braile / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-11T14:35:59Z (GMT). No. of bitstreams: 1 Leal_JoaoCarlosFerreira_D.pdf: 5038174 bytes, checksum: ad94b28be3168b7ddcb5c89801eef75f (MD5) Previous issue date: 2008 / Resumo: Objetivo: avaliar se há ou não associação na ocorrência de fibrilação atrial (FA) e os níveis séricos de troponina I cardíaca no pós-operatório imediato da revascularização do miocárdio (RM). Casuística e Método: estudo retrospectivo incluindo 95 pacientes submetidos à revascularização cirúrgica do miocárdio, entre dezembro de 1996 a março de 1998. Os pacientes foram divididos em 2 grupos: Grupo I constituído de 25 pacientes (26,31%) com fibrilação atrial (FA); Grupo II constituído de 70 pacientes (73,69%) sem FA. As variáveis avaliadas foram: tempos de circulação extracorpórea (CEC), pinçamento aórtico e isquemia, fração de ejeção e o diâmetro do átrio esquerdo. O ritmo cardíaco foi avaliado por monitorização contínua por exames eletrocardiográficos durante o período de internação. Todos os pacientes foram submetidos à dosagens dos níveis séricos de troponina-I cardíaca no pré e pós-operatório imediato da RM pelo método de quimioluminiscência, admitindo-se como normais valores abaixo de 0,1 ng/ml. Resultados: Os grupos I e II não apresentaram diferenças significantes quanto à fração de ejeção, diâmetro do átrio esquerdo, tempos de pinçamento da aorta e de isquemia. O tempo de CEC mostrou diferença significante entre os grupos. A análise pareada dos valores séricos da troponina I cardíaca dos pacientes dos grupos I e II no pré-operatório não mostrou diferença significante, com valor de P=0,9689. No pós-operatório, houve diferença significante entre os grupos, sendo que o grupo I mostrou maior aumento em relação ao II com P=0,0018. O valor de corte de troponina I cardíaca que melhor se associou com ocorrência de FA foi = 0,936 µg/ L. Conclusão: A ocorrência da FA está associada com os níveis séricos de troponina I cardíaca no pós-operatório imediato da RM quando considerado o valor de corte = 0,936 µg/L, sugerindo que a troponina I cardíaca é um marcador para FA e alertando para a necessidade de medidas diagnósticas ou terapêuticas preventivas / Abstract: Objective: To evaluate if there is any association among atrial fibrillation (AF) events and serum cardiac Troponin I levels in the immediate postoperative period of myocardium revascularization (MR). Patients and method: A retrospective study was made of 95 patients who underwent myocardial revascularization surgery between December 1996 and March 1998. The patients were divided into 2 groups: Group I comprised 25 patients (26.31%) who presented with atrial fibrillation (AF) and Group II 70 patients (73.69%) without AF. The variables evaluated were: time of extracorporeal circulation (ECC), aortic clamping and ischemia, ejection fraction and the diameter of the left atrium. The heart rhythm was evaluated by continuous monitoring by electrocardiography during hospitalization. The serum cardiac Troponin I levels were measured for all patients in the pre- and immediate postoperative periods of MR by chemoluminescence; normal values were consider to be below 0.1 ng/mL. Results: There were no significant differences between groups in respect to the ejection fraction, diameter of the left atrium and duration of aortic clamping and ischemia. The ECC time gave a significant difference between the groups. A comparison of the serum cardiac Troponin I levels of the patients in both groups in the preoperative period did not prove to be statistically significant (P-value = 0.9689). In the postoperative period however, there was a significant difference; Group I presented with a greater increase when compared to Group II (P-value = 0.0018). Levels of cardiac Troponin I =0.936 µg/L were associated with a risk of AF. Conclusion: AF events are associated with serum cardiac Troponin I levels =0.936 µg/L in the immediate postoperative period of MR. This suggests that cardiac Troponin I is a marker for AF, highlighting the necessity of diagnostic investigations and preventive therapeutic procedures / Doutorado / Cirurgia / Doutor em Cirurgia

A fibrilação atrial (FA) é a arritmia cardíaca mais comum na prática clínica e que apresenta a maior morbidade, principalmente com o avançar da idade. O sistema nervoso autonômico, particularmente o balanço adrenérgico/colinérgico, tem profunda influência na ocorrência de fibrilação atrial. A FA pode ser gerada e mantida por uma variedade de mecanismos eletrofisiológicos e uma mudança na atividade autonômica poderá afetar cada um deles de forma diferente. Além do sistema nervoso autônomo, simpático e parassimpático, envolvidos na gênese e manutenção da FA, já é sabido que existem vários outros fatores envolvidos e, dentre eles, as células intersticiais tipo-Cajal (CITC), semelhantes às células intersticiais que contribuem para a atividade motora peristáltica do trato gastrointestinal. Essas células foram encontradas no miocárdio atrial e ventricular, e poderiam ser a origem da atividade deflagradora de focos elétricos ectópicos geradores de FA. O presente estudo teve como objetivos analisar possíveis alterações na expressão miocárdica dos receptores beta-adrenérgicos e quantificar as células intersticiais tipo-Cajal nos átrios de corações humanos, em particular, no esquerdo, e sua relação com a fibrilação atrial permanente (FAP). Para o primeiro objetivo, foram estudados 19 casos de corações de autópsias de portadores de FAP e cardiopatia crônica definida (grupo I), e 19 corações pareados com as mesmas cardiopatias, porém sem evidências de qualquer arritmia supraventricular (grupo II). Foram ressecadas uma amostra no teto do átrio direito, duas no átrio esquerdo, e uma em terminação nervosa envolvida em tecido gorduroso no epicárdio do átrio esquerdo (fat-pad). A expressão miocárdica dos receptores beta-adrenérgicos 1 a 3 e da quinase-5 do receptor adrenérgico acoplado à proteína G (GRK5) foi avaliada pela proporção positiva no miocárdio nos cortes citados. Não houve diferença estatisticamente significante entre os dois grupos quando analisamos a expressão dos receptores adrenérgicos (beta-1, beta-2, beta-3 e GRK5), independentemente do uso ou não de beta-bloqueador. Para o segundo objetivo, foram estudados 6 casos de corações de autópsias de portadores de FAP e cardiopatia crônica definida (grupo I), e 6 corações pareados com as mesmas cardiopatias, porém sem evidências de qualquer arritmia supraventricular (grupo II). As CITC foram avaliadas na região média da parede diafragmática do átrio esquerdo. Não houve alterações estatisticamente significantes entre os grupos estudados, quando avaliamos o número de células positivas no miocárdio pela área do miocárdio em mm2, o número de células positivas no corte inteiro pela área do miocárdio em mm2 ou o número de células positivas no corte inteiro/área do corte inteiro em mm2, seja em relação a cada corte individualmente, ao átrio esquerdo isoladamente e a todos os cortes juntos. Em conclusão, nem alterações na expressão de receptores beta-adrenérgicos nem a presença de células tipo-Cajal parecem ter maior papel na patogênese da fibrilação atrial permanente / Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice, presenting the highest morbidity, especially with advancing age. The autonomic nervous system, particularly the adrenergic/cholinergic balance, has a profound influence on the occurrence of AF. AF can be generated and maintained through a variety of electrophysiological mechanisms, and a change in autonomic activity may affect each of mechanism differently. In addition to the autonomous, sympathetic, and parasympathetic nervous systems involved in the genesis and maintenance of AF, there are several other factors known to be involved, including the interstitial cells of Cajal (ICCs), similar to the interstitial cells that contribute to the peristaltic motor activity of the gastrointestinal tract. These cells were found in the atrial and ventricular myocardium, and could be the source of the triggering activity of ectopic electrical foci that generate AF. In the present study, we aimed to analyze the possible changes in the myocardial expression of beta-adrenergic receptors and to quantify ICCs in the atria of human hearts, in particular in the left atrium, and its relation with permanent AF (PAF). For the first objective, we studied 19 hearts from autopsies of patients with PAF and defined chronic cardiomyopathy (group I), and 19 paired hearts with the same cardiomyopathy but without evidence of any supraventricular arrhythmia (group II). A tissue sample from the ceiling of the right atrium, two from the left atrium, and one from the nerve ending involved in the adipose tissue in the epicardium of the left atrium (fat pad) were resected. The myocardial expression of beta-adrenergic receptors 1 and 3, and of the G protein-coupled receptor kinase 5 (GRK5) was assessed according to the positive proportion in the myocardium in the mentioned sections. There was no statistically significant difference between the two groups in the expression of adrenergic receptors (beta-1, beta-2, beta-3, and GRK5), regardless of the use or nonuse of beta-blockers. For the second objective, six hearts from autopsied patients with PAF and defined chronic cardiopathy (group I) were studied, along with six paired hearts with the same cardiopathies but without evidence of any supraventricular arrhythmia (group II). The ICCs were evaluated in the middle region of the diaphragmatic wall of the left atrium. There were no statistically significant changes between the groups when we evaluated the number of positive cells in the myocardium by area of the myocardium in mm2, the number of positive cells in the full section by area of the myocardium in mm2, or the number of positive cells in the full section/area of the full section in mm2, be it in relation to each section individually, the left atrium alone, or all sections together. In conclusion, neither changes in the expression of beta-adrenergic receptors nor the presence of ICCs seem to have a large role in the pathogenesis of permanent AF

Avaliamos os efeitos da estimulação atrial temporária na prevenção da fibrilação atrial no pós-operatório de revascularização do miocárdio com circulação extracorpórea e identificamos os fatores de risco para o aparecimento dessa arritmia. Estudamos 240 pacientes que ao término da cirurgia de revascularização miocárdica submeteram-se ao implante de eletrodos epicárdicos na parede lateral do átrio direito e no teto do átrio esquerdo e foram randomizados em grupo não estimulado, grupo com estímulo atrial direito e grupo com estímulo simultâneo nos átrios direito e esquerdo. Concluímos que a estimulação atrial temporária reduziu a incidência de fibrilação atrial pós-operatória e que a idade avançada e a não estimulação atrial foram fatores preditivos independentes para a ocorrência da arritmia / We studied the effects of temporary atrial pacing to prevent the atrial fibrillation after coronary artery bypass graft surgery and the risk factors to occurrence of this arrhytmia. We followed-up 240 patients after coronary artery bypass graft surgery who suffered temporary pacing atrial implantation at the end of operation. The patients were randomized into three groups according pacing stimulation into right atrial pacing, biatrial pacing and no stimulated patients. We concluded that the temporary atrial pacing reduced the incidence of postoperative atrial fibrillation. In addition older age was also a predictive factor of occurrence of atrial fibrillation