The Role of the Immune System on the Cardiac Complications Observed in SARS-CoV-2

Abstract An acute respiratory syndrome caused by SARS-CoV2 was declared a pandemic by the World Health Organization. Current data in the world and in Brazil show that approximately 40% of patients who died have some type of cardiac comorbidity. There are also robust reports showing an increase in IL-6 / IL-1B / TNF-alpha and the presence of lymphopenia in patients with COVID-19. Our team and others have shown that increased cytokines are the link between arrhythmias/Left ventricular dysfunction and the immune system in different diseases. In addition, it has been well demonstrated that lymphopenia can not only be a good marker, but also a factor that causes heart failure. Thus, the present review focused on the role of the immune system upon the cardiac alterations observed in the SARS-CoV2 infection. Additionally, it was well described that SARS-CoV-2 is able to infect cardiac cells. Therefore, here it will be reviewed in deep.

Evaluación y validación diagnóstica de las variables iQT, razón iQTRR, razón iRTRR para el diagnóstico DEQTc prolongado / Validation of iQT, iQTRR, iRT/RR ratio for estimation of QTc

ANTECEDENTES: El intervalo QT representa la despolarización y repolarización ventricular y su prolongación está asociada a un mayor riesgo de arritmias graves y muerte súbita. Depende de la frecuencia cardíaca y su rápida valoración es difícil de obtener en la práctica clínica. Una forma que facilita este proceso es medir sólo el intervalo QT pero este no siempre se relaciona con un intervalo QTc prolongado. Debido a esto, se postula que una variable compuesta debería tener mejor rendimiento diagnóstico para este objetivo. OBJETIVO: Describir la correlación de 3 variables electrocardiográficas; intervalo QT (iQT), razón del intervalo QT intervalo RR (%iQTRR) y razón del intervalo RT intervalo RR (%iRTRR), en relación a la variable QT corregido (iQTc). Se efectuó una evaluación diagnóstica y validación de las variables mencionadas para establecer el diagnóstico de intervalo QT largo y las propiedades diagnósticas de las mismas para el diagnóstico de iQTc prolongado según la fórmula Bazett. METODOS Y RESULTADOS: Se efectuó un estudio transversal descriptivo-relacional, usando una muestra no probabilística formada por 220 electrocardiogramas registrados en la base de datos del centro cardiovascular. Las mediciones provenían de ECGs registrados en reposo con medición con cáliper de los intervalos QT y RR en derivadas D2 y/o V5, expresadas en milisegundos. Se excluyó la presencia de isquemia, preexcitación y repolarización precoz. Se obtuvo como resultado que la variable razón iQTRR tiene mejor correlación, concordancia, sensibilidad y valor predictivo negativo para el diagnóstico del iQTc prolongado, versus las variables iQT y razón iRTRR, principalmente en mujeres. CONCLUSIONES: La variable razón iQTRR tiene una mejor correlación, concordancia, sensibilidad y valor predictivo negativo (VPN) para el diagnóstico del iQTc prolongado, comparado con las variables iQT y razón iRTRR, principalmente, en mujeres. Utilizando ambas variables este efecto se potencia y permite concluir que si una mujer tiene un iQT observado <470 ms, y una razón QTRR< 47,5%, esto se corresponde con un intervalo QTc normal, con un VPN de 100% .

BACKGROUND: The QT interval (QT) includes depolarization and repolarization phases of cardiac cycle. Its prolongation is associated to an increa sed risk of serious arrhythmia and sudden death. QT depends on heart rate and it is usually corrected using the Bazett formula (QTc). Prolonged QT is not usually well related to QTc. We postulate that a composite formula muy have a greater value for predicting serious arrhythmia. AIM: To correlate the predictive value of a different approach to estimate a corrected QT interval: the ratio of RT to RR intervals (QT/RR, expressed as a percentage METHODS and RESULTS: A non probabilistic sample of 220 ECGs were obtained from our data base. ECGs were recorded at rest and measurements were performed in leads Ds and/or V5 using zetcalipers, the values being expressed in ms. The presence of ischemia, pre excitation and early repolarization were excluded. The QT/RR ratio showed better correlation, concordance, sensitivity, and negative predicted value with the usual QTc interval compared to QT alone or de RT/RR ratio, especially so in women.

Arritmias cardíacas en habitantes de gran altura con diagnóstico de corazón pulmonar crónico / Cardiac arrhythmias in highlanders with a diagnosis of chronic cor pulmonale

Resumen Antecedentes: El corazón pulmonar crónico (CPC) muestra un incremento en habitantes que viven en grandes altitudes. Objetivo: Investigar la frecuencia de arritmias cardíacas y factores de riesgo para su desarrollo. Métodos: Estudio descriptivo y transversal; se revisó el registro de pacientes internados del Departamento de Cardiología del Instituto Nacional de Tórax, La Paz, Bolivia, entre enero de 2017 y junio de 2018; se incorporó a todos los individuos con diagnóstico de CPC, definido por criterios clínicos, electrocardiográficos y ecocardiográficos; se incluyó a 162 pacientes que cumplieron los criterios en el análisis; se utilizaron la t de Student y ANOVA. Resultados: Arritmias: fibrilación auricular (FA), 125 (75%); aleteo auricular (AA), 17 (10.5%); taquicardia auricular (TA), 17 (10.5%); extrasístoles, 3 (1.9%). Según el análisis univariado, los factores relacionados con el desarrollo de arritmias fueron: eritrocitosis: FA, RR: 1.33, otras arritmias (RR: 1.67), p = 0.0001; hipertensión arterial pulmonar: FA, RR: 3.10, otras arritmias (RR: 3.21), p = 0.0001; dilatación de aurícula derecha (AD): FA, RR: 1.92, otras arritmias (RR: 2.13), p = 0.0001; obesidad: FA, RR: 3.47, p = 0.001, otras arritmias (RR: 3.70), p = 0.001; hipertensión arterial sistémica: FA, RR: 3.10, p = 0.001, otras arritmias (RR: 3.21), p = 0.001. Según el análisis multivariado: eritrocitosis (RR: 2.2), dilatación de AD (RR: 1.2), p = 0.0001. Conclusiones: Se encontró FA con mayor frecuencia en los pacientes con CPC; los factores de riesgo con mayor significancia estadística para su presentación fueron la eritrocitosis y la dilatación de la AD.

Abstract Background: Chronic cor pulmonale (CPC), with increased presentation in high-altitude inhabitants. Objectives: Investigating the frequency of cardiac arrhythmias, and risk factors for its development. Methods: Descriptive, cross-sectional study, the inpatient registry of the Department of Cardiology of the National Institute of Torax, La Paz-Bolivia, from January 2017 to June 2018 was reviewed, all were incorporated with the diagnosis of CPC, defined by clinical criteria, electrocardiographic and echocardiographic, 162 patients who met the criteria were taken, the student's t-test and ANOVA were used for the analysis. Results: Arrhythmias: atrial fibrillation (AF) 125 (75%), atrial flutter (AA) 17 (10.5%), atrial tachycardia (AT) 17 (10.5%), extrasystoles 3 (1.9%). Univariate analysis of factors related to the development of arrhythmias: erythrocytosis: FA, RR: 1.33, other arrhythmias RR: 1.67, p = 0.0001, pulmonary arterial hypertension: FA, RR: 3.10, other arrhythmias RR: 3.21, p = 0.0001, right atrial dilation (AD): FA, RR: 1.92, other arrhythmias RR: 2.13, p = 0.0001, obesity: FA, RR: 3.47, p = 0.001, other arrhythmias RR: 3.70, p = 0.001, systemic arterial hypertension: FA: RR: 3.10, p = 0.001, other arrhythmias RR: 3.21, p = 0.001. Multivariate analysis: erythrocytosis (RR: 2.2), AD dilation (RR: 1.2), p = 0.0001. Conclusions: AF was found more frequently in patients with CPC, the risk factors with the greatest statistical significance for presentation were: erythrocytosis and AD dilation.

Translational Approach for Percutaneous Interventions for the Treatment of Cardiac Arrhythmias

Abstract New translational concepts on cellular and tissue substrate of cardiac arrhythmias have been responsible for the development of non-pharmacological interventions, with important achievements compared to the conventional approach with antiarrhythmic drugs. In addition, the increasing knowledge of anatomical and electrophysiological studies, sophisticated mapping methods, special catheters, and controlled clinical trials have favored the progression of ablation of tachyarrhythmias, particularly of ventricular tachyarrhythmias and atrial fibrillation.

Increased sympathetic cardiac autonomic modulation after two consecutive tilt tests in women with polycystic ovary syndrome / Aumento da modulação autonômica cardíaca simpática após dois testes de inclinação consecutivos em mulheres com síndrome dos ovários policísticos

Abstract Objective The present study aimed to analyze cardiac autonomic modulation via spectral and symbolic analysis of heart rate variability (HRV) in women with polycystic ovary syndrome (PCOS) who were subjected to two consecutive tilt tests. Methods A total of 64 women were selected and divided into 2 groups: control (without PCOS), and PCOS. Concentrations of follicle-stimulating hormone, luteinizing hormone, prolactin, estradiol, homocysteine, sex hormone-binding globulin, thyroid stimulating hormone, fasting insulin, testosterone, androstenedione, and 17-hydroxyprogesterone levels, triglycerides, free androgen index (FAI), and homeostasis assessment model (HOMA-IR) were assessed. Cardiac autonomic modulation was evaluated by spectral and symbolic analyses during two consecutive tilt tests (two moments) and supine moments before, between and after (three moments) the tilt tests. Results Women with PCOS had higher fasting insulin, HOMA-IR indexes, testosterone and FAI. Additionally, we observed that the PCOS group had greater sympathetic autonomic cardiac modulation in supine 2, tilt 1, and supine 3 moments compared with controls. Conclusion Women with PCOS had higher autonomic sympathetic cardiac modulation even after a second tilt test. No adaptation to this provocative test was observed. Spectral analysis was more sensitive for identifying differences between groups than the symbolic analysis.

Resumo Objetivo O presente estudo teve como objetivo analisar a modulação autonômica cardíaca por análise espectral e simbólica da variabilidade da frequência cardíaca (VFC) em mulheres com síndrome dos ovários policísticos (SOP) que foram submetidas a dois testes consecutivos de inclinação. Métodos Um total de 64 mulheres foram selecionadas e divididas em 2 grupos: controle (sem SOP) e SOP. Concentrações de hormônio folículo-estimulante, hormônio luteinizante, prolactina, estradiol, homocisteína, globulina de ligação a hormônios sexuais, hormônio estimulante da tireóide, insulina em jejum, testosterona e androstenediona e níveis de 17-hidroxiprogesterona, triglicerídeos, índice de andrógeno livre (FAI) e homeostase modelo de avaliação (HOMA-IR) foram avaliados. A modulação autonômica cardíaca foi avaliada por análises espectrais e simbólicas durante dois testes de inclinação consecutivos (dois momentos) e momentos supinos antes, entre e após (três momentos) os testes de inclinação. Resultados Mulheres com SOP apresentaram insulina em jejuM, índices HOMA-IR, testosterona e FAI mais altos. Além disso, observamos que o grupo PCOS apresentou maior modulação cardíaca autonômica simpática nos momentos supino 2, inclinado 1 e supino 3 em comparação aos controles. Conclusão Mulheres com SOP apresentaram modulação cardíaca simpática autonômica mais alta mesmo após um segundo teste de inclinação. Nenhuma adaptação a esse teste provocativo foi observada. A análise espectral foi mais sensível para identificar diferenças entre os grupos do que a análise simbólica.

Evaluation of Electrocardiographic Ventricular Depolarization and Repolarization Variables in Type 1 Diabetes Mellitus / Avaliação de Variáveis Eletrocardiográficas de Despolarização e Repolarização Ventricular em Diabetes Mellitus Tipo 1

Abstract Background: The risk of cardiovascular events and sudden death increases with type 1 diabetes mellitus (T1DM). Objective: To evaluate electrocardiographic markers of arrhythmias in T1DM patients. Methods: Electrocardiographic parameters reflecting ventricular depolarization and repolarization, namely, QT, QTc, QTd, QTdc, Tp-e, JT, and JTc intervals and Tp-e/QT and Tp-e/QTc ratios, of 46 patients diagnosed with T1DM were retrospectively analyzed and compared with 46 healthy age-, sex-, and body mass-matched controls. Correlations between T1DM duration, hemoglobin A1c (HbA1c), and ventricular repolarization variables were analyzed. P values lower than 0.05 were considered statistically significant. Results: Diabetes duration was 16.6 ± 7.1 years, and HbA1c was 10.81% ± 3.27% in the T1DM group. In comparison with the control group, heart rate, QTc, QTd, QTdc, Tp-e and JTc intervals, Tp-e/QT ratio (p < 0.001), and Tp-e/QTc ratio (p = 0.007) were significantly higher in T1DM patients. T1DM duration and HbA1c levels were significantly correlated with QTc, QTd, QTdc, Tp-e, and JTc intervals and Tp-e/QT and Tp-e/QTc ratios. Conclusions: In T1DM patients, potential electrocardiographic repolarization predictors were significantly increased in correlation with disease duration and HbA1c levels. These findings may contribute to the understanding of sudden cardiac death in patients with T1DM.

Resumo Fundamento: O risco de eventos cardiovasculares e morte súbita aumenta com diabetes mellitus tipo 1 (DM1). Objetivo: Avaliar alguns marcadores eletrocardiográficos de arritmias em pacientes com DM1. Métodos: Parâmetros eletrocardiográficos que refletem despolarização e repolarização ventricular, a saber, os intervalos QT, QTc, QTd, QTdc, Tp-e, JT e JTc e as relações Tp-e/QT e Tp-e/QTc, de 46 pacientes diagnosticados com DM1 foram retrospectivamente analisados e comparados com 46 controles saudáveis, pareados por idade, sexo e massa corporal. As correlações entre duração de DM1, HbA1c e variáveis de repolarização ventricular foram analisadas. Foram considerados estatisticamente significativos os valores de p inferiores a 0,05. Resultados: A duração de diabetes foi de 16,6 ± 7,1 anos, e HbA1c foi 10,81% ± 3,27% no grupo DM1. Em comparação com o grupo controle, a frequência cardíaca, os intervalos QTc, QTd, QTdc, Tp-e e JTc, a relação Tp-e/QT (p < 0,001) e a relação Tp-e/QTc (p = 0,007) foram significativamente mais altos em pacientes com DM1. A duração de DM1 e os níveis de HbA1c foram significativamente correlacionados com os intervalos QTc, QTd, QTdc, Tp-e e JTc e com as relações Tp-e/QT e Tp-e/QTc. Conclusões: Em pacientes com DM1, potenciais preditores eletrocardiográficos de repolarização foram significativamente aumentados em correlação com a duração da doença e com os níveis de HbA1c. Estes achados podem contribuir à compreensão da morte súbita cardíaca em pacientes com DM1.

QT dispersion changes after transcatheter aortic valve implantation in patients with aortic stenosis

Abstract Objective: The aim of this study was to evaluate the QT dispersion and echocardiographic parameters in patients before and after transcatheter aortic valve implantation (TAVI). Methods: One hundred and fifty-two patients with severe aortic valve stenosis (AS) were included in our study. Ninety five patients who underwent aortic valve replacement with TAVI were included in the TAVI group and 57 patients, who refused TAVI, were included in the medical treatment group. The QT interval and echocardiographic parameters of all patients were assessed before and after the procedure (first and sixth months and first year). The QT intervals were taken from the onset of the QRS to the end of the T wave. Results: All patients had severe AS. The average mean aortic valve gradient was 46.1±12. Left ventricular internal diastolic diameter (LVIDD) and interventricular septum diastolic thickness (IVSDT) did not change significantly after TAVI (P>0.05). QT dispersion, corrected QT dispersion, and mean aortic valve gradient changed significantly six months after TAVI (P<0.05). Compared to the medical treatment group, QT dispersion and corrected QT dispersion were significantly decreased at the sixth month in the TAVI group. The incidence of malignant arrhythmias was smaller in the TAVI group than in the medical treatment group. The mortality rate was lower at the first-year follow-up in the TAVI group than in the medical treatment group. Conclusion: Increased QT dispersion is associated with severe symptomatic AS. After TAVI, QT dispersion reduces.

Cardiac sympathetic denervation for conventional treatment refractory arrhythmias / Denervación simpática cardíaca en arritmias refractarias al tratamiento convencional

Abstract Objective: Cardiac sympathetic denervation (CSD) using video-assisted thoracoscopy is a therapeutic alternative for cardiac arrhythmias refractory to conventional treatment in patients with ventricular structural heart disease, mainly due to ischemia, and in patients with hereditary conditions associated with sudden death such as long QT syndrome. In general, it is performed in cases with recurrent episodes of ventricular tachycardia or electrical storm, in spite of conventional treatment. The objective of this study is to show the experience of this institution with DSCI in refractory patients to conventional management and the results derived from its application. Methods: This was an observational retrospective study. The records of patients with a history of ventricular arrhythmias treated in our center with pharmacological treatment, catheter ablation, or implantation of an implantable cardioverter-defibrillator (ICD), who underwent video-assisted CSD were analyzed and described. Results: A total of six patients were included in the study. Patients with structural heart disease were the most frequent, median age was 56 � 16 years; 67% were male. The procedure evolved without complications in any of the patients and an overall significant improvement was observed. A 24-month follow-up was conducted; two patients had recurrence episodes presenting as slow ventricular tachycardia without severe symptoms and a third patient presented an episode of ventricular fibrillation aborted by the ICD. Conclusion: Video-assisted CSD should be considered as a treatment option for patients with potentially dangerous arrhythmias that do not respond to conventional treatment, especially in recurrent ventricular tachycardia.

Resumen Objetivo: La denervación simpática cardiaca izquierda (DSCI) por toracoscopia se ha convertido en una alternativa terapéutica para el manejo de arritmias cardíacas refractarias al tratamiento convencional en pacientes con cardiopatía estructural, principalmente isquémicos, y enfermedades hereditarias asociadas con muerte súbita como el síndrome de QT largo. Generalmente se realiza en quienes manifiestan episodios recurrentes de arritmias ventriculares o incluso tormenta eléctrica a pesar del tratamiento convencional. El objetivo de este estudio es mostrar la experiencia de esta institución con la DSCI en pacientes refractarios al manejo convencional y los resultados derivados de su aplicación. Métodos: Se revisaron los registros de 6 pacientes con antecedente de arritmias ventriculares tratados previamente con medicamentos y en algunos casos con ablación con catéter y la mayoría con desfibrilador automático implantable, que fueron llevados DSCI por toracoscopia video-asistida (VATS). Resultados: La principal enfermedad de base fue la cardiopatía estructural, la indicación más prevalente fue tormenta arrítmica incontrolable, la edad promedio fue de 56 +- 16 años, el 67% de los individuos fueron hombres. Este procedimiento no mostró complicaciones en ninguno de los pacientes y se encontró mejoría sintomática en todos los casos. Se realizó seguimiento por 24 meses; dos pacientes tuvieron recurrencias por taquicardia ventricular lenta sin síntomas severos y uno por fibrilación ventricular. Conclusion: La DSCI por VATS debe considerarse como opción terapéutica para pacientes con arritmias de difícil manejo.

Análise crítica dos estudos que mudaram a prática clínica recente: arritmias / Critical analysis of studies that changed recent clinical practice: arrhythmias

Os maiores avanços no tratamento das arritmias cardíacas, que geraram propostas de mudança e/ou incorporação de novas tecnologias de tratamento medicamentoso ou intervencionista, referem-se à fibrilação atrial, arritmia sustentada mais frequente na prática clínica, razão pela qual demos maior ênfase a essa análise. Os últimos estudos que têm proporcionado revisões, atualizações e perspectivas das principais diretrizes mundiais são os que envolvem as comparações dos esquemas de combinações de anticoagulação e antiagregação plaquetária em pacientes com fibrilação atrial no contexto da doença arterial coronariana com intervenção planejada ou imediata, bem como os que envolvem a estratégia de ablação por cateteres com opção no início do tratamento da fibrilação atrial nos pacientes com insuficiência cardíaca com fração de ejeção reduzida

The greatest advances in the treatment of cardiac arrhythmias, which have led to proposals of change and/or the incorporation of new drug or intervention treatment technologies, relate to atrial fibrillation, the most common sustained arrhythmia in medical practice, which is why we have placed more emphasis on it in this analysis. The latest studies to have revised, updated, and offered new perspectives on the principal global guidelines are those that involve comparisons of regimens that combine anticoagulation and antiaggregation of platelets in patients with atrial fibrillation within the context of coronary artery disease with planned or immediate intervention, as well of those that involve a catheter ablation strategy as an option at the beginning of treatment for atrial fibrillation in patients with heart failure with reduced ejection fraction

An easy and reliable way to prevent electrocardiographic deteriorations of patients undergoing off-pump coronary artery bypass surgery: preoperative anxiolytic treatment

Abstract Objective: To investigate the effects of preoperative anxiety relieving on electrophysiological changes in patients undergoing off-pump coronary artery bypass surgery. Methods: A total of 61 patients at ASA III risk group in the age range of 18-65 years were enrolled in the present study. Patients were randomly divided into two groups. Group S (Sedation group) was administered 0.04 mg/kg lorazepam per os (PO) twice before the operation. Group C (control group) was not administered with any anxiolytic premedication. State Trait Anxiety Inventory (STAI-I) and Beck Anxiety Inventory (BAI) were used to evaluate the level of anxiety. Electrocardiography (ECG), pulse oximeter and standard monitoring were performed for each patient. QT and P dispersions in each derivation of all ECGs were calculated. Results: Preoperative STAI-I scores were significantly lower in sedation group compared to the controls. Mean values of QT dispersion measured before induction, at the 1st minute of induction, 30th second of intubation and 4th minute of intubation in sedation group were significantly reduced compared to controls (P=0.024; P=0.027; P=0.001; P=0.033, respectively). The mean values of P dispersion measured before induction, at the 3rd minute of induction, 30th second of intubation and 4th minute of intubation in sedation group were significantly reduced compared to controls (P=0.001; P=0.020; P=0.023; P=0.005, respectively). Conclusion: Elevated anxiety levels in patients undergoing coronary bypass surgery have a negative effect through prolonged QT and P-wave dispersion times. Anxiolytic treatment before surgery may be useful to prevent ventricular and atrial arrhythmias and associated complications through decreasing the QT and P-wave dispersion duration.

Subclinical Thyroid Dysfunction was not Associated with Cardiac Arrhythmias in a Cross-Sectional Analysis of the ELSA-Brasil Study / Disfunção Tireoidiana Subclínica não foi Associada com Arritmias Cardíacas em Análise Transversal do Estudo ELSA-Brasil

Abstract Background: The association of subclinical thyroid dysfunction (STD) with cardiac arrhythmias remains controversial, particularly in the non-elderly population. Objective: To investigate whether STD was associated with cardiac arrhythmias in a cohort of middle-aged and older adults. Methods: Baseline data of the Longitudinal Study of Adult Health, ELSA-Brasil (35-74 years) were collected from 2008 to 2010. After exclusion of clinical hypothyroidism and hyperthyroidism, participants were categorized as euthyroidism (TSH = 0.4-4.0 µU/mL), subclinical hypothyroidism (TSH > 4.0 µU/mL; FT4 = 0.8-1.9 ng/dL), and subclinical hyperthyroidism (TSH < 0.4 µU/mL; FT4 = 0.8-1.9 ng/dL). The prevalence rates of tachycardia (HR > 100) and bradycardia (HR < 60), atrial fibrillation/flutter, conduction disorders, extrasystoles, low QRS voltage, prolonged QT intervals, and persistent supraventricular rhythms were compared between groups after adjusting for age, sex, comorbidities, lifestyle, body mass index and medications. Results: The HR data of 13,341 participants (52% female; median age, 51 years) and the electrocardiogram readings of 11,795 were analyzed; 698 participants (5.23%) were classified as subclinical hypothyroidism, 193 (1.45%) as subclinical hyperthyroidism, and 12,450 (93.32%) as euthyroidism. The prevalence of rhythm and conduction disorders was similar, as were HR medians, even in the subgroups with TSH < 0.01 UI/mL or > 10.0 UI/mL or in older adults. Conduction disorders were less prevalent in older adults with subclinical hypothyroidism (adjusted OR = 0.44; 95% CI 0.24 to 0.80). Conclusion: In this large, multicenter and cross-sectional study, STD was not associated with cardiac arrhythmias, but a longitudinal assessment is necessary.

Resumo Fundamento: A associação de disfunção tireoidiana subclínica (DST) com arritmias cardíacas permanece controversa, particularmente na população não idosa. Objetivo: Investigar se a DST está associada a arritmias cardíacas em uma coorte de adultos de meia-idade e idosos. Métodos: Dados da linha de base do Estudo Longitudinal de Saúde do Adulto, ELSA-Brasil (35-74 anos) foram coletados de 2008 a 2010. Após exclusão de hipo e hipertireoidismo clínicos, os participantes foram categorizados como eutireoidismo (TSH = 0,4 a 4,0 µU/mL), hipotireoidismo subclínico (TSH > 4,0 µU/mL; T4L = 0,8-1,9 ng/dL) e hipertireoidismo subclínico (TSH <0,4 µU/mL; T4L = 0,8 a 1,9 ng/dL). As prevalências de taquicardia (Frequência cardíaca [FC] > 100) e bradicardia (FC < 60), fibrilação atrial/flutter, distúrbios de condução, extrassístoles, baixa voltagem do QRS, intervalos QT prolongados e ritmo supraventricular persistente foram comparadas entre os grupos após ajuste por idade, sexo, comorbidades, estilo de vida, índice de massa corporal e uso de medicamentos. Resultados: Foram analisados os dados da FC de 13.341 participantes (52% do sexo feminino; idade média de 51 anos) e das leituras de 11.795 ECG; 698 participantes (5,23%) foram classificados como hipotireoidismo subclínico, 193 (1,45%) como hipertireoidismo subclínico e 12.450 (93,32%) como eutireoidismo. A prevalência de distúrbios de ritmo e condução foi semelhante, assim como as médias de FC, mesmo nos subgrupos com TSH < 0,01 UI/mL ou > 10,0 UI/mL ou em idosos. Distúrbios de condução foram menos prevalentes em idosos com hipotireoidismo subclínico (OR ajustado = 0,44; IC95% 0,24-0,80). Conclusão: Neste grande estudo multicêntrico e transversal, a DST não foi associada a arritmias cardíacas, mas uma avaliação longitudinal é necessária.

TpTe and TpTe/QT: novel markers to predict sudden cardiac death in ESRD? / TpTe e TpTe/QT: novos marcadores para prever morte súbita cardíaca na DRT?

ABSTRACT Introduction: Reliable markers to predict sudden cardiac death (SCD) in patients with end stage renal disease (ESRD) remain elusive, but echocardiogram (ECG) parameters may help stratify patients. Given their roles as markers for myocardial dispersion especially in high risk populations such as those with Brugada syndrome, we hypothesized that the Tpeak to Tend (TpTe) interval and TpTe/QT are independent risk factors for SCD in ESRD. Methods: Retrospective chart review was conducted on a cohort of patients with ESRD starting hemodialysis. Patients were US veterans who utilized the Veterans Affairs medical centers for health care. Average age of all participants was 66 years and the majority were males, consistent with a US veteran population. ECGs that were performed within 18 months of dialysis initiation were manually evaluated for TpTe and TpTe/QT. The primary outcomes were SCD and all-cause mortality, and these were assessed up to 5 years following dialysis initiation. Results: After exclusion criteria, 205 patients were identified, of whom 94 had a prolonged TpTe, and 61 had a prolonged TpTe/QT interval (not mutually exclusive). Overall mortality was 70.2% at 5 years and SCD was 15.2%. No significant difference was observed in the primary outcomes when examining TpTe (SCD: prolonged 16.0% vs. normal 14.4%, p=0.73; all-cause mortality: prolonged 55.3% vs. normal 47.7%, p=0.43). Likewise, no significant difference was found for TpTe/QT (SCD: prolonged 15.4% vs. normal 15.0%, p=0.51; all-cause mortality: prolonged 80.7% vs. normal 66.7%, p=0.39). Conclusions: In ESRD patients on hemodialysis, prolonged TpTe or TpTe/QT was not associated with a significant increase in SCD or all-cause mortality.

RESUMO Introdução: Marcadores confiáveis para predizer morte súbita cardíaca (MSC) em pacientes com doença renal terminal (DRT) permanecem elusivos, mas os parâmetros do ecocardiograma (ECG) podem ajudar a estratificar os pacientes. Devido a seus papéis como marcadores para a dispersão miocárdica, especialmente em populações de alto risco, como aquelas com síndrome de Brugada, nós hipotetizamos que o intervalo pico da onda T ao final da onda T (TpTe) e TpTe/QT são fatores de risco independentes para MSC na DRT. Métodos: Revisão retrospectiva do prontuário foi realizada em uma coorte de pacientes com DRT iniciando a hemodiálise. Os pacientes eram veteranos de guerra americanos que utilizavam os centros médicos do Veterans Affairs para atendimento médico. A idade média de todos os participantes foi de 66 anos e a maioria era do sexo masculino, consistente com uma população veterana dos EUA. ECGs que foram realizados dentro de 18 meses após o início da diálise, e foram avaliados manualmente para TpTe e TpTe/QT. Os desfechos primários foram MSC e mortalidade por todas as causas, e estes foram avaliados até 5 anos após o início da diálise. Resultados: Após o critério de exclusão, foram identificados 205 pacientes, dos quais 94 com TpTe prolongado e 61 com intervalo TpTe/QT prolongado (não mutuamente exclusivo). A mortalidade geral foi de 70,2% em 5 anos e a MSC foi de 15,2%. Nenhuma diferença significativa foi observada nos desfechos primários ao se avaliar o TpTe (MSC: prolongado 16,0% versus normal 14,4%, p = 0,73; mortalidade por todas as causas: prolongado 55,3% vs. normal 47,7%, p = 0,43). Da mesma forma, nenhuma diferença significativa foi encontrada para TpTe/QT (MSC: prolongado 15,4% vs. normal 15,0%, p = 0,51; mortalidade por todas as causas: prolongado 80,7% vs. normal 66,7%, p = 0,39). Conclusões: Em pacientes com insuficiência renal terminal em hemodiálise, TpTe ou TpTe/QT prolongados não foram associados a um aumento significativo da morte súbita ou mortalidade por todas as causas.

Arritmias e alterações cardíacas no paciente cirrótico / Arrhythmias and cardiac alterations in the cirrhotic patient

No Brasil, a cirrose é um problema de saúde pública, que afeta aproximadamente 2 milhões de pessoas. As causas mais comuns são a doença hepática alcoólica, as hepatites virais e a doença hepática não alcoólica. A relação entre desordens cardíacas e hepatopatias é descrita na literatura, e a mais importante delas é o prolongamento do intervalo QT. A cirrose, independente de sua causa, é uma patologia frequentemente encontrada na população brasileira. Por este motivo, elucidar dados referentes às arritmias cardíacas em pacientes cirróticos é de grande importância dentro do estudo desta subpopulação. O objetivo deste artigo é fazer uma revisão de literatura com as informações referentes a epidemiologia, fisiopatologia, fatores de risco e prognóstico para as arritmias cardíacas em portadores de cirrose. (AU)

In Brazil, cirrhosis is a public health problem affecting approximately 2 million people. The most common causes are alcoholic liver disease, viral hepatitis, and non-alcoholic liver disease. The relationship between cardiac disorders and liver diseases is described in the literature, and the most important one is the QT interval prolongation. Cirrhosis, regardless of its causes, is a pathology that is frequently found in the Brazilian population. For this reason, elucidating data regarding cardiac arrhythmias in cirrhotic patients is of great importance within the study of this subpopulation. The aim of this article is to review the literature with information on the epidemiology, pathophysiology, risk factors, and prognosis for cardiac arrhythmias in patients with cirrhosis. (AU)

Simulation of inter atrial block based on a human atrial model / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Inter atrial block (IAB) is a prevailing cardiac conduction abnormality that is under-recognized in clinical practice. IAB has strong association with atrial arrhythmia, left atrial enlargement, and electromechanical discordance, increasing the risk of atrial fibrillation (AF) and myocardial ischemia. IAB was generally believed to be caused by impaired conduction along the Bachmann bundle (BB). However, there are three other conduction pathways, including the fibers posteriorly in the vicinity of the right pulmonary veins (VRPV), transseptal fibers in the fossa ovalis (FO), and muscular bundles on the inferior atrial surface near the coronary sinus (CS). We hypothesized that the importance of BB on IAB might have been overestimated. To test this hypothesis, various combinations of conduction pathway blocks were simulated based on a realistic human atrial model to investigate their effects on the index of clinical diagnosis standard of IAB using a simulated 12-lead electrocardiogram (ECG). Firstly, the results showed that the BB block alone could not generate typical P wave morphology of IAB, and that the combination of BB and VRPV pathway block played important roles in the occurrence of IAB. Secondly, although single FO and CS pathways play subordinate roles in inter atrial conduction, their combination with BB and VRPV block could also produce severe IAB. In summary, this simulation study has demonstrated that the combinations of different inter atrial conduction pathways, rather than BB alone, resulted in ECG morphology of IAB. Attention needs to be paid to this in future pathophysiological and clinical studies of IAB.

Obstructive Sleep Apnea is Common and Associated with Heart Remodeling in Patients with Chagas Disease / Apneia Obstrutiva do Sono é Comum e está Associada à Remodelação Cardíaca em Pacientes com Doença de Chagas

Abstract Background: Chagas Disease (CD) is an important cause of morbimortality due to heart failure and malignant arrhythmias worldwide, especially in Latin America. Objective: To investigate the association of obstructive sleep apnea (OSA) with heart remodeling and cardiac arrhythmias in patients CD. Methods: Consecutive patients with CD, aged between 30 to 65 years old were enrolled. Participants underwent clinical evaluation, sleep study, 24-hour Holter monitoring, echocardiogram and ambulatory blood pressure monitoring. Results: We evaluated 135 patients [age: 56 (45-62) years; 30% men; BMI: 26 ± 4 kg/m2, Chagas cardiomyopathy: 70%]. Moderate to severe OSA (apnea-hypopnea index, AHI, ≥ 15 events/h) was present in 21% of the patients. OSA was not associated with arrhythmias in this population. As compared to patients with mild or no OSA, patients with moderate to severe OSA had higher frequency of hypertension (79% vs. 72% vs. 44%, p < 0.01) higher nocturnal systolic blood pressure: 119 ± 17 vs. 113 ± 13 vs. 110 ± 11 mmHg, p = 0.01; larger left atrial diameter [37 (33-42) vs. 35 (33-39) vs. 33 (30-36) mm, p < 0.01]; and a greater proportion of left ventricular dysfunction [LVEF < 50% (39% vs. 28% vs. 11%), p < 0.01], respectively. Predictor of left atrial dimension was Log10 (AHI) (b = 3.86, 95% CI: 1.91 to 5.81; p < 0.01). Predictors of ventricular dysfunction were AHI > 15 events/h (OR = 3.61, 95% CI: 1.31 - 9.98; p = 0.01), systolic blood pressure (OR = 1.06, 95% CI: 1.02 - 1.10; p < 0.01) and male gender (OR = 3.24, 95% CI: 1.31 - 8.01; p = 0.01). Conclusions: OSA is independently associated with atrial and ventricular remodeling in patients with CD.

Resumo Fundamento: A doença de Chagas (DC) é uma causa importante de morbimortalidade por insuficiência cardíaca e arritmias malignas em todo o mundo, especialmente na América Latina. Objetivo: Investigar a associação entre apneia obstrutiva do sono (AOS) com remodelação cardíaca e arritmias cardíacas em pacientes com DC. Métodos: Foram incluídos pacientes consecutivos com DC, com idade entre 30 e 65 anos. Os participantes foram submetidos à avaliação clínica, estudo do sono, Holter de 24 horas, ecocardiograma e monitorização ambulatorial da pressão arterial. Resultados: Foram avaliados 135 pacientes [idade: 56 (45-62) anos; 30% homens; IMC: 26 ± 4 kg/m2, cardiomiopatia chagásica: 70%]. AOS moderada a grave (índice de apneia-hipopneia, IAH, ≥ 15 eventos/h) estava presente em 21% dos pacientes. AOS não estava associada a arritmias nessa população. Em comparação com pacientes com AOS leve ou ausente, pacientes com AOS moderada a grave apresentaram maior frequência de hipertensão (79% vs. 72% vs. 44%, p < 0,01) e pressão arterial sistólica noturna mais alta: 119 ± 17 vs. 113 ± 13 vs. 110 ± 11 mmHg, p = 0,01; diâmetro do átrio esquerdo maior [37 (33‑42) vs. 35 (33-39) vs. 33 (30-36) mm, p < 0,01]; e maior proporção de disfunção ventricular esquerda [FEVE < 50% (39% vs. 28% vs. 11%), p < 0,01], respectivamente. O preditor de dimensão do átrio esquerdo foi Log10 (IAH) (β = 3,86, IC 95%: 1,91 a 5,81; p < 0,01). Os preditores de disfunção ventricular foram IAH >15 eventos/h (OR = 3,61, IC 95%: 1,31 - 9,98; p = 0,01), pressão arterial sistólica (OR = 1,06, IC95%: 1,02 - 1,10; p < 0,01) e sexo masculino (OR = 3,24, IC 95%: 1,31 - 8,01; p = 0,01). Conclusões: A AOS está independentemente associada à remodelação atrial e ventricular em pacientes com DC.

Cardioprotective effect of preconditioning is more efficient than postconditioning in rats submitted to cardiac ischemia and reperfusion

Abstract Purpose: To investigate the cardioprotective effects of ischemic preconditioning (preIC) and postconditioning (postIC) in animal model of cardiac ischemia/reperfusion. Methods: Adult rats were submitted to protocol of cardiac ischemia/reperfusion (I/R) and randomized into three experimental groups: cardiac I/R (n=33), preCI + cardiac I/R (n=7) and postCI + cardiac I/R (n=8). After this I/R protocol, the incidence of ventricular arrhythmia (VA), atrioventricular block (AVB) and lethality (LET) was evaluated using the electrocardiogram (ECG) analysis. Results: After reestablishment of coronary blood flow, we observed variations of the ECG trace with increased incidence of ventricular arrhythmia (VA) (85%), atrioventricular block (AVB) (79%), and increase of lethality (70%) in cardiac I/R group. The comparison between I/R + preIC group with I/R group demonstrated significant reduction in VA incidence to 28%, AVB to 0% and lethality to 14%. The comparison of I/R + postIC group with I/R group was observed significance reduction in AVB incidence to 25% and lethality to 25%. Conclusion: The preconditioning strategies produce cardioprotection more efficient that postconditioning against myocardial dysfunctions and lethality by cardiac ischemia and reperfusion.

Is There any Relationship Between Myocardial Repolarization Parameters and the Frequency of Ventricular Premature Contractions? / Há Alguma Relação entre os Parâmetros de Repolarização do Miocárdio e a Frequência de Contrações Ventriculares Prematuras?

Abstract Background: Ventricular premature contractions (VPCs) may trigger lethal ventricular arrhythmias in patients with structural heart disease. However, this role of VPCs in healthy people remains controversial once that not enough clinical trials are available. Recently, some myocardial repolarization markers, such as Tp-e interval, Tp-e/QT, and Tp-e/QTc ratios, have been reported to be useful for predicting lethal ventricular arrhythmias in various clinical disorders without structural heart disease. Objective: In this study, we aimed to investigate the relation between VPC frequent and myocardial repolarization markers in individuals without structural heart disease. Methods: This study included 100 patients who had complaints of dizziness and palpitations. Twelve-lead electrocardiography and 24-hour ambulatory Holter recordings were obtained from all patients. VPC burden was calculated as the total number of VPCs divided by the number of all QRS complexes in the total recording time. P-values < 0.05 were considered significant. Results: Tp-e interval and Tp-e/QTc ratio were significantly higher in patients with higher VPC burden than in patients with lower VPC burden, and a positive correlation was found between these markers and VPC burden. Tp-e (β = 1.318, p = 0.043) and Tp-e/QTc (β = -405.136, p = 0.024) in the lead V5 were identified as independent predictors of increased VPC burden. Conclusions: Tp-e interval and Tp-e/QTc ratio increased in patients with high VPC number. Our study showed that VPCs may have a negative effect on myocardial repolarization. This interaction may lead to an increased risk of malignant arrhythmias.

Resumo Fundamento: As contrações ventriculares prematuras (CVPs) podem provocar arritmias ventriculares letais em pacientes com doença cardíaca estrutural, no entanto o papel das CVPs em indivíduos saudáveis permanece controverso, já que não há muitos estudos clínicos disponíveis. Recentemente, alguns marcadores de repolarização do miocárdio, tais como o intervalo Tp-e e as relações Tp-e/QT e Tp-e/QTc, foram relatados como úteis para prognosticar arritmias ventriculares letais em diversos transtornos clínicos sem doença cardíaca estrutural. Objetivo: Neste estudo, o objetivo foi investigar a relação entre os marcadores de repolarização do miocárdio e as CVPs frequentes em indivíduos sem doença cardíaca estrutural. Métodos: Este estudo incluiu 100 pacientes com queixas de tonturas e palpitações. Eletrocardiografia de 12 derivações e registros de Holter ambulatorial de 24 horas foram obtidos de todos os pacientes. A carga de CVP foi calculada como o número total de CVPs dividido pelo número de todos os complexos de QRS no tempo de registro total. Foram considerados significativos valores p < 0,05. Resultados: O intervalo Tp-e e a relação Tp-e/QTc foram significativamente mais altos em pacientes com carga de CVP mais alta do que nos pacientes com carga de CVP inferior, e encontrou-se correlação positiva entre esses marcadores e a carga de CVP. Tp-e (β = 1,318, p = 0,043) e Tp-e/QTc (β = -405,136, p = 0,024) na derivação V5 foram identificados como preditores independentes da carga de CVP aumentada. Conclusões: O intervalo Tp-e e a razão Tp-e/QTc foram mais altos em pacientes com um valor mais alto de CVP. Nosso estudo mostrou que CVPs podem ter um efeito negativo na repolarização do miocárdio. Essa interação pode resultar em risco aumentado de arritmias malignas.