Chagas Cardiomyopathy and Myocardial Sympathetic Denervation.

PURPOSE OF REVIEW: More than a century since its discovery, the pathogenesis of Chagas heart disease (CHD) remains incompletely understood. The role of derangements in the autonomic control of the heart in triggering malignant arrhythmia before the appearance of contractile ventricular impairment was reviewed. RECENT FINDINGS: Although previous investigations had demonstrated the anatomical and functional consequences of parasympathetic dysautonomia upon the heart rate control, only recently, coronary microvascular disturbances and sympathetic denervation at the ventricular level have been reported in patients and experimental models of CHD, exploring with nuclear medicine methods their impact on the progression of myocardial dysfunction and cardiac arrhythmias. More important than parasympathetic impaired sinus node regulation, recent evidence indicates that myocardial sympathetic denervation associated with coronary microvascular derangements is causally related to myocardial injury and arrhythmia in CHD. Additionally, 123I-MIBG imaging is a promising tool for risk stratification of progression of ventricular dysfunction and sudden death.

The Folding Pathway of ABC Transporter CFTR: Effective and Robust.

De novo protein folding into a native three-dimensional structure is indispensable for biological function, is instructed by its amino acid sequence, and occurs along a vectorial trajectory. The human proteome contains thousands of membrane-spanning proteins, whose biosynthesis begins on endoplasmic reticulum-associated ribosomes. Nearly half of all membrane proteins traverse the membrane more than once, including therapeutically important protein families such as solute carriers, G-protein-coupled receptors, and ABC transporters. These mediate a variety of functions like signal transduction and solute transport and are often of vital importance for cell function and tissue homeostasis. Missense mutations in multispan membrane proteins can lead to misfolding and cause disease; an example is the ABC transporter Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). Even though our understanding of multispan membrane-protein folding still is rather rudimental, the cumulative knowledge of 20 years of basic research on CFTR folding has led to development of drugs that modulate the misfolded protein. This has provided the prospect of a life without CF to the vast majority of patients. In this review we describe our understanding of the folding pathway of CFTR in cells, which is modular and tolerates many defects, making it effective and robust. We address how modulator drugs affect folding and function of CFTR, and distinguish protein stability from its folding process. Since the domain architecture of (mammalian) ABC transporters are highly conserved, we anticipate that the insights we discuss here for folding of CFTR may lay the groundwork for understanding the general rules of ABC-transporter folding.

Incidental parasympathetic cardiac denervation during atrial fibrillation ablation using high power short duration: a marker of long-term success.

BACKGROUND: There are multiple factors in both technique and substrate that lead to recurrence of atrial fibrillation after ablation. We sought to examine whether the degree of heart rate increase (HRI) caused by concurrent high-power-short-duration (HPSD) incidental parasympathetic denervation during AF ablation predicts long term success. Between December 2018 and December 2021, prospectively enrolled 214 patients who presented in sinus rhythm at AF ablation. Used 50 W of power and contact force (CF) of 5-15 g and 10-20 g at a flow rate of 40 mL/min on the anterior and posterior left atrial walls, respectively. RESULTS: Males were 143 (66.8%) and paroxysmal was 124 (57.9%) patients. Mean age 61.1 ± 12.3 years and follow-up time was 32.8 ± 13.2 months. Arrhythmia occurred after 90 days in 39 (18.2%) patients, 19 (48.7%) from the paroxysmal and 20 (51.3%) from the persistent AF patients. Recurrence group showed a lower HRI from a mean of 57 ± 7.7 to 64.4 ± 10.4 bpm (12.3%) while in success group HRI was from 53.8 ± 9.7 to 66.8 ± 11.6 bpm [(24.2%) p = 0.04]. We divided HRI in 3 percentiles of ≤ 8%, > 8 ≤ 37% and > 37%. A predictor of recurrence was identified in those in the first (< 8%, p = 0.006) and a predictor of success in the later (> 37%, p = 0.01) HRI percentile. CONCLUSION: Atrial fibrillation ablation with HPSD incidental cardiac parasympathetic denervation identified that patients with lower heart rate increase are prone to recurrence while those with higher heart rate increase had higher maintenance of sinus rhythm at a long-term follow-up.

Anesthetic management for lower extremity vascular bypass procedures: The impact of general or regional anesthesia on clinical outcomes.

PURPOSE: Postoperative complications after major surgery, especially vascular procedures, are associated with a significant increase in costs and mortality. Previous studies evaluating general anesthesia versus regional or neuraxial anesthesia for infrainguinal bypass have produced conflicting results. The main aim of the present study is to review current evidence on the application of regional or general anesthesia in patients undergoing infrainguinal bypass surgery and its potential favorable effects on postoperative outcomes. CONTENTS: Patients undergoing vascular surgery often have multiple comorbidities, and it is important to outline both benefits and risks of regional anesthesia techniques. Neuraxial anesthesia in vascular surgery allows overall avoidance of general anesthesia and does provide short-term benefits beyond analgesia. Previous observational studies suggest that neuraxial anesthesia for lower limb revascularization may reduce morbidity and length of stay. However, evidence of long-term benefits is lacking in most procedures and further work is still warranted. CONCLUSIONS: Neuraxial anesthesia is usually an effective anesthesia technique for infrainguinal bypass surgery. Elderly patients and those with underlying respiratory problems may display some benefit from neuraxial anesthesia. Further evaluation within institutions should be performed to identify which patients would most benefit from regional techniques. Notably, systemic antithrombotic and anticoagulation therapy is common among this population and may affect anesthetic choices.

Autologous stem cell transplantation improves cardiopulmonary exercise testing outcomes in systemic sclerosis patients.

OBJECTIVES: Autologous haematopoietic stem cell transplantation (AHSCT) is a disease-modifying treatment for patients with severe SSc. Here, we aimed at assessing cardiopulmonary function outcomes of SSc patients after AHSCT. METHODS: Twenty-seven SSc adult patients treated with AHSCT were included in this retrospective study. Most had the diffuse cutaneous subset (93%) and pulmonary involvement (85%). Before and 12 months after AHSCT, patients underwent cardiopulmonary exercise testing, transthoracic echocardiography, pulmonary function test with diffusing capacity for carbon monoxide (DLCO), 6-min walk test (6MWT) and quality of life evaluations. RESULTS: After AHSCT, the peak VO2 increased from 954 to 1029 ml/min (P = 0.02), the percentage of predicted peak VO2 increased from 48.9 to 53.5 m (P = 0.01), and the distance measured by the 6MWT increased from 445 to 502 m (P = 0.01), compared with baseline. Improvements in peak VO2 correlated positively with improvements in 6MWT distance, and negatively with a decrease in resting heart rate. At baseline, patients with DLCO >70% had higher peak VO2 values than those with DLCO <70% (P = 0.04), but after AHSCT all patients showed improved VO2 values, regardless of baseline DLCO levels. Increases in VO2 levels after AHSCT positively correlated with increases in the physical component scores of the Short Form-36 quality of life questionnaire (r = 0.70; P = 0.0003). CONCLUSION: AHSCT improves the aerobic capacity of SSc patients probably reflecting combined increments in lungs, skeletal muscle and cardiac function.

The Impact of the COVID-19 Pandemic on ST Elevation Myocardial Infarction Care Indicators at a Public Hospital in Brazil

Abstract Background International publications have shown that the COVID-19 pandemic has negatively impacted the indicators of care for ST-segment elevation acute myocardial infarction (STEMI), with a potential increase in morbidity and mortality. Objectives To compare mortality, time from symptom onset to primary angioplasty (total delay [TD]), time from symptom onset to initial medical contact (patient delay [PD]), and time from initial medical contact to guidewire insertion in the hemodynamics laboratory (system delay [SD]) among patients admitted for STEMI at the Hemodynamics Service of Santa Casa de Passos, Minas Gerais, Brazil before and after the declaration of the COVID-19 pandemic by the World Health Organization, assessing the impact of the COVID-19 pandemic on STEMI care indicators. Methods This is a before-and-after study involving patients hospitalized with STEMI undergoing primary angioplasty. Data were collected retrospectively through medical record review. Clinical and demographic profiles and outcomes between the pre-pandemic and pandemic groups were compared using the chi-square test for categorical variables or Student's t-test for continuous variables. A significance level of p < 0.05 was adopted. Results There were no differences in TD (pre-pandemic: 300 min [± 159 min], 95% CI 277.1 to 322.6; pandemic: 300 min [± 148 min], 95% CI 274.3 to 326.6, p = 0.97). However, there was an increase in SD (pre-pandemic: 145 min [± 97 min], 95% CI 122.7 to 167.9; pandemic: 178 min [± 96 min], 95% CI 157.4 to 197.9, p = 0.037). There was no increase in PD (pre-pandemic: 145 min ± 133 min; pandemic: 130 min ± 117 min, p = 0.44), and no differences in mortality were observed (pre-pandemic: 9.7%; pandemic: 12%, p = 0.49). Conclusion The COVID-19 pandemic increased SD in the management of STEMI in the region of Passos, Minas Gerais. There were no differences in PD, TD, and in-hospital mortality.

Ressonância Magnética Cardíaca como Ferramenta Diagnóstica Etiológica em Pacientes Recuperados de Morte Súbita Cardíaca ou Arritmias Ventriculares Instáveis / Cardiac Magnetic Resonance as an Etiological Diagnosis Tool in Recovered Sudden Cardiac Death or Unstable Ventricular Arrhythmia Patients

Resumo Fundamento A ressonância magnética cardíaca (RMC) tem relevância diagnóstica crescente em sobreviventes de morte súbita cardíaca (MSC) ou arritmia ventricular instável (AVI) em países desenvolvidos. Objetivo Procuramos avaliar retrospectivamente o papel adicional da RMC em um país em desenvolvimento com poucos recursos disponíveis e que pode direcionar um uso mais eficaz desses recursos. Métodos Foram incluídos sobreviventes de MSC ou AVI admitidos entre 2009 e 2019 em uma instituição acadêmica terciária após a realização de RMC. Dados demográficos, clínicos e laboratoriais foram coletados dos prontuários. Imagens e laudos de RMC foram analisados e o impacto disso no diagnóstico etiológico final foi afirmado. Realizou-se análise descritiva e definiu-se p<0,05 como significativo. Resultados Sessenta e quatro pacientes, 54,9±15,4 anos, sendo 42 (71,9%) do sexo masculino. A maioria dos eventos (81,3%) foi extra-hospitalar e a taquicardia ventricular foi o ritmo mais comum. Medicamentos cardiovasculares foram utilizados anteriormente por 55 pacientes, sendo os betabloqueadores os medicamentos mais utilizados (37,5%). O eletrocardiograma apresentava áreas elétricas inativas em 21,9% e todos apresentavam fibrose na RMC. A média da fração de ejeção do ventrículo esquerdo (FEVE) foi de 44±14%, com 60,9% ≤50% e apenas 29,7% ≤35%. Identificou-se realce tardio com gadolínio em 71,9%, com padrão transmural em 43,8%. A miocardiopatia chagásica foi a etiologia mais comum (28,1%), seguida da miocardiopatia isquêmica (17,2%). Entre 26 sem etiologia previamente identificada, foi possível definir com RMC (15 pacientes - 57%). Conclusão De acordo com estudos anteriores em países desenvolvidos, a RMC foi capaz de aumentar o diagnóstico etiológico e identificar o substrato arritmogênico, permitindo melhor atendimento em metade dos pacientes subdiagnosticados.

Abstract Background Cardiac magnetic resonance (CMR) has an increasing diagnostic relevance in survivors of sudden cardiac death (SCD) or unstable ventricular arrhythmia (UVA) in developed countries. Objective To evaluate retrospectively the additional role of CMR in a developing country where few resources are available, and should be used more effectively. Methods The study included SCD or UVA survivors admitted between 2009 and 2019 at a tertiary academic institution referred to CMR. Demographic, clinical, and laboratory data were collected from the medical records. CMR images and reports were reviewed and their impact on the final etiological diagnosis was determined. A descriptive analysis was performed and p<0.05 established as significant. Results Sixty-four patients, 54.9±15.4 years old, and 42 (71.9%) males. Most events (81.3%) were out of the hospital and ventricular tachycardia was the most common rhythm. Cardiovascular medications were previously used by 55 patients, and beta-blockers were the most used medications (37.5%). Electrocardiogram had electrical inactive areas in 21.9% and all of them had fibrosis at CMR. Mean left ventricular ejection fraction (LVEF) was 44±14%, with 60.9% ≤50% and only 29.7% ≤35%. Late gadolinium enhancement was identified in 71.9%, with a transmural pattern in 43.8%. Chagas cardiomyopathy was the most common etiology (28.1%), followed by ischemic cardiomyopathy (17.2%). Among 26 without a previously identified etiology, CMR could define it (15 patients - 57%). Conclusion In accordance with previous studies in developed countries, CMR was capable of increasing etiological diagnosis and identifying the arrhythmogenic substrate, allowing better care in half of the underdiagnosed patients.

Perfil clínico e hemodinâmico de pacientes consecutivos com estenose aórtica valvar estudados na era pré-implante transcateter valvar aórtico em instituição acadêmica. Análise comparativa da avaliação invasiva com a ecocardiográfica / Clinical and hemodynamic profile of consecutive patients with aortic valve stenosis studied in the pre-transcatheter aortic valve implantation era at an academic institution. Comparative analysis of invasive evaluation with echocardiography

Introdução: Face à melhor compreensão da fisiopatologia da estenose valvar aórtica, cresceu paralelamente a complexidade da avaliação de sua gravidade, persistindo relevante incerteza quanto à aplicabilidade dos métodos invasivos pelo cateterismo cardíaco e os não invasivos, com base em ecocardiografia. O objetivo deste estudo foi analisar os padrões hemodinâmicos da avaliação com ecocardiografia comparativamente à estimativa da gravidade da estenose aórtica com o cateterismo em pacientes consecutivos referidos para avaliação diagnóstica por laboratório de hospital acadêmico terciário no triênio 2016-2018. Métodos: Estudo observacional, descritivo e retrospectivo das características clínicas e dos resultados das avaliações da gravidade da estenose valvar aórtica obtidas em 96 pacientes consecutivos, por meio de cateterismo e ecocardiografia. Resultados: Amostra populacional de 49 homens e 47 mulheres, com mediana de idade de 66,5 (56,5 a 72,8) anos, estenose valvar aórtica degenerativa em 49% e reumática em 40%, além de diversas comorbidades, inclusive doença coronária (37%). Pelo cateterismo, com base no gradiente pico de 48 (20 a 68), a estenose valvar aórtica foi avaliada como grave em 56%, sendo a pressão telediastólica ventricular de 20mmHg (16 a 30mmHg). Pela ecocardiografia, a área valvar foi 0,9cm2 (0,7 a 1,2cm2), sendo indexado 0,5cm2/m2 (0,43 a 0,5cm2/m2), com gradiente pico de 62±26 mmHg. A estenose valvar aórtica foi considerada severa em 69,2%. Houve discordância entre os métodos sobre a severidade da estenose valvar aórtica em 30% dos exames, com coeficiente de Spearman entre área valvar pelo ecocardiograma e gradiente pico pelo cateterismo de -0,7 (p<0,001). Conclusão: Em amostra representativa dos vários padrões hemodinâmicos, a avaliação da gravidade da estenose valvar aórtica, como praticada rotineiramente em laboratório acadêmico, limitou-se à medida de pico de gradiente transvalvar. A estimativa da área valvar pelo método ecocardiográfico, sendo indireta e também passível de crítica, contribui para as discrepâncias encontradas, tornando-se justificável buscar o aperfeiçoamento de ambos os métodos, em vista da complexidade clínica e hemodinâmica detectada.

Background: In view of the better understanding of the pathophysiology of aortic valve stenosis, the complexity of assessing its severity has simultaneously grown, with relevant uncertainty persisting as to the applicability of invasive methods by cardiac catheterization and non-invasive methods based on echocardiography. The objective of this study was to analyze the hemodynamic patterns of evaluation with echocardiography compared to the estimation of severity of aortic stenosis with catheterization in consecutive patients referred for diagnostic evaluation by the laboratory of a tertiary academic hospital in the 2016 to 2018 triennium. Methods: An observational, descriptive and retrospective study of clinical characteristics and results of assessments of severity of aortic valve stenosis obtained in 96 consecutive patients, through catheterization and echocardiography. Results: A population sample of 49 men and 47 women, with a median age of 66.5 (56.5 to 72.8) years, degenerative aortic valve stenosis in 49%, and rheumatic aortic stenosis in 40%, in addition to several comorbidities, including coronary disease (37%). Using catheterization, based on the peak gradient of 48 (20 to 68), aortic valve stenosis was assessed as severe in 56%, with ventricular end-diastolic pressure of 20mmHg (16 to 30mmHg). Using echocardiography, the valve area was 0.9cm2 (0.7 to 1.2cm2), indexed valve area was 0.5cm2/m2 (0.43 to 0.5cm2/m2), with peak gradient of 62±26mmHg. Aortic valve stenosis was considered severe in 69.2%. There was disagreement between the methods regarding severity of aortic valve stenosis in 30% of exams, with a Spearman coefficient between the valve area on the echocardiogram and the peak gradient on catheterization of -0.7 (p<0.001). Conclusion: In a representative sample of various hemodynamic patterns, the assessment of severity of aortic valve stenosis, as routinely practiced in an academic laboratory, was limited to measuring the peak transvalvular gradient. The estimation of the valve area using the echocardiographic method was indirect and also subject to criticism, and contributed to the discrepancies found, rendering it justifiable to seek the improvement of both methods, in view of the clinical and hemodynamic complexity detected.

Teste de Limiar de Desfibrilação e Seguimento a Longo Prazo de Pacientes com Cardiopatia Crônica da Doença de Chagas / Defibrillation Threshold Testing and Long-term Follow-up in Chagas Disease

Resumo Fundamento A morte súbita cardíaca (MSC) é a causa mais comum de óbito na cardiomiopatia crônica da doença de Chagas (CCDC). Visto que muitos pacientes com CCDC que são candidatos a receber um cardioversor desfibrilador implantável (CDI) atendem a critérios que sugerem alto risco de apresentarem limiares de desfibrilação elevados, sugere-se realizar um teste de limite de desfibrilação (LDF). Objetivos Investigamos o uso do teste de LDF em pacientes com CCDC, com enfoque nos óbitos relacionados ao implante do CDI e na ocorrência de eventos arrítmicos e o tratamento oferecido durante o seguimento de longo prazo. Métodos Avaliações retrospectivas de 133 pacientes com CCDC que receberam CDI, principalmente para prevenção secundária. Foram coletados dados demográficos, clínicos e laboratoriais, escore de Rassi e dados do teste de LDF. Adotou-se p<0,05 como estatisticamente significativo. Resultados A média de idade foi 61±13 anos, e 72% da amostra era do sexo masculino. A fração de ejeção basal do ventrículo esquerdo foi 40±15%, e o escore de Rassi médio foi 10±4 pontos. Não ocorreram óbitos durante o teste de LDF, e não foram documentadas falhas do CDI. Foi identificada relação entre escore de Rassi basal mais elevado e LDFs mais elevados (ANOVA =0,007). O tempo médio até o primeiro choque foi de 474±628 dias, mas a aplicação de choque foi necessária em apenas 28 (35%) pacientes com TV, visto que a maioria dos casos se resolveu espontaneamente ou através da programação de ATP. Após seguimento clínico de 1728±1189 dias, em média, ocorreram 43 óbitos, relacionados principalmente a insuficiência cardíaca progressiva e sepse. Conclusões Um teste de LDF de rotina pode não ser necessário para pacientes com CCDCs que receberam CDI para prevenção secundária. LDFs elevados parecem ser incomuns e podem estar relacionados a escore de Rassi elevado.

Abstract Background Sudden cardiac death is the most common cause of death in chronic Chagas cardiomyopathy (CCC). Because most CCC patients who are candidates for implantable cardioverter-defibrillators (ICD) meet criteria for high defibrillation threshold values, a defibrillator threshold test (DTT) is suggested. Objectives We investigated the use of DTT in CCC patients, focusing on deaths related to ICD and arrhythmic events, as well as treatment during long-term follow-up. Methods We retrospectively evaluated 133 CCC patients who received an ICD mainly for secondary prevention. Demographic, clinical, laboratory data, Rassi score, and DTT data were collected, with p < 0.05 considered significant. Results The mean patient age was 61 (SD, 13) years and 72% were men. The baseline left ventricular ejection fraction was 40 (SD, 15%) and the mean Rassi score was 10 (SD, 4). No deaths occurred during DTT and no ICD failures were documented. There was a relationship between higher baseline Rassi scores and higher DTT scores (ANOVA = 0.007). The mean time to first shock was 474 (SD, 628) days, although shock was only necessary for 28 (35%) patients with ventricular tachycardia, since most cases resolved spontaneously or through antitachycardia pacing. After a mean clinical follow-up of 1728 (SD, 1189) days, 43 deaths occurred, mainly related to progressive heart failure and sepsis. Conclusions A routine DTT may not be necessary for CCC patients who receive an ICD for secondary prevention. High DTT values seem to be unusual and may be related to high Rassi scores.

Blood DNA methylation marks discriminate Chagas cardiomyopathy disease clinical forms.

Chagas disease is a parasitic disease from South America, affecting around 7 million people worldwide. Decades after the infection, 30% of people develop chronic forms, including Chronic Chagas Cardiomyopathy (CCC), for which no treatment exists. Two stages characterized this form: the moderate form, characterized by a heart ejection fraction (EF) ≥ 0.4, and the severe form, associated to an EF < 0.4. We propose two sets of DNA methylation biomarkers which can predict in blood CCC occurrence, and CCC stage. This analysis, based on machine learning algorithms, makes predictions with more than 95% accuracy in a test cohort. Beyond their predictive capacity, these CpGs are located near genes involved in the immune response, the nervous system, ion transport or ATP synthesis, pathways known to be deregulated in CCCs. Among these genes, some are also differentially expressed in heart tissues. Interestingly, the CpGs of interest are tagged to genes mainly involved in nervous and ionic processes. Given the close link between methylation and gene expression, these lists of CpGs promise to be not only good biomarkers, but also good indicators of key elements in the development of this pathology.