ABSTRACT
Abstract Background Sudden cardiac death is the main lethal mechanism associated with Chagas cardiomyopathy. Studies suggest that dysautonomia may represent a relevant, intense, independent, and early phenomenon in the natural history of the disease, even when ventricular systolic function is preserved, and may also be the mechanism that triggers malignant ventricular arrhythmias. Objective To evaluate the degree of dysautonomia and its possible association with ventricular arrhythmias in patients with Chagas cardiomyopathy, according to different categories of mortality risk, as defined by the score proposed by Rassi, used as a surrogate outcome for death. Methods A cross-sectional study involving 43 patients with Chagas cardiomyopathy stratified into risk categories based on the Rassi score, with 23 being classified as low risk and 20 as intermediate-to-high risk. Heart rate variability (HRV) was assessed using Holter monitoring for long-term recordings of 24 hours (time domain) and for short-term recordings of 5 minutes (frequency domain) at rest and after autonomic tests: deep breathing and Valsalva maneuver. The HRV variables were compared between the groups using the Student's t-test and α=0.05. Results Comparison of the results between the risk stratification groups showed no differences in HRV indexes, either in the time or frequency domain. However, results showed a significant increase in the number of arrhythmias as a function of increased risk (p=0.02). Conclusion There was no association between the degree of dysautonomia, evaluated by Holter monitoring, and the categories of mortality risk, despite a direct association between the rate of arrhythmias and the higher risk group.
ABSTRACT
Os eventos tromboembólicos são complicações significativas da fibrilação atrial (FA) e podem ser prevenidos com a anticoagulação oral plena. A varfarina reduz em 64% o risco de tromboembolismo, no entanto, a dificuldade no seu manejo clínico motivou a busca por novos anticoagulantes orais (NOACs). Os NOACs inibem especificamente um único fator na cascata da coagulação, têm meia vida curta, efeito previsível e estável, dispensam monitorização e interagem pouco com alimentos e medicamentos.Os estudos RE-LY, ROCKET-AF, ARISTOTLE e ENGAGE AFTIMI48 compararam a varfarina com a dabigratana, rivaroxabana,apixabana e edoxabana, respectivamente, e evidenciaram que os NOACS são equivalentes (dabigatrana 110 mg, rivaroxabana,edoxabana) ou superiores (dabigatrana 150 mg, apixabana) à varfarina na prevenção de tromboembolismo sistêmico ou AVC em pacientes com FA não valvar. Ademais, apresentam índices de hemorragias intracranianas substancialmente menores do quea varfarina. Já a apixabana foi superior à aspirina na prevençãode AVC, com os mesmos índices de sangramento. Os NOACs não devem ser usados em gestantes, crianças, e em pacientes com estenose mitral significativa, próteses valvares ou função renal muito deprimida. Porém, podem ser usados nos cenários de cardioversão e ablação da FA. Ainda não há estudos comparativos entre os diversos NOACs, nem consenso de quando recomendara troca da varfarina em pacientes com RNI estável. Cerca de 50%dos pacientes com FA e indicação de anticoagulação não recebem terapia anticoagulante. Portanto, com advento dos NOACs, a expectativa é reduzir essa parcela, diminuindo a incidência de fenômenos tromboembólicos na FA.
Thromboembolic events are important complications of atrialfibrillation (AF) and can be prevented by oral anticoagulation.Warfarin reduces by 64% the risk of thromboembolism,however, the difficulties in its clinical management promptedthe search for novel oral anticoagulants (NOACs). The NOACsspecifically inhibit a single factor in the coagulation cascade,have a short half-life, predictable and stable effect, do not requiremonitoring and have minor interactions with food and drugs.The RE-LY, ROCKET-AF, ARISTOTLE and ENGAGE AFTIMI48 trials compared warfarin to dabigatran, rivaroxaban,apixaban and edoxaban, respectively, and showed that NOACSare equivalent (110 mg dabigatran, rivaroxaban, edoxaban) orsuperior (dabigatran 150 mg, apixaban) to warfarin in preventingstroke or systemic embolism in patients with nonvalvular AF.Furthermore, they are associated with substantially lower levelsof intracranial bleeding than warfarin. Apixaban was superiorto aspirin in preventing strokes, with the same rate of bleeding.The NOACs should not be used in pregnant women, children,and patients with significant mitral stenosis, prosthetic valvesor impaired renal function. However, these novel drugs can beused in the scenarios of cardioversion and AF ablation. Thereare no studies comparing individual NOACs or consensus aboutswitching patients on warfarin with stable INR. Approximately50% of patients with AF and recommendation for anticoagulationdo not receive anticoagulant therapy. Therefore, with the adventof NOACs, the expectation is to improve this figure, ultimatelydecreasing the incidence of thromboembolic events in AF.
Subject(s)
Humans , Aged , Anticoagulants/chemistry , Arrhythmias, Cardiac/epidemiology , Warfarin/adverse effects , Cost-Benefit Analysis/methods , Ventricular Dysfunction/complications , Cardiac Electrophysiology/methods , Clinical Trials as Topic , Heart Failure/complicationsABSTRACT
Os estudos randomizados PIAF, STAF, RACE e AFFIRM demonstraram que o controle do ritmo, em relação ao controle da frequência cardíaca, não reduz a mortalidade e o risco de acidentes vasculares cerebrais em pacientes com fibrilação atrial e idade superior a 65 anos. Além disso, o estudo AF-CHF ampliou essa estratégia para os pacientes com insuficiência cardíaca. Como consequência, ambas as estratégias podem ser consideradas como abordagem primária no tratamento de pacientes com fibrilação atrial. No entanto, a subanálise de seguimento do AFFIRM demonstrou que o ritmo sinusal é benéfico, sugerindo que o problema é relacionado aos efeitos colaterais das drogas antiarrítmicas disponíveis. Portanto, o desenvolvimento de novas drogas (dronedarona) e de técnicas não-farmacológicas (ablação por cateter e por cirurgia minimamente invasiva) ganhou importância. Estudos comparativos entre as drogas antiarrítmicas e a ablação demonstraram superioridade da ablação para a manutenção do ritmo sinusal. O estudo PABA-CHF conbinou qualidade de vida, fração de ejeção e capacidade de exercício...
PIAF, STAF, RACE and AFFIRM randomized trials have shown that rhythm control, compared to heart rate control does not reduce the mortality and risk of stroke in patients with atrial fibrillation over 65 years of age. Furthermore, the AF-CHF study has expanded this strategy for patients with heart failure. As a result, both strategies may be considered as a primary approach in the treatment of patients with atrial fibrillation. However, the AFFIRM follow-up subanalysis showed that sinus rhythm is beneficial, suggesting the problem is related to the side effects of the available antiarrhythmic drugs. Therefore, the development of new drugs (dronedarone) and non-pharmacological techniques (catheter ablation, minimally invasive surgery) has gained importance. Comparative studies of antiarrhythmic drugs and ablation demonstrated a superiority of ablation in maintaining sinus rhythm. The PABA-CHF study combined quality of life with improved ejection fraction and exercise capacity as a primary outcome and concluded that ablation was superior to heart rate control (atrioventricular node ablation + biventricular pacemaker) suggesting ablation may be an option in selected patients with atrial fibrillation and heart failure. This article reviews recently published clinical trials on these topics and discusses their clinical implications.
Subject(s)
Humans , Arrhythmias, Cardiac/therapy , Atrial Fibrillation/genetics , Heart Rate/physiology , Catheter Ablation/methods , Catheter Ablation , Clinical Trials as Topic , Risk FactorsSubject(s)
Humans , Arrhythmias, Cardiac/diagnosis , Cardiovascular Diseases/history , Cardiovascular Diseases/prevention & control , Cardiovascular Diseases/therapy , Hypertension/complications , Hypertension/pathology , Hypertension/therapy , Tachycardia, Ventricular/diagnosis , Tachycardia, Ventricular/therapy , Endocarditis/surgery , Endocarditis/pathology , Endocarditis/rehabilitationABSTRACT
Atualmente, são muitas as possibilidades de tratamento para a população de pacientes acometidos por taquiarritmias supraventriculares e ventriculares, incluindo a ablação por cateter, as drogas antiarrítmicas e os dispositivos implantáveis. Além disso, o avanço no campo das terapias moleculares tem revelado a importância dos fatores genéticos no desenvolvimento e tratamento das arritmias. A utilização clínica desse amplo arsenal diagnóstico e terapêutico pode ser muito facilitada pelo entendimento dos mecanismos fundamentais as arritmias cardíacas. Este artigo descreve sucintamente os mecanismos básicos das arritmias cardíacas com ênfase em seus aspectos relevantes à prática clínica.