Arrhytmias, Cardiac – ABC CARDIOL

ABC

Editorial

The Immense Challenge of Searching for the Best Evidence

To generate the best scientific evidence, it is crucial to follow rigorous research methods, use representative samples, apply appropriate statistical analyses, and ensure peer review in reputable scientific publications. Transparency and replicability are also key. Systematic reviews and meta-analyses aim to summarize a body of available evidence for a given question and provide a high-quality answer.

New situations add variables not previously analyzed, and the COVID-19 pandemic has raised big questions. The urgency to find effective treatments and develop vaccines has encouraged a global mobilization of the scientific community. Contributing factors were: the global health emergency, international mobilization, priority funding sources, greater availability of data networks, and high technology, which stimulated a real race in search of answers. This convergence of factors resulted in an explosion of publications, seeking to better understand the pathophysiology, treatment options, prevention measures, and socioeconomic impacts. As would be expected, in the rush, most of the publications were of poor quality, some of which generated misinformation with serious consequences, as many of these had great repercussions in the media. During the course of the pandemic, numerous guidelines were generated and changed. There were notable discrepancies between different guidelines regarding recommendations on the management of COVID-19 in Brazil.

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ABC

Research Letter

Coherent Map for Atypical Atrial Flutter – A Step Forward for the Understanding of the Arrhythmia Mechanism

Pedro A. Sousa et al. Sérgio Barra Mariana Pereira Luís Elvas

Case Presentation

An 86-year-old woman with a previous history of paroxysmal atrial fibrillation was referred for atypical atrial flutter (AFL) ablation. She had never been submitted to catheter ablation before. The transthoracic echocardiogram revealed a left ventricular ejection fraction of 65%, a mildly dilated left atrium (42mm) and moderate mitral regurgitation. The baseline 12-lead ECG exhibited positive F waves in V1 and the lower limb leads, isoelectric F waves in DI and negative F wave in aVL. () Given the earlier concentric activation in the coronary sinus (CS), with a tachycardia cycle length (TCL) of 330ms, () a right atrial (RA) activation map, performed with the PentaRay^® catheter, was initially analyzed using the HD Coloring tool (CARTO^® 3V7, Biosense Webster, CA, USA). It revealed an earlier activation in the interatrial septum with only 1/3 of the TCL (). A subsequent left atrial (LA) activation map revealed a large area of scar with likely conduction block in almost all of the anterior wall, represented as a white line by the lower threshold Extended Early Meets Late (EEML) feature, and several areas with early local activation time (LAT) points – in the left atrial appendage (LAA), the anterior aspect of the mitral valve (MV) and the roof near the anterior segment of the right superior pulmonary vein (RSPV). It also showed two zones of re-entry as established by the Early Meets Late (EML) feature ( and ). These maps suggested a probable circuit around the right pulmonary veins but did not explain the color activation in the LAA and MV. A new mapping algorithm – Coherent (CARTO^® 3V7, Biosense Webster) – unveiled the circuit ( and ). What is the mechanism of this atypical AFL?

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ABC

Editorial

Subclinical Thyroid Dysfunction was not Associated with Cardiac Arrhythmias in the Cross-Sectional Analysis of the ELSA-Brasil Study

Alexandre de Matos Soeiro

Brazil lacks large cohort studies with analyses of incidence and prevalence of diseases in all areas. In this context, the ELSA-Brasil study was an important milestone for the evaluation of cardiovascular diseases in the country. This study shows a very detailed means of exposing relevant facts to the occurrence or not of arrhythmogenic electrocardiographic manifestations in patients with subclinical thyroid hormone disorders. This issue is extremely relevant, has biological plausibility and generates several doubts regarding the patient.

The study included a relevant sample of 13,341 patients in total, with a mean age of 51 years. The data collection, electrocardiographic specifications and laboratory tests were protocolized according to predetermined and uniform specifications in all patients. Moreover, they were comprehensively evaluated, from arrhythmias supposedly more frequent in thyroid disorders such as atrial fibrillation, plus basal heart rate, presence of extrasystoles and conduction intervals.

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IJCS

Review Article

Cardiac Disorder in Chronic Hepatitis C

André Gustavo da Silva Rezende et al. Edmundo Pessoa Lopes Brivaldo Markman-Filho

Abstract

Chronic hepatitis C (CHC) has a high prevalence in the world. In addition to hepatic complications with cirrhosis in about 20% of patients and high risk for hepatocarcinoma, extrahepatic manifestations may also occur. Cardiac involvement in patients with CHC is associated with several factors, such as increased risk for coronary artery disease, primary cardiomyopathies, or hemodynamic and electrophysiological changes observed in liver cirrhosis. Furthermore, antiviral treatment may, in rare cases, causes cardiovascular adverse effects. Cardiac arrhythmias are the main form of clinical presentation, and, often, markers of poor prognosis in individuals with advanced liver disease. Although some mechanisms that justify these changes have already been reported, many questions remain unanswered, especially about the true involvement of the hepatitis C virus in the genesis of primary cardiac abnormalities, and the risk factors for cardiac-related complications of antiviral treatment.

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The Immense Challenge of Searching for the Best Evidence

Coherent Map for Atypical Atrial Flutter – A Step Forward for the Understanding of the Arrhythmia Mechanism

Case Presentation

Subclinical Thyroid Dysfunction was not Associated with Cardiac Arrhythmias in the Cross-Sectional Analysis of the ELSA-Brasil Study

Cardiac Disorder in Chronic Hepatitis C

Abstract

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