Coronary Artery Disease/physiopathology

IJCS

Editorial

Obesity: A Risk Marker or an Independent Risk Factor for Coronary Artery Disease?

Tufi Dippe Jr et al. Rodrigo Julio Cerci

We congratulate Pereira et al. for their study investigating the role of obesity as a risk factor for coronary artery disease (CAD) using coronary computed tomography angiography. The study included 1,383 patients, none with a history of CAD.

Obesity is a multifactorial chronic disease, characterized by accumulation of subcutaneous and visceral fat, that predisposes individuals to metabolic disorders. Several mechanisms are involved in the association between obesity and atherosclerosis, including lipid abnormalities, insulin resistance, chronic inflammation, endothelial dysfunction, reduction of fibrinolysis and hypercoagulability. In addition, the production of proinflammatory cytokines, such as IL-6, TNF-alpha, MCP-1 and leptin contributes to chronic subclinical inflammation. More recent data have indicated that impaired autophagy and altered gut microbiome homeostasis are contributing factors for the development of atherosclerosis in obese individuals.

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IJCS

Original Article

QT Interval Dispersion Behavior in Patients With and Without Obstructive Coronary Artery Disease Undergoing Exercise Test

Alexandre Maulaz Barcelos et al. Marcelo Perim Baldo Sérgio Lamego Rodrigues José Geraldo Mill

Abstract

Background:

Stress test is used to detect coronary artery disease (CAD). The QTc interval dispersion (dQTc) is an electrocardiographic index of ventricular repolarization heterogeneity. Some researchers have linked transient myocardial ischemia induced by physical exertion with increased heterogeneity of ventricular repolarization measured by dQTc.

Objectives:

To study the patterns of dQT in patients with and without chronic obstructive CAD and to define a reliable cutoff point for dQT that could become a diagnostic criterion for myocardial ischemia.

Methods:

We retrospectively analyzed the electrocardiogram in resting and in exercise of 63 patients submitted to exercise test and cardiac catheterization. We divided the patients into three groups: true negative (VN), true positive (VP) and false positive (FP). VN: patients with coronary lesion lower than 70% and exercise test without myocardial ischemia; VP: individuals with stenosis greater than 70% in coronary arteries and a test suggestive of myocardial ischemia; FP: people with stenosis lower than 70% in the coronary arteries and stress test with ischemia criteria. Values of p < 0.05 were considered statistically significant.

Results:

Resting dQTc was not different among the three groups. However, for the dispersion of the QTc interval in exercise was, respectively, 47 ± 17 ms, 72 ± 42 ms, and 61 ± 31 ms for VN, VP and FP (p = 0.003).

Conclusions:

Obstructive chronic coronary disease patients have an increase in dQTc during exercise. Measurement of dQTc may be helpful in the diagnosis of myocardial ischemia in the stress test.