Serum levels of homocysteine and circulating antioxidants associated with heart rate variability in patients with unstable angina pectoris

To the Editor: Autonomic dysfunction is an important factor in the pathogenesis of unstable angina pectoris (UAP). It affects coronary artery systolic function, induces coronary spasm, aggravates myocardial ischemia, reduces ventricular fibrillation threshold, and increases the incidence of sudden cardiac death in UAP.[1] Oxidative stress, which is defined as an excessive production of reactive oxygenated species (ROS) that cannot be...