We performed this study to determine whether electrocardiographic corrected QT (QTc) interval predicts alterations in sympathovagal balance during orthostatic intolerance (OI). We reviewed 1,368 patients presenting with symptoms suggestive of OI who underwent electrocardiography and composite autonomic function tests (AFTs). Patients with a positive response to the head-up tilt test were classi...

AIM Breath-holding spells are common in infancy and early childhood, and patients are frequently referred to paediatric cardiology clinics for exclusion of heart disease. Recent data reveal subsequent development of epilepsy and neurocardiogenic syncope. Autonomic dysregulation and increased vagal stimulation leading to cardiac arrest and cerebral ischaemia is considered as the cause. Iron defi...

Background: Passive cigarette smoking is a known cause of a variety of diseases.  However, most of the studies done in this field have focused on its chronic effects on human health.  Studies considering the acute effect of smoking on QT dispersion, on the other hand, with its known predictive role in the occurrence ventricular arrhythmia and sudden cardiac death are sparse. Objectives: This st...

BACKGROUND Chronic renal failure and hemodialysis affect many ECG parameters which can affect cardiac repolarization. OBJECTIVE To investigate the change in ventricular repolarization before and after kidney transplantation in children. METHODS A total of 45 children with end-stage renal disease, 45 children at least 6 months after successful renal transplantation, and 45 normal age-matched...

BACKGROUND Sudden cardiac death (SCD) is common in patients with Emery-Dreifuss muscular dystrophy (EDMD) and is attributed to the development of life-threatening arrhythmias that occur in the presence of normal left ventricular systolic function. Heterogeneity of ventricular repolarization is considered to provide an electrophysiological substrate for malignant arrhythmias. QTc dispersion (QTc...

QT dispersion, a measure of inhomogenous ventricular repolarization, was measured in diabetic patients with foot ulcer. We recruited 75 patients with non insulin-dependent diabetes mellitus: patients with neuropathic ulcer (n=15, NU group), with ischemic ulcer (n=20, IU group), with previous myocardial infarction (n=20, MI group) and without any diabetic microangiopathies (n=20, DC group). We a...

Background—Exercise training is being promoted increasingly for patients with chronic obstructive pulmonary disease (COPD). Many of these patients experience exercise related arterial desaturation but the clinical importance of these hypoxaemic episodes is not known. QTc dispersion is a marker of myocardial repolarisation abnormalities and there has been much interest in its role as a non-invas...

OBJECTIVE Parasympathetic dysfunction is an independent risk factor in individuals with coronary artery disease, and cholinergic stimulation is a potential therapeutical option. We determined the effects of pyridostigmine bromide, a reversible anticholinesterase agent, on electrocardiographic variables of healthy individuals. METHODS We carried out a cross-sectional, double blind, randomized,...

background: cigarette smoking has several known detrimental effect on cardiovascular system.  qt dispersion (qtd) is among the important predictors of cardiac death.   objective:   to assess the acute effect of smoking of a single standard cigarette on qt and qtc (corrected qt) dispersion, hence on the risk of ventricular arrhythmias in healthy smokers and non-smokers.   methods: 111 healthy me...