OBJECTIVE To determine the normal values of QT and QTc dispersion and the effects of sinus arrhythmia on QT dispersion in healthy children. PATIENTS AND SETTING The study was carried out in a university hospital on 372 local schoolchildren (200 male, 172 female), aged seven to 18 years. METHODS The QT and preceding RR intervals of at least one sinus beat were measured manually in a range of...

BACKGROUND Although sudden cardiac death (SCD) is heritable, its genetic underpinnings are poorly characterized. The QT interval appears to have a graded relationship to SCD, and 35% to 45% of its variation is heritable. We examined the relationship among recently reported common genetic variants, QT interval, and SCD. METHODS AND RESULTS We genotyped 15 common (minor allele frequency >1%) ca...

BACKGROUND Electrophysiological information as well as anatomic information are important for the detection of coronary artery lesions. The aim of this study was to assess the efficacy of resting magnetocardiography (MCG) in stable coronary artery disease (CAD) and cardiac allograft vasculopathy (CAV). METHODS AND RESULTS MCG and coronary angiography were performed within 1 month in 75 patien...

In the present study, quercetin (QT), morin (MR), and quercetin-3-O-glucopyranoside (QG) isolated from guava leaves were comparatively tested for antioxidant activity using DPPH, ABTS, and FRAP methods. QT was the most active among them. The free radical scavenging activity of QT was approximately four times higher than MR and two times higher than QG. The reducing power of QT was eight times h...

Background Breath-holding spells (BHS) are brief periods when young children stop breathing for up to 1 minute and are widely recognized types of non-epileptic severe occasions in early stages of childhood. This study aimed to evaluate QTd and QTc changes in children with breath-holding spells compared with healthy children. <stron...

The evaluation of every electrocardiogram should also include an effort to interpret the QT interval to assess the risk of malignant arrhythmias and sudden death associated with an aberrant QT interval. The QT interval is measured from the beginning of the QRS complex to the end of the T-wave, and should be corrected for heart rate to enable comparison with reference values. However, the correc...

OBJECTIVES We sought to determine whether the relationship between heart rate (HR) and QT interval (QT) differs as HR increases in response to exercise, atropine and isoproterenol. BACKGROUND Autonomic nervous system influences on repolarization are poorly understood and may complicate the interpretation of QT measurements. METHODS Twenty-five normal subjects sequentially underwent graded-i...

BACKGROUND Short-QT syndrome is an inherited disorder characterized by a short QT interval and an increased risk of sudden cardiac death. The clinical significance of a short QT interval observed in a randomly recorded ECG is not known. Therefore, we assessed the prevalence and prognostic significance of a short QT interval in a general population. METHODS AND RESULTS QT intervals were measur...

STUDY OBJECTIVE Antipsychotic drugs are frequently reported to cause QT prolongation and torsade de pointes. We aim to investigate the potential risk of torsade de pointes in antipsychotic overdose by assessing the QT interval with the QT nomogram. METHODS All presentations to a toxicology service between January 1987 and May 2013 were reviewed. Admissions with single ingestions of an antipsy...

AIMS Methadone is a widely used opioid agonist treatment associated with QT prolongation and torsades de pointes. We investigated the QT interval in patients treated with methadone or buprenorphine using continuous 12-lead Holter recordings. METHODS We prospectively made 24-h Holter recordings in patients prescribed methadone or buprenorphine, compared to controls. After their normal dose a c...