QT interval decreases with increasing heart rate (HR), hence to define normal values of QT interval for different heart rates requires the application of a QT interval rate correction formula. However, it’s unknown the influence of HR on the ratios between several ventricular repolarization intervals, that can be useful as risk predictors of malignant ventricular arrhythmias. This study analyze...

Torsade de points (TdP), a life-threatening arrhythmia that can increase the risk of sudden cardiac death, is associated with drug-induced QT-interval prolongation on electrocardiogram (ECG). While many modern ECG machines provide automated measurements QT-interval, these QT values are usually correct only for noise-free normal sinus rhythm, in which T-wave morphology well defined. As QT-prolon...

seventy seven adult large mixed breed dogs of either sex were included in this study. the animals were randomly divided into four groups and received the following drug combinations intramuscularly: group 1 xylazine (0.5 mg/kg) and acepromazine (0.05 mg/kg), group 2 xylazine (0.8 mg/kg) and acepromazine (0.03 mg/kg), group 3 xylazine (0.3 mg/kg) and acepromazine (0.08 mg/kg) and group 4 xylazin...

The association between physiologic levels of sex hormones and QT-interval duration in humans was evaluated using data from 727 men enrolled in the Third National Health and Nutrition Examination Survey and 2,942 men and 1,885 postmenopausal women enrolled in the Multi-Ethnic Study of Atherosclerosis (MESA). Testosterone, estradiol, and sex hormone-binding globulin levels were measured in serum...

Seventy seven adult large mixed breed dogs of either sex were included in this study. The animals were randomly divided into four groups and received the following drug combinations intramuscularly: Group 1 xylazine (0.5 mg/kg) and acepromazine (0.05 mg/kg), Group 2 xylazine (0.8 mg/kg) and acepromazine (0.03 mg/kg), Group 3 xylazine (0.3 mg/kg) and acepromazine (0.08 mg/kg) and Group 4 xylazin...

OBJECTIVE To investigate the possible electrophysiological background of the greater excitability of concentric and eccentric left ventricular hypertrophy types in relation to the asymmetric type. METHODS 187 patients with essential hypertension, without ishaemic heart disease were divided into three groups with regard to left ventricule type: concentric (relative wall thickness >0.42, interv...

STUDY OBJECTIVE To evaluate the effects of methadone on QT-interval dispersion. DESIGN Single-center, prospective, cohort study. SETTING Methadone maintenance treatment facility. PATIENTS One hundred eighteen patients who were newly admitted to the facility. Intervention. Twelve-lead electrocardiograms (ECGs) were performed in patients at both baseline and 6 months after the start of meth...

AIMS The long QT syndrome is mainly defined by QT interval prolongation (QTc > 0.44s). However, data obtained in genotyped patients showed that resting QTc measurement alone may be inaccurate for ascertaining the phenotype. The aim of this study was to evaluate the diagnostic performance of QT interval rate-dependence in untreated chromosome 11-linked patients. METHODS The study population co...

Many drugs can significantly influence cardiac repolarisation causing an increased duration of this repolarisation phase, challenging the repolarisation reserve. This may set the stage for life-threatening ventricular arrhythmias such as torsades de pointes (TdP). TdP generally occurs in conjunction with a prolonged QT interval (QT) on the electrocardiogram. The Dutch Poisons Information Centre...