Fourteen patients undergoing routine cardiac catheterisation were paced at a steady frequency; after this test, stimuli were introduced with a variable preceding interval (test pulse interval). The QT interval of the electrocardiogram and the duration of the monophasic action potential of the right ventricle were measured. QT interval is a function of action potential duration; the two variable...

We have read with interest the paper of Cuculi et al. in a recent issue of the Swiss Medical Weekly [1]. Clearly, one plausible explanation for the high mortality of patients with alcohol withdrawal syndromes may be the occurrence of malignant cardiac arrhythmias. Prolonged QT interval is considered as one marker for such life threatening rhythm disturbances and indeed, in the studied group of ...

Prolonged heart-rate adjusted QT intervals on the electrocardiogram (ECG) are associated with an increased risk for coronary heart disease and sudden death. However, the diagnosis of the prolonged QT interval is hampered by lack of standards. We studied variations in the prevalence of prolonged QT, based on different common definitions, in a large nonhospitalized population, and compared our re...

Suggestions were made that increased myocardial sympathetic activity is reflected by elevated QT variability (dynamic changes in QT interval duration). However, the relationship between QT variability and the amount of norepinephrine released from the cardiac sympathetic terminals is unknown. We thus attempted to assess this relationship. The study was performed in 17 subjects (12 with major de...

Long QT syndrome is characterized by prolongation of the corrected QT (QTc) interval on the surface electrocardiogram and is associated with precipitation of torsade de pointes (TdP), a polymorphic ventricular tachycardia that may cause sudden death. Acquired long QT syndrome describes pathologic excessive prolongation of the QT interval, upon exposure to an environmental stressor, with reversi...

The QT interval represents ventricular depolarisation and repolarisation. Prolongation of this interval can lead to life-threatening complications. These can include arrhythmias such as Torsades de Pointes and Ventricular Fibrillation, which may ultimately lead to death. Many risk factors have been identified in prolonging the QT interval, one of which is medication commonly used in the treatme...

BACKGROUND Drug-induced QT interval prolongation, a risk factor for life-threatening ventricular arrhythmias, is a potential side effect of many marketed and withdrawn medications. The contribution of common genetic variants previously associated with baseline QT interval to drug-induced QT prolongation and arrhythmias is not known. METHODS We tested the hypothesis that a weighted combination...

We have shown previously that noncoding variants mapping around a specific set of 170 genes encoding cardiomyocyte intercalated disc (ID) proteins are more enriched for associations with QT interval than observed for genome-wide comparisons. At a false discovery rate (FDR) of 5%, we had identified 28 such ID protein-encoding genes. Here, we assessed whether coding variants at these 28 genes aff...

Aprolonged QT interval signifies a delay in the ventricular repolarisation phase, which renders the heart vulnerable to malignant arrhythmias such as torsade de pointes ventricular tachycardia. This sign of disease is sometimes subtle and may avoid recognition unless meticulously sought. In this issue of Heart, Malik and colleagues draw attention to methodological difficulties in the measuremen...