Whereas someone exhibiting marked prolongation of the QT interval with QTc exceeding 500 ms who was just externally defibrillated from torsades de pointes while swimming poses negligible diagnostic ...

A prolonged QT interval has a variety of causes and can be a very serious ECG finding, as it may lead to the potentially fatal arrhythmia polymorphic ventricular tachycardia (Torsades de Pointes).

Lower heart rates also result in a longer QT interval. A quick way to distinguish a prolonged QT interval is to examine if the T wave ends beyond the halfway point between the RR interval.

Purpose: The association of antipsychotic and antidepressant drugs with Q-T interval prolongation is reviewed. Summary: Prolongation of the Q-T interval can be of particular concern to ...

Purpose: The association of methadone with Q-T interval prolongation and torsades de pointes (TdP) is reviewed, and recommendations for preventing Q-T interval prolongation in methadone users are ...

Patients with LQTS have impaired adaptation of the QT interval in response to changes in heart rate. A study by Dr Sami Viskin and colleagues has now shown that this maladaptation is exaggerated ...

LQTS is a heritable syndrome often characterized by a prolonged QT interval and predisposition to sudden cardiac death. Mutation of one of several genes, most of which encode cardiac ion channels ...

Also known as long QT syndrome, QT prolongation is a heart condition in which the time between two points on an electrocardiogram, called the QT interval, is longer than normal, which means there ...

Caution with drugs that prolong the QT interval (eg, Class 1A [eg ... anticholinergic effects; QT prolongation, Torsades de Pointes, dystonia, hypersensitivity reactions, cerebrovascular reactions.

Risk of QT prolongation: electrolyte disturbances ... concomitant drugs known to prolong the QT interval. Seizures. Thyrotoxicosis. Pre-existing low WBCs or history of leukopenia/neutropenia ...