Long QT: The art of measurement

Measurement of the QT interval.

Ventricular repolarization is reflected by the T-wave of the surface electrocardiogram, the QT interval being the time taken for ventricular recovery. QT measurement has assumed clinical importance as prolongation is associated with a variety of conditions includingthe Romano-Ward' and JervellLange-Neilson syndromes, drug toxirity' and an adverse prognosis following acute myocardial infarction....

The Long QT Syndrome

Introduction The Long QT syndrome (LQTS) can be inherited or acquired and is of particular interest and concern at present. Patients with LQTS are predisposed to the ventricular tachyarrhythmia torsade de pointes (TdP) which causes syncope and sudden death. Inherited LQTS is the prototype of the "primary cardiac arrhythmias" or "cardiac ion channelopathies". The study of inherited LQTS has prov...

Measurement of QT dispersion.

The Measurement of the QT Interval

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...

[The long QT interval syndrome].

The syndrome of long QT interval frequently follows to syncope or a sudden cardiac death on the basis of originated polymorphic ventricular tachycardia of the "torsade de pointes" type. The prolongation of the QT interval in the hereditary form is based on mutation of the genes responsible for the formation of sodium and potassium channels. The authors analyze the occurrence, clinical findings,...