title: QT interval prolongation.
abstract: The QT interval is a function of ventricular repolarization time and is measured from the onset of the QRS complex to the end of the T wave. The length of this interval is inversely related to heart rate. A prolonged QT interval is most often secondary to the use of Type I antidysrhythmic medications (quinidine, procainamide). It is also associated with phenothiazines, organophosphates, hypocalcemia, liquid protein diets and the congenital long QT syndromes. QT prolongation is associated with a variety of ventricular dysrhythmias, most characteristically Torsades des pointes. Treatment consists of correction of the underlying metabolic disorder or discontinuation of the offending medication.
authors.forename: J L
authors.initials: JL
authors.lastname: Scott
authors.forename: R M
authors.initials: RM
authors.lastname: Walls
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects; D000929:Antidepressive Agents, Tricyclic / Q000009:adverse effects; D001145:Arrhythmias, Cardiac / Q000209:etiology*; D003937:Diagnosis, Differential; D004562:Electrocardiography; D006801:Humans; D006947:Hyperkalemia / Q000175:diagnosis; D006993:Hypnotics and Sedatives / Q000627:therapeutic use; D008133:Long QT Syndrome / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology*; D013610:Tachycardia / Q000150:complications
chemical_list: D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D000929:Antidepressive Agents, Tricyclic; D006993:Hypnotics and Sedatives