Electrocardiographic implications of the prolonged QT interval

• Published in: The American journal of emergency medicine Vol. 31; no. 5; pp. 866 - 871
• Main Authors: Moskovitz, Joshua B., MD, MPH, Hayes, Bryan D., PharmD, Martinez, Joseph P., MD, Mattu, Amal, MD, Brady, William J., MD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2013; Elsevier Limited
• Subjects: Adolescent; Aged; Arrhythmias, Cardiac - diagnosis; Arrhythmias, Cardiac - etiology; Arrhythmias, Cardiac - therapy; Cardiac arrhythmia; Electrocardiography; Emergency; Emergency medical care; Heart rate; Humans; Long QT syndrome; Long QT Syndrome - diagnosis; Long QT Syndrome - etiology; Long QT Syndrome - therapy; Male; Middle Aged; Potassium; Risk factors; Sinuses; Trauma
• ISSN: 0735-6757; 1532-8171
• DOI: 10.1016/j.ajem.2012.12.013

Abstract The QT interval measures the time from the start of the QRS complex to the end of the T wave. Prolongation of the QT interval may lead to malignant ventricular tachydysrhythmias, including torsades de pointes. Causes of QT prolongation include congenital abnormalities of the sodium or potassium channel, electrolyte abnormalities, and medications; idiopathic causes have also been identified. Patients can be asymptomatic or present with syncope, palpitations, seizure-like activity, or sudden cardiac death. Management involves looking for and treating reversible causes. For patients with congenital or idiopathic QT interval prolongation, the use of beta-blockers can be considered. Certain subsets of patients benefit from implantation of a cardioverter-defibrillator. Clinicians must remain vigilant for QT interval prolongation when interpreting electrocardiograms, especially in patients presenting with syncope or ventricular arrhythmias.