Genetic in long QT syndromes

Iturralde-Torres, Pedro; Medeiros Domingo, Argelia (2009). Genetic in long QT syndromes. Archivos de cardiología de México, 79 Suppl 2, pp. 26-30. Instituto Nacional de Cardiología Ignacio Chávez

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The long QT syndrome (LQTS) is a genetic disorder characterized by prolongation of the QT interval in the electrocardiogram (ECG) and a propensity to "torsades de pointes" ventricular tachycardia frequently leading to syncope, cardiac arrest, or sudden death usually in young otherwise healthy individuals. LQTS caused by mutations of predominantly potassium and sodium ion channel genes or channel-interacting proteins leading to positive overcharge of myocardial cell with consequent heterogeneous prolongation of repolarization in various layers and regions of myocardium. These conditions facilitate the early after-depolarization and reentry phenomena underlying development of polymorphic ventricular tachycardia observed in patients with LQTS. Obtaining detailed patient history regarding cardiac events in the patient and his/her family members combined with careful interpretation of standard 12-lead ECG (with precise measurement of QT interval in all available ECGs and evaluation of T-wave morphology) usually is sufficient to diagnose the syndrome. The LQTS show great genetic heterogeneity and has been identified more than 500 mutations distributed in 10 genes: KCNQ1, HERG, SCN5A, KCNE1, KCNE2, ANKB, KCNJ2, CACNA1A, CAV3 and SCN4B. Despite advances in the field, 25-30% of patients remain undiagnosed genetic. Genetic testing plays an important role and is particularly useful in cases with nondiagnostic or borderline ECG findings.

Item Type:

Journal Article (Review Article)


04 Faculty of Medicine > Department of Cardiovascular Disorders (DHGE) > Clinic of Cardiology

UniBE Contributor:

Medeiros Domingo, Argelia


600 Technology > 610 Medicine & health




Instituto Nacional de Cardiología Ignacio Chávez




Argelia Medeiros Domingo

Date Deposited:

20 Jun 2014 10:56

Last Modified:

26 Jun 2016 01:47

PubMed ID:



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