[Short QT syndrome].
Short QT syndrome is a new genetic disorder associated with familial atrial fibrillation and/or sudden death or syncope. To date, different mutations in genes encoding for cardiac ion channels (KCNH2, KCNQ1, and KCNJ2) have been identified to cause the short QT syndrome. The mutations lead to a gain of function of the affected current (IKr, IKs, and IK1). The phenotype is characterized by a shortened QT interval<335 ms after correction for heart rate at rates<80 beats/min. Furthermore, the QT interval poorly adapts to heart rate. Patients exhibit shortened atrial and ventricular effective refractory periods and, in the majority, inducibility of ventricular fibrillation. Death occurs already in newborns. Therapy of choice seems to be the implantable cardioverter defibrillator because of the high incidence of sudden death. Pharmacological treatment has been studied and it could be demonstrated, that some mutant currents may be insufficiently suppressed by drugs targeted to block the specific current such as, e.g., sotalol or ibutilide in patients with a mutation in the IKr-coding gene KCNH2 (HERG). Quinidine proved to be efficient in prolonging the QT interval and normalizing the effective refractory periods in some patients.
Wolpert
Christian
C
Medizinische Klinik, Universitätsklinikum Mannheim, Theodor-Kutzer-Ufer 1-3, 68259, Mannheim, Germany. christian.wolpert@med.ma.uni-heidelberg.de
Schimpf
Rainer
R
Veltmann
Christian
C
Borggrefe
Martin
M
D000328:Adult; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000235:genetics*; D053447:Channelopathies / Q000175:diagnosis / Q000235:genetics*; D002648:Child; D004252:DNA Mutational Analysis; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D003937:Diagnosis, Differential; D000072237:ERG1 Potassium Channel; D004562:Electrocardiography; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005820:Genetic Testing; D006801:Humans; D007231:Infant, Newborn; D051657:KCNQ1 Potassium Channel / Q000235:genetics; D010641:Phenotype; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics
D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; C489457:KCNJ2 protein, human; D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human; D024661:Potassium Channels, Inwardly Rectifying