title: Sodium-channel blockers might contribute to the prevention of ventricular tachycardia in patients with long QT syndrome type 2: a description of 4 cases.
abstract: Four patients with long QT type 2, aged 11 to 18 years from unrelated families, with recurrent syncope and polymorhic ventricular tachycardia were studied. Long QT syndrome was diagnosed in these children at ages 4 to 7 years. Syncope, QT prolongation on electrocardiogram (corrected QT interval ≥ 490 milliseconds), notched T-wave morphology, bradycardia, and polymorphic ventricular arrhythmia were found in all of the patients. The KCNH2-L586M; KCNH2-G604S, KCNH2-L1045F; and a combined mutation KCNH2 T613M + SCN5A R190G were genotyped. Syncope, implantable cardioverter-defibrillator shocks, and tachycardia persisted in these patients, although they were receiving a full dose of β-blocker therapy. Adding a sodium-channel blocker (IC class) led to a reduction in the polymorphic ventricular arrhythmia. No syncope episodes were registered during the patients' 8 to 60 months of follow-up on the combined antiarrhythmic therapy. Further studies are needed to better define the possible role of sodium-channel blockers in patients with long QT type 2.
authors.affiliation: Moscow Research Institute of Pediatrics and Pediatric Surgery, Federal Russian Centre for Children's Arrhythmia, Moscow, Russian Federation.
authors.forename: Rukijat
authors.initials: R
authors.lastname: Ildarova
authors.forename: Maria A
authors.initials: MA
authors.lastname: Shkolnikova
authors.forename: Maria
authors.initials: M
authors.lastname: Kharlap
authors.forename: Vera
authors.initials: V
authors.lastname: Bereznitskaya
authors.forename: Leonid
authors.initials: L
authors.lastname: Kalinin
mesh_terms: D000293:Adolescent; D000889:Anti-Arrhythmia Agents; D002648:Child; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008133:Long QT Syndrome / Q000175:diagnosis / Q000188:drug therapy* / Q000235:genetics*; D008297:Male; D026941:Sodium Channel Blockers / Q000627:therapeutic use*; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000235:genetics* / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; D026941:Sodium Channel Blockers