title: [Effect of tests with dosed physical load on sinus node function and repolarization in children with hereditary long QT syndrome].
abstract: The study is devoted to assessment of effect of physical effort of sinus rhythm rate and the state of the process of repolarization in children with 1 and 2 molecular-genetic variants of the long QT syndrome (LQT). We have shown that LQT1 is characterized by inadequate increment of heart rate (HR) and substantial increase of QTc interval during exercise. In LQT2 compared with control reduction of HR increment also takes place while shortening of QTc interval is more pronounced. Delta QTc<0 is an important differential diagnostic criterion in patients with LQT1 and LQT2. Variatins in T wave morphology in LQT1 and LQT2 diminish at the background of physical exercise. The use of β-blockers influences relationship between length of QT interval and HR in patients with LQT but does not eliminate distinction from a group of patients with analogous variant of the syndrome not taking these drugs.
authors.forename: L A
authors.initials: LA
authors.lastname: Kalinin
authors.forename: R A
authors.initials: RA
authors.lastname: Il'darova
authors.forename: M A
authors.initials: MA
authors.lastname: Shkol'nikova
mesh_terms: D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D002648:Child; D004562:Electrocardiography / Q000187:drug effects*; D022062:Electrophysiologic Techniques, Cardiac; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008133:Long QT Syndrome / Q000151:congenital / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D012849:Sinoatrial Node / Q000187:drug effects / Q000503:physiopathology; D016896:Treatment Outcome
chemical_list: D000319:Adrenergic beta-Antagonists