Q-T peak dispersion in congenital long QT syndrome: possible marker of mutation of HERG.
Congenital long QT syndrome (LQTS) is caused by mutations in various cardiac potassium or sodium channel genes, with 6 different genotypes thus far identified. However, it is unknown whether these genotypes can be differentiated by QT variables. The electrocardiograms obtained from 16 patients with a mutation in KCNQ1 (LQT1), 7 patients with a mutation in HERG (LQT2) and 20 control subjects were analyzed. The corrected QT interval (QTc), Q-T peak interval (QTpc) and dispersion of QTc or QTpc were measured in 6 precordial leads. The corrected interval from T peak to T end (Tpec) was measured in lead V(5). The maximum QTc, QTc dispersion, and Tpec were significantly increased in the LQT1 and LQT2 patients than in the controls. However, there were no significant differences in these indices between the LQT1 and LQT2 patients. In contrast, QTpc dispersion was significantly increased in the LQT2 patients (78+/-25 ms) compared with the LQT1 patients (29+/-15 ms) and controls (26+/-19 ms). These results suggest that increased lag of the peak of the T wave in each precordial lead (QTpc dispersion) may be a possible index to differentiate LQTS patients with HERG mutation from those with KCNQ1 mutation.
Inoue
Masaru
M
Molecular Genetics of Cardiovascular Disorders, Division of Cardiovascular Medicine, Graduate School of Medical Science, Kanazawa University, Japan.
Shimizu
Masami
M
Ino
Hidekazu
H
Yamaguchi
Masato
M
Terai
Hidenobu
H
Hayashi
Kenshi
K
Kiyama
Masaru
M
Sakata
Kenji
K
Hayashi
Tatsumi
T
Mabuchi
Hiroshi
H
D000328:Adult; D019943:Amino Acid Substitution; D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins; D000072237:ERG1 Potassium Channel; D004562:Electrocardiography; D051638:Ether-A-Go-Go Potassium Channels; D005260:Female; D006801:Humans; D051656:KCNQ Potassium Channels; D051657:KCNQ1 Potassium Channel; D008133:Long QT Syndrome / Q000145:classification / Q000151:congenital* / Q000235:genetics / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D015221:Potassium Channels / Q000172:deficiency / Q000235:genetics* / Q000502:physiology; D024642:Potassium Channels, Voltage-Gated; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG
D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins; C072312:ERG protein, human; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; C092509:KCNH6 protein, human; D051656:KCNQ Potassium Channels; D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG