[T wave abnormalities on Holter monitoring of congenital long QT syndrome: phenotypic marker of a mutation of LQT2 (HERG)].
The two genes which code for the potassium channels, KCNQ1 and HERG, are responsible for the most common forms of the long QT syndrome, LQT1 and LQT2. Abnormalities of duration and morphology of the ventricular repolarisation are amongst the diagnostic criteria of this syndrome. The morphology of the T waves was studied by 24 hour Holter monitoring in 190 subjects with a long QT syndrome due to KCNQ1 (LQT1) [N = 133] or HERG (N = 57) and in 100 controls, and it was compared with the ECG T wave. The T wave was characterised according to 3 morphological features: grade 0 (G0) = normal, grade 1 (G&) = slight ST depression and grade 2 (G2) = presence of ST elevation of the descending phase of the T wave. The T wave morphology on Holter ECG was normal for most LQT1 and control subjects compared with LQT2 (92%, 96% and 19% respectively, p < 0.01). Grade 1 appearances were observed more often in LQT2 (18 vs 8% for LQT1 and 4% for controls, p < 0.01). Grade 2 appearances were only observed in the cases of LQT2 (63%). The predictive factors of G2 were young age and an anti-sense mutation of the transmembrane domaines of HERG. The authors conclude that Holter monitoring improves detection of T wave changes compared with the ECG. Grade 2 changes seem to be a phenotype marker for a HERG mutation, especially those situated in the transmembrane domaines.
Lupoglazoff
J M
JM
Service de cardiologie pédiatrique, hôpital Robert-Debré, 48, boulevard Sérurier 75019 Paris.
Denjoy
I
I
Berthet
M
M
Hainque
B
B
Vaksmann
G
G
Klug
D
D
Villain
E
E
Lucet
V
V
Guicheney
P
P
Coumel
P
P
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015415:Biomarkers; D027682:Cation Transport Proteins; D002648:Child; D016373:DNA, Antisense / Q000235:genetics; D004268:DNA-Binding Proteins; D000072237:ERG1 Potassium Channel; D015716:Electrocardiography, Ambulatory; D051638:Ether-A-Go-Go Potassium Channels; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000151:congenital* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D017354:Point Mutation; D015221:Potassium Channels / Q000235:genetics*; D024642:Potassium Channels, Voltage-Gated; D012307:Risk Factors; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG
D015415:Biomarkers; D027682:Cation Transport Proteins; D016373:DNA, Antisense; 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; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG