Long QT syndrome and life threatening arrhythmia in a newborn: molecular diagnosis and treatment response.
Intrauterine and neonatal manifestations of congenital long QT syndrome are associated with a high cardiac risk, particularly when atrioventricular block and excessive QT prolongation (> 600 ms(1/2)) are present. In a female newborn with these features, treatment with propranolol and mexiletine led to complete reduction of arrhythmia that was maintained 1.5 years later. High throughput genetic analysis found a sodium channel gene (LQT3) mutation. Disappearance of the 2:1 atrioventricular block and QTc shortening (from 740 ms(1/2) to 480 ms(1/2)), however, was achieved when mexiletine was added to propranolol. This effect was considered to be possibly genotype related. Early onset forms of long QT syndrome may benefit from advanced genotyping.
Schulze-Bahr
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Department of Cardiology and Angiology, Hospital of the University of Münster, D-48129 Münster, Germany. heart@uni-muenster.de
Fenge
H
H
Etzrodt
D
D
Haverkamp
W
W
Mönnig
G
G
Wedekind
H
H
Breithardt
G
G
Kehl
H-G
HG
D004562:Electrocardiography; D005260:Female; D005838:Genotype; D006801:Humans; D007231:Infant, Newborn; D008133:Long QT Syndrome / Q000151:congenital* / Q000175:diagnosis / Q000628:therapy; D009154:Mutation / Q000235:genetics; D010375:Pedigree; D010641:Phenotype; D016896:Treatment Outcome