Atrial Arrhythmia and Bradycardia as a Presentation of Congenital Long QT Syndrome.

We present a term newborn with atrial arrhythmia on the first day of life (DOL). An echocardiogram showed normal structure and normal function; laboratory testing showed normal electrolytes and thyroid function. After initiation of flecainide, the EKG on DOL 2 showed significant and increasing bradycardia with atrial arrhythmia and extremely prolonged QTc interval.

The single-strand DNA/RNA-binding protein, Purbeta, regulates serum response factor (SRF)-mediated cardiac muscle gene expression.

Single-strand DNA-binding proteins, Puralpha and Purbeta, play a role in cell growth and differentiation by modulating both transcriptional and translational controls of gene expression. We have previously characterized binding of Puralpha and Purbeta proteins to a purine-rich negative regulatory (PNR) element of the rat cardiac alpha-myosin heavy chain (MHC) gene that controls cardiac muscle specificity. In this study we investigated the role of upstream sequences of the alpha-MHC promoter in Purbeta-mediated gene repression.

Defibrillator for primary prevention in congenital heart disease.

A 21-year-old patient with repaired double-outlet right ventricle and normal ventricular function underwent internal cardioverter defibrillator implantation for primary prevention of sudden death. First occurrence of spontaneous ventricular tachycardia resulted in hemodynamic collapse and syncope but the internal cardioverter defibrillator rescued the patient. ICD implantation for primary prevention may be an appropriate goal in adults with repaired congenital heart disease, even in the setting or normal ventricular function.