The Jervell and Lange-Nielsen Syndrome

J-LN syndrome is a most severe variant of LQTS, with a very early onset and major QTc prolongation, and in which beta-blockers have limited efficacy. Subgroups at relatively lower risk for CA/SD are identifiable and include females, patients with a QTc < or =550 ms, those without events in the first year of life, and those with mutations on KCNE1. Early therapy with implanted cardioverter/defibrillators must be considered.