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.

[Long QT-syndromes: diagnosis and genetics].

The long-QT syndrome (LQTS) is a familiar disease characterized by abnormal myocardial repolarization and a high risk of sudden cardiac death. As a hallmark of the disease, the heart-rate corrected QT interval is intrinsically prolonged. Recent advances in molecular genetics have elicited that various inborn defects in cardiac ion channel genes regulating cardiac ion currents underlie this propensity to develop malignant ventricular arrhythmias.