Blocco cardiaco completo congenito e manifestazioni correlate (lupus neonatale)

Congenital complete heart block (CCHB) is a rare disorder (maybe 1/20.000 live-born infants) that is caused by the transplacental transport of maternal antibodies (anti-Ro/SSA, particularly anti 52 kD, and/or anti- La/SSB). These antibodies may induce a myocarditis and/or may directly interact with calcium channel proteins, resulting in perturbation of transmembrane signaling at the level of the conduction tissue. The mothers have a specific HLA pattern: A1/B8/DR3/DQ2 and B44/DR5. Depending on the severity of the process the fetus may die in utero or a few days after birth, or survive to the perinatal period and have a near normal life; in most survivors a pacemaker must be implanted. Skin lesions, anemia, thrombocytopenia, hepatic cholestasis are other transient clinical features of the syndrome. The risk of recurrence of CCHB seems range from 8 to 20%. Most of the mothers are asymptomatic at delivery and are identified only by the birth of an affected child. Also their longterm outcome is more reassuring than generally assumed; in fact arthralgias and dry eyes are the commonest symptoms, and in many cases the symptoms are mild and occur many years after the index delivery; therefore the term 'neonatal lupus' is in fact misleading in most cases. A standard therapy for CCHB detected in utero does not exist; we are proposing a multicentre controlled randomized study of dexamethasone versus salbutamol for this condition.