Rare Cause of Infranodal Block.

The patient exhibits multiple features suggestive of Timothy syndrome, which is a multisystem autosomal-dominant condition with findings that include prolonged QT interval, hand and foot abnormalities, dysmorphic facial features, and mental retardation. A 2:1 infranodal atrioventricular block may occasionally be seen in the setting of severely prolonged QT interval. Functional nature of atrioventricular block is demonstrated by resumption of 1:1 conduction with changes in heart rate.