Familial multiforme ventricular extrasystoles with short stature, hyperpigmentation and microcephaly-a new syndrome.

A previously undescribed syndrome with ventricular extrasystoles and presumed cardiac syncopy, hyperpigmentation, short stature and microcephaly in a mother and son was presented. Physiologic and pharmacologic studies suggest that the mechanism of the ventricular arrhythmia depends on multiple and reentrant pathways occurring below the bundle of His.