Asymptomatic Complete Heart Block in an Adult with Down’s Syndrome and Structurally Normal Heart: A Rare Association

Down's syndrome (DS) is caused by an extra copy of the chromosome 21. Patients with DS have short stature, intellectual impairment, and characteristic physical features. Cardiovascular disease is the leading cause of morbidity and mortality in patients with DS. An estimated 40%-60% of DS patients have congenital heart disease (CHD). Cardiac conduction disturbances in association with CHD have been described in patients with DS. However, isolated cardiac conduction defect is exceptionally rare in DS, and we report an unusual case of asymptomatic complete heart block in an adult case of DS with structurally normal heart and review the literature about the conduction disturbances in DS.