Sick sinus syndrome and primary systemic amyloidosis.

A sixty-eight-year-old woman with documented sick sinus syndrome was found to have, five year later, florid clinical features of systemic amyloidosis which only then led to recognition of an underlying IgA, Kappa paraproteinaemia. The literature on this association is outlined. Underlying plasma cell dyscrasias should be excluded in cases of unexplained sick sinus syndrome.