[Sick sinus syndrome caused by amyloidosis associated with multiple myeloma]

A 65-year-old man, who had been treated for multiple myeloma (MM) since 1986, was admitted because of loss of consciousness in September 1989. An electrocardiogram taken just before admission showed a sinus arrest, junctional escaped rhythm, and marked bradycardia. The diagnosis of sick sinus syndrome (SSS) was made. Soon a temporary pacemaker was inserted, and the dyspnea ameliorated. However on the second day in the hospital, he had a high fever and Staphylococcus aureus was detected in the cultured blood. A diagnosis of septicemia was made, and the pacemaker was removed. He was then treated with beta-stimulants, but died in November 1989. Necropsy revealed cardiomegaly and microscopic examination showed amyloid deposits in the sinoatrial node, and the walls of the ventricles and coronary arteries. Although amyloidosis is often a complication of MM and the heart is frequently affected, SSS caused by amyloidosis associated with MM is quite unusual. In such patients, the use of a pacemaker is controversial, because amyloid deposits are occasionally accelerated by insertion of a pacemaker and for patients with hematological disorders, septicemia associated with pacemaker insertion may prove fatal.