Wellens H J, Cats V M, Düren D R
Am J Med. 1975 Aug;59(2):285-7. doi: 10.1016/0002-9343(75)90365-4.
Symptomatic sinus node abnormalities occurred in a woman receiving lithium carbonate. Stimulation studies of the heart revealed that only the sinus node was affected. The abnormalities disappeared completely following cessation of lithium therapy.