Complete heart block in an adult with systemic lupus erythematosus and recent onset of hydroxychloroquine therapy

Complete heart block (CHB) is a rare complication of systemic lupus erythematosus (SLE), mainly seen during an acute flare-up of the disease or after high-dose long-term treatment with antimalarial drugs, although anti-Ro and anti-RNP antibodies have also been implied by some authors. A 40-y-old woman developed CHB in the context of an acute flare-up of SLE, first diagnosed three years ago, having recently commenced hydroxychloroquine (HCQ) treatment. Anti-Ro and anti-RNP antibodies were also positive. No features of myocarditis were found. A temporary pacemaker was required and complete resolution was achieved on steroid therapy with withdrawal of antimalarial therapy. The characteristics of previous cases are well publicised and discussion focuses on the possible aetiology and pathogenesis of the present case.