In heart failure, tissue hypoxia caused either by low cardiac output or by sympathetic vasoconstriction may also trigger an increase in the production of free radicals (4), which is a potent stimulus for the synthesis of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) (5–7). The gene discussed is IL6; the disease is heart failure.