The role of thyroid hormone therapy in acutely ill cardiac patients

The presence of a 'low T3 syndrome' in the setting of nonthyroidal illness has long been recognized as the 'euthyroid sick syndrome', with the recommendation to observe and not treat with thyroid hormone replacement therapy. That approach has recently been challenged in the setting of critical cardiac illness. Research demonstrating that thyroid hormone therapy may improve hemodynamic parameters has rekindled interest in the use of thyroid hormone therapy in critical illness. Continued improvements in survival after critical cardiac illness provokes the question of whether thyroid hormone therapy would provide further incremental benefit.