Congestive Heart Failure and Thyroid Dysfunction: The Role of the Low T3 Syndrome and Therapeutic Aspects

BACKGROUND: Both the morbidity and mortality of congestive heart failure (CHF) remain elevated despite the medical and non-medical management of the disease, suggesting the existence of residual risk factors such as thyroid dysfunction. Particularly, the 15-30% of patients with CHF, especially those with severe ventricular dysfunction, displays the so called low T3 syndrome (LT3S) which seems to negatively affect the cardiovascular prognosis. OBJECTIVE: Only few clinical trials have been carried out to verify both safety and efficacy of thyroid replacement in the LT3S aiming to ameliorate the prognosis of CHF, and most of the results were controversial. METHODS: Considering that official recommendations about the management of this endocrine disorder in this clinical setting are lacking, the aim of the present review was to briefly overview both the indication and contraindication of thyroid replacement, particularly triiodothyronine, in patients with both CHF and the LT3S. RESULTS: Studies conducted in both animal models and human provided controversial information about the effectiveness and safety of the T3 replacement for improving ventricular dysfunction, particularly in the long-term. CONCLUSION: Further clinical trials are needed to better explore the rule of the LT3S in patients with CHF and its therapeutic strategy.