The Thyroid-cardiac Axis: Thyroid Function, Cardiac Rhythmology, and Sudden Cardiac Death.

It is well known that thyroid dysfunction increases the risk of cardiovascular mortality and morbidity. The pleiotropic effect of thyroid hormones has a profound effect on the cardiovascular system, influencing both the formation of a normal cardiac rhythm and rhythm disturbance. A number of research studies have demonstrated correlations between TSH and FT4 levels and significant cardiovascular events. The pathophysiological mechanisms underlying these complex associations are, however, inadequately defined. A system-based examination of the relationship between thyroid homeostasis and cardiovascular disease could pave the way for novel study areas and a more individualised strategy for the management of individuals at cardiovascular risk.