Heart in thyroid diseases.

The paper examines the basic pathophysiologic mechanisms playing a role in the development of cardiovascular changes on thyroid hyper- and hypofunction. The haemodynamic changes typically associated with increased and decreased secretion of thyroid hormones are described and compared. Using echocardiography, the haemodynamics changes are documented in 12 patients with hyperthyroidism and 19 patients with myxoedema prior to thyrostatic and substitution therapy. Characteristic findings in florid hyperthyroidism include a significant rise in left ventricular end-diastolic volume as well as increases in stroke volume (SV) and cardiac index (CI). Mean velocity of circumferential fibre shortening (mVCF) is also significantly increased. Left ventricular myocardial weight shows a tendency towards an increase. Hypothyreosis is primarily associated with decreases in SV and CI; mVCF also declines. The paper underlines the importance of causative therapy as the above haemodynamics changes are fully reversible on attaining normal thyroid function.