Heart disease in patients with thyroid dysfunction: hyperthyroidism, hypothyroidism and beyond

Area of Science:

• Endocrinology
• Cardiology
• Internal Medicine

Background:

• The thyroid and cardiovascular systems share intricate physiological and pathological links.
• Overt thyroid disease and subclinical forms of hyperthyroidism/hypothyroidism are known to increase cardiovascular mortality.
• Emerging evidence links milder thyroid dysfunction, like low T3 syndrome, to cardiovascular risks.

Purpose of the Study:

• To provide an overview of thyroid physiology and pathophysiology.
• To focus on the relationship between milder thyroid dysfunction and cardiovascular disease.
• To discuss the impact of "low T3 syndrome" and physiological T3 variations on heart health.

Main Methods:

• Literature review of thyroid physiology and pathophysiology.
• Analysis of studies investigating thyroid hormone levels and cardiovascular outcomes.
• Synthesis of current understanding regarding mild thyroid dysfunction and heart disease.

Main Results:

• Thyroid dysfunction, even in subclinical or mild forms, is associated with adverse cardiovascular outcomes.
• Low T3 syndrome, characterized by reduced triiodothyronine, is increasingly recognized as a cardiovascular risk factor.
• Variations in T3 levels within the physiological range may also correlate with coronary artery disease.

Conclusions:

• Understanding milder thyroid dysfunction is crucial for cardiovascular risk assessment.
• Further research is needed to elucidate the mechanisms linking mild thyroid dysfunction to heart disease.
• Clinical attention should extend to subtle thyroid hormone variations in managing cardiovascular health.