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Left ventricular diastolic dysfunction in patients with subclinical hypothyroidism
B Biondi1, S Fazio, E A Palmieri
1Department of Endocrinology of the University Federico II, Naples, Italy.
The Journal of Clinical Endocrinology and Metabolism
|June 18, 1999
Summary
Subclinical hypothyroidism impairs diastolic cardiac function, but L-T4 therapy can reverse these abnormalities. This study investigated cardiovascular effects in patients with subclinical hypothyroidism and the impact of treatment.
Area of Science:
- Cardiology
- Endocrinology
- Thyroidology
Background:
- Subclinical hypothyroidism (SCH) diagnosis is common, yet treatment with levothyroxine (L-T4) remains debated.
- The cardiovascular system is sensitive to thyroid hormone levels, suggesting potential SCH-induced cardiac abnormalities.
Purpose of the Study:
- To investigate if subclinical hypothyroidism causes cardiovascular abnormalities.
- To assess the effects of L-T4 substitutive therapy on cardiac function in SCH patients.
Main Methods:
- Doppler-echocardiography was used to evaluate 26 SCH patients and 30 matched controls.
- A subgroup of 10 SCH patients received L-T4 therapy for 6 months and were re-evaluated.
Main Results:
- SCH patients exhibited impaired diastolic function, including prolonged isovolumic relaxation time and altered mitral flow velocities.
- L-T4 therapy normalized thyroid hormone levels, improved systolic function, and significantly enhanced diastolic function indices.
- Systemic vascular resistance decreased following L-T4 replacement therapy.
Conclusions:
- Subclinical hypothyroidism adversely affects cardiac diastolic function.
- L-T4 substitutive therapy can effectively reverse these diastolic dysfunction abnormalities in SCH patients.