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Cardiac left ventricular function before and during early thyroxine treatment in severe hypothyroidism
R Bernstein1, C Müller, K Midtbø
1Department of Medicine, University of Oslo Medical School, Norway.
Journal of Internal Medicine
|December 1, 1991
Summary
Thyroxine replacement therapy can worsen or improve angina. Verapamil may help manage exercise-induced cardiac dysfunction during early thyroxine treatment for severe hypothyroidism.
Area of Science:
- Cardiology
- Endocrinology
- Pharmacology
Background:
- Severe hypothyroidism can paradoxically affect angina pectoris, with thyroxine replacement therapy showing variable effects.
- Cardiac function assessment is crucial in managing patients with severe hypothyroidism undergoing treatment.
Purpose of the Study:
- To investigate the effects of thyroxine replacement therapy on cardiac function and exercise capacity in severe hypothyroidism.
- To evaluate the role of verapamil in mitigating exercise-induced cardiac dysfunction during early thyroxine treatment.
Main Methods:
- Radionuclide ventriculography (RNV) was used to assess cardiac function at rest and during exercise in eight hypothyroid patients.
- Cardiac function was measured before and during thyroxine treatment, with and without verapamil administration.
Main Results:
- Exercise-induced decreases in left ventricular ejection fraction (LVEF) were observed in some patients before and during early thyroxine therapy.
- Verapamil attenuated the exercise-induced fall in LVEF and significantly increased it during exercise.
- Sustained thyroxine treatment led to significant improvements in exercise LVEF, both with and without verapamil.
Conclusions:
- Findings suggest reversible coronary artery dysfunction in severe hypothyroidism, potentially managed with verapamil during early thyroxine therapy.
- Supplementing thyroxine with verapamil is recommended during the initial phase of treatment for patients with severe hypothyroidism and cardiac concerns.