Thyrotoxic heart

Thyrotoxic heart is a clinical syndrome of myocardial damage due to direct or indirect exposure to excessive amounts of thyroid hormones. Etiology and pathogenesis

- Hyperthyroxine and triiodothyroninemia
- Uncoupling of oxidative phosphorylation in the myocardium
- Decreased formation of ATP and creatinine phosphate
- Compensatory increase in glycolysis and protein breakdown, decrease in protein and glycogen synthesis in cardiomyocytes
- Decreased concentration of potassium ions and threshold excitability of cardiomyocytes, creating conditions for atrial fibrillation.

Clinical picture

- Sinus tachycardia – observed in 99% of cases of toxic goiter
- Atrial fibrillation (in 10-20% of patients), especially its paroxysmal form, may be the only symptom of toxic goiter
- Systolic arterial hypertension
- cardiomegaly
- Heart failure (15-25% of cases)
- Angina pectoris (relative coronary insufficiency due to increased myocardial oxygen demand).

Laboratory research

- Elevated levels of iodine bound to serum proteins
- Increased accumulation of iodine in the thyroid gland.

Differential Diagnosis

- ischemic heart disease
- Myocarditis
- Rheumatic heart disease
- tuberculosis intoxication.

Drug therapy

- Thyrostatic products (mercasolil)
- Potassium preparations
- (3-Adrenergic blockers. Surgical treatment – resection of the thyroid gland (total or subtotal).

Synonym. Thyrotoxic myocardial dystrophy See also Diffuse toxic goiter, Hyperthyroidism, Thyrotoxic ICD crisis. 143.8 Cardiomyopathy in other diseases classified elsewhere