Hypothyroidism can cause changes on the electrocardiogram (ECG) that reflect the systemic effects of reduced thyroid hormone levels on the cardiovascular system. These changes are often associated with bradycardia, myocardial dysfunction, and fluid accumulation in the tissues, including the pericardium.

Electrocardiographic Changes

  • Low QRS voltage
  • Sinus bradycardia
  • Reduced T-wave amplitude or T-wave inversion
  • ST-segment depression
  • Atrioventricular block
  • QTc prolongation

ECG in Hypothyroidism

Electrocardiogram in hypothyroidism

Hypothyroidism. Patient with decompensated hypothyroidism whose ECG shows sinus bradycardia and diffuse low QRS voltage.

References

  1. Scheffer MK, De Marchi MFN, de Alencar Neto JN, Felicioni SP. Eletrocardiograma de A a Z. São Paulo: Manole, 2024.