From the Guidelines
Hypothyroidism can cause palpitations, although the mechanism is different from that of hyperthyroidism, and the incidence is lower. Palpitations, which are sensations of a racing, pounding, or fluttering heart, can occur in hypothyroidism due to several mechanisms. When your thyroid hormone levels are low, your body may compensate by increasing adrenaline production, which can trigger heart palpitations [ 1 ]. Additionally, hypothyroidism can lead to anemia or electrolyte imbalances that may contribute to irregular heartbeats.
Key Points to Consider
- Hypothyroidism is associated with a decreased cardiac output, bradycardia, and increased systemic vascular resistance [ 1 ].
- However, some studies suggest that hypothyroidism can increase the incidence of atrial fibrillation, particularly in the elderly [ 1 ].
- Proper treatment of hypothyroidism with appropriate thyroid hormone replacement therapy often resolves these cardiac symptoms.
- Persistent palpitations should never be ignored as they could also indicate a separate heart condition requiring different treatment.
Clinical Implications
- If you have hypothyroidism and are experiencing palpitations, it's essential to discuss this with your healthcare provider.
- They may need to adjust your thyroid medication dosage (such as levothyroxine) or investigate other potential causes.
- A thorough evaluation of the patient's medical history, physical examination, and laboratory tests is necessary to determine the underlying cause of palpitations in hypothyroidism.
From the Research
Hypothyroidism and Palpitations
- Hypothyroidism is commonly associated with sinus bradycardia, low QRS complexes, prolonged QT interval, and conduction blocks, but it can rarely cause arrhythmias, including supraventricular tachycardia 2.
- A case study reported a patient with severe hypothyroidism who presented with presyncope and supraventricular tachycardia, and the arrhythmia disappeared after restoration of euthyroidism, suggesting a possible link between hypothyroidism and supraventricular tachycardia 2.
- Another study found that thyroid hormone replacement therapy can improve thyroid hormone levels and electrocardiogram changes, including heart rate and ventricular repolarization, in geriatric patients with hypothyroidism 3.
- However, it is worth noting that palpitations are more commonly associated with hyperthyroidism, and symptoms such as anxiety, weight loss, and palpitations are typical of hyperthyroidism 4, 5.
- A case study reported a patient who transitioned from hypothyroidism to hyperthyroidism, experiencing symptoms such as anxiety, weight loss, and palpitations, highlighting the complexity of thyroid disease and its effects on the heart 4.