How hyperthyroidism affects the heart

Thyroid hormones influence how strongly and quickly the heart works. With excess hormone, you may notice a racing, pounding, or fluttering heartbeat, a higher resting pulse, breathlessness on exertion, or reduced exercise tolerance. The rhythm may feel uneven. Sweating, heat intolerance, anxiety, poor sleep, and weight change can occur in the same presentation.

Palpitations are a common presentation of several conditions and do not usually mean hyperthyroidism. Caffeine, stress, anaemia, medicines, and heart rhythm disorders can also contribute. An assessment may include a pulse check, blood pressure, an ECG, and thyroid blood tests.

Arrange a medical appointment if new palpitations persist, recur, or come with tiredness or breathlessness. Keep a record of timing, duration, activity, triggers, and whether the rhythm feels regular. Limit personal triggers such as excess caffeine or nicotine, and do not stop prescribed thyroid or heart medicine without advice. Ask before starting supplements that may affect thyroid function.

Call emergency services for chest pain, severe breathlessness, fainting, confusion, or a fast or irregular heartbeat with marked weakness. Prompt assessment is also appropriate for new swelling, worsening exercise breathlessness, or symptoms that do not settle with rest. An untreated overactive thyroid with severe heart symptoms can become dangerous.

Could my thyroid be affecting my rhythm or pulse? Do I need an ECG or monitoring? Which medicines and supplements should I avoid? How should I respond if palpitations return, and when should I seek emergency care?