Usually thyroid nodules do not affect the heart. If thyroid nodules are combined with hyperthyroidism or hypothyroidism, they may affect the heart. Determining whether a thyroid nodule affects the heart depends on the individual case and cannot be generalized. Generally, simple thyroid nodules do not affect the heart and are mainly caused by abnormal localized growth of thyroid cells, so patients do not need to worry too much. However, when thyroid nodules are combined with other thyroid disorders such as hyperthyroidism and hypothyroidism, they may affect the heart. Abnormal thyroid function can lead to metabolic disorders in the body, causing the patient to develop cardiac arrhythmia, which can be manifested as persistent tachycardia, slowed heart rate, etc., and in severe cases, heart failure may also occur. To summarize, when patients check out the thyroid nodules, if there are symptoms of heart discomfort, they need to do further examination to clarify the specific causes, and cooperate with doctors to actively treat.