The Connection Between AFib and Thyroid Function
Your thyroid gland is located over your voice box in your throat. It controls your metabolic rate, which means it is responsible for how fast or slow all of the processes in your body occur. If your thyroid is healthy, the processes occur at an optimal rate.
Studies have shown that thyroid function has an impact on the frequency with which atrial fibrillation occurs. This is important information if you have a diagnosis of either AFib or thyroid disease.
Hypothyroidism
If your thyroid is not producing enough hormones; your metabolic rate will slow down. This condition is known as hypothyroidism. When hypothyroidism is present, you may feel tired. Your skin and hair may be dry and fall out. You may feel sluggish and gain weight.
If you suffer from hypothyroidism you may also experience bradycardia, which is a heart rate below sixty beats per minute. Depression may occur. Your cholesterol and triglyceride levels may be elevated.
The most common treatment for hypothyroidism is supplementation with thyroid pills or synthetic thyroid hormones. Hypothyroidism is often not recognized. Your thyroid function may be diminished without symptoms being apparent.
Hyperthyroidism
If your thyroid produces an excess of hormones, then all of the processes in your body will speed up. This is known as hyperthyroidism. A sign of hyperthyroidism is a feeling of everything racing. Your heart beat may increase, you may experience palpitations, and AFib may develop. You may lose weight and your eyes may bulge. Feeling jittery and anxious is common. You may need surgery, radiation or medication to relieve your condition.
The Hormonal Connection to Thyroid Function
Your thyroid gland produces hormones. They are called thyroxine, T3; and idothyronine, T4. Your hypothalamus and pituitary gland work with your thyroid gland to ensure that the optimal level of thyroid hormones circulate in your bloodstream. If your hypothalamus detects that you do not have enough thyroid hormones in your blood stream, it sends a message to your pituitary gland, which is located in your brain, to produce more hormones. Your pituitary gland secretes a hormone, thyroid stimulation hormone, TSH, to notify the thyroid gland that more thyroid hormones are needed.
Doctors and other health care professionals are able to determine the levels of thyroid hormones in your bloodstream by measuring levels of T3, T4 and TSH. They use these markers to diagnose thyroid health and disease. A treatment plan is created based upon the levels of these hormones in your blood.
The Research
Researchers studied more than 500,000 people over a ten-year period to see if AFib was related to thyroid function. They looked at individuals who had normal thyroid function, hypothyroidism, and hyperthyroidism.
They also included individuals who were described as having subclinical hypothyroidism – people with elevated levels of TSH, but normal levels of T3 – and subclinical hyperthyroidism – low levels of TSH, but normal levels of T3. Signs of subclinical hyperthyroidism include an elevated pulse rate, abnormal heart beats, and changes in cardiac function.
