Is Thyroid Disease Putting you at a Higher Risk for Atrial Fibrillation?

July 14th, 2016

Thyroid cancer generally has a very good prognosis, with a five-year survival rate of 98%. However, standard treatment for this type of cancer usually involves a complete thyroidectomy and radioiodine treatment, which is followed with thyroid hormone suppression therapy. The goals of suppressive therapy are to replace thyroid hormone while suppressing pituitary TSH, since it can promote the growth of cancerous thyroid cells. While many patients must go on replacement thyroid hormone for the rest of their life, some concerns have been raised about the potential negative cardiovascular effects that patients face after thyroidectomy.

Recent estimates show that about 56,870 new cases of thyroid cancer will be diagnosed in 2017.This type of cancer is generally diagnosed at a younger age than many other types of adult cancer, and about 75% of thyroid cancer cases are found in women. Interestingly enough, atrial fibrillation is diagnosed more in women as well, although the CDC notes that this may be because women tend to live longer than men do.

 

What is Atrial Fibrillation?

Atrial fibrillation is a type of irregular and often fast heart rate that has the potential to increase your risk of heart failure, stroke, and a number of other cardiac complications. When atrial fibrillation occurs, the two upper chambers of your heart beat irregularly and chaotically, and they are out of sync with the bottom two chambers of the heart. Atrial fibrillation that doesn’t go away may require treatment since it can lead to complications like blood clots.

While many people are unaware that they have atrial fibrillation, some of the signs and symptoms that may be noticed with atrial fibrillation include:

  • Weakness
  • Fatigue
  • Heart palpitations
  • Shortness of breath
  • Dizziness
  • Difficulty exercising
  • Chest pain
  • Lightheadedness
  • Confusion

Studies are beginning to show a definite link between thyroidectomy and atrial fibrillation. Not only do you have a higher risk of atrial fibrillation after your thyroidectomy, you may also be more susceptible to some of the complications that may come along with it, such as blood clots and stroke.

One study showed that patients previously diagnosed with thyroid cancer were twice as likely to develop atrial fibrillation. Other studies have also shown a higher than normal risk of atrial fibrillation in patients after thyroidectomy, particularly those who are treated with suppressive therapy. Researchers are beginning to learn more about the risk of atrial fibrillation after thyroidectomy, and it’s important for you to understand this risk and what can be done to minimize it.

 

What Causes Atrial Fibrillation After Thyroidectomy?

Since multiple studies show that there is a link between thyroidectomy and an increased risk of atrial fibrillation, what causes this increased risk in thyroidectomy patients? One theory on what causes an increased risk of atrial fibrillation after thyroidectomy is the risk of suppression induced hyperthyroidism. Hyperthyroidism increases the risk of atrial fibrillation in people who have subclinical hyperthyroidism and suppressed TSH levels by about 40%.

A recent study presented at the Cancer Survivorship Symposium also showed that there’s a long-term cardiovascular risk, including a higher risk of atrial fibrillation, ischemic stroke, and coronary heart disease, in patients treated with levothyroxine after a thyroidectomy. Long-term administration of levothyroxine has the ability to cause hyperthyroidism in patients, increasing the cardiovascular risks.

Who is at Risk for Atrial Fibrillation Post Thyroidectomy?

Patients being treated with suppression therapy have the highest risk of atrial fibrillation after a thyroidectomy. However, age may also come into play, since the risk of atrial fibrillation is known to increase with age. Other risk factors for atrial fibrillation include:

  • High blood pressure
  • Heart disease
  • Obesity
  • Family history
  • Chronic conditions, such as metabolic syndrome, lung disease, diabetes, and kidney disease
  • Consuming alcohol

Other Causes of Atrial Fibrillation

Many different abnormalities or damage to the structure of your heart can result in atrial fibrillation. A simple echocardiogram, which is a painless test that uses ultrasound waves to take pictures of the heart, can be used to rule out structural problems. Once structural problems to the heart have been ruled out, doctors are better able to treat the condition. Some of the most common causes of atrial fibrillation include:

  • Metabolic imbalances, such as an overactive thyroid
  • High blood pressure
  • Abnormal heart valves
  • Heart attack
  • Lung disease
  • Viral infections
  • Exposure to stimulants, such as alcohol, caffeine, medications, or tobacco
  • Coronary artery disease
  • Congenital heart defects
  • Sleep apnea
  • Previous heart surgeries
  • Stress due to illness, surgery, or pneumonia

Is it Possible to Prevent Atrial Fibrillation?

After thyroidectomy, you may need to take suppressive therapy for a lifetime. Taking the right dosage amount of your medication can be instrumental in preventing atrial fibrillation. Take some other measures to live a heart-healthy lifestyle can also help prevent atrial fibrillation. Some preventive steps you can take on your own include:

  • Keeping your weight at a healthy level
  • Eating a diet that is heart-healthy
  • Avoiding alcohol, smoking, and caffeine
  • Reducing your stress levels, since anger and intense stress levels can cause problems with your heart rhythm
  • Increasing the amount of routine physical activity that you engage in
  • Being cautious about your use of over-the-counter medications, since some cough and cold medications (specifically, decongestants) have stimulants in them that can result in a rapid heartbeat. In fact, it’s generally recommended that all thyroidectomy patients avoid taking decongestants.

 

Treating Atrial Fibrillation in Thyroidectomy Patients

The treatment for atrial fibrillation can vary depending on how bothersome the symptoms are, how long you’ve had the problem and the underlying cause. Treatment goals for atrial fibrillation include blood clot prevention, decreasing stroke risk, and controlling the rate or resetting the heart’s rhythm. The strategy chosen by your doctor can depend on various factors, including whether you’re able to take medications to help control the heart rhythm and whether you have any other heart problems. More invasive treatments, such as surgery or using catheters, may be used in some cases.

In thyroidectomy patients, suppressive therapy resulting in hyperthyroid symptoms is often the underlying cause of atrial fibrillation, so in many cases, adjusting your thyroxine doses and better controlling suppression may be enough to reduce the problems with atrial fibrillation.

When symptoms become bothersome, your heart’s rhythm may need to be reset to normal. Certain medications can be used to restore the heart’s normal rhythm. Antiarrhythmics may be given orally or intravenously. In most cases, this is done in a hospital while your heart is continually monitored.

Electrical cardioversion may be used to reset the heart to the normal sinus rhythm when medications don’t provide results. This involves delivering an electrical shock to the heart, momentarily stopping the heart’s electrical activity. After the shock, the heart should go back to the normal rhythm on its own. You’ll be sedated for this procedure, and most patients do not feel the shock.

After electrical cardioversion or restoring the heart’s natural rhythm with medications, anti-arrhythmic medications may be prescribed to prevent atrial fibrillation in the future. These medications may include Propafenone, Dofetilide, Sotalol, Amiodarone, and Flecainide. Medications may also be prescribed to control your heart rate. Digoxin is often used to control heart rate, but since it doesn’t work as well during activities, you may require the addition of beta blockers or calcium channel blockers.

In some cases, conservative treatments for atrial fibrillation don’t work. When this happens, your physician may recommend doing a procedure that eliminates the faulty pathway that causes the disruption of electricity in your heart, getting the heart back to its normal rhythm. One option is catheter ablation. Many people who experience atrial fibrillation have “hot spots” that work like abnormal pacemaker cells, firing rapidly and making the upper chambers of the heart quiver instead of beating normally. A catheter ablation involves having long, thin tubes inserted into the groin, and those tubes are directed carefully to the heart. Electrodes on the tips of the catheters can be used to eliminate these faulty pathways, scarring this tissue to normalize the erratic signals coming from these areas This corrects the problem without using implantable devices or medications, and most patients are able to get back to their normal activities in just a few days.

Since individuals with atrial fibrillation have a higher risk for blood clots and stroke, you may need to take blood-thinning medications as well. Warfarin is a commonly prescribed option, but you’ll need to be monitored by your doctor while on this powerful medication. Newer anticoagulants (blood thinners) are also available, and they are often less dangerous than Warfarin and just as effective. I personally take two baby aspirin each day to reduce this risk.

 

Tips for Improving Heart Health After Thyroidectomy

Taking care of your heart is always important, and because of the increased risk for cardiovascular problems after a thyroidectomy, focusing on heart health becomes even more crucial. Making lifestyle changes that improve the overall health of the heart can help, as can taking measures to prevent conditions like heart disease and high blood pressure. Some of the tips I’ve learned to keep my heart as healthy as possible include:

Eating a Heart-Healthy Diet – A heart-healthy diet should be low in salt, low in fats, and rich in whole grains, vegetables, and fruits. My LAT diet focuses on heart-healthy eating, and it is based on suggestions from a well-known cardiologist. 

Keeping Weight in Check – It’s tough to keep your weight in check after a thyroidectomy, which is why I recommend my LAT diet. Being overweight increase the risk of heart disease and other cardiac complications, so eating a healthy diet and working to maintain a healthy weight go hand in hand.

Exercise Regularly – Increasing physical activity can also promote better heart health and will make it easier to keep your weight in check. Just make sure you talk to your doctor before you start a new exercise program.

Ensure Cholesterol and Blood Pressure Levels are Controlled – High cholesterol and high blood pressure can increase your risk of heart problems, so it’s important to make healthy lifestyle changes and take any medications as they are prescribed to ensure your cholesterol and blood pressure levels are controlled.

Follow-Up with Your Physicians – Following up regularly with your physicians is also important. Any problems you have can be monitored and your doctors can be on the lookout for any new developments. If you are dealing with atrial fibrillation and your symptoms get worse, it’s important to tell your doctor.

Make Sure You’re Getting Essential Vitamins and Minerals – Vitamin and mineral deficiencies can cause serious heart problems and since you already have a higher risk of atrial fibrillation after a thyroidectomy, deficiencies can make the problem occur if they become severe. Ensuring that you get essential vitamins and minerals is crucial to your heart health. Taking a supplement, such as ThyVita® can help you make sure that you’re getting the vitamins and minerals you need to support heart and overall health.

If you experience heart palpitations or tachycardia, make sure you notify your doctor or head to your local emergency room. Many different health problems can cause these symptoms, so it’s essential to be checked out so your medical care team can find the root cause of the problem.

 

 

Source:

https://thyroidresearchjournal.biomedcentral.com/articles/10.1186/1756-6614-2-4

https://academic.oup.com/jcem/article-lookup/doi/10.1210/jc.2015-2782

http://circep.ahajournals.org/content/6/5/952

http://www.bmj.com/content/345/bmj.e7895

http://emrc.mui.ac.ir/sites/emrc.mui.ac.ir/files/Journal_Club/Increased%20Risk%20of%20Atrial%20Fibrillation%20After%20Treatment.pdf

http://www.targetedonc.com/publications/targeted-therapy-news/2017/march-2017/levothyroxine-linked-to-heart-risks-in-patients-with-thyroid-cancer

https://www.cancer.org/cancer/thyroid-cancer/about/key-statistics.html

https://www.mayoclinic.org/diseases-conditions/premature-ventricular-contractions/basics/definition/CON-20030205

https://www.mayoclinic.org/diseases-conditions/atrial-fibrillation/symptoms-causes/syc-20350624