Mitral Valve Prolapse and Thyroid Disease

Medical research has found that the prevalence of mitral valve prolapse (MVP)—a condition in which the heart's mitral valve does not close properly and allows blood to leak into the left atrium of the heart—is substantially greater in patients with autoimmune thyroid disorders such as Graves' disease and Hashimoto's thyroiditis. It's estimated that 2 million or more Americans are diagnosed with MVP, and around 80 percent are women.

The mitral valve is one of the heart's four valves. Valves are like doors, and the mitral valve opens and closes between the left atrium (upper chamber) and two chambers of the left ventricle (lower chamber and pumping chamber).

The mitral valve has two flaps. Normally, the valve allows blood to flow only in one direction. Both flaps open when blood is flowing from the left atrium and filling the left ventricle. Both flaps then close tightly when the left ventricle contracts and pumps the blood out to the body.

When you have MVP, one or both valve flaps are enlarged. When the heart contracts or pumps, the flaps don't close smoothly or evenly. Instead, part of one or both flaps collapses backward into the left atrium. This sometimes allows a small amount of blood to leak backward through the valve and may cause a heart murmur.

Mitral valve prolapse is also sometimes referred to as: 

• Click-murmur syndrome
• Barlow's syndrome
• Balloon mitral valve
• Floppy valve syndrome 

While the relationship between autoimmune thyroid disease and MVP is established, the reason for the connection is not clear, and there doesn't appear to be substantial research on the subject to date. Most people with MVP are born with it.

Many people live with mitral valve prolapse without experiencing symptoms When symptoms do occur, they may include:

• Pounding, fast heartbeat (tachycardia)
• Irregular heartbeat, palpitations, feelings of "heart flutter" or extra heartbeats: Usually, these are harmless. Rarely, potentially serious heart rhythm abnormalities may cause palpitations, requiring further evaluation and treatment.
• Fatigue, weakness, tiring easily, and having a low tolerance for exercise: These are the most common complaints. There are theories that people with MVP may have imbalances in their autonomic nervous system (which regulates heart rate and breathing) that cause inadequate blood oxygen delivery to the working muscles during exertion, thereby causing fatigue.
• Chest pain that can be sharp or dull: This can last from a few seconds to several hours. The chest pain with MVP rarely takes place during or after exercise or exertion.
• Panic attacks, anxiety attacks, and depression. Like fatigue, these symptoms are believed to be related to imbalances of the autonomic nervous system.
• Headaches and migraines
• Sleeplessness
• Dizziness, fainting spells, or lightheadedness, especially when first standing up

It's not unusual for the symptoms to disappear spontaneously for months or even years and reappear again. Certain lifestyle factors can increase the intensity or frequency of MVP. These include:

• Emotional stress
• Excessive fatigue
• Unaccustomed physical activity
• Being anxious or nervous
• Caffeine 
• Medicines with stimulants
• Sweets
• Being in a hot, dry environment
• Dehydration
• Flu, cold, or other illnesses
• Lack of sleep
• Alcohol
• Smoking
• Skipping meals
• Rushing around
• Having a menstrual period
• Menopause

MVP can often be detected by a doctor during a routine physical and can be confirmed with an echocardiogram. The majority of patients with mitral valve prolapse have no debilitating symptoms or complications and therefore need no treatment other than an annual or semi-annual follow-up exam.

Patients who have more significant symptoms are sometimes given beta-blocker drugs, such as Tenormin (atenolol), Lopressor (metoprolol), and Inderal (propranolol). Only in rare, serious cases is surgery indicated for repair or replacement of the mitral valve.

A Word From Verywell

While having a thyroid condition increases your risk of having mitral valve prolapse, MVP is not a serious condition and does not damage the heart. Talk to your doctor if you are troubled by symptoms, which can usually be successfully treated.