Mitral valve disease affects the valve that controls blood flow between two chambers on the left side of your heart. This condition can develop over time or be present from birth, and while many people experience no symptoms, others may face serious complications that significantly impact their quality of life and heart health.
Understanding Mitral Valve Disease
The mitral valve is one of four vital valves in your heart, positioned between the left atrium (the upper chamber) and the left ventricle (the lower chamber). This valve acts like a door, allowing oxygen-rich blood from your lungs to flow from the left atrium into the left ventricle, where it is then pumped out to nourish your entire body. When this valve becomes diseased or damaged, it cannot perform its job properly, which can lead to various health problems over time.[1][2]
The mitral valve is made of two strong flaps of tissue called leaflets or cusps. These flaps work like coordinated traffic directors, opening and closing in rhythm to let blood flow from the left atrium to the left ventricle. When they are healthy, they close tightly to prevent blood from leaking backward. However, when disease affects these leaflets, they may become too thick, too stiff, too stretchy, or unable to close properly.[2]
Mitral valve disease takes three main forms, and understanding each one helps explain how the valve’s function can be compromised. In mitral valve stenosis, the valve’s flaps become thick and stiff, narrowing the valve opening and making it harder for blood to pass through. In mitral valve prolapse, the flaps become too stretchy and bulge backward into the left atrium, preventing the valve from closing properly. This sometimes leads to leakage. In mitral valve regurgitation, also called a leaky valve or mitral insufficiency, the valve’s flaps cannot close all the way, allowing blood to leak backward into the left atrium instead of moving forward as it should.[1][2]
Who Is Affected by Mitral Valve Disease
Mitral valve disease affects people of all ages and backgrounds. Some babies are born with problems in their mitral valve, a condition called congenital mitral valve disease. However, most adults develop the condition gradually over time as the valve slowly deteriorates with age. The disease can be acquired, meaning it develops during a person’s lifetime, often as part of the natural aging process.[2][5]
Mitral valve prolapse, one form of the disease, is particularly common among women. However, research shows that when men have mitral valve prolapse, it tends to be more dangerous for them, as they are more likely to develop severe regurgitation that requires treatment. Some adults are affected suddenly due to an infection in their heart or following a heart attack, but these cases are less common than gradual age-related deterioration.[2]
The annual incidence of degenerative mitral valve disease in industrialized nations is estimated at around two to three percent, making it the second most common clinically significant form of heart valve disease in adults. This disease occurs with increasing frequency as part of degenerative changes that happen naturally during the aging process.[7][14]
What Causes Mitral Valve Disease
Mitral valve disease can be caused by defects or abnormalities in the mitral valve itself, or it can result from other disorders or conditions that damage the valve over time. Understanding these causes helps explain why the valve stops functioning properly and how different health conditions contribute to valve problems.[3]
One of the most common conditions requiring mitral valve repair is myxomatous degeneration, also known as “floppy valve.” This occurs when the mitral valve leaflets become floppy or loose, preventing the valve from opening and closing properly. In most cases, this condition does not cause symptoms and does not require treatment. However, in more severe cases, it can cause mitral valve regurgitation, where blood leaks backward into the lungs. This backward flow may result in the heart walls becoming stretched and weakened, a condition called heart dilation.[4]
Rheumatic fever, typically a childhood disease, is a significant cause of mitral valve stenosis. This condition results from the body’s immune response to a streptococcal bacterial infection. Rheumatic fever is a serious complication of strep throat or scarlet fever, and it can cause scarring of the mitral valve. This scarring can lead to narrowing of the valve opening and weakening of the heart as it struggles to pump enough blood through the smaller opening. Symptoms of mitral valve stenosis usually appear sixteen to forty years after the episode of acute rheumatic fever.[7][8]
A heart attack can cause mitral valve disease by damaging the muscles and structures that support the valve. When blood flow to the heart muscle is interrupted during a heart attack, the papillary muscles and chordae tendineae, which are the anchor cords that help the valve function properly, may be damaged. This damage can prevent the valve from closing properly, leading to regurgitation.[3]
Endocarditis, an infection affecting the heart valves or the inner surface of the heart called the endocardium, can also cause mitral valve disease. This infection typically occurs when bacteria or other germs from the mouth, intestinal tract, or urinary tract travel through the bloodstream and lodge in the heart. While these bacteria usually do not cause problems in normal hearts, hearts with defects or those that have been repaired are particularly vulnerable to infection. Once infection occurs, the bacteria continue to grow and may seriously damage the heart valves.[3][4]
Other causes include cardiomyopathy, an abnormality of the heart muscle that can lead to widening of the mitral valve ring, making it difficult for the leaflets to close properly. Connective tissue disorders, such as Marfan syndrome, are associated with some forms of mitral valve prolapse. In Marfan syndrome, patients have long bones and very flexible joints, and the valve leaflets may be affected by the same connective tissue problems. Some people with mitral valve prolapse are small-framed or have minor chest wall deformities, scoliosis, or other skeletal disorders.[3][5][6]
Risk Factors for Developing Mitral Valve Disease
Several factors increase the risk of developing mitral valve disease or can contribute to worsening an existing condition. Age is a significant risk factor, as the valve naturally deteriorates over time. Older adults are more likely to experience degenerative changes in the valve, leading to conditions like mitral valve prolapse or regurgitation.[14]
A history of rheumatic fever significantly increases the risk of developing mitral valve stenosis later in life. People who had strep throat or scarlet fever in childhood and developed rheumatic fever as a complication may have scarring on their mitral valve that only becomes symptomatic decades later.[7][8]
Having other heart conditions increases the risk of mitral valve problems. People with coronary artery disease, a history of heart attack, or heart failure are at higher risk. Additionally, individuals who have undergone radiation therapy to the chest area for cancer treatment may develop valve problems as a long-term complication of their treatment.[3]
Genetic factors and family history play a role in some cases. Mitral valve prolapse runs in families, and people with connective tissue disorders like Marfan syndrome or other hereditary conditions affecting connective tissue are more likely to develop mitral valve problems. Those with congenital heart defects, meaning heart problems present from birth, may also have associated mitral valve abnormalities.[3][6]
Symptoms of Mitral Valve Disease
Many people with mitral valve disease do not experience any symptoms, especially in the early stages when the condition is mild. The disease can be present for years without causing noticeable problems. However, as the condition progresses or becomes more severe, symptoms can develop either gradually or suddenly, depending on the cause and type of valve problem.[2][3]
Shortness of breath is one of the most common symptoms of mitral valve disease. This occurs because blood may back up into the lungs when the valve is not working properly. People may notice they become breathless during physical activity or exercise, or in severe cases, even when lying down or resting. This symptom can significantly impact daily activities and quality of life.[3][7]
Fatigue and extreme tiredness are frequent complaints among people with mitral valve disease. Because the heart is not pumping blood efficiently through the body, muscles and organs may not receive enough oxygen-rich blood. This can make people feel weak, exhausted, and unable to perform their usual activities or exercise. Some describe having trouble breathing after exercise or feeling unusually tired even after mild exertion.[3][6]
Chest pain or discomfort can occur in mitral valve disease. Some patients describe feeling sharp chest pain, while others experience a sensation of tightness or pressure. Additionally, palpitations, which feel like the heart is skipping a beat, racing, or fluttering, are common. These irregular heartbeats or rapid heart rate sensations can be alarming and uncomfortable.[3][6]
Dizziness and feeling lightheaded can happen when the heart is not pumping enough blood to the brain. In severe cases, people may experience syncope, which means fainting or passing out. Coughing is another symptom that may develop, particularly when fluid backs up into the lungs.[3][7]
Swelling in the feet, ankles, or legs can occur when fluid accumulates in the body due to poor blood circulation. This is often accompanied by unexplained weight gain as the body retains fluid. Some people may also develop fever if the valve disease is caused by an infection like endocarditis.[3][7]
When mitral valve prolapse occurs, most people do not have symptoms at all. When symptoms do happen, they are often mild and may include shortness of breath, especially when lying down, chest pain, extreme fatigue, heart palpitations, coughing, and trouble breathing after exercise. A rapid heartbeat, called tachycardia, can occur but is rare.[6]
How Mitral Valve Disease Affects the Body
Understanding how mitral valve disease changes the normal functioning of the heart helps explain why symptoms develop and why treatment is important. When the mitral valve is healthy, it opens smoothly to let blood flow from the left atrium into the left ventricle during the relaxation phase of the heartbeat. Then it closes tightly to prevent blood from flowing backward when the left ventricle contracts to pump blood out to the body.[5]
In mitral valve stenosis, the valve opening becomes narrowed. This narrowing prevents the valve from opening fully, reducing the amount of blood that can flow through the heart. Over time, this can cause high blood pressure in the left atrium and in the blood vessels of the lungs. As pressure builds up in the lungs, it leads to breathing difficulties and fluid accumulation. The heart must work harder to pump blood through the narrowed opening, which can weaken the heart muscle over time.[1][4]
In mitral valve regurgitation, the valve flaps do not close completely, allowing blood to leak backward into the left atrium when the left ventricle contracts. This means that not all the blood pumped by the heart moves forward to supply oxygen to the body. Some of it flows backward with each heartbeat. As a result, the heart must pump harder and handle a larger volume of blood to compensate for the leakage. Over time, this extra work can cause the left ventricle to enlarge and weaken. The left atrium may also enlarge as it receives both the normal blood flow from the lungs and the blood leaking backward through the faulty valve.[1][15]
When the heart chambers become enlarged and the walls stretched, a condition called heart dilation develops. This can lead to serious complications, including heart failure, where the heart fails to keep up with the volume of blood flowing through it. Additionally, heart rhythm problems may occur, including atrial fibrillation, an irregular and often rapid heart rate that can further compromise heart function and increase the risk of blood clots.[2][4]
If left untreated, severe mitral valve disease can lead to life-threatening complications. The heart may become so weakened that it cannot pump enough blood to meet the body’s needs, resulting in heart failure. Blood clots may form in the enlarged heart chambers, and these clots can travel to other parts of the body, potentially causing strokes or other serious problems. The buildup of fluid in the lungs can cause progressive breathing difficulties and reduce quality of life significantly.[2][8]
Prevention Strategies
While some forms of mitral valve disease cannot be prevented, especially those related to congenital defects or genetic conditions, there are several steps people can take to reduce their risk of developing valve problems or prevent existing conditions from worsening. These preventive measures focus on maintaining overall heart health and addressing risk factors that can contribute to valve disease.[17]
Maintaining a healthy diet provides long-term health benefits and reduces the risk of developing chronic diseases, including heart conditions that can affect the valves. Eating a variety of fruits, vegetables, and whole grains regularly helps support cardiovascular health. Changing protein sources to be more plant-based, such as nuts and legumes, or choosing fish and seafood instead of animal meats, can benefit heart health. It is important to reduce salt, sugar, and alcohol intake, avoid processed foods (especially processed meats like sausage, ham, and bacon), and avoid saturated fats including animal fat, coconut, and palm oils. Balancing energy intake and expenditure while avoiding overeating helps maintain a healthy weight.[17]
Regular exercise strengthens the heart and improves overall cardiovascular health. Moderate to high-intensity exercises such as dancing, running, jogging, or speed walking can improve physical fitness, strengthen bones and muscles, help control or lose weight, lower high blood pressure and harmful cholesterol levels, boost sleep quality and energy, and reduce stress. Adults should aim for one hundred fifty to three hundred minutes of moderate to high-intensity aerobic exercise per week, along with resistance or weight training two to three days per week.[17]
Keeping blood pressure under good control is especially important to slow the progression of mild or moderate mitral valve regurgitation. High blood pressure makes the heart work harder and can worsen valve leakage over time. Working with a healthcare provider to monitor and manage blood pressure through lifestyle changes and, if necessary, medication can help protect the valve.[16]
Dental care plays an important role in preventing infections that could affect the heart valves. Research shows that people who brush their teeth twice a day for a minimum of two minutes have a significantly lower risk of developing heart disease. It is crucial to carry out proper daily dental care for oral hygiene and heart health. Having regular checkups with a dentist, at least one to two visits per year, helps prevent infections that could potentially spread to the heart.[17]
Quitting smoking is one of the most important steps for heart health. Smoking or tobacco use is hazardous to almost every organ and is one of the main risk factors for cardiovascular diseases. Chemicals in cigarette smoke can damage the heart and blood vessels, increasing the risk of developing various heart problems. Secondhand smoke can also harm people who are non-smokers. Quitting cigarette smoking benefits not only your own health but also the health of those around you.[17]
Preventing strep throat infections and treating them promptly when they occur can help reduce the risk of rheumatic fever, which is a significant cause of mitral valve stenosis. If strep throat is diagnosed, completing the full course of antibiotics as prescribed by a healthcare provider is essential to prevent complications.[8]