Overview

What is the mitral valve?

Before looking at mitral valve disease (MVD), you must first understand what the mitral valve (MV) is. The MV are small flaps located between two chambers of the heart, known as the left atrium and the left ventricle. Blood flows in one direction from the left atrium to the left ventricle, and your MV ensures that the blood flows in one direction and that there is no backflow of blood, which can have adverse effects on your heart’s health.¹

The above image shows the anatomy of the heart, showing the location of the MV between the left atrium and the left ventricle.

What is mitral valve disease?

Problems with the MV in your heart can sadly result in MVD. MVD encompasses the following conditions:

• Mitral valve regurgitation (MVR): The leaflets (mitral valve flaps), do not close tightly, causing blood to flow backwards from the left ventricle to the left atrium. MVR can also occur due to mitral valve prolapse (MVP), where the leaflets of the MV bulge into the left atrium. This causes blood to leak back into the left atrium from the left ventricle
• Mitral valve stenosis (MVS): the flaps of the MV become thick and stiff, which can cause them to partially fuse together. This means that when the valve opens there is a narrower opening, and  less blood can flow from the left atrium to the left ventricle

The above image highlights the changes in the heart when there is MVD present. In the case of MVR, there is backflow of blood from the left ventricle to the left atrium. In the case of MVS, the smaller arrow indicates that less blood is flowing into the left ventricle due to the narrowing of the valve opening.

Overview of mitral valve disease

Causes and risk factors

Congenital defects

Congenital malformations of the MV are malformations that are present at birth and can sadly result in MVD.²

Rheumatic fever

Rheumatic fever is a complication that arises when you have untreated strep throat. Rheumatic fever can in turn cause rheumatic heart disease, which is an inflammatory disease, affecting the connective tissues within your heart, including those in the MV. This in turn can result in MVR. Rheumatic heart disease can also result in the calcification of the MV. This process is degenerative to the  MV and can result in MVS.³

Age-related degeneration

As you get older, your valves can naturally degenerate, and this is more prevalent in the MV than in other valves.

Other causes and risk factors

Other causes and risk factors of MVD include the following:

• Family history: MVP can be passed down through generations
• Radiation treatment: this can result in thickening of the valves
• Lifestyle habits: excessively drinking alcohol, being obese, and smoking can put you at risk of developing MVD
• Heart attack: this can damage the part of your heart muscle that supports your MV, in turn, this can result in MVR
• Damaged tissue cords: Damage to the tissue cords that attach the MV flaps to the heart wall can result in MVR

Please note that this list is not exhaustive.

Symptoms of MVD

The symptoms of MVD are listed below:

• Breathlessness
• Having an irregular heartbeat
• Fatigue
• Dizziness (a symptom of MVP which can result in MVR)

(Mayo Clinic, NHS)

Impact of exercise on mitral valve disease

Benefits of exercise for cardiovascular health

Exercise naturally increases both heart rate and cardiac output.³ Cardiac output refers to how much blood your left ventricle ejects, which is then pumped around your body. A higher cardiac output, due to exercise, can result in more blood being circulated around your body.⁴

Potential risks of exercise in MVD patients

Risks of exercise after MV surgery

One study found that exercise-based rehabilitation for those who have had MV surgery does increase the individual's capacity for exercise. However, for some individuals this may have adverse effects, causing atrial fibrillation and heart failure.⁵

However, it is important to note that this study looked at a small group of individuals. Therefore these findings cannot be generalised to the whole population of individuals who have undergone MV surgery.⁵

Risk of exercise in those with MVS

Exercise naturally increases your heart rate and cardiac output, which in turn can have adverse effects if you have MVS, which can result in the onset of atrial fibrillation and/or supraventricular tachyarrhythmias.³

Risk of exercise in those with MVR

Exercise naturally increases both your heart rate and blood pressure, which can increase MVR in those with the condition. Additionally, if you have MVR, when exercising you may develop right ventricular dysfunction and exercise-induced pulmonary hypertension.³

Guidelines for exercising with mitral valve disease

Pre-exercise medical evaluation

Importance of consulting a cardiologist (heart specialist doctor)

Depending on if you have MVS or MVR, as well as the severity of the condition, and if you are showing symptoms, you will be prescribed different types of exercises that you can participate in. It is important to always follow the guidance provided by your cardiologist, as too much strain on the heart, due to exercise, can have adverse effects on your health.³

Diagnostic tests

An echocardiogram is a type of ultrasound scan used to visualise your heart monitor. This allows a cardiologist to see how blood moves through different chambers of your heart, asses the chambers of your heart and the overall heart structure.

An exercise echocardiogram will look at how your heart changes in response to ‘stress’, which is exercise, such as walking on a treadmill or riding a stationary bike. An echocardiogram will be taken before exercise and straight after exercise. The echocardiogram prior to exercise will be compared with the echocardiogram after exercise. An exercise echocardiogram allows the cardiologist to directly evaluate your symptoms in response to exercise, and deduce what your capacity for exercise is.⁶

Exercise in different stages of MVD

Mitral valve stenosis

Mild MVS

If you have mild MVS you can participate in all recreational sports and leisure-time exercise, according to the European Sports Cardiology Guidelines. 

However, you may have the question: can I participate in competitive sports if I have mild MVS? Well, If you have mild MVS with normal sinus rhythm and you have a near-normal systolic pulmonary artery pressure (less than 40mmHg)³ and normal exercise stress testing, you can participate in competitive sports too.³

Moderate MVS

If you are asymptomatic and suffer from moderate MVS you can participate in recreational and leisure time sports, but this must be at a low to moderate intensity³

Severe MVS

If you have symptomatic MVS or severe MVS you should not be participating in recreational exercise or leisure-time activities at a moderate to high intensity.³

However, if you are mildly symptomatic you may be able to participate in low-intensity leisure-time activities and recreational exercise, but only after you have had an evaluation with your cardiologist. Here they will conduct an exercise stress echocardiography with you to see how your heart copes when it is working harder during exercise.³

Sadly, if you have severe MVS you are advised not to participate in any competitive sports due to the high risk of complications this may cause.³

Mitral valve regurgitation

Mild MVR

If you have asymptomatic mild MVR you can participate in recreational and leisure-time sports. You can also participate in competitive sports with annual echocardiographic monitoring.³

Moderate MVR

If you have asymptomatic moderate MVR you can only participate in low to moderate-intensity recreational sports, such as skill sports.³

Severe MVR

If you have asymptomatic severe MVR you should only participate in low-intensity prescribed exercises by your doctor.³

What should you do if you have symptomatic MVR, regardless of the classification?

If you have symptomatic MVR, you should not be participating in any sport. However, your doctor may recommend that you participate in low-intensity aerobic exercise prior to cardiac surgery in order to improve your physical capacity.³

Special considerations

Post-surgical exercise

After surgery to repair the mitral valve or having a prosthetic valve replaced, you will undergo a clinical assessment involving the following:³

• Echocardiogram
• Electrocardiogram (ECG)
• Exercise testing

Importantly, an exercise stress test is conducted so that the cardiologist can prescribe the best type, duration and intensity of exercise you should be participating in post-surgery. Post-surgery exercise is useful to the patient after their inactivity in the intensive care unit after their surgery. Exercise post-surgery also maximises cardiovascular fitness by improving your circulatory system’s response to exercise. Exercise post-surgery has been shown to counteract anxiety and depression.³

Summary

• Mitral valve disease includes mitral valve prolapse, which can result in mitral valve regurgitation and mitral valve stenosis
• Prior to being prescribed an exercise plan by a cardiologist, you will have to have an echocardiogram and an exercise stress test to evaluate how your heart performs under stress and decide which type and intensity of exercise is recommended
• The exercise prescribed depends on the severity of the condition, the type of mitral valve disease, and whether you are symptomatic or asymptomatic
• After undergoing mitral valve repairment surgery or prosthetic mitral valve replacement surgery, post-surgery exercise can benefit your cardiovascular health, and counteract anxiety and depression