What Causes Mitral Valve Prolapse? 

The mitral valve is designed to be a precise, one-way gate that prevents blood from flowing backward into the lungs when the heart pumps. In mitral valve prolapse (often called ‘floppy valve syndrome’), the flaps (leaflets) of the valve do not close perfectly. Instead, they bulge or ‘parachute’ backward into the left atrium. While this sounds alarming, most people with the condition are born with it and lead entirely normal lives. However, understanding the underlying cause is important for long-term monitoring. This article explores why some valves become floppy and what factors contribute to this structural change. 

What We’ll Discuss in This Article 

• The clinical definition of mitral valve prolapse and how it affects heart mechanics. 

• The primary causes, including genetics and connective tissue changes. 

• What ‘myxomatous degeneration’ means for your valve tissue. 

• Secondary causes related to other medical conditions. 

• Triggers that can lead to complications like mitral regurgitation. 

• Differentiation between simple prolapse and significant valve disease. 

Understanding Mitral Valve Prolapse 

Mitral valve prolapse (MVP) is a condition where the leaflets of the mitral valve bulge upward into the left atrium as the heart contracts. This occurs because the leaflets are slightly oversized or the ‘chordae tendineae’ (the tiny strings that tether the valve) are too long or stretchy. While most cases are harmless, in some people, this bulging prevents the valve from forming a tight seal, leading to a leak known as mitral regurgitation. 

In the UK, MVP is often discovered during a routine check-up when a doctor hears a ‘mid-systolic click’ followed by a murmur through a stethoscope. It is estimated to affect approximately 2% to 3% of the population. 

• Floppy Leaflets: The valve tissue is more elastic than usual. 

• Click-Murmur Syndrome: The characteristic sound of the valve bulging and then leaking. 

• Structural Variation: Often a minor anatomical difference rather than a ‘disease’. 

• Primary vs. Secondary: Most cases are inherited (primary), while others are linked to other health issues. 

What are the Primary Causes of Mitral Valve Prolapse? 

The most common cause of mitral valve prolapse is a genetic condition called ‘myxomatous degeneration’. This is a term for a change in the connective tissue that makes up the valve. In people with MVP, the body produces an excess of certain proteins that make the valve leaflets thick and stretchy rather than thin and firm. This process is usually present from birth and slowly develops over time. 

Genetic Inheritance 

MVP often runs in families. If one parent has a floppy mitral valve, there is a higher chance their children will also have the condition. Researchers have identified specific gene mutations that affect how heart valve tissue is built. 

Myxomatous Changes 

In a healthy valve, the tissue is tough and fibrous. In a prolapsed valve, the middle layer of the leaflet becomes spongy and weak. This weakness allows the valve to stretch out of shape under the high pressure of the heart’s pumping chamber. 

What Secondary Conditions Cause Mitral Valve Prolapse? 

While most cases are stand-alone genetic variations, MVP can be caused by or associated with other medical conditions that affect connective tissue. People with Marfan syndrome, Ehlers-Danlos syndrome, or polycystic kidney disease are significantly more likely to have mitral valve prolapse because their bodies naturally produce more flexible or fragile connective tissue throughout. 

• Marfan Syndrome: A genetic disorder affecting the body’s connective tissue, often leading to very stretchy heart valves. 

• Ehlers-Danlos Syndrome: A group of disorders that affect the ‘glue’ (collagen) that holds the body together. 

• Graves’ Disease: Some studies suggest a link between thyroid issues and changes in valve tissue. 

• Scoliosis: Curvature of the spine and other skeletal issues are often found in people with MVP, suggesting a shared developmental cause. 

What are the Triggers for Worsening Valve Prolapse? 

Mitral valve prolapse itself is a static structural issue, but certain ‘triggers’ can cause it to progress into a more serious problem like severe regurgitation. High blood pressure is a major trigger; it increases the force pushing against the floppy valve, which can eventually cause the tiny tethering strings (chordae) to stretch further or even snap (rupture). 

• Chronic Hypertension: Consistent high pressure puts extra mechanical strain on the ‘floppy’ tissue. 

• Endocarditis: A bacterial infection of the heart can easily settle on a prolapsed valve, causing further damage. 

• Ageing: Like any mechanical part, a floppy valve may become less efficient after decades of use. 

• Significant Physical Stress: Very intense, sudden exertion can occasionally cause a weakened chord to tear. 

Differentiation: MVP vs. Mitral Regurgitation 

It is important to differentiate between mitral valve prolapse (the movement of the valve) and mitral regurgitation (the leak caused by that movement). You can have prolapse without any leak at all. Prolapse is the ‘action’ of the valve bulging; regurgitation is the ‘result’ if that bulging prevents the valve from closing properly. Most people have prolapse with only a ‘trace’ or ‘mild’ leak that never requires surgery. 

Feature	Mitral Valve Prolapse (MVP)	Mitral Regurgitation (MR)
What it is	The valve flaps bulge backward.	Blood leaks backward through the valve.
Nature	A structural/mechanical variation.	A functional problem with blood flow.
Symptoms	Often none (sometimes palpitations).	Breathlessness and fatigue if severe.
Requirement	Can exist without any leak.	Is often caused by MVP, but not always.

Conclusion 

Mitral valve prolapse is primarily a result of a genetic change in the way the heart’s connective tissue is built, making the valve flaps more flexible or ‘floppy’. While it is often associated with other connective tissue disorders, most people with MVP are otherwise healthy and require only occasional monitoring. The main risk is the development of a significant leak over time, which can be managed effectively if caught early. Understanding the cause helps your doctor determine how often you need an echocardiogram to keep your heart safe. 

If you experience severe, sudden, or worsening symptoms, such as intense chest pain, sudden breathlessness, or fainting, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article has been reviewed by Dr. Stefan Petrov, a UK-trained physician with an MBBS and postgraduate certifications including Basic Life Support (BLS) and Advanced Cardiac Life Support (ACLS). Dr. Petrov has extensive hands-on experience in general medicine, surgery, and intensive care units, performing diagnostic and therapeutic procedures. Drawing on his clinical background, this guide provides a medically accurate overview of the causes of mitral valve prolapse. Our goal is to provide safe, factual, and clear information to help you understand this common heart valve condition.