Mitral Valve Disease: Symptoms, Types, Causes and Treatment

Mitral valve disease is one of the most common heart valve disorders worldwide, affecting millions and significantly impacting quality of life. The mitral valve—located between the left atrium and left ventricle—ensures one-way blood flow through the heart. When this valve malfunctions, it can lead to a spectrum of symptoms, underlying causes, and treatment options. Understanding the nuances of mitral valve disease is essential for recognizing early warning signs, distinguishing between disease subtypes, and choosing the best therapeutic strategies for each patient.

Symptoms of Mitral Valve Disease

Living with mitral valve disease can be an unpredictable and sometimes subtle experience. Symptoms often develop gradually, and many people may not realize they have a problem until the disease has progressed. Recognizing the warning signs is crucial for early diagnosis and intervention.

Symptom	Description	Commonality	Source(s)
Shortness	Difficulty breathing, especially on exertion or lying down	Most common	3 4 6
Fatigue	Unusual tiredness, reduced exercise tolerance	Very common	3 4 6 9
Palpitations	Sensation of rapid, fluttering, or pounding heartbeat	Frequent	3 4
Edema	Swelling in legs, ankles, or abdomen	In advanced stages	3 4 6

Table 1: Key Symptoms

Understanding the Symptoms

Mitral valve disease may manifest differently depending on the underlying problem (regurgitation, stenosis, or prolapse) and its severity.

Shortness of Breath and Fatigue

• Shortness of breath is often the earliest and most noticeable symptom.
• It results from increased pressure in the lungs when the heart can’t efficiently move blood forward, causing fluid to back up.
• Fatigue typically follows, as the body receives less oxygen-rich blood due to compromised heart function.
• Both symptoms may worsen with physical activity or when lying flat, prompting people to sleep propped up with pillows.

Palpitations

• Many patients describe a fluttering, rapid, or irregular heartbeat.
• Palpitations are more common in mitral valve prolapse or regurgitation, where the valve fails to close properly, allowing blood to leak backward and sometimes triggering arrhythmias 4.

Swelling (Edema)

• Swelling in the lower limbs or abdomen usually appears in advanced cases where heart failure has developed.
• This occurs as blood backs up in the venous system, leading to fluid leakage into surrounding tissues 3 6.

Additional Symptoms

• Less commonly, people may experience chest pain, dizziness, fainting, or a persistent cough—especially if the disease progresses to heart failure or causes atrial fibrillation.
• Symptoms can fluctuate, sometimes disappearing for weeks or months before returning.

Types of Mitral Valve Disease

Mitral valve disease isn’t a single condition—it encompasses several distinct disorders, each with unique features and implications. Understanding the main types is key for proper diagnosis and management.

Type	Main Feature	Prevalence	Source(s)
Regurgitation	Leak of blood backward	Most common	2 3 4 5 6
Stenosis	Narrowed valve opening	Less common (US)	3 4
Prolapse	Valve bulges into atrium	Up to 5% population	4 5
Degenerative	Tissue weakening/prolapse	Leading primary cause	1 5 7

Table 2: Main Types of Mitral Valve Disease

Breaking Down the Types

Mitral Regurgitation (MR)

• Definition: The valve doesn’t close tightly, causing blood to flow backward into the left atrium when the heart contracts.
• Primary MR: Caused by structural abnormalities of the valve itself (e.g., degenerative disease, prolapse) 2 3 4 5 6.
• Secondary MR: Result of changes in the left ventricle (e.g., after a heart attack or in heart failure), where the valve structure is normal but cannot function properly due to altered geometry 2 3 6.
• Prevalence: MR is the most frequently encountered form of mitral valve disease in developed countries 2 3 4.

Mitral Stenosis (MS)

• Definition: The valve becomes narrowed or obstructed, impeding blood flow from the left atrium to the left ventricle.
• Main Cause: Rheumatic fever remains the most common cause globally, though it’s rare in the U.S. 3 4.
• Effects: The left atrium enlarges as it struggles to push blood through the tight opening, leading to symptoms and increased risk of atrial fibrillation and stroke 3 4.

Mitral Valve Prolapse (MVP)

• Definition: The valve leaflets bulge (prolapse) backward into the left atrium during heart contraction.
• Prevalence: MVP affects up to 5% of the population and is a leading cause of primary MR 4 5.
• While often benign, it can sometimes progress to severe regurgitation requiring intervention 5 11.

Degenerative Mitral Valve Disease

• Includes: Two main forms—Barlow’s disease and fibroelastic deficiency (FED).
  • Barlow’s disease: Characterized by excess valve tissue and complex, multi-segment prolapse.
  • Fibroelastic deficiency: Involves thinning and weakening of the mitral leaflets, often with a single segment affected 1 5.
• Significance: These degenerative changes are the primary cause of mitral valve prolapse and regurgitation in developed nations 1 5 7.

Causes of Mitral Valve Disease

Understanding what leads to mitral valve disease is crucial for prevention and appropriate treatment. Causes range from inherited traits and age-related changes to infections and other heart conditions.

Cause	Description	Example/Note	Source(s)
Degeneration	Age-related tissue weakening	Barlow’s/FED	1 5 7
Rheumatic Disease	Inflammatory after infection	Stenosis	3 4
Congenital	Present at birth	Valve defects	6 8
Secondary	Result of LV disease/remodeling	Heart failure	2 3 6
Genetic Factors	Mutations affecting structure	MVP	6 11
Mechanobiology	Physical/mechanical stress	Cellular changes	6 8

Table 3: Common Causes of Mitral Valve Disease

Exploring the Causes

Degenerative Changes

• Aging is the main driver of degenerative mitral valve disease, especially in developed countries.
• Over time, the supporting tissues of the valve weaken, leading to prolapse and regurgitation.
• Barlow’s disease and fibroelastic deficiency are two phenotypes with distinct features 1 5 7.

Rheumatic Heart Disease

• Caused by an autoimmune response to untreated streptococcal infection (rheumatic fever).
• Leads to chronic inflammation, thickening, and scarring of the valve, most often resulting in stenosis 3 4.
• Remains the leading cause of mitral valve disease worldwide, particularly in developing nations.

Congenital Defects

• Some people are born with malformed mitral valves, which may cause symptoms during childhood or later in life.
• These cases often involve abnormal leaflet shape or supporting structures 6.

Secondary (Functional) Causes

• When the left ventricle becomes enlarged or dysfunctional (from heart attack, cardiomyopathy, or heart failure), the mitral valve can’t close properly, resulting in secondary MR 2 3 6.

Genetic and Molecular Mechanisms

• Certain genetic mutations predispose to mitral valve prolapse and elongation 6 11.
• Mechanotransduction—the process by which cells sense and respond to mechanical stress—plays a pivotal role in valve health and disease 6 8.
• Research also points to the involvement of serotonin (5HT) and transforming growth factor beta (TGF-β) in valve degeneration and remodeling 7.

Treatment of Mitral Valve Disease

The landscape of mitral valve disease treatment is rapidly evolving. Modern therapies aim not just to alleviate symptoms but to address underlying mechanisms, restore normal valve function, and improve survival.

Treatment	When Used	Key Features	Source(s)
Monitoring	Mild/asymptomatic cases	Regular echo, lifestyle	2 3 9
Medications	Symptom control, not a cure	Diuretics, beta-blockers	3 9
Surgery	Severe/primary disease	Repair preferred over replacement	1 2 3 9
Catheter-based	High-risk/inoperable cases	MitraClip, TMVI	9 10 12
Percutaneous	Stenosis (rheumatic)	Balloon valvuloplasty	3
Experimental	Targeting molecular pathways	5HT/TGF-β modulation	7 8 11

Table 4: Treatment Approaches

Approaches to Treatment

Watchful Waiting and Monitoring

• For mild or asymptomatic disease, close monitoring with regular echocardiography and clinical review is recommended.
• Lifestyle modifications—such as avoiding excessive salt and monitoring weight—are often advised 2 3 9.

Medications

• Drugs do not cure the underlying valve defect but can relieve symptoms and prevent complications.
• Common options include:
  • Diuretics to reduce fluid overload
  • Beta-blockers or ACE inhibitors to lower blood pressure and heart workload
  • Anticoagulants if atrial fibrillation develops, to prevent stroke 3 9

Surgical Interventions

• Valve Repair: The gold standard for severe primary mitral regurgitation, especially in degenerative disease. Preserves the patient’s own valve and provides better long-term outcomes 1 2 3 9.
  • Barlow’s disease may require a highly skilled surgeon due to complex anatomy 1.
  • Fibroelastic deficiency is more often amenable to standard repair techniques 1 5.
• Valve Replacement: Reserved for cases where repair isn’t feasible.
• Surgery is generally recommended before the onset of advanced symptoms or irreversible heart damage 2 3 9.

Catheter-Based and Minimally Invasive Therapies

• For patients at high surgical risk or with contraindications to open surgery:
  • MitraClip: A transcatheter device that clips the valve leaflets together, reducing regurgitation 9.
  • Transcatheter Mitral Valve Implantation (TMVI): Involves placing a replacement valve via a catheter. Promising for high-risk and elderly patients, with ongoing research into its long-term efficacy 10 12.
• Balloon Valvuloplasty: The preferred treatment for rheumatic mitral stenosis in eligible patients. A balloon is inflated to widen the narrowed valve 3.

Future and Experimental Therapies

• Research is underway to develop drugs that target the molecular mechanisms of valve degeneration, such as serotonin (5HT) and TGF-β signaling pathways 7 8 11.
• Genetic and mechanobiological discoveries may pave the way for personalized and preventive therapies in the future 6 8 11.

Conclusion

Mitral valve disease is a complex, evolving field with significant impact on global health. A nuanced understanding of its symptoms, types, causes, and treatments empowers patients and clinicians alike to make informed choices and seek timely intervention.

Key Takeaways:

• Symptoms include shortness of breath, fatigue, palpitations, and edema—often developing insidiously 3 4 6 9.
• Types encompass regurgitation, stenosis, prolapse, and degenerative forms like Barlow’s disease and fibroelastic deficiency 1 2 3 4 5.
• Causes range from age-related degeneration and rheumatic fever to congenital defects, secondary ventricular changes, and genetic/molecular mechanisms 1 2 3 4 5 6 7 8 11.
• Treatments span monitoring, medications for symptom relief, surgery (especially valve repair), catheter-based interventions (like MitraClip and TMVI), and emerging experimental therapies 1 2 3 7 8 9 10 11 12.

With advances in imaging, surgery, and molecular science, the future holds promise for earlier diagnosis, less invasive therapies, and ultimately, better outcomes for those living with mitral valve disease.