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Atrioventricular ValveEdit

Atrioventricular valves are the heart’s gatekeepers between the atria and ventricles. In humans, there are two of them: the mitral valve sits between the left atrium and left ventricle, and the tricuspid valve lies between the right atrium and right ventricle. Each valve is structured to open when the atria fill and close as the ventricles contract, preventing backflow into the atria. Proper AV valve function is essential for efficient cardiac output and stable rhythm; problems can lead to symptoms such as shortness of breath, fatigue, and edema, and in severe cases can necessitate surgical or percutaneous intervention.

From a practical standpoint, the AV valves exemplify how the heart maintains unidirectional flow under varying pressures. They rely on a coordinated apparatus of leaflets, fibrous rings, chordae tendineae, and papillary muscles to ensure reliable closure during systole. The mitral valve typically has two leaflets, while the tricuspid valve has three; both are connected to the ventricle by chordae tendineae that anchor the leaflets to papillary muscles. The annulus fibrosus forms a nonuniform ring that supports leaflet coaptation as pressures rise during ventricle contraction. These structural elements contribute to valve competence, but they also introduce potential failure modes when anatomy is altered by disease, aging, infections, or congenital conditions. For overview purposes, see mitral valve and tricuspid valve.

Anatomy and physiology

  • Structure of the AV valves
    • The mitral valve and the tricuspid valve share a common design logic: leaflets that meet to seal the atrioventricular orifices, supported by chordae tendineae and papillary muscles. The left heart experiences higher pressures, so the mitral apparatus is generally subjected to greater mechanical demand than its right‑sided counterpart. See leaflets and cordae tendineae for more on the microscopic components; for a broad view of the heart’s valves, refer to valvular heart disease.
  • Function in the cardiac cycle
    • During diastole, the AV valves open to allow ventricular filling. As systole begins and ventricular pressure rises, the leaflets close to avert regurgitation into the atria. The papillary muscles contract in concert with the ventricles, maintaining tension on the chordae tendineae to prevent leaflet prolapse. The coordination of annulus dynamics and leaflet motion is essential for efficient systolic ejection and forward flow.
  • Development and variation
    • Congenital anomalies, such as variations in leaflet number or chordal attachments, can alter valve function from birth. Acquired changes—degenerative disease, fibrosis, or dilation of the annulus—can reduce coaptation and promote regurgitation or stenosis. When assessing the valves, clinicians rely on imaging modalities that visualize leaflet motion and measure pressures across the valves; see echocardiography for a primary diagnostic tool.

Pathophysiology and disease

  • Regurgitation (insufficiency)
    • AV valve regurgitation occurs when leaflets fail to seal fully, allowing blood to leak backward into the atria during ventricular contraction. Etiologies include myxomatous degeneration of the mitral valve, leaflet tethering from ventricular dilation, infection, and functional regurgitation from chamber enlargement. Chronic regurgitation can lead to atrial or ventricular dilation and heart failure if untreated.
  • Stenosis
    • Stenosis narrows the valve opening, impeding blood flow from the atrium to the ventricle. Mitral stenosis, historically linked to rheumatic fever in some regions, increases atrial pressure and can precipitate atrial enlargement and atrial fibrillation. Tricuspid stenosis is rarer but can accompany right‑sided heart disease or congenital defects.
  • Other etiologies
    • Infective endocarditis can damage leaflet tissue, while inflammatory or autoimmune processes may cause thickening or restricted mobility. Carcinoid disease is a less common cause of tricuspid valve dysfunction and tends to affect the right heart more than the left.

Diagnosis and assessment

  • Clinical evaluation
    • Auscultation often reveals characteristic sounds corresponding to AV valve lesions, such as murmurs that reflect abnormal leaflet motion or regurgitant flow. The timing, quality, and radiation of these sounds help distinguish between valve types and disease severity.
  • Imaging and tests
    • Echocardiography (including Doppler assessments) is the primary diagnostic modality to visualize leaflets, measure regurgitant volume or orifice area, and estimate pressure gradients. Additional imaging, such as cardiac MRI or CT when indicated, can refine anatomy and guide treatment planning. See echocardiography and cardiac imaging for broader context.

Treatments and therapies

  • Conservative and medical management
    • Mild valve disease with preserved function may be observed with regular follow-up. Medical therapy often targets symptoms and the hemodynamic consequences of valve disease, such as heart failure or atrial fibrillation, rather than curing the valve itself.
  • Surgical repair and replacement
    • When intervention is warranted, mitral repair (annuloplasty with or without leaflet repair) is generally preferred over replacement when feasible, because it preserves native tissue and tends to yield better long‑term durability and ventricular function. Replacement options include mechanical or bioprosthetic valves, each with distinct durability, anticoagulation considerations, and lifestyle implications. See mitral valve repair and mitral valve replacement for more detail, and tricuspid valve repair for the right‑sided counterpart.
  • Percutaneous and transcatheter approaches
    • Less invasive techniques have expanded options for patients at higher surgical risk. Transcatheter mitral valve repair devices, such as those used in MitraClip procedures, enable leaflet approximation via catheter-based delivery. These approaches are part of a broader trend toward percutaneous solutions that aim to balance efficacy, safety, recovery time, and healthcare resources. See MitraClip and transcatheter mitral valve repair for more.

Historical and practical notes

  • Evolution of approaches
    • The management of AV valve disease has evolved from open surgical repair and replacement to increasingly refined percutaneous methods, guided by outcomes data and evolving clinical guidelines. The balance between preserving native valve function and providing durable correction informs decision-making in older adults and younger patients alike.
  • Economic and policy considerations
    • In markets where private healthcare providers, insurers, and public programs intersect, decisions about when to intervene hinge on cost, access, and the perceived value of newer technologies. Advocates emphasize patient access to innovative devices and streamlined pathways to treatment, while critics focus on safety, long‑term costs, and appropriate patient selection. Proponents argue that modern devices and repair techniques reduce hospital stay durations and improve quality of life, whereas skeptics emphasize prudent use and post‑market surveillance to avoid unnecessary procedures.

See also