विवरण
Mitral valve stenosis is a heart condition that affects the opening and closing of the mitral valve, which is responsible for regulating blood flow between the left atrium and ventricle. This condition occurs when the mitral valve becomes stiff or narrowed, restricting blood flow and causing symptoms such as shortness of breath, fatigue, and palpitations. There are several causes of mitral valve stenosis, including rheumatic fever, congenital heart defects, and calcium deposits on the valve. Diagnosis of mitral valve stenosis is typically made through a physical exam, electrocardiogram, echocardiogram, and other imaging tests. Treatment for mitral valve stenosis may involve medication to manage symptoms, as well as procedures such as balloon valvuloplasty or valve replacement surgery. The choice of treatment depends on the severity of the stenosis and the overall health of the patient.
सारांश
- **Etiology of Mitral Stenosis (MS):**
- Rheumatic heart disease is the most common cause of MS, especially in certain regions. Other causes include congenital MS (e.g., parachute mitral valve), drug-induced valvulopathy, and calcific MS. Less common congenital causes include arcade MS, double orifice mitral valve, and supra-valvular mitral ring.
- **Drug-Induced Valvulopathy:**
- Certain drugs, such as anorexiants, dopamine agonists, and recreational drugs like MDMA (ecstasy), can induce valvulopathy affecting the mitral valve. Discontinuing the offending drug can lead to normalization of valve morphology over time. The tricuspid valve is most commonly affected, followed by the mitral valve.
- **Clinical Assessment of MS:**
- Clinical assessment involves examining the cardiovascular system for diastolic murmur, complications like atrial fibrillation (irregular pulse), and involvement of other valves, such as mitral regurgitation. Coexisting conditions like atrial septal defect (ASD) can mask the symptoms of MS.
- **Echocardiography as Gold Standard:**
- Echocardiography, including 2D, 3D, and Doppler, is the gold standard for assessing MS. Parameters measured include pressure gradients across the mitral orifice using continuous wave Doppler, mitral valve area by planimetry, pressure half-time, and continuity equation.
- **Severity of MS by Echocardiography:**
- MS severity is classified based on mean pressure gradient and mitral valve area. Mild MS: gradient less than 5 mmHg, area greater than 1.5 cm². Moderate MS: gradient 5-10 mmHg, area 1-1.5 cm². Severe MS: gradient more than 10 mmHg, area less than 1 cm². The American Society of Echocardiography uses slightly different criteria.
- **Left Atrial Size and Appendage:**
- Echocardiography assesses left atrial (LA) size (normal less than 35 mm). Enlarged LA (greater than 50 mm is markedly elevated) and the presence of LA thrombus, especially in atrial fibrillation, are evaluated in the left atrial appendage.
- **Echocardiographic Techniques (M-Mode, 2D, 3D, Doppler):**
- M-mode echo shows features of MS. 2D and 3D echo provides more accurate mitral valve area measurements. Doppler assesses pressure gradients and mitral regurgitation. 3D echo offers improved accuracy but requires expertise and experience.
- **Doppler Pitfalls:**
- When interrogating the mitral valve for velocity/gradients, be mindful not to interrogate aortic regurgitation, which can give a false reading.
- **Doppler for MV Area:**
- Doppler assessment of mitral valve area includes the continuity equation. The flow through the aortic valve divided by the VTI across the mitral valve yields mitral valve area. It also includes pressure half-time and the piece of method, although not used much because of limitations.
- **Balloon Mitral Valvuloplasty (BMV) and Wilkins Score:**
- The Wilkins score assesses valve suitability for BMV, considering mitral valve thickening, calcification, subvalvular involvement, and leaflet mobility. A score less than 8 indicates a good valve for BMV, while a score greater than 10 is not suitable.
- **Management of MS:**
- Management includes medical treatment (diuretics, beta-blockers), BMV, or mitral valve replacement. Medical treatment is more often used during pregnancy, unless a valve issue is severe.
नमूना प्रमाण पत्र
वक्ताओं के बारे में
Dr KK Kapur
MBBS, MD, DM, Interventional Cardiologist Senior Consultant, New Delhi, India
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