Mitral stenosis
Narrowing of the lumen of the mitral valve is mitral stenosis.
Normal mitral valve orifice: 4-6 sq.cm
Minimal MS: >2 sq.cm
Mild MS: 1.5-2 sq.cm
Moderate MS: 1-1.5 sq.cm
Severe MS: <1 sq.cm
Causes:
-Rheumatic (most common)
-Congenital
-Severe mitral annular calcification
-Collagen vascular diseases
Symptoms:
1.Breathlessness
2 Cough with hemoptysis (because of rupture of pulmonary veins, pulmonary infarction and acute pulmonary oedema)
3.Paroxysmal nocturnal dyspnea
4.Orthopnoea
5.Past history of Rheumatic fever
Signs of MS:
Pulse:Low volume, regular (may be irregular if Atrial fibrillation develops as a complication)
Apex beat: Tapping, normal in position (left 5th intercostal space, ½ inch medial to the midclavicular line)
*Apex beat maybe shifted outward in RVH due to the development of pulmonary hypertension as a complication.
*Apex beat maybe shifted outward and downward due to LVH in MS with MR.
S1: Loud
S2: Audible
(P2 will be loud if pulmonary hypertension develops)
Diastolic Thrill is heard at apex.
Left parasternal heave (it is present if pulmonary hypertension develops)
Murmur: mid-diastolic rumbling murmur with presystolic accentuation heard best at the apex in left lateral position through the bell of the stethoscope at the end of expiration
Opening snap (because of bellowing down of the mitral valve cusps) is heard just after S2
Causes of soft S1 in MS?
Calcified Mitral valve
Atrial fibrillation
Left atrial failure
MS with MR Or with AR
Obesity, thick chest wall
Emphysema
Why is the murmur mid-diastolic?
In early diastole, there is isovolumetric relaxation of the ventricles as the mitral valve cusps are closed. There is no blood flow from the atrial to the ventricles, hence murmur is not present in the early diastole.
In mid diastole, the mitral valve opens and blood flows passively from the atrial to the ventricles. Due to blood flow through a stenosed valve, there is murmur.
In late diastole (or during presystole), there is active flow of blood from the atria to the ventricles as the atria contract. Hence, there is presystolic accentuation of murmur as there is increased turbulence.
Order of involvement of chambers in MS is
1.Left atrium
2.Right ventricle
3.Right atrium
Left ventricle is not involved in pure MS.
Mitral facies:
1.Pinkish purple patches on cheeks
2.Peripheral cyanosis (because of vasoconstriction as the cardiac output is low)
3.Malar flush (because of vasodilatation in the malar area)
Complications of MS:
Pulmonary hypertension
Right ventricular failure
Atrial fibrillation
Atrial flutter
Embolism
Hemoptysis
Infective endocarditis
Due to giant left atrium-
Hoarseness of voice (because of compression of the recurrent laryngeal nerve)
Dysphagia (because of compression of the oesophagus)
Investigations:
a.Chest X-ray:
Increase in the transverse diameter of the heart because of RVH
Mitralisation (straightening of the left border of the heart)
Double contour of the right border of the heart
Evidence of pulmonary hypertension- Dilatation of upper lobe pulmonary veins,Kerley B lines, Bat wing appearance,
b.Fluoroscopy: May show calcification of the mitral valve
c.ECG:
LAH- P mitrale (wide and notched P wave)
RVH
Atrial fibrillation- f waves
d.Echocardiography: to see chamber enlargement and valve pathology
e.Doppler flow studies
f.Cardiac catheterisation
Treatment
1.Drugs
2.Valvotomy (closed or open)
3.Valvuloplasty (treatment of choice)
4.Valve reconstruction with annuloplasty
5.Valve replacement (Starr-Edward ball valve, Bjork-Shiley disc valve)
Drugs used in the treatment of MS
CCF: restriction of physical activity, salt restriction, diuretics, digoxin
Atrial fibrillation: Anticoagulation
Prophylaxis for infective endocarditis
Secondary prophylaxis for rheumatic fever
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