Mitral Stenosis And Regurgitation Flashcards
What is the most common disease cause of mitral stenosis
RHD secondary to previous RHF due to infection with group A - beta streptococcus
How does mitral stenosis come about
Inflammation leads to commissural fusion and a reduction in mitral valve orifice area leading to the characteristic doming pattern seen on echocardiography. Over many years the condition progresses to valve thickening, cusp fusion, calcium deposition, a severely narrowed (stenotic) valve orifice and progressive immobility of the valve cusps
What are some causes of mitral stenosis
Lutembacher’s syndrome, which is the combination of acquired mitral stenosis and an atrial septal defect a rare form of congenital mitral stenosis
In the elderly, a syndrome similar to mitral stenosis, which develops because of calcification and fibrosis of the valve, valve ring and subvalvular apparatus (chordae tendineae)
Carcinoid tumours metastasizing to the lung, or primary bronchial carcinoid
What is the pathophysiology for mitral stenosis
When the normal valve orifice area of 4–6 cm 2 is reduced to <1 cm2 , severe mitral stenosis is present. In order that sufficient cardiac output will be maintained, the left atrial pressure increases and left atrial hypertrophy and dilatation occur. Consequently, pulmonary venous, pulmonary arterial and right heart pressures also increase. The increase in pulmonary capillary pressure is followed by the development of pulmonary oedema particularly when the rhythm deteriorates to atrial fibrillation with tachycardia and loss of coordinated atrial contraction. This is partially prevented by alveolar and capillary thickening and pulmonary arterial vasoconstriction (reactive pulmonary hypertension). Pulmonary hypertension leads to right ventricular hypertrophy, dilatation and failure with subsequent tricuspid regurgitation
What are some symptoms of mitral stenosis
Usually there are no symptoms until the valve orifice is moderately stenosed (i.e. has an area of 2 cm2). In Europe, this does not usually occur until several decades after the first attack of rheumatic fever, but children of 10–20 years of age in the Middle or Far East may have severe calcific mitral stenosis
Because of pulmonary venous hypertension and recurrent bronchitis, progressively severe dyspnoea develops. A cough productive of blood-tinged, frothy sputum or frank haemoptysis may occur. The development of pulmonary hypertension eventually leads to right heart failure and its symptoms of weakness, fatigue and abdominal or lower limb swelling.
The large left atrium favours atrial fibrillation, giving rise to symptoms such as palpitations. Atrial fibrillation may result in systemic emboli, most commonly to the cerebral vessels resulting in neurological sequelae, but mesenteric, renal and peripheral emboli are also seen
What are some signs of mitral stenosis (pulse, murmur sounds)
Severe mitral stenosis with pulmonary hypertension is associated with the so-called mitral facies or malar flush. This is a bilateral, cyanotic or dusky pink discoloration over the upper cheeks that is due to arteriovenous anastomoses and vascular stasis
Mitral stenosis may be associated with a small-volume pulse which is usually regular early on in the disease process when most patients are in sinus rhythm. However, as the severity of the disease progresses, many patients develop atrial fibrillation resulting in an irregularly irregular pulse. The development of atrial fibrillation in these patients often causes a dramatic clinical deterioration
If right heart failure develops, there is obvious distension of the jugular veins. If pulmonary hypertension or tricuspid stenosis is present, the ‘a’-wave will be prominent provided that atrial fibrillation has not supervened
There is a tapping impulse felt parasternally on the left side
Auscultation reveals a loud first heart sound if the mitral valve is pliable, but it will not occur in calcific mitral stenosis. As the valve suddenly opens with the force of the increased left atrial pressure, an ‘opening snap’ will be heard. This is followed by a low-pitched ‘rumbling’ mid-diastolic murmur best heard with the bell of the stethoscope held lightly at the apex with the patient lying on the left side
What are the ways in which you could judge the severity of mitral stenosis
The presence of pulmonary hypertension implies that mitral stenosis is severe. Pulmonary hypertension is recognized by a right ventricular heave, a loud pulmonary component of the second heart sound, eventually with signs of right-sided heart failure, such as oedema and hepatomegaly. Pulmonary hypertension results in pulmonary valvular regurgitation that causes an early diastolic murmur in the pulmonary area known as a Graham Steell murmur
The closeness of the opening snap to the second heart sound is proportional to the severity of mitral stenosis. The length of the mid-diastolic murmur is proportional to the severity
As the valve cusps become immobile, the loud first heart sound softens and the opening snap disappears
When pulmonary hypertension occurs, the pulmonary component of the second sound is increased
Patient is suspected of mitral stenosis. What investigations should you do to confirm
Chest X-ray
The chest X-ray usually shows a generally small heart with an enlarged left atrium. Late in the course of the disease a calcified mitral valve may be seen on a penetrated or lateral view. The signs of pulmonary oedema or pulmonary hypertension may also be apparent when the disease is severe
Electrocardiogram
In sinus rhythm the ECG shows a bifid P wave owing to delayed left atrial activation (Fig. 14.72). However, atrial fibrillation is frequently present. As the disease progresses, the ECG features of right ventricular hypertrophy (right axis deviation and perhaps tall R waves in lead V1)
Echocardiogram
Transthoracic echocardiography should be used to determine left and right atrial and ventricular size and function. The Wilkins score can be used to determine if the valve is suitable for percutaneous valvotomy. Transoesophageal echocardiography (TOE) is performed to detect the presence of left atrial thrombus (p. 687) or prior to consideration of surgical or percutaneous intervention
Cardiac magnetic resonance (CMR)
This can accurately show mitral valve anatomy although it is rarely used in mitral stenosis
What are some treatments of mitral valve stenosis
Mild mitral stenosis may need no treatment other than prompt therapy of attacks of bronchitis. Infective endocarditis in pure mitral stenosis is uncommon. Early symptoms of mitral stenosis such as mild dyspnoea can usually be treated with low doses of diuretics. The onset of atrial fibrillation requires treatment with digoxin and anticoagulation to prevent atrial thrombus and systemic embolization. If pulmonary hypertension develops or the symptoms of pulmonary congestion persist despite therapy, surgical relief of the mitral stenosis is advised. There are four operative measures
What are some operative measures for mitral stenosis
Trans-septal balloon valvotomy
Closed valvotomy
Open valvotomy
Mitral valve replacement
When is mitral valve replacement necessary
Mitral regurgitation is also present There is a badly diseased or badly calcified stenotic valve that cannot be reopened without producing significant regurgitation
There is moderate or severe mitral stenosis and thrombus in the left atrium despite anticoagulation
Artificial valves may work successfully for >20 years. Anticoagulants are generally necessary to prevent the formation of thrombus, which might obstruct the valve or embolize
What are the most frequent causes of mitral regurgitation
The most frequent causes of mitral regurgitation are degenerative (myxomatous) disease, ischemic heart disease, rheumatic heart disease, and infectious endocarditis. Mitral regurgitation is also seen in diseases of the myocardium (dilated and hypertrophic cardiomyopathy), rheumatic autoimmune diseases, e.g. systemic lupus erythematosus, collagen diseases, e.g. Marfan’s and Ehlers–Danlos syndromes, and drugs including centrally acting appetite suppressants (fenfluramine) and dopamine agonists (cabergoline)
What is the pathophysiology of mitral regurgitation
Regurgitation into the left atrium produces left atrial dilatation but little increase in left atrial pressure if the regurgitation is long-standing, as the regurgitant flow is accommodated by the large left atrium. With acute mitral regurgitation the normal compliance of the left atrium does not allow much dilatation and the left atrial pressure rises. Thus, in acute mitral regurgitation the left atrial v-wave is greatly increased and pulmonary venous pressure rises to produce pulmonary oedema. Since a proportion of the stroke volume is regurgitated, the stroke volume increases to maintain the forward cardiac output and the left ventricle therefore enlarges
The Carpentier classification uses mitral leaflet motion to divide patients into different classes according to the mechanism of regurgitation which can be useful when considering surgical intervention
What are some symptoms of mitral regurgitation
Mitral regurgitation can be present for many years and the cardiac dimensions greatly increased before any symptoms occur. The increased stroke volume is sensed as a palpitation’. Dyspnoea and orthopnoea develop owing to pulmonary venous hypertension occurring as a direct result of the mitral regurgitation and secondarily to left ventricular failure. Fatigue and lethargy develop because of the reduced cardiac output. In the late stages of the disease the symptoms of right heart failure also occur and eventually lead to congestive cardiac failure. Cardiac cachexia may develop. Thromboembolism is less common than in mitral stenosis, but subacute infective endocarditis is much more common
What are some signs of uncomplicated mitral regurgitation
Soft first heart sound, owing to the incomplete apposition of the valve cusps and their partial closure by the time ventricular systole begins Pansystolic murmur, owing to the occurrence of regurgitation throughout the whole of systole, being loudest at the apex but radiating widely over the precordium and into the axilla
Prominent third heart sound, owing to the sudden rush of blood back into the dilated left ventricle in early diastole
The signs related to atrial fibrillation, pulmonary hypertension, and left and right heart failure develop later in the disease. The onset of atrial fibrillation has a much less dramatic effect on symptoms than in mitral stenosis
