Mitral stenosis

• Case history #1• A 52-year-old woman presents with gradually increasing dyspnoea

on exertion over the past 2 years. Recently she has required 2 pillows at night to alleviate recumbent dyspnoea. On examination, she has an apical diastolic murmur.

• Case history #2• A 36-year-old prima gravida presents with dyspnoea on exertion and

2 pillow orthopnoea during her second trimester. Previous physical examinations had disclosed no cardiac abnormalities. On current physical examination, she has a loud S1 and a 2/6 diastolic rumble.

• Other presentations• May present with atrial fibrillation, heart failure, or systemic

embolism.

• A 45-year-old woman working as a supermarket cashier comes to the outpatient clinic with the diagnosis of mitral stenosis. She tells a history of rheumatic fever during childhood but remained asymptomatic until the age of 38, when the diagnosis of rheumatic valve disease was established after a first episode of atrial fibrillation (AF). Electrical cardioversion was attempted but AF ultimately relapsed and became permanent the year after. With effective rate control, the patient resumed to an asymptomatic status and has been treated with warfarin and atenolol. Currently, she is in NYHA class I. On physical examination, an accentuated first heart sound with a low-pitched rumbling diastolic murmur is heard at the apex, with no other relevant abnormalities. ECG demonstrates atrial fibrillation with 65 bpm, otherwise unremarkable. On chest X-ray, the cardiac silhouette shows signs of left atrial enlargement and redistribution of pulmonary vascular flow towards the upper lung fields (Fig.1).

• Which of the treatment options would you consider adequate for an appropriate management of this patient?

•A. Recommend rheumatic fever prophylaxisB. Recommend infective endocarditis prophylaxisC. Add a diuretic to her current medicationD. Perform a cardioversion to restore sinus rhythmE. None of the previous

• Wrong Answer, right answer(s): E. None of the previousA-D: Despite the decrease in the prevalence of rheumatic heart disease in Western countries, rheumatic valve disease still remains a public health problem in developing countries. Rheumatic fever with carditis and residual heart disease requires antibiotic prophylaxis of recurrent episodes for 10 years or until the age of 40, whichever is longer (1).

• So, this patient doesn’t need rheumatic fever prophylaxis. Endocarditis prophylaxis for routine dental and respiratory procedures is no longer recommended for patients with mitral stenosis unless they have had implantation of an artificial valve (2). The mainstay of treatment are β-blockers or calcium channel blockers (eg, diltiazem) for heart rate control, and warfarin for prevention of embolic events in patients with any of the following: permanent or paroxysmal atrial fibrillation, prior embolism, dense spontaneous echo contrast, enlarged left atrium (diameter >50 mm) or a left atrial thrombus. Diuretics or long-acting nitrates are indicated in symptomatic patients, which is not the case of our patient (3). Significant mitral valve disease is a known factor that predisposes to AF recurrence and difficulty in maintenance of sinus rhythm. For permanent AF in these patients, cardioversion is not indicated, and AF is managed by rate control.

• The patient underwent an echocardiographic evaluation that revealed pure moderate mitral stenosis (orifice valve area of 1.3 cm2 by 2-D planimetry and 1.2 cm2 by the PHT method, with a mean gradient of 9 mmHg) - (video1 and figure2). The aortic and tricuspid valves were not affected. The left atrium was significantly enlarged (end-systolic biplane indexed volume of 110 ml/m2) and pulmonary artery systolic pressure was 33 mmHg. Laboratory results were normal except for a NT-pro BNP value of 342 pg/ml (reference value <125 pg/ml).

Case 2

• A 35 year old lady complained of progressive exertional shortness of breath in the past two years. Physical examination revealed a loud first heart sound, an opening snap and a mid diastolic rumbling murmur with an irregularly irregular pulse.

• 1. What diagnosis do these findings suggest?

• The physical examination findings suggest mitral stenosis with atrial fibrillation.

• 2. What is the underlying etiology?

• Most cases of mitral stenosis are caused by chronic rheumatic heart disease, although more than 50% of these patients do not have a known history of rheumatic fever. In the acute phase, rheumatic fever may cause mitral regurgitation. Mitral stenosis may develop a few years later and symptoms may not develop until many years afterwards. The stenosis is due to the thickening of the valve leaflets with fibrous obliteration. There may be calcium deposition of the leaflets, chordae and the annulus with commissural and chordal fusion. Eventually, a funnel-shaped mitral valve with a fish-mouth orifice may occur.

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• 3. What investigation is useful?

• Echocardiogram is the most convenient and accurate investigation of choice. It provides a definitive diagnosis, it assesses the severity of the stenosis and it can also evaluate the suitability of the valve (by assessing the degree of calcification, thickening and mobility of the valve leaflets) for percutaneous balloon valvuloplasty.

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• 4. What treatment does she need?

• Patients without symptoms only require antibiotic prophylaxis for infective endocarditis. Those with mild symptoms may be treated with diuretics to lower the left atrial pressure. In patients with atrial fibrillation, rate control is important to increase diastolic filling time. Digitalis and beta-blockers are the drugs of choice. As patients with mitral stenosis and atrial fibrillation are prone to thromobembolism and stroke, anticoagulation therapy with warfarin is mandatory unless contraindicated.

• Attempts to restore sinus rhythm with antiarrhythmic drugs or cardioversion are likely futile unless the degree of mitral stenosis is minimal. For symptomatic patients with moderate or severe mitral stenosis, open heart surgery (open mitral valvotomy/ mitral valve replacement) or percutaneous balloon mitral valvuloplasty would be indicated. In general, if the mitral valve is pliable, mobile and not heavily calcified and there is no associated significant mitral regurgitation, valvuloplasty would be the first choice as it is a minimally invasive procedure compared with open heart surgery.

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