Mitral Stenosis
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Direct answer
Nearly every mitral stenosis in India is rheumatic: commissural fusion and leaflet thickening shrink the orifice from its normal 4-6 square centimetres, so dyspnoea, atrial fibrillation, haemoptysis and embolic stroke follow as left atrial pressure climbs. The bedside triad — loud first heart sound, mitral opening snap and a mid-diastolic rumbling murmur at the apex, with presystolic accentuation lost in atrial fibrillation — remains the clinical spine. Severity is echocardiographic: severe stenosis means a valve area of 1 square centimetre or less with mean gradient above 10 mmHg and pulmonary hypertension. Symptomatic patients with pliable, minimally calcified valves, no left atrial thrombus and no more than mild regurgitation are the candidates for percutaneous balloon mitral valvotomy rather than valve replacement.
What you must remember
- Cause and demography: rheumatic heart disease accounts for the overwhelming majority of Indian cases, affecting young women especially — mitral stenosis is the commonest valve lesion encountered in Indian pregnancy.
- Auscultation sequence: loud S1, opening snap with A2-to-OS interval that shortens as the stenosis tightens, low-pitched mid-diastolic rumble with presystolic accentuation (lost in atrial fibrillation); Graham Steell murmur of pulmonary regurgitation signals severe pulmonary hypertension.
- Severity numbers: normal area 4-6 square centimetres; severe is 1 or less; mean gradient above 10 mmHg is severe (below 5 mild); pulmonary artery systolic pressure completes the assessment.
- Complication list: atrial fibrillation with left atrial thrombus and systemic embolism (stroke); haemoptysis from bronchial vein rupture (pulmonary apoplexy) and pink frothy pulmonary oedema; Ortner syndrome of hoarseness from left recurrent laryngeal nerve compression; pulmonary hypertension with right heart failure.
- Investigations: echocardiography for orifice planimetry, gradient, valve morphology (Wilkins score: leaflet mobility, thickening, calcification, subvalvular disease; roughly 8 or less favours percutaneous intervention), left atrial thrombus and coexistent regurgitation; ECG for atrial fibrillation and P mitrale; radiograph for left atrial enlargement (double density, posterior displacement) and Kerley B lines.
- Percutaneous transluminal mitral commissurotomy (balloon mitral valvotomy): indication — symptomatic patient with area 1.5 square centimetres or less, favourable morphology; exclusions — left atrial thrombus, moderate-to-severe mitral regurgitation, heavy commissural calcification, needing surgery for other valves; mechanism — splitting the fused commissures, hence rheumatic (not calcific degenerative) stenosis responds.
- Atrial fibrillation management: rate control with beta-blockers and anticoagulation with a vitamin K antagonist (INR 2-3); direct oral anticoagulants are not recommended in valvular atrial fibrillation.
- Pregnancy rule: load-tolerant care — avoid tachycardia and overload, beta-blockers for rate, balloon valvotomy for refractory New York Heart Association class III-IV disease.
From murmur to balloon
A 28-year-old woman has two years of exertional dyspnoea and now palpitation; she is in atrial fibrillation at 110 per minute, with a tapping apex, loud S1, opening snap and apical rumble. The echocardiogram quantifies the problem: valve area 1.1 square centimetres, mean gradient 12 mmHg, Wilkins score 7 with mobile leaflets and mild subvalvular change, no more than mild regurgitation, no left atrial thrombus, pulmonary artery systolic pressure 55 mmHg. Reason the pathway: anticoagulation with warfarin and rate control settle the immediate risk; the valve anatomy is favourable and she is symptomatic, so percutaneous balloon mitral commissurotomy offers definitive relief without a sternotomy or a prosthesis, expecting the area to approach 1.8-2 square centimetres; the acute complication to watch for is procedure-induced severe mitral regurgitation, and the long-term reality is restenosis over years. Had the echo shown thrombus or heavy calcification with significant regurgitation, the conversation would move directly to surgical repair or replacement — the score exists to route patients, not to delay them.
The Indian reality
Rheumatic mitral stenosis in a young woman is among the commonest cardiac diagnoses in Indian OPDs, and three programme-level facts matter. Secondary prophylaxis with monthly benzathine penicillin prevents the next attack and the next valve — treating the episode while forgetting the injection is the most common failure of care. Pregnancy collides with mitral stenosis constantly: the volume and rate load of the second and third trimesters turn a tolerable lesion into pulmonary oedema, so pre-conception counselling, strict rate control and balloon valvotomy for refractory cases are the sequence taught in Indian obstetric-cardiology rounds. Balloon mitral valvotomy is widely available and far cheaper than valve replacement, but warfarin monitoring and follow-up echo discipline remain genuine barriers.
Frequently asked questions
What is the commonest cause of mitral stenosis in India?
Rheumatic heart disease — commissural fusion from earlier carditis, overwhelmingly affecting young adults, women more than men.
Which echo parameters define severe mitral stenosis?
Valve area 1 square centimetre or less, mean diastolic gradient above 10 mmHg, with elevated pulmonary artery systolic pressure.
When is balloon mitral valvotomy contraindicated?
Left atrial thrombus, more than mild mitral regurgitation, unfavourable heavily calcified valves, or disease requiring surgery on other valves.
What does a short A2-to-opening snap interval indicate?
A higher left atrial pressure — the valve opens earlier in diastole, so the interval shortens as stenosis worsens.
Which anticoagulant suits atrial fibrillation with moderate-to-severe mitral stenosis?
A vitamin K antagonist targeting INR 2-3; direct oral anticoagulants are not recommended in this valvular atrial fibrillation.