PassFinals
Cardiovascular

Mitral Stenosis

Mitral stenosis obstructs LA emptying, causing raised LA pressure, pulmonary hypertension and AF; rheumatic disease remains the classic cause.

In a nutshell

Mitral stenosis obstructs LA emptying. Recognise the opening snap and mid-diastolic rumble, confirm with echo, assess AF and embolism, and refer severe rheumatic disease for valvotomy or surgery.

Classic presentation

Exertional breathlessness or AF with an apical mid-diastolic rumble and opening snap.

Key points

  • Rheumatic disease is classic, but degenerative calcification and congenital disease also occur.
  • Tachycardia worsens symptoms by shortening diastolic filling time.
  • Echo assesses valve area, gradient, morphology, pulmonary pressure, RV response and thrombus risk.
  • AF and embolic symptoms are central complications; moderate/severe MS is outside the usual NICE DOAC pathway.
  • Consider transcatheter valvotomy for suitable severe rheumatic MS; surgery is used when unsuitable.
  • Pregnancy can unmask severe haemodynamic disease and warrants early specialist review.

First-line investigation

TTE, with TOE when thrombus or intervention anatomy needs clarification.

Management

Recognise decompensation

  • Acute pulmonary oedema, severe breathlessness, embolism or unstable AF needs urgent hospital/cardiology assessment.1,3

Define valve and rhythm status

  • Use TTE and ECG; add TOE before intervention or when LA thrombus is a concern.2,1

Relieve congestion and tachycardia

  • Use diuretics for congestion and consider a beta-blocker for moderate/severe MS with HF; manage rate under specialist/local protocol.1

Address AF and embolic risk

  • Moderate/severe MS is outside the usual NICE AF DOAC pathway; obtain specialist anticoagulation advice.3

Refer severe rheumatic MS

  • Consider valvotomy when suitable; offer surgical replacement when valvotomy is unsuitable.1,2

Surveil by severity

  • Use symptom-led review and UK echo intervals; new AF, TIA, pulmonary hypertension or RV impairment warrants earlier review.4,1

Exam traps

  • The opening snap is after S2 and becomes earlier as stenosis worsens; it is not itself a severity measure.
  • AF removes regular presystolic accentuation.
  • Do not use a generic DOAC rule for moderate/severe MS; follow the specialist valve/anticoagulation pathway.
  • Normal resting findings do not exclude exercise-related pulmonary hypertension.

Illustrations

Severe mitral stenosis on echocardiographyEchocardiographic panels demonstrating a markedly reduced mitral valve area and high transmitral Doppler velocity, with secondary right-sided pressure overload.Xue X et al., Frontiers in cardiovascular medicine 2026, CC-BY-4.0 · CC-BY-4.0

Key sources

  1. NICE NG208: Heart valve disease presenting in adults (Referral, investigation, pharmacological management, intervention and follow-up recommendations)Published 17 Nov 2021 | Updated 24 Oct 2025
  2. British Society of Echocardiography: Echocardiographic assessment of the mitral valve (UK assessment guideline for mitral stenosis and regurgitation)Published 1 Sept 2021
  3. NICE NG196: Atrial fibrillation: diagnosis and management (Anticoagulation recommendations and scope)Published 27 Apr 2021 | Updated 19 Jun 2024
  4. BSE/BHVS: Clinical indications and triage for echocardiography in heart valve disease (UK consensus on referral, red flags and surveillance)Published 1 Aug 2024

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.