What is the management approach for a patient presenting with criteria suggestive of mitral stenosis, including a 'p mitrale' (P-wave abnormality) on electrocardiogram (ECG)?

Management of Mitral Stenosis with P Mitrale on ECG

Patients with P mitrale on ECG suggesting mitral stenosis should undergo comprehensive echocardiographic assessment followed by intervention based on valve morphology, with percutaneous mitral commissurotomy (PMC) as first-line treatment for symptomatic patients with favorable valve anatomy. 1

Diagnostic Approach

ECG Finding: P Mitrale

• P mitrale (wide, notched P waves ≥0.12 seconds in duration) indicates left atrial enlargement, a common finding in mitral stenosis 2
• This ECG finding should prompt further evaluation for mitral valve disease

Initial Assessment

• Echocardiography is the cornerstone of diagnosis and should include:
  • Measurement of mitral valve area (MVA) using planimetry (reference method) 1
  • Assessment of mean transvalvular gradient
  • Evaluation of pulmonary artery pressure
  • Assessment of valve morphology (for PMC suitability)
  • Evaluation of concomitant valvular lesions 1

Severity Classification

Severity	MVA (cm²)	Mean Gradient (mmHg)	PASP (mmHg)
Mild	>1.5	<5	<30
Moderate	1.0-1.5	5-10	30-50
Severe	<1.0	>10	>50

Additional Testing

• Transesophageal echocardiography (TOE) should be performed:
  • To exclude left atrial thrombus before PMC
  • After embolic episodes
  • When transthoracic echo provides suboptimal data 1
• Exercise echocardiography is indicated when:
  • Symptoms are disproportionate to resting hemodynamics
  • Patient is asymptomatic but has severe stenosis 1

Management Algorithm

For Symptomatic Patients with Moderate to Severe MS (MVA <1.5 cm²):

1. Evaluate valve morphology for PMC suitability:

   • Favorable characteristics: mobile valve, minimal subvalvular thickening, minimal calcification
   • Unfavorable characteristics: extensive calcification, severe subvalvular apparatus involvement, severe leaflet thickening 1

2. For patients with favorable valve morphology:

   • PMC is indicated as first-line treatment (Class I recommendation) 1
   • Surgical commissurotomy may be considered by experienced teams, especially in young patients with mild to moderate mitral regurgitation 1

3. For patients with unfavorable valve morphology:

   • Consider PMC as initial treatment in selected patients with mild to moderate calcification or impaired subvalvular apparatus who have otherwise favorable clinical characteristics 1
   • Mitral valve surgery (usually valve replacement) is indicated for patients unsuitable for PMC 1

4. For patients with contraindications to surgery:

   • PMC is indicated regardless of valve anatomy if surgical risk is high 1

For Asymptomatic Patients with Moderate to Severe MS:

1. PMC should be considered when:

   • Patient has favorable valve morphology AND one of the following:
     • High thromboembolic risk (history of embolism, dense spontaneous contrast in LA, new-onset AF)
     • High risk of hemodynamic decompensation (PASP >50 mmHg, need for major non-cardiac surgery, desire for pregnancy) 1

2. Surgery is indicated when:

   • Patient has high risk of cardiac complications
   • PMC is contraindicated
   • Surgical risk is low 1

Important Considerations

Left Atrial Thrombus

• Left atrial thrombus is the most important contraindication to PMC 1
• If thrombus is located in the LA appendage:
  • PMC may be considered after 1-3 months of oral anticoagulation if repeat TOE shows thrombus resolution
  • Surgery is indicated if thrombus persists 1

Atrial Fibrillation

• Common in patients with mitral stenosis and P mitrale
• Vitamin K antagonists remain the standard of care for anticoagulation in patients with moderate to severe rheumatic mitral stenosis with AF 4
• NOACs (specifically rivaroxaban) showed worse outcomes compared to warfarin in the INVICTUS trial 4

Follow-up

• Symptomatic patients who do not undergo intervention should have regular clinical and echocardiographic follow-up
• Asymptomatic patients with severe MS should be followed annually with clinical and echocardiographic evaluation 1

Pitfalls to Avoid

• Do not rely solely on MVA for determining severity; consider mean gradient and pulmonary pressures
• Do not delay intervention in symptomatic patients with severe MS
• Do not use NOACs instead of vitamin K antagonists in patients with moderate to severe rheumatic MS and AF
• Do not overlook the possibility of left atrial thrombus before PMC