What are the typical symptoms of mitral valve stenosis?

Symptoms of Mitral Valve Stenosis

Exertional dyspnea is the most common presenting symptom of mitral stenosis, developing gradually as patients unconsciously reduce their activity levels to avoid symptoms. 1

Primary Symptom Presentation

Dyspnea on exertion is the hallmark symptom that develops as mitral valve area decreases below 1.5 cm². 2 The key clinical challenge is that patients often adapt by progressively limiting their activities, making symptom assessment difficult. 1 Clinicians should specifically ask what the most vigorous activity the patient currently undertakes is and compare this with their previous capabilities to accurately assess functional limitation. 1

Symptom Triggers and Progression

Symptoms are initially precipitated by conditions that increase transmitral flow or decrease diastolic filling period, including: 2

• Exercise or emotional stress - increases cardiac output demands 2
• Infection or fever - increases metabolic demands 2
• Pregnancy - increases blood volume and cardiac output 2
• Atrial fibrillation with rapid ventricular response - shortens diastolic filling time and eliminates atrial kick 2, 3

As stenosis severity increases, progressively less effort is required to trigger symptoms, eventually leading to dyspnea at rest. 2

Spectrum of Clinical Manifestations

Heart Failure Symptoms (Most Common)

Heart failure symptoms predominate in 94% of symptomatic patients, with 64% presenting in NYHA class III or IV. 1 These include: 2

• Progressive dyspnea - from exertional to rest dyspnea
• Orthopnea - difficulty breathing when lying flat
• Paroxysmal nocturnal dyspnea - sudden nighttime breathlessness
• Pulmonary edema - in severe cases with acute decompensation 2

Pulmonary Manifestations

• Hemoptysis - occurs from rupture of bronchial veins due to elevated pulmonary venous pressure 2, 4
• Chronic cough - from pulmonary congestion 2
• Recurrent respiratory infections - from chronic pulmonary congestion 2

Cardiac Rhythm Disturbances

Atrial fibrillation is common, especially as disease progresses, and often precipitates acute decompensation due to loss of atrial contraction and shortened diastolic filling time. 2, 1, 3 Palpitations may be the presenting complaint. 1

Advanced Disease Manifestations

When pulmonary hypertension develops, patients may experience: 2

• Right ventricular failure symptoms - peripheral edema, ascites, hepatomegaly 2, 4
• Fatigue and weakness - from low cardiac output state 2, 1
• Systemic embolic events - stroke or peripheral embolism from left atrial thrombus formation 2, 4

Special Populations

Pediatric Presentation

In children, symptoms may be limited to: 1

• Tachypnea (rapid breathing)
• Dyspnea
• Failure to thrive

Physical Examination Findings

A diastolic rumbling murmur best heard at the apex with the patient in left lateral position is the characteristic auscultatory finding. 1 Additional findings include: 2, 1

• Opening snap after the second heart sound (characteristic of rheumatic MS) 2
• Loud first heart sound (S1) in early disease 2
• Signs of pulmonary hypertension - loud P2, right ventricular heave 1
• Signs of right heart failure - elevated jugular venous pressure, peripheral edema 1

Natural History and Symptom Development

There is typically a long latent period of 20 to 40 years from rheumatic fever to symptom onset in developed countries. 2 Once symptoms develop, there is another period of almost a decade before symptoms become disabling. 2 However, once significant limiting symptoms occur, untreated patients have a dismal 0% to 15% 10-year survival rate. 2

Critical Clinical Pitfall

Patients may appear "asymptomatic" while actually having severe functional limitation because they have unconsciously adapted their lifestyle to avoid symptom-provoking activities. 1 Exercise testing may safely elicit symptoms or demonstrate reduced exercise capacity in apparently asymptomatic patients, potentially reclassifying them from asymptomatic (Stage C) to symptomatic (Stage D). 1 The 6-minute walk test is a simple, reproducible tool for objectively assessing functional capacity, particularly in frail or elderly patients. 1

Hemodynamic Correlation

Symptoms typically do not occur at rest until mitral valve area decreases below 1.5 cm². 2 As cardiac output becomes subnormal at rest and fails to increase during exercise, effort tolerance progressively declines. 2 The degree of pulmonary vascular disease is also an important determinant of symptoms—paradoxically, severe pulmonary hypertension may protect against pulmonary edema by creating a "second obstruction" at the pulmonary arteriolar level. 2