1 Mitral stenosis
Instruction
This patient developed shortness of breath and orthopnoea during pregnancy, please examine.
This 55-year-old patient has atrial fibrillation, please do the relevant clinical examination.
Salient features
History
Examination
• Pulse is regular or irregularly irregular (from atrial fibrillation).
• Jugular venous pressure (JVP) may be raised.
• Tapping apex beat in the 5th intercostal space just medial to midclavicular line.
• Left parasternal heave (indicating right ventricular enlargement).
• Opening snap (OS; often difficult to hear; a high-pitched sound that can vary from 0.04 to 0.10 s after the second sound (S) and is heard best at the apex with the patient in the lateral decubitus position).
• Rumbling, low-pitched, mid-diastolic murmur, best heard in the left lateral position on expiration. In sinus rhythm there may be presystolic accentuation of the murmur. If you are not sure about the murmur, tell the examiner that you want the patient to perform sit-ups or hopping on one foot to increase the heart rate. This will increase the flow across the mitral valve and the murmur is better heard.
Notes
1 Remember the signs of pulmonary hypertension include loud P2, right ventricular lift, elevated neck veins, ascites and oedema. This is an ominous sign of the disease progression because pulmonary hypertension increases the risk associated with surgery (Br Heart J 1975;37:74–8).
2 In patients with valvular lesions, a candidate would be expected to comment on rhythm, the presence of heart failure and signs of pulmonary hypertension.
3 In atrial septal defect, large flow murmurs across the tricuspid valve can cause mid-diastolic murmurs. The presence of wide, fixed splitting of second sound, absence of loud first heart sound, and an opening snap and incomplete right bundle branch block should indicate the correct diagnosis. However, about 4% of the patients with atrial septal defect have mitral stenosis, a combination called Lutembacher syndrome.
Diagnosis
This patient has mitral stenosis (lesion), which is almost always caused by rheumatic heart disease (aetiology), and has atrial fibrillation, pulmonary hypertension and congestive cardiac failure (functional status).
Questions
What is the pathology of mitral stenosis?
The main features are leaflet thickening, nodularity and commissural fusion, all of which result in narrowing of the valve to the shape of a fish mouth.
What is the natural history of mitral stenosis?
• From the occurrence of rheumatic fever to the onset of symptoms, there is a long latent period of 20 to 40 years in Europe and North America.
• Moreover, there is a further period of about 10 years before symptoms become disabling.
• The 10-year survival of untreated patients is 50% to 60%, depending on symptoms at presentation:
• Mortality of untreated patients is caused by:
What does the opening snap indicate?
The opening snap is caused by the opening of the stenosed mitral valve and indicates that the leaflets are pliable. The opening snap is usually accompanied by a loud first heart sound. It is absent when the valve is diffusely calcified. When only the tips of the leaflets are calcified, the opening snap persists.
What is the mechanism of a loud first heart sound?
The loud first heart sound occurs when the valve leaflets are mobile. The valve is open during diastole and is suddenly slammed shut by ventricular contraction in systole.
What is the mechanism of presystolic accentuation of the murmur?
In sinus rhythm it is caused by the atrial systole, which increases flow across the stenotic valve from the left atrium to the left ventricle (LV); this causes accentuation of the loudness of the murmur. This may also be seen in atrial fibrillation and is explained by the turbulent flow caused by the mitral valve starting to close with the onset of ventricular systole. This occurs before the first heart sound and gives the impression of falling in late diastole. It is, however, caused by the start of ventricular systole.
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