For those sitting exams soon. And for those who haven’t opened Talley & O’Connor’s for a while.
Mitral stenosis
Normal surface: 4 – 6 cm2; patients become symptomatic when surface < 2 cm2 and life expectancy (without surgical treatment) is 2 – 5 years after onset of symptoms
Causes:
– rheumatic fever – onset ~ 2 yrs after the acute episode
– congenital – parachute valve
Symptoms:
– dyspnoea / orthopnoea / paroxysmal nocturnal dyspnoea
– haemoptysis; fatigue (pulmonary hypertension)
– dysphonia / dysphagia if grossly enlarged left atrium compressing the left recurrent laryngeal nerve or oesophagus
Once right ventricular failure occurs – ascites, peripheral oedema.
10 – 15 % of patients have chest pain due to acute right ventricular pressure overload or due to emboli from the left atrium into the coronary circulation.
Signs:
tachypnoea
atrial fibrillation
mitral facies / peripheral cyanosis in severe cases
tapping apex beat; right ventricular heave
prominent a wave (JVP) if pulmonary hypertension is present (but lost if patient is in atrial fibrillation)
loud S1; loud P2 (if pulmonary hypertension present)
low-pitched rumbling diastolic murmur (best auscultated over the apex with the bell and the patient in left lateral decubitus; louder after exercise)
ECG findings:
– right axis deviation in severe disease
Severe mitral stenosis:
– symptoms / signs of pulmonary hypertension
– early opening snap
– long diastolic murmur
– decreased pulse pressure
– valve area < 1 cm2 on echo
– presence of pulmonary or tricuspid regurgitation
Management precautions:
– increased cardiac output or heart rate will increase the flow across the valve and the transvalvular pressure gradients – AVOID tachycardia and both hypovolaemia and fluid overload
– avoid ketamine
– cautious use of nitrous oxide (Entonox) as it can increase the pulmonary vascular resistance