2 Mitral regurgitation
Salient features
History
• Asymptomatic or mild symptoms: often
• Shortness of breath (from pulmonary congestion)
• Fatigue (from low cardiac output)
• Palpitation (from atrial fibrillation or LV dysfunction)
• Fluid retention (in late-stage disease)
• Obtain a history of myocardial infarction, rheumatic fever, connective tissue disorder, infective endocarditis.
Examination
• Peripheral pulse may be normal or jerky (i.e. rapid upstroke with a short duration).
• Apex beat will be displaced downwards and outwards and will be forceful in character.
• First heart sound will be soft.
• Third heart sound is common (left ventricular gallop sound).
• Pansystolic murmur (Hope murmur) (Fig. 2.1) conducted to the axilla, best detected with the diaphragm and on expiration. (Note: It is important to be sure that there is no associated tricuspid regurgitation.)
• Loud pulmonary second sound and left parasternal heave when there is associated pulmonary hypertension.
Fig. 2.1 (A) Phonocardiogram of a patient with acute severe mitral regurgitation showing a decrescendo early systolic murmur and diastolic filling sound (S3). (B) Pressure waveforms showing an abrupt rise in LA pressure and attenuation of the LV–LA pressure gradient, resulting in the duration and configuration of the murmur.
Note: When mitral regurgitation is caused by left ventricular dilatation and diminished cardiac contractility, the systolic murmur may be mid, late or pansystolic. Other causes of short systolic murmurs at the apex include mitral valve prolapse, papillary muscle dysfunction and aortic stenosis. In calcific aortic stenosis of the elderly, the murmur may be more prominent in the apex and may be confused with mitral regurgitation. In such instances try to listen to the murmur after a pause with premature beat or listen to the beat after a pause with atrial fibrillation. The murmur of aortic stenosis becomes louder, whereas that of mitral regurgitation shows little change.
Diagnosis
This patient has mitral regurgitation (lesion) as evidenced by grade III/VI pansystolic murmur, which is probably caused by ischaemic or rheumatic heart disease (aetiology), and is in cardiac failure as evidenced by bibasal crackles (functional status). The patient is in NYHA class III heart failure.
Questions
How would you investigate this patient?
• ECG: look for broad bifid P waves (P mitrale), left ventricular hypertrophy, atrial fibrillation. When coronary artery disease is the cause, there is often evidence of inferior or posterior wall myocardial infarction.
• Radiography can assess pulmonary congestion, large heart, left atrial enlargement and pulmonary artery enlargement (if severe and long-standing).
• Echocardiography determines the anatomy of the mitral valve apparatus, left atrial and left ventricular size and function (typical features include large left atrium, large LV, increased fractional shortening, regurgitant jet on colour Doppler, leaflet prolapse, floppy valve or flail leaflet). The echocardiogram provides baselines estimation of LV and left atrial volume, an estimation of left ventricular ejection fraction, and approximation of the severity of regurgitation. It can be helpful to determine the anatomic cause of mitral regurgitation. In the presence of even mild tricuspid regurgitation, an estimate of pulmonary artery pressure can be obtained.
• Transoesophageal echocardiogram is useful when transthoracic echocardiography provides non-diagnostic images. It may give better visualization of mitral valve prolapse. It is useful intraoperatively to establish the anatomic basis for mitral regurgitation and to guide repair.
• Cardiac catheterization is useful to determine coexistent coronary artery or aortic valve disease. Large ‘v’ waves are seen in the wedge tracing. Left ventriculogram and haemodynamic measurements are indicated when non-invasive tests are inconclusive regarding the severity of mitral regurgitation, LV function, or the need for surgery.
How would you differentiate between mitral regurgitation and tricuspid regurgitation?
| Mitral regurgitation | Tricuspid regurgitation | |
|---|---|---|
| Pulse | Jerky or normal | Normal |
| Jugular venous pressure | Prominent ‘v’ wave | |
| Palpation | Left ventricular heave | Left parasternal heave |
| Auscultation | Pansystolic murmur | Pansystolic murmur |
| Intensity increases with expiration | Intensity increases with inspiration | |
| Radiates to the axilla | ||
| Other signs | Hepatic pulsations |
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