Mitral regurgitation full

• Mitral regurgitation (MR)


  Abnormalities of the valve leaflets, the annulus, the chordae tendineae or papillary muscles, or the left ventricle
• Causes of mitral regurgitation


  • Degenerative (myxomatous) disease
  • Ischemic heart disease
  • Rheumatic heart disease
  • Infectious endocarditis
• Other diseases associated with mitral regurgitation


  • Dilated and hypertrophic cardiomyopathy
  • Rheumatic autoimmune diseases, e.g. systemic lupus erythematosus
  • Collagen diseases, e.g. Marfan's and Ehlers–Danlos syndromes
  • Drugs including centrally acting appetite suppressants (fenfluramine) and dopamine agonists (cabergoline)
• Pathophysiology of mitral regurgitation

  1. Regurgitation into the left atrium produces left atrial dilatation

  2. In acute mitral regurgitation, the normal compliance of the left atrium does not allow much dilatation and the left atrial pressure rises, producing pulmonary oedema

  3. Since a proportion of the stroke volume is regurgitated, the stroke volume increases to maintain the forward cardiac output and the left ventricle therefore enlarges
• Carpentier classification

  Uses mitral leaflet motion to divide patients into different classes according to the mechanism of regurgitation, which can be useful when considering surgical intervention
• Mitral regurgitation

  • Can be present for many years
  • Cardiac dimensions greatly increased before any symptoms occur
  • Increased stroke volume is sensed as a palpitation
  • Dyspnoea and orthopnoea develop due to pulmonary venous hypertension
  • Fatigue and lethargy develop due to reduced cardiac output
  • In late stages, symptoms of right heart failure occur and lead to congestive cardiac failure
  • Cardiac cachexia may develop
  • Thromboembolism is less common than in mitral stenosis
  • Subacute infective endocarditis is much more common
• Physical signs of uncomplicated mitral regurgitation

  • Laterally displaced (forceful) diffuse apex beat and a systolic thrill (if severe)
  • Soft first heart sound, owing to the incomplete apposition of the valve cusps and their partial closure by the time ventricular systole begins
  • Pansystolic murmur, owing to the occurrence of regurgitation throughout the whole of systole, being loudest at the apex but radiating widely over the precordium and into the axilla
  • With a floppy mitral valve there may be a mid-systolic click, which is produced by the sudden prolapse of the valve and the tensing of the chordae tendineae that occurs during systole. This may be followed by a late systolic murmur owing to some regurgitation
  • Prominent third heart sound, owing to the sudden rush of blood back into the dilated left ventricle in early diastole (sometimes a short mid-diastolic flow murmur may follow the third heart sound)
• The signs related to atrial fibrillation, pulmonary hypertension, and left and right heart failure develop later in the disease
• The onset of atrial fibrillation has a much less dramatic effect on symptoms than in mitral stenosis
• Chest X-ray


  • Shows left atrial and left ventricular enlargement
  • Increase in the CTR
  • Valve calcification is seen
• Electrocardiogram

  1. Shows left atrial delay (bifid P waves)

  2. Shows left ventricular hypertrophy (tall R waves in left lateral leads, deep S waves in right-sided precordial leads)

  3. SV1 plus RV5 or RV6 >35 mm indicates left ventricular hypertrophy

  4. Atrial fibrillation may be present
• Left ventricular hypertrophy occurs in about 50% of patients with mitral regurgitation
• Echocardiogram


  A diagnostic test that uses ultrasound waves to create an image of the heart
• Echocardiogram findings

  • Dilated left atrium and left ventricle
  • Specific features of chordal or papillary muscle rupture
• Assessing severity of regurgitation using echocardiogram

  1. Colour Doppler to look at jet area and size of vena contracta

  2. Calculating regurgitant fraction, volume or orifice area
• Ventricular function dynamics

  Useful information regarding severity of condition can be obtained indirectly by observing
• Transoesophageal echocardiography


  Can be helpful to identify structural valve abnormalities before surgery and intraoperative TOE can aid assessment of the efficacy of valve repair
• Cardiac catheterization


  A diagnostic test that demonstrates a prominent left atrial systolic pressure wave and shows regurgitation of contrast injected into the left ventricle into an enlarged left atrium during systole
• Treatment for mild mitral regurgitation in the absence of symptoms

  1. Managed conservatively by following the patient with serial echocardiograms

  2. Prophylaxis against endocarditis is discussed in Chapter 4 (see p. 87)
• Evidence of progressive cardiac enlargement

  Generally warrants early surgical intervention
• Surgical intervention

  Either mitral valve repair or replacement
• Indications for surgical intervention

  • Symptomatic severe mitral regurgitation, left ventricular ejection fraction >30% and end-diastolic dimension of under 55 mm
  • Asymptomatic patients with left ventricular dysfunction (end-systolic dimension >45 mm and/or ejection fraction of under 60%)
  • Asymptomatic severe mitral regurgitation with preserved left ventricular function and atrial fibrillation and/or pulmonary hypertension
• The advantages of surgical intervention are diminished in more advanced disease
• Sudden torrential mitral regurgitation, as seen with chordal or papillary muscle rupture or infective endocarditis, necessitates emergency mitral valve replacement
• Management for patients not appropriate for surgical intervention, or in whom surgery will be performed at a later date

  1. Treatment with ACE inhibitors

  2. Diuretics

  3. Possibly anticoagulants
• Percutaneous mitral valve repair (MitraClip)


  Compared to cardiac surgery in the EVEREST II trial and appears effective in the short-term at reducing the severity of mitral regurgitation and providing symptomatic relief
• Percutaneous mitral valve repair (MitraClip)


  Appropriate in patients unsuitable for cardiac surgery
• Mitral regurgitation (MR)


  Abnormality or disease process that affects any one or more of the five functional components of the mitral valve apparatus (leaflets, annulus, chordae tendineae, papillary muscles, and subjacent myocardium)
• Causes of acute MR

  • Acute myocardial infarction with papillary muscle rupture
  • Blunt chest wall trauma
  • Infective endocarditis
• With acute MI, the posteromedial papillary muscle is involved much more frequently than the anterolateral papillary muscle because of its singular blood supply
• Transient, acute MR can occur during periods of active ischemia and bouts of angina pectoris
• Rupture of chordae tendineae can result in "acute on chronic MR" in patients with myxomatous degeneration of the valve apparatus
• Causes of chronic MR

  • Rheumatic disease
  • Mitral valve prolapse
  • Extensive mitral annular calcification
  • Congenital valve defects
  • Hypertrophic obstructive cardiomyopathy
  • Dilated cardiomyopathy
• Rheumatic heart disease is the cause of chronic MR in only about one-third of cases and occurs more frequently in males
• Rheumatic process


  Produces rigidity, deformity, and retraction of the valve cusps and commissural fusion, as well as shortening, contraction, and fusion of the chordae tendineae
• MR associated with mitral valve prolapse and hypertrophic obstructive cardiomyopathy


  Usually dynamic in nature
• MR in hypertrophic obstructive cardiomyopathy

  Occurs as a consequence of anterior papillary muscle displacement and systolic anterior motion of the anterior mitral valve leaflet into the narrowed LV outflow tract
• Annular calcification is especially prevalent among patients with advanced renal disease and is commonly observed in elderly women with hypertension and diabetes
• MR may occur as a congenital anomaly, most commonly as a defect of the endocardial cushions (atrioventricular cushion defects)
• A cleft anterior mitral valve leaflet accompanies primum atrial septal defect