Page 112 - Clinical Pearls in Cardiology

100 Clinical Pearls in Cardiology

2. What is the natural history of mitral regurgitation?
The patients with chronic mitral regurgitation are usually
asymptomatic. In chronic mitral regurgitation, the left
atrium is more compliant and dilated than in acute
mitral regurgitation. So the left atrial pressure is normal
even if the regurgitation is severe. Therefore, those
with severe chronic mitral regurgitation may have only
minimal symptoms for years. Fatigue due to low cardiac
output (due to regurgitation of part of the stroke volume
into the left atrium) and mild excertional dyspnea (due
to dysfunction of the dilated left ventricle) are the usual
initial symptoms. However, acute pulmonary edema may
be precipitated by any of the following:
• New onset of atrial fibrillation
• Sudden increase in the severity of regurgitation in
conditions like endocarditis or ruptured chordae
• New onset ischemia causing worsening of left
ventricular dysfunction.
Sudden death is one of the dreaded complications of
severe asymptomatic mitral regurgitation. In those with
acute onset of regurgitation, the sudden regurgitation
of large volume of blood into a non-compliant left
atrium results in high left atrial and pulmonary venous
pressures, producing acute pulmonary edema.
3. What are the characteristics of functional mitral
regurgitation?
In some diseases affecting the myocardium, like chronic
myocardial ischemia or in cardiomyopathies like dilated
cardiomyopathy, there is left ventricular dilatation. The
abnormal shape and systolic contraction of the left
ventricle produce an excessive traction on the chordae,
which is mainly transmitted to the anterior mitral