Page 113 - Clinical Pearls in Cardiology

Valvular Heart Diseases 101

leaflet. This results in an abnormal anterior position of
this leaflet during systole with consequent reduction
in the area of coaptation of the leaflets. This, in turn,
leads to regurgitation of blood into the left atrium from
the left ventricle, even though the mitral leaflets are
structurally normal. This is referred to as functional
mitral regurgitation.
In functional MR, the regurgitant volume is relatively
small and the left ventricular dilatation and dysfunction
is relatively large when compared to the degree of
regurgitation. Also, the left atrium is less compliant.
Hence, these cases present early with symptoms like
pulmonary edema.
4. What are the important causes of dilated cardiomy-
opathy?
Dilated or congestive cardiomyopathy is an important
cause of systolic heart failure. The important causes of
dilated cardiomyopathy are the following:
• Infective (usually viral, rarely bacterial or fungal
myocarditis).
• Alcoholic cardiomyopathy due to ethanol abuse
(>90 g/day).
• Nutritional deficiency (e.g. wet beriberi in thiamine
deficiency).
• Drugs (e.g. doxorubicin, cyclophosphamide,
trastuzumab, etc.).
• Peripartum cardiomyopathy (last trimester or within
six months of delivery).
• Endocrinopathies (thyroid dysfunction, acromegaly,
etc.).
• Connective tissue disorders.