Page 129 - Clinical Pearls in Cardiology

Valvular Heart Diseases 117

Both the above mechanisms allow reflux of blood from
the aorta into the left ventricle. Causes of incompetent
valve cusps leading to AR include the following:
• Congenital—unicuspid or bicuspid aortic valve.
• Inflammatory—rheumatic fever, rheumatoid
arthritis, etc.
• Infective—endocarditis.

Aortic regurgitation due to the dilatation of the aortic
root occurs in the following conditions:
• Infective—syphilis.
• Degenerative—Marfan’s syndrome, Ehlers-Danlos
syndrome, etc.
• Inflammatory—connective tissue diseases.
26. What is the natural history of chronic aortic
regurgitation?
Aortic regurgitation produces a classic volume overload
state. The left ventricle initially dilates (eccentric
hypertrophy) to accommodate the excess volume of
blood refluxing into the ventricle from the aorta, and
it ejects more blood during systole. The left ventricular
compliance increases, and so the left ventricular filling
pressure remains relatively normal. The only symptom
at this stage may be palpitations due to the awareness of
the forceful left ventricular contraction. But with increase
in the regurgitant fraction (i.e. > 30%), there is decrease
in the compliance of the left ventricle, with subsequent
elevation of the left ventricular filling pressure. At this
point, symptoms of mild pulmonary congestion like
exertional dyspnea appear. As progressive left ventricular
dilatation occurs, there is depression of the myocardial
contractility, and features of left ventricular failure like
dyspnea and orthopnea appear. Some people with