Aortic Regurgitation produces a different kind of strain on the heart. The failure of the aortic valve to close properly allows blood to leak back into the left ventricle, instead of continuing up through the ascending aorta. The heart must compensate for this leakage to keep up with the demand for blood throughout the body.

To compensate for leakage, the heart can beat faster or pump more blood with each beat. The heart typically chooses the latter, because it needs time between beats to relax and nourish itself. To pump more blood with each beat the heart must expand, making the hollow space in the left ventricle larger. An enlarged left ventricle can be filled with more blood than a normal sized left ventricle. As the heart squeezes the enlarged left ventricle, more blood is pumped per beat.

Left Ventricular Dilatation (expansion) is well tolerated to a point (about twice its normal dimensions). However, like an elastic waistband that keeps getting stretched, ultimately, it cannot return to normal. Irreversible damage to the heart occurs if it stretches too far.

Echo cardiograms are used to follow the course of this dilatation and determine the severity of the regurgitation. In general, the left ventricular end systolic dimension should never exceed 5.5 cm and some cardiologists believe 5.0 is to big. The ejection fraction should also be monitored and not allowed to fall below 50%. Exercise echo's or nuclear ventriculograms can also be used to test the reserve capacity of the heart. An increase in ejection fraction is normal with exercise. Failure to increase or evidence of decrease in ejection fraction with exercise is a sign that surgery should be considered sooner rather than later to prevent further loss of reserve. This is extremely important because many patients have little if any symptoms (usually shortness of breath on exertion) until the heart has been damaged to a great extent. Of course, if symptoms should appear before the numbers look bad, the doctor should listen to the patient! Symptoms are an indication for surgery.

Medications such as nifedipine and possible ACE inhibitors or ARB's may allow surgery to be delayed in asymptomatic patients for as long as two years, but these patients must be followed closely with echo for signs of deterioration. Every six months is reasonable.