American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the volume contraction (RV) associated with diagnosed severe aortic regurgitation?

1. Less than 30 mL/beat

2. Between 30-59 mL/beat

3. 60 mL/beat or greater

4. Exactly 30 mL/beat

The correct answer is: 60 mL/beat or greater

In the context of severe aortic regurgitation, the volume contraction, or regurgitant volume (RV), is an important parameter in understanding the hemodynamic changes that occur in this condition. Aortic regurgitation leads to the backflow of blood from the aorta into the left ventricle during diastole, which significantly increases the workload on the heart and results in various compensatory mechanisms. A volume contraction of 60 mL/beat or greater indicates that there is a significant degree of backward flow, which aligns with the classification of severe aortic regurgitation. This high volume of regurgitation suggests that the left ventricle is receiving an excessive amount of blood that it must pump out during systole, which can lead to left ventricular dilation and ultimately heart failure if not managed properly. In clinical practice, identifying such a substantial volume contraction is essential as it helps in determining the urgency of surgical intervention and the need for further evaluation of the patient's cardiovascular status. Monitoring regurgitant volume is a critical aspect in assessing the severity of aortic regurgitation, and the threshold of 60 mL/beat or more serves as a clear clinical marker for severe cases.