Final answer:
A steep diastolic deceleration slope less than 200 msec indicates severe aortic regurgitation (AR).
Step-by-step explanation:
A steep diastolic deceleration slope (PHT less than 200 msec) is consistent with severe aortic regurgitation (AR). In general, diastolic deceleration slope refers to the rate at which the diastolic pressure decreases. A steep slope indicates a rapid decrease in diastolic pressure, which suggests severe AR. Severe AR means that the aortic valve is not closing properly and blood is leaking back into the left ventricle during diastole, causing the diastolic pressure to fall rapidly.