Task: Answer Verification
Input (English): Question: Does the tissue Doppler imaging derived post-systolic velocity notch originate at the aortic annulus?
Answer: The AA represents the site of the earliest onset and maximal amplitude of the PSN on the longitudinal velocity curve suggesting its mechanism to be that of an energy release at the instant of the aortic valve closure causing an apically directed acceleration of the myocardium. A substantial number of healthy subjects exhibit a second PSN spike predominantly at the level of the AA. Its mechanism remains to be elucidated.
Output (English): yes