. Author manuscript; available in PMC: 2014 Jul 7.
Published in final edited form as: J Am Soc Echocardiogr. 2013 Mar 21;26(5):548–555. doi: 10.1016/j.echo.2013.02.009
© 2013 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.