. Author manuscript; available in PMC: 2013 Oct 28.
Published in final edited form as: J Am Soc Echocardiogr. 2009 Jun 23;22(8):10.1016/j.echo.2009.05.002. doi: 10.1016/j.echo.2009.05.002
© 2009 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.