. Author manuscript; available in PMC: 2010 Dec 1.
Published in final edited form as: J Am Soc Echocardiogr. 2009 Oct 31;22(12):1396–1402. doi: 10.1016/j.echo.2009.09.012
© 2009 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.