Submitted on: 08 November 2014.
Revised on: 06 December 2014.
Accepted on: 01 February 2015.
___________________Cardiovascular Ultrasound---BMC
http://reply.papertrans.cn/1/48/4791/4791-32.png
Submitted on: 26 November 2006.
Revised on: 21 March 2007.
Accepted on: 29 April 2007.
___________________Cardiovascular Ultrasound---BMC
http://reply.papertrans.cn/1/48/4791/4791-34.png
Submitted on: 27 December 2008.
Revised on: 08 March 2009.
Accepted on: 01 April 2009.
___________________Cardiovascular Ultrasound---BMC
http://reply.papertrans.cn/1/48/4791/4791-36.png