Encyclopedia http://www.heart.org/HEARTORG/Encyclopedia/Heart-and-Stroke-Encyclopedia_UCM_445084_Encyclopedia.jsp The American Heart Association's Heart and Stroke Encyclopedia. Thu, 02 May 2013 19:27:00 GMT http://www.heart.org/HEARTORG/Encyclopedia/Heart-and-Stroke-Encyclopedia_UCM_445084_Encyclopedia.jsp 2013-05-02T19:27:00Z