An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
el-Sherif N, Bekheit SS, Henkin R.el-Sherif N, et al.J Am Coll Cardiol. 1989 Jul;14(1):252-7. doi: 10.1016/0735-1097(89)90082-x.J Am Coll Cardiol. 1989.PMID: 2738268Free article.