An official website of the United States government
Here's how you know
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Kaplan-Meier curve for survival among 76 subjects stratified according to whether heart rate declined by 13 beats from min 6 during the 6MWT to 1 min after the 6MWT.