Fig 2. Kaplan-Meier survival curve of incident HF by quartiles of SDNN.
HF: heart failure; SDNN: standard deviation of normal-to-normal RR interval.
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.