When one of your headline tests finds a winner, by default Chartbeat will play that winning headline on your homepage to all visitors.
If you want to stop autoplaying a winning headline, open the Heads Up Display pin for that headline, and in the 'Headline Testing' tab, select 'stop'.
Or, in the Headline Testing results page, headlines that are autoplaying have a green play button next to them. Select that button to stop an autoplaying headline.
If you've stopped a headline that Chartbeat was auto-playing and want that headline to be permanently played to all readers, you must change the headline directly in your CMS.