The new video heartbeat capability is provided as part of the Adobe Analytics solution (formerly known as Omniture SiteCatalyst). This enables you to measure video consumption on your website, including video starts, video completes, time spent watching video, video ad impressions, etc. There is extensive documentation about how to enable this in your Adobe Analytics account here:
Additionally, if your are also using Adobe Primetime video player SDK to build your media player, the video heartbeats are able to capture quality-of-streaming information about your video playback in real-time (such as error rate, buffer rate, bitrate changes, etc.)
Please let me know if there is anything specific I can help you with.