Heartbeat 1 -

But there is a more specific use:

: Every single beat originates from a specialized cluster of pacemaker cells in the right atrium known as the sinoatrial (SA) node. This node generates an electrical impulse that sweeps across the heart tissue. heartbeat 1

If you meant something else by "heartbeat 1" (e.g., a medical term, software heartbeat, hardware signal), tell me which and I’ll produce a tailored guide. But there is a more specific use: :