Invite a spectator to take your pulse. To ensure there is nothing restricting your pulse, allow them to check under your arms and examine your arms completely. They will agree there are no devices on you.
Ask them to find your pulse. When they have it, ask them to snap their fingers along with it... They will keep track of your pulse rate. Tell them no matter what happens to you, make sure they report ANY changes in your pulse rate.
You close your eyes and begin to breathe deeply and slowly... ask them if your pulse is getting stronger. They will agree it's beating harder. Then close your eyes and ask them if they feel the rate changing... they will say it's getting slower... and slower... and eventually only 1 beat every few seconds, and then it speeds back up to normal and goes faster and faster. Then the performer turns his attention inward and has a self-induced attack! This is "cardiac arrest"! The performer takes a deep breath and holds it and his pulse stops... after a few seconds it eases back to normal.
Comes complete with 7 page booklet of detailed instructions and routine.