the precordial thump has a very low success rate for the cardioversion of shockable rhythm. It needs to be delivered within the first few seconds of onset of VT/VF.
delivery of a precordial thump must not delay calling for help or accessing a defibrillator
should be considered appropriate only when several clinicians are present at a witnessed and monitored sudden collapse, and when a defibrillator is not immediately to hand.
a precordial thump should be undertaken immediately after confirmation of cardiac arrest but only by healthcare professionals trained in the technique
using the ulnar edge of a tightly clenched fist, deliver a sharp impact to the lower half of the sternum from a height of about 20 cm, then retract the fist immediately to create an impulse-like stimulus
a precordial thump is most likely to be successful in converting VT to sinus rhythm. Successful treatment of VF by precordial thump is much less likely. There are very rare reports of a precordial thump converting a perfusing to a non-perfusing rhythm