Medical Term:

pseudofusion beat


Definition: an electrocardiographic representation of a cardiac depolarization produced by superimposition of an ineffectual electronic pacemaker spike on a QRS-complex originating from a spontaneous focus within the heart; the pacemaker spike is ineffectual because the electronic discharge, which it represents graphically, occurred within the absolute refractory period of the spontaneous beat and is therefore not indicative of pacemaker malfunction.