pseudofusion beat


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pseu·do·fu·sion beat

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.

pseudofusion beat

Cardiology A cardiac complex or an ECG waveform, which corresponds to the superimposition of an ineffective pacemaker spike on a spontaneous P or QRS complex originating from a single focus; the pacing stimulus is delivered after the chamber has already spontaneously depolarized; thus the stimulus does not cause contraction. Cf Fusion beat, Pseudopseudofusion beat.