title: Electrical alternans of pacemaker spike amplitude: an unusual manifestation of permanent pacemaker generator malfunction.
abstract: A case of electrical alternans of pacemaker stimulus amplitude is presented, with constant alternation of large and small amplitude pacemaker spikes without loss of ventricular capture, due to a defect in the oscillator hybrid of a rate programmable Medtronic unit. This represents an unusual electrocardiographic manifestation of pacemaker generator malfunction which, to our knowledge, has not been reported previously.
mesh_terms: D004562:Electrocardiography; D004868:Equipment Failure; D006327:Heart Block / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial / Q000009:adverse effects*