Abstract :
During continuous pacing experiments at the University of Missouri Medical Center, Columbia, with the micromodule pacemaker receiver´ implanted on the left ventricle of thirty-six mongrel dogs in complete heart block, it was observed that after 24 days in one case, 52 days in another, and 35 days in a third, micromodules with stainless steel electrodes failed to pace. Upon reoperation it was discovered that the positive electrode of one module had been reduced to a short stub. In another module the positive electrode was loose, disrupting the circuit. In the third module the positive electrode was completely missing.
