The occurrence of anodal stimulation during bipolar pacing in implantable pacemakers

An attempt was made to determine the anodal threshold during bipolar pacing using different pacemaker leads from three manufacturers and to determine whether simultaneous anodal and cathodal stimulation were responsible for the observed morphological changes in the evoked electrogram. Seven animals were studied. The results indicated that the anodal threshold was not a definitive value, but was a probability curve. The studies determined that the lowest anodal threshold ranged from 1.8 V to >6.7 V. In addition, the occurrence of anodal stimulation was highly correlated with changes in the bipolar evoked electrogram. There was also a correlation between anodal stimulation threshold during bipolar pacing and the anodal unipolar pacing threshold.<
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