Improved pacing thresholds for capturing the heart are achieved by forming
a discontinuity in the cardiac tissue of the heart chamber, disposing a
pacing electrode at a distance less than a space constant of the cardiac
tissue from the discontinuity in the cardiac tissue, and applying a
stimulus of a first polarity at an energy insufficient to cause the
directly stimulated tissue adjacent to the pacing electrode to propagate
a depolarization wave through the cardiac tissue mass of the heart
chamber but sufficient to induce a transmembrane potential change at the
tissue adjacent to the discontinuity that results in a propagated wave
front. Thus, pacing energy is advantageously reduced.