Figure 7.

Unipole electrogram delay and unipolar voltage gradient. A: Quantification of conduction delay between unipolar pairs was performed by determining the difference in Uni1 and Uni2 activation times at short versus long extrastimulus coupling interval. There was a small but significant increase in conduction delay at sites showing extrastimulus coupling interval associated bipolar voltage attenuation. B: Quantification of unipolar voltage change with extrastimulus coupling interval was performed by determining the gradient of the initial voltage attenuation (m in Figure 1B) for unipolar signals. Unipolar voltage attenuation was significantly greater at sites demonstrating bipolar voltage attenuation