Effects of electrode size and spacing on the resolution of intracardiac electrograms.

Background: Electrogram fractionation can result when multiple groups of cardiac cells are excited asynchronously within the recording region of a mapping electrode. The spatial resolution of an electrode thus plays an important role in mapping complex rhythms.

Methods: We used a computational model, validated against experimental measurements in vitro, to determine how spatial resolution is affected by electrode diameter, electrode length, interelectrode distance (in the case of bipolar recordings), and height of the electrode above a dipole current source.

Results: We found that increases in all these quantities caused progressive degradation in two independent measures of spatial resolution, with the strongest effect being due to changes in height above the tissue.

Conclusion: Our calculations suggest that if electrodes could be constructed to have negligible dimensions compared with those in use today, we would increase resolution by about one order of magnitude at most.