What is the difference between single and dual field PV catheters?

The single field method uses one excitation electrode located at the proximal end of the measurement area and one ground electrode located at the distal end of the measurement area to generate an electrical field with in the heart. The change in conductance as the blood pool changes is measured across each electrode segment and then summed for a total volume signal. Single field catheters can be quickly identified by the uniform spacing of the electrodes over the entire length of the measurement area.

The dual field method also uses one excitation electrode located at the proximal end of the measurement area and one ground electrode located at the distal end of the measurement area to generate an electrical field with in the heart. In addition to these electrodes, a secondary excitation electrode and a secondary ground electrode is placed next to the primary ground electrode at the distal end of the measurement area. These electrodes create a second electrical field which serves to expand the primary field to create a more uniform electrical field over the length of the measurement area. The change in conductance as the blood pool changes is then measured across each electrode segment and then summed for a total volume signal in the same manner as the single field configuration. Dual field catheters can be quickly identified by the group of 3 closely spaced electrodes at either the proximal or distal end of the measurement area.