CURRENT STEERING FOR CARDIAC PACING

The disclosure describes capturing the cardiac tissue using current steering techniques with a multi-pole cardiac lead implanted near the cardiac tissue. The techniques may include current-controlled sources in an IMD to provide current regulation to the pacing pulses allowing direct stimulation through multiple electrode contacts with known current delivery to the tissue. This current steering technique may use a delivery current source coupled to a delivery electrode and a receiving current source coupled to a receiving electrode to steer the current to the desired tissue to be stimulated. In some examples, different electrode pairs may be paced sequentially or together. In other examples, two or more electrodes may be considered the "delivery electrodes" and two or more electrodes may be considered the "receiving electrodes." In some examples a current-controlled source in the IMD may be implemented using a source degeneration circuit.