A medical system comprising: an implantable medical device coupled to a cardiac lead and configured to deliver pacing therapy to cardiac tissue of a heart via a plurality of electrodes of the cardiac lead, wherein the implantable medical device comprises a first current source (Ihigh, 108) configured to output an electrical current stimulation pulse and a second current source (Ilow, 125) configured to sink the electrical current stimulation pulse to capture a portion of the cardiac tissue; and processing circuitry configured to: electrically connect the first current source to a first electrode (102, 44) of the plurality of electrodes to output the electrical current stimulation pulse to the cardiac tissue; and electrically connect the second current source to a second electrode (120, 45) of the plurality of electrodes to sink the electrical current stimulation pulse to the cardiac tissue, wherein a first channel of implantable medical device comprises the first current source, the first channel further comprising: a first switch (S1P, 104) configured to connect an output terminal of the first current source (Ihigh, 108) to the first electrode (LV1, 102, 44); a first recharge switch (S1R, 112) configured to connect the first electrode to a reference voltage; a second recharge switch (S2R, 114) configured to connect the first electrode to the reference voltage through a capacitor; a further current source (Ilow, 110) comprising an input terminal and an output terminal wherein: the output terminal of the further current source connects to the reference voltage, the input terminal of the further current source is configured to connect to the first electrode through the capacitor and a second switch (S2P, 106), and the further current source is configured to sink current from the first electrode when the second switch is closed for conducting current. an implantable medical device coupled to a cardiac lead and configured to deliver pacing therapy to cardiac tissue of a heart via a plurality of electrodes of the cardiac lead, wherein the implantable medical device comprises a first current source (Ihigh, 108) configured to output an electrical current stimulation pulse and a second current source (Ilow, 125) configured to sink the electrical current stimulation pulse to capture a portion of the cardiac tissue; and processing circuitry configured to: electrically connect the first current source to a first electrode (102, 44) of the plurality of electrodes to output the electrical current stimulation pulse to the cardiac tissue; and electrically connect the second current source to a second electrode (120, 45) of the plurality of electrodes to sink the electrical current stimulation pulse to the cardiac tissue, electrically connect the first current source to a first electrode (102, 44) of the plurality of electrodes to output the electrical current stimulation pulse to the cardiac tissue; and electrically connect the second current source to a second electrode (120, 45) of the plurality of electrodes to sink the electrical current stimulation pulse to the cardiac tissue, wherein a first channel of implantable medical device comprises the first current source, the first channel further comprising: a first switch (S1P, 104) configured to connect an output terminal of the first current source (Ihigh, 108) to the first electrode (LV1, 102, 44); a first recharge switch (S1R, 112) configured to connect the first electrode to a reference voltage; a second recharge switch (S2R, 114) configured to connect the first electrode to the reference voltage through a capacitor; a further current source (Ilow, 110) comprising an input terminal and an output terminal wherein: the output terminal of the further current source connects to the reference voltage, the input terminal of the further current source is configured to connect to the first electrode through the capacitor and a second switch (S2P, 106), and the further current source is configured to sink current from the first electrode when the second switch is closed for conducting current. a first switch (S1P, 104) configured to connect an output terminal of the first current source (Ihigh, 108) to the first electrode (LV1, 102, 44); a first recharge switch (S1R, 112) configured to connect the first electrode to a reference voltage; a second recharge switch (S2R, 114) configured to connect the first electrode to the reference voltage through a capacitor; a further current source (Ilow, 110) comprising an input terminal and an output terminal wherein: the output terminal of the further current source connects to the reference voltage, the input terminal of the further current source is configured to connect to the first electrode through the capacitor and a second switch (S2P, 106), and the further current source is configured to sink current from the first electrode when the second switch is closed for conducting current. the output terminal of the further current source connects to the reference voltage, the input terminal of the further current source is configured to connect to the first electrode through the capacitor and a second switch (S2P, 106), and the further current source is configured to sink current from the first electrode when the second switch is closed for conducting current.