An apparatus for electrical coupling to a plurality of implantable electrodes, the apparatus comprising: a cardiac signal sensing circuit configured to sense a cardiac activity signal using a sensing channel that includes implantable electrodes of the plurality of electrodes; a stimulus circuit configured to provide electrical pulse energy using at least a first left ventricular (LV) pacing channel that includes a first LV electrode , and a second LV pacing channel that includes a second LV electrode ; and a control circuit operatively coupled to the stimulus circuit and the cardiac signal sensing circuit and configured to: initiate delivery of electrical pulse energy using the first and second pacing channels according to a first multi-site LV pacing mode; determine a cardiac event associated with a change in cardiac conduction path using a sensed cardiac activity signal; and change to a second multi-site LV pacing mode in response to determining the cardiac event, wherein the second multi-site LV pacing mode is different from the first multi-site LV pacing mode in one or more of a pacing site location and an inter-electrode stimulus timing, wherein the stimulus circuit is configured to provide electrical pulse energy using an atrial pacing channel that includes an atrial electrode , wherein the sensing channel includes the same or different atrial electrode , wherein the control circuit is configured to initiate delivery of electrical pulse energy according to the first multi-site LV pacing mode when sensing an intrinsic atrial event, and initiate delivery of electrical pulse energy according to the second multi-site LV pacing mode when determining that electrical pulse energy is to be delivered to an atrium. a cardiac signal sensing circuit configured to sense a cardiac activity signal using a sensing channel that includes implantable electrodes of the plurality of electrodes; a stimulus circuit configured to provide electrical pulse energy using at least a first left ventricular (LV) pacing channel that includes a first LV electrode , and a second LV pacing channel that includes a second LV electrode ; and a control circuit operatively coupled to the stimulus circuit and the cardiac signal sensing circuit and configured to: initiate delivery of electrical pulse energy using the first and second pacing channels according to a first multi-site LV pacing mode; determine a cardiac event associated with a change in cardiac conduction path using a sensed cardiac activity signal; and change to a second multi-site LV pacing mode in response to determining the cardiac event, wherein the second multi-site LV pacing mode is different from the first multi-site LV pacing mode in one or more of a pacing site location and an inter-electrode stimulus timing, initiate delivery of electrical pulse energy using the first and second pacing channels according to a first multi-site LV pacing mode; determine a cardiac event associated with a change in cardiac conduction path using a sensed cardiac activity signal; and change to a second multi-site LV pacing mode in response to determining the cardiac event, wherein the second multi-site LV pacing mode is different from the first multi-site LV pacing mode in one or more of a pacing site location and an inter-electrode stimulus timing, wherein the stimulus circuit is configured to provide electrical pulse energy using an atrial pacing channel that includes an atrial electrode , wherein the sensing channel includes the same or different atrial electrode , wherein the control circuit is configured to initiate delivery of electrical pulse energy according to the first multi-site LV pacing mode when sensing an intrinsic atrial event, and initiate delivery of electrical pulse energy according to the second multi-site LV pacing mode when determining that electrical pulse energy is to be delivered to an atrium. <EOS>