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 pacing channel that includes a first LV electrode (160, 162, 164, 165), and a second LV pacing channel that includes a second LV electrode (160, 162, 164, 165); 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 (125, 130), wherein the sensing channel includes the same or different atrial electrode (125, 130), 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 pacing channel that includes a first LV electrode (160, 162, 164, 165), and a second LV pacing channel that includes a second LV electrode (160, 162, 164, 165); 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 (125, 130), wherein the sensing channel includes the same or different atrial electrode (125, 130), 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.