An apparatus for electrical coupling to a plurality of implantable electrodes, the apparatus comprising: a stimulus circuit configured to provide electrical pulse energy to at least a first pacing channel that includes a first left ventricular electrode (165; 260; 565) as a cathode and a second pacing channel that includes a second LV electrode (164; 262, 264; 560) as a cathode; a cardiac signal sensing circuit configured to sense cardiac activity signals using at least a first sensing channel that includes one of the first LV electrode (165; 260; 565) or the second LV electrode (164; 262, 264; 560); a control circuit electrically coupled to the cardiac signal sensing circuit and the stimulus circuit, wherein the control circuit includes a capture detection sub-circuit configured to: initiate delivery of electrical pulse energy to both the first pacing channel and the second pacing channel; sense cardiac depolarization of a ventricle using the first sensing channel; determine a first cardiac capture pulse energy level threshold for the first pacing channel, and a second cardiac capture pulse energy level threshold for the second pacing channel; and provide indications of the first and second cardiac capture pulse energy level thresholds to a user or process, wherein the capture detection sub-circuit is configured to initiate a change in pulse energy level of the electrical pulse energy delivered to both the first pacing channel and the second pacing channel; wherein the control circuit includes a signal processing sub-circuit configured to identify a change in morphology in a cardiac activity signal sensed in association with a change from a first level of electrical pulse energy delivered to both the first pacing channel and the second pacing channel to a second level of electrical pulse energy delivered to both the first pacing channel and the second pacing channel; and wherein the capture detection sub-circuit is further configured to distinguish, using the identified change in morphology, between cardiac capture by one of the first and second pacing channels from cardiac capture by both pacing channels. a stimulus circuit configured to provide electrical pulse energy to at least a first pacing channel that includes a first left ventricular electrode (165; 260; 565) as a cathode and a second pacing channel that includes a second LV electrode (164; 262, 264; 560) as a cathode; a cardiac signal sensing circuit configured to sense cardiac activity signals using at least a first sensing channel that includes one of the first LV electrode (165; 260; 565) or the second LV electrode (164; 262, 264; 560); a control circuit electrically coupled to the cardiac signal sensing circuit and the stimulus circuit, wherein the control circuit includes a capture detection sub-circuit configured to: initiate delivery of electrical pulse energy to both the first pacing channel and the second pacing channel; sense cardiac depolarization of a ventricle using the first sensing channel; determine a first cardiac capture pulse energy level threshold for the first pacing channel, and a second cardiac capture pulse energy level threshold for the second pacing channel; and provide indications of the first and second cardiac capture pulse energy level thresholds to a user or process, wherein the capture detection sub-circuit is configured to initiate a change in pulse energy level of the electrical pulse energy delivered to both the first pacing channel and the second pacing channel; wherein the control circuit includes a signal processing sub-circuit configured to identify a change in morphology in a cardiac activity signal sensed in association with a change from a first level of electrical pulse energy delivered to both the first pacing channel and the second pacing channel to a second level of electrical pulse energy delivered to both the first pacing channel and the second pacing channel; and wherein the capture detection sub-circuit is further configured to distinguish, using the identified change in morphology, between cardiac capture by one of the first and second pacing channels from cardiac capture by both pacing channels.