A system comprising: means for sensing a first cardiac signal segment that includes a QRS complex; means for sensing a second cardiac signal segment that includes a fiducial indicative of local ventricular activation at one or more electrodes of a first cardiac lead; means for determining, by the medical device, a time duration between a fiducial of the QRS complex of the first cardiac signal segment and the fiducial of the second cardiac signal segment; means for generating, using the determined time duration, an indication of optimality of placement of the one or more electrodes of the first cardiac lead for delivering therapy; and means for providing the indication to at least one of a user or process, wherein the means for sensing a first cardiac signal segment includes a cardiac signal sensing circuit connectable to a first cardiac lead and configured to: sense the first cardiac signal segment that includes a QRS complex; wherein the means for sensing a second cardiac signal segment includes the first cardiac signal sensing circuit configured to sense the second cardiac signal segment that includes a fiducial indicative of local ventricular activation at one or more electrodes of the first cardiac lead; wherein the means for determining a time duration includes a processor circuit communicatively coupled to the cardiac signal sensing circuit, wherein the processor circuit includes a site activation timer circuit configured to determine a time duration between a fiducial of the QRS complex of the first cardiac signal segment and the fiducial of the second cardiac signal segment; wherein the means for generating an indication of optimality of placement includes the processor circuit configured to generate, using the determined time duration, an indication of optimality of placement of the one or more electrodes of the first cardiac lead for delivering therapy; and wherein the means for providing the indication includes the processor circuit configured to provide the indication to at least one of a user or process, characterised in that the site activation timer circuit is configured to measure at least one of: a time interval between a fiducial in the second cardiac signal segment indicative of left ventricular activation and a fiducial in the first cardiac signal segment corresponding to an end of the QRS complex (LV-S interval), or a time interval between a fiducial in the second cardiac signal segment indicative of right ventricular activation and a fiducial in the first cardiac signal segment corresponding to the end of the QRS complex (RV-S interval), and wherein the processor circuit is configured to generate an indication of optimality of placement according to at least one of a minimum LV-S interval or a minimum RV-S interval. means for sensing a first cardiac signal segment that includes a QRS complex; means for sensing a second cardiac signal segment that includes a fiducial indicative of local ventricular activation at one or more electrodes of a first cardiac lead; means for determining, by the medical device, a time duration between a fiducial of the QRS complex of the first cardiac signal segment and the fiducial of the second cardiac signal segment; means for generating, using the determined time duration, an indication of optimality of placement of the one or more electrodes of the first cardiac lead for delivering therapy; and means for providing the indication to at least one of a user or process, wherein the means for sensing a first cardiac signal segment includes a cardiac signal sensing circuit connectable to a first cardiac lead and sense the first cardiac signal segment that includes a QRS complex; wherein the means for sensing a second cardiac signal segment includes the first cardiac signal sensing circuit configured to sense the second cardiac signal segment that includes a fiducial indicative of local ventricular activation at one or more electrodes of the first cardiac lead; wherein the means for determining a time duration includes a processor circuit communicatively coupled to the cardiac signal sensing circuit, wherein the processor circuit includes a site activation timer circuit configured to determine a time duration between a fiducial of the QRS complex of the first cardiac signal segment and the fiducial of the second cardiac signal segment; wherein the means for generating an indication of optimality of placement includes the processor circuit configured to generate, using the determined time duration, an indication of optimality of placement of the one or more electrodes of the first cardiac lead for delivering therapy; and wherein the means for providing the indication includes the processor circuit configured to provide the indication to at least one of a user or process, a time interval between a fiducial in the second cardiac signal segment indicative of left ventricular activation and a fiducial in the first cardiac signal segment corresponding to an end of the QRS complex (LV-S interval), or a time interval between a fiducial in the second cardiac signal segment indicative of right ventricular activation and a fiducial in the first cardiac signal segment corresponding to the end of the QRS complex (RV-S interval), and wherein the processor circuit is configured to generate an indication of optimality of placement according to at least one of a minimum LV-S interval or a minimum RV-S interval.