A system, comprising: a lead having multi-site left ventricular, MSLV, electrodes; a lead having right ventricular, RV, electrodes (122, 124, 126): memory (152, 604, 606, 608) configured to store program instructions; one or more processors (164, 602) that, when executing the program instructions, are configured to: deliver cardiac resynchronization therapy, CRT, at one or more pacing sites from the MSLV electrodes; and obtain cardiac signals, associated with a candidate beat, from the MSLV electrodes distributed along a left ventricle, characterized in that the MSLV electrodes comprises a distal left ventricular, LV, electrode, LVD1,, a first mid-LV electrode, LVM2,, a second mid-LV electrode, LVM3, and a proximal LV electrode, LVP4,, the one or more processors (164, 602) are, when executing the program instructions, further configured to: analyze the cardiac signals to collect a MSLV conduction pattern comprising mean LV activation times relative to an RV activation time and associated with an RV-to-LVD1 activation interval, an RV-to-LVM2 activation interval, an RV-to-LVM3 activation interval, and an RV-to-LVP4 activation interval; compare the MSLV conduction pattern to one or more associated templates (402, 404, 422, 424, 442, 444, 464, 464); label the candidate beat as a pseudo-fusion beat based on the comparing; and adjust the CRT based on the labeling. a lead having multi-site left ventricular, MSLV, electrodes; a lead having right ventricular, RV, electrodes (122, 124, 126): memory (152, 604, 606, 608) configured to store program instructions; one or more processors (164, 602) that, when executing the program instructions, are configured to: deliver cardiac resynchronization therapy, CRT, at one or more pacing sites from the MSLV electrodes; and obtain cardiac signals, associated with a candidate beat, from the MSLV electrodes distributed along a left ventricle, characterized in that deliver cardiac resynchronization therapy, CRT, at one or more pacing sites from the MSLV electrodes; and obtain cardiac signals, associated with a candidate beat, from the MSLV electrodes distributed along a left ventricle, characterized in that the MSLV electrodes comprises a distal left ventricular, LV, electrode, LVD1,, a first mid-LV electrode, LVM2,, a second mid-LV electrode, LVM3, and a proximal LV electrode, LVP4,, the one or more processors (164, 602) are, when executing the program instructions, further configured to: analyze the cardiac signals to collect a MSLV conduction pattern comprising mean LV activation times relative to an RV activation time and associated with an RV-to-LVD1 activation interval, an RV-to-LVM2 activation interval, an RV-to-LVM3 activation interval, and an RV-to-LVP4 activation interval; compare the MSLV conduction pattern to one or more associated templates (402, 404, 422, 424, 442, 444, 464, 464); label the candidate beat as a pseudo-fusion beat based on the comparing; and adjust the CRT based on the labeling. analyze the cardiac signals to collect a MSLV conduction pattern comprising mean LV activation times relative to an RV activation time and associated with an RV-to-LVD1 activation interval, an RV-to-LVM2 activation interval, an RV-to-LVM3 activation interval, and an RV-to-LVP4 activation interval; compare the MSLV conduction pattern to one or more associated templates (402, 404, 422, 424, 442, 444, 464, 464); label the candidate beat as a pseudo-fusion beat based on the comparing; and adjust the CRT based on the labeling.