Described herein are implantable systems and devices, and methods for use therewith, that can be used to monitor and treat heart failure (HF). Such implantable systems preferably includes a lead having at least two electrodes implantable in a patient's left ventricular (LV) chamber. A plurality of different sensing vectors are used to obtain a plurality of IEGMs each of which is indicative of an evoked response at a corresponding different region of the LV chamber. For each of the IEGMs, there is a determination of one or more evoked response metrics indicative of a localized cardiac function at the corresponding region of the LV chamber. The evoke response metrics can be, e.g., paced depolarization integral (PDI) and/or maximum upward slope of an R-wave, but are not limited thereto. The patient's HF condition is monitored based on the localized cardiac function at the plurality of different regions of the LV chamber as determined based on the one or more evoked response metrics determined for each of the IEGMs.
