Described herein are implantable systems and devices, and methods for use therewith, that can be used to increase compliance with a predetermined preferred ventricular electrical activation pattern. Such implantable systems preferably includes a first lead having at least one electrode implantable in a right ventricular (RV) chamber, and a second lead having at least two electrodes implantable in a left ventricular (LV) chamber. A plurality of different sensing vectors are used to obtain a plurality of IEGMs that collectively enable electrical activations to be detected in at least the RV chamber and at at least two separate regions of the LV chamber. The IEGMs can be obtained while the patient's LV chamber is not being paced, or during bi-ventricular (BiV) pacing that includes pacing at only a single site within the LV chamber. An actual ventricular electrical activation pattern is determined based on the plurality of IEGMs. Additionally, there is a determination of whether the actual ventricular electrical activation pattern matches the predetermined preferred ventricular electrical activation pattern. If the actual ventricular electrical activation pattern does not match the predetermined preferred ventricular electrical activation pattern, then multisite LV (MSLV) pacing is delivered to achieve the predetermined preferred ventricular electrical activation pattern.
