An implantable medical device includes a sensor configured to generate an endocardial acceleration (EA) signal representative of activity of a patient's heart. The device further includes one or more circuits configured to identify within the EA signal at least one EA signal component corresponding to at least one peak of endocardial acceleration, and extract from the at least one EA signal component at least two characteristic parameters. The one or more circuits are further configured to generate a composite index based on a combination of the at least two characteristic parameters, determine a plurality of values of the composite index for a plurality of pacing configurations, and select a current pacing configuration from among the plurality of pacing configurations based on the plurality of values of the composite index.