A processor-based method for use with an active implantable medical device for cardiac pacing, resynchronization, and/or defibrillation includes forming a plurality of first and second endocardial acceleration vectors using a plurality of endocardial acceleration signals acquired using stimulation to cause capture and a spontaneous rhythm of the patient in the absence of ventricular pacing, respectively. An at least two dimension space is created using the first and second endocardial acceleration vectors, including two subspaces corresponding to the presence and absence of capture, respectively. Ventricular capture is tested for after acquiring a new endocardial acceleration signal. The testing includes forming a new endocardial acceleration signal based on the new vector. Presence or absence of capture is determined for the new signal based on the position of the new vector relative to the two subspaces.
