A medical device for stimulating the heart using biventricular stimulation. The device includes a sensor for detecting an endocardial acceleration parameter and a processing circuit configured to receive the endocardial acceleration parameter. The device further includes stimulation electronics coupled to the processing circuit. The processing circuit is configured to use the EA parameter to evaluate the biventricular stimulation. The evaluation includes comparing the value of the EA parameter in biventricular mode to the value of the EA parameter in left only mode or right only mode, and using the comparison and an assessment of the variability of the EA parameter as a function of the AVD in the left or right mode to distinguish between cases comprising: (a) normal operation, (b) a loss of RV or LV capture, (c) possible anodal stimulation. The processing circuit is further configured to conduct at least one update to operational parameters of the device based on the determined case.
