Implantable cardiac resynchronizer with biventricular pacing and detection of loss of capture and anodal stimulation

An active implantable medical device that provides cardiac resynchronization by biventricular pacing, comprising:

• at least one sensor for detecting of atrial and ventricular events;
• at least one electrode for stimulation of the right and left ventricles;
• a processor that causes an atrioventricular delay AVD to be added to the stimulation, the AVD counted from the detection of a spontaneous or paced atrial event and at the end of which a right ventricular pacing is applied in the absence of detected spontaneous ventricular event, wherein the processor further causes an interventricular delay VVD between the respective times of stimulation of the left and right ventricles, wherein the processor is further configured to cause the device to selectively operate in either a right mode (RV only) wherein only the right ventricle is paced, or a left mode (LV only) wherein only the left ventricle is stimulated, or in a biventricular mode (BiV) wherein both ventricles are stimulated together with or without the application of a VVD;
• a sensor to deliver an endocardial acceleration signal EA, wherein the processor extracts, from the EA signal, at least one predetermined characteristic EA parameter;
• and
• wherein the processor comprises a plurality of executable computer code modules stored in memory, the modules comprising:
• a first module configured to compare the values of the characteristic EA parameter obtained respectively in biventricular mode and in left mode and to determine whether the difference between these values exceeds a first predetermined threshold;
• a second module configured to compare the values of the characteristic EA parameter obtained respectively in biventricular mode and in right mode and to determine if the difference between these values exceeds a second predetermined threshold;
• a third module configured to determine whether the change in the characteristic EA parameter for different AVD in left mode exceeds a given third threshold;
• a fourth module configured to determine if the change to the different characteristic EA parameter for different AVD exceeds a given fourth threshold;
• a fifth module configured to compare the values of the characteristic EA parameter obtained in biventricular mode respectively with a negative or positive VVD and to determine if the difference between these values exceeds a predetermined fifth threshold;
• and
• a sixth module configured to determine in response to the first, second, third, fourth and fifth means, the occurrence of a possible loss of capture in the left or right cavities, or the presence of a phenomenon of anodal stimulation.

An medical device for stimulating the heart using biventricular stimulation, comprising:

• a sensor for detecting an endocardial acceleration parameter;
• a processing circuit configured to receive the endocardial acceleration parameter;
• stimulation electronics coupled to the processing circuit;
• wherein the processing circuit is configured to use the EA parameter to evaluate the biventricular stimulation, the evaluation comprising 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 to further compare to at least one threshold indicating 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;
• and
• wherein the processing circuit is further configured to conduct at least one update to operational parameters of the device based on the determined case.