Methods and apparatus for capture management in multi-chamber pacing are disclosed. In one embodiment, the invention includes determining a combination of electrodes from a plurality of electrodes that yields the lowest polarization potential immediately following delivery of an electrical stimulus to a heart; and performing capture detection using that combination of electrodes. In order to distinguish loss of capture in one ventricle in bi-ventricular pacing, certain embodiments may also include measuring a width of a QRS complex and determining when the width is greater than a predetermined value. A method for detecting single ventricular loss of capture in bi-ventricular pacing is also described utilizing comparison of evoked QRS complex morphology to a predefined waveform.
The present invention provides a technique for verifying pacing capture of a ventricular chamber, particularly to ensure desired delivery of a ventricular pacing regime (e.g., cardiac resynchronization therapy or "CRT"). The invention also provides for ventricular capture management by delivering a single ventricular pacing stimulus and checking inter-ventricular conduction during a temporal window to determine if the ventricular pacing stimulus captured the chamber. If a loss-of-capture (LOC) signal results from the capture management testing, then the characteristics of the applied pacing pulses are modified and the conduction test repeated. In the event that the LOC signal persists, a pacing mode-switch to an atrial-based pacing therapy and/or non-bi-ventricular pacing regimen can be implemented.
