Patent ID: 8442634

Claim:
A method for controlling the delivery of cardiac pacing therapy using an implantable cardiac stimulation device, the method comprising: measuring an inter-atrial conduction time delay (IACT) and an atrio-ventricular conduction delay (AR/PR); determining an atrio-ventricular pacing delay (AV/PV) and an interventricular pacing delay (W) for use in pacing the heart of the patient based, in part, on the measured inter-atrial conduction time delay (IACT); comparing the atrio-ventricular pacing delay (AV/PV) with the measured atrio-ventricular conduction delay (AR/PR); if the atrio-ventricular pacing delay (AV/PV) is less than the measured atrio-ventricular conduction delay (AR/PR), delivering biventricular pacing using the atrio-ventricular pacing delay (AV/PV) and the interventricular pacing delay (VV); and if the atrio-ventricular pacing delay (AV/PV) is not less than the corresponding atrio-ventricular conduction delay (AR/PR), selectively enabling an alternative pacing regime; wherein selectively enabling an alternative pacing regime includes selectively enabling one of monoventricular pacing, biventricular pacing with negative hysteresis, and biventricular pacing with AV/PV delays reduced using predetermined offset values; wherein selectively enabling monoventricular pacing includes: determining a minimum value (PR MIN /AR MIN ) for the atrio-ventricular conduction delay (PR/AR) based on a comparison of AR/PR values measured for the left ventricle (LV) and the right ventricle (RV); comparing the minimum value (PR MIN /AR MIN ) for the atrio-ventricular conduction delay against a predetermined minimum delay threshold (PR MIN-TH /AR MIN-TH ) while also comparing the inter-atrial conduction delay (IACT) against a predetermined inter-atrial conduction delay threshold (IACT TH ); and selectively enabling monoventricular pacing if either the inter-atrial conduction delay (IACT) is greater than the inter-atrial delay threshold (IACT TH ) or if the minimum value (PR MIN /AR MIN ) for the intrinsic atrio-ventricular pacing delay (IACT) is less than the predetermined minimum delay threshold (PR MIN-TH /AR MIN-TH ).