Patent ID: 8180449

Claim:
An implantable medical device comprising: a pacing pulse circuit connectable to cardiac leads adapted to deliver cardiac pacing pulses to cardiac tissue via said cardiac leads; a monitoring circuit that monitors atrial and/or ventricular events, allowing atrio-ventricular conduction to be detected; a switching circuit that switches between operation modes of the implantable medical device including a DDI-II mode, a DDI mode and a DDD mode, said DDI-II mode being an operation mode with an atrial inhibited pacing and a DDI-II mode ventricular pacing rate being lower than a predetermined base rate of the pulse circuit; a control circuit configured to: operate said device in said DDI-II mode during periods with atrio-ventricular conduction conditions; if a block in atrio-ventricular conduction is detected and at least one first switching criterion is satisfied, control said switching circuit to switch from said DDI-II mode to said DDI mode; and if a block in atrio-ventricular conduction is detected and at least one second switching criterion is satisfied, control said switching circuit to switch from said DDI mode to said DDD mode; and said control circuit being configured to control said switching circuit to switch back to said DDI-II mode at satisfaction of at least one re-initiating criterion in said DDD mode.