IMPLANTABLE MEDICAL DEVICE WITH ADAPTIVE OPERATION

An implantable medical device operates with an algorithm that promotes intrinsic conduction and reduces ventricular pacing. The IMD monitors the occurrence of necessary ventricular pacing and takes certain actions based upon whether this occurrence has been relatively high or relatively low. When noise is detected, asynchronous pacing is provided when the occurrence is relatively high and is not provided when relatively low. When atrial threshold testing is performed, the incidence will determine which methodology is utilized.