Patent ID: 6988002

Claim:
An implantable device, comprising: ventricular sensing channels for sensing right and left ventricular depolarizations and generating ventricular sense signals in accordance therewith; telemetry interface means for communicating information; an exertion level sensor means for measuring exertion levels; a ventricular pacing channel for pacing a ventricle; and controller means for providing a ventricular pace delivered upon expiration of a ventricular escape interval without receiving a ventricular sense from either ventricular sensing channel, wherein the ventricular escape interval starts with either a ventricular pace or a ventricular sense, the reciprocal of the ventricular escape interval being the lower rate limit, the controller means measuring an R—R interval associated with each ventricular sense, wherein an R—R interval is the time between a ventricular sense and the preceding ventricular sense or ventricular pace, the reciprocal of the R—R interval thus being the measured intrinsic ventricular rate, and the controller means adjusting the ventricular escape interval in accordance with a measured R—R interval so that the lower rate limit adjusts in accordance with changes in the measured intrinsic ventricular rate, wherein the controller means is coupled to the exertion level sensor means to implement rate-adaptive pacing and the controller means is connected to the telemetry interface means for communications by the implantable device.