System and method for preventing atrial competition during sensor-driven operation of a dual-chamber pacemaker

Claim 1

In a rate-responsive, dual-chamber pacemaker configured to operate in a DDDR mode of operation, a system for preventing atrial competition comprising: means for defining a physiological pacing rate; control means for generating timing signals indicative of when an atrial and/or ventricular stimulation pulse should be generated by said pacemaker in order to maintain said physiological pacing rate; sensing means coupled to said control means for sensing atrial and ventricular activity, such as P-waves, indicating natural atrial activity, and R-waves, indicating natural ventricular activity, said control means generating the timing signals needed to generate atrial and/or ventricular stimulation pulses on demand as needed in the absence of intrinsic P-waves and/or R-waves; stimulation pulse generating means coupled to said control means for generating said atrial and/or ventricular stimulation pulses in response to said timing signals; said control means including: PVARP generating means for generating a post ventricular atrial refractory period (PVARP) subsequent to the generation of each ventricular stimulation pulse or the sensing of an R-wave, said PVARP defining a time interval during which sensed atrial activity is not considered as a valid P-wave; and atrial pulse prevention means for preventing an atrial stimulation pulse from being generated that is in competition with atrial activity sensed during said PVARP comprising: means for generating an atrial competition prevention (ACP) interval in response to atrial activity sensed during said PVARP; and means for preventing any atrial stimulation pulse from being generated during said ACP interval, whereby an atrial pacing pulse is not generated in competition with sensed atrial activity that occurs during said PVARP for at least the duration of said ACP interval.

Claim 12

A method of operating a rate-responsive, dual-chamber pacemaker so as to avoid generating atrial stimulation pulses that might compete with natural atrial activity, said pacemaker being programmed to operate in a DDDR mode of operation, said method comprising the steps of: (a) sensing intrinsic P-waves; (b) determining if a given sensed intrinsic P-wave occurred during a post ventricular atrial refractory period (PVARP) associated with the programmed DDDR mode of operation of said pacemaker, said PVARP being generated by said pacemaker subsequent to any sensed or paced ventricular activity; (c) in the event that a sensed intrinsic P-wave does occur during PVARP, as determined in step (b), starting an atrial competition prevention (ACP) period; and (d) preventing the generation of any atrial stimulation pulse during said ACP period, if any, in the event said ACP period has not timed out by the time said atrial stimulation pulse would otherwise be generated by said programmed DDDR mode of operation.

Claim 13

A method of operating a rate-responsive, dual-chamber pacemaker so as to avoid generating atrial stimulation pulses that might compete with natural atrial activity, said pacemaker being programmed to operate in a DDDR mode of operation, said method comprising the steps of: (a) sensing intrinsic P-waves; (b) determining if a given sensed intrinsic P-wave occurred during a post ventricular atrial refractory period (PVARP) associated with the programmed DDDR mode of operation of said pacemaker, said PVARP being generated by said pacemaker subsequent to any sensed or paced ventricular activity; (c) in the event that a sensed intrinsic P-wave does occur during PVARP, as determined in step (b), starting an atrial competition prevention (ACP) period; and (d) preventing the generation of any atrial stimulation pulse during said ACP period, if any, in the event said ACP period has not timed out by the time said atrial stimulation pulse would otherwise be generated by said programmed DDDR mode of operation.