Control of pacing rate in mode switching implantable medical devices

An implantable medical device method of pacing, the method comprising:

• switching from a DDD, DDDR, VDD, or VDDR first pacing mode to a DDI, DDIR, VVI, or VVIR second pacing mode, respectively, upon detection of a period of accelerated atrial arrhythmia, wherein the second pacing mode has an associated predetermined lower pacing rate;
• at least initially, upon switching from the first pacing mode to the second pacing mode, adjusting the predetermined lower pacing rate to an elevated adjusted lower rate;
• and
• decelerating from the elevated adjusted lower rate towards a programmed basic pacing rate during a deceleration period, wherein the programmed basic pacing rate is as fast or faster than the predetermined lower pacing rate.

An implantable medical device comprising:

• pacing generator circuitry operable to generate pacing pulses at one or more pacing rates during at least first and second pacing modes, wherein the first pacing mode paces at least one ventricle based on sensed atrial activity, and further wherein the second pacing mode paces the at least one ventricle based on sensed ventricular activity at a predetermined lower rate with such pacing inhibited based on intrinsic ventricular activity;
• sensing circuitry operable to sense atrial and ventricular activity;
• and
• a pacing controller operable to switch from the first pacing mode to the second pacing mode upon detecting a period of accelerated atrial arrhythmias based on information from the sensing circuitry, wherein the pacing controller is further operable to at least initially, upon switching from the first pacing mode to the second pacing mode, adjust the predetermined lower rate to an elevated adjusted lower rate such that pacing of the at least one ventricle is not inhibited based on detected intrinsic ventricular activity.

An implantable medical device comprising:

• pacing generator circuitry operable to generate pacing pulses at one or more pacing rates during at least first and second pacing modes, wherein the first pacing mode comprises a DDD, DDDR, VDD, or VDDR pacing mode and wherein the second pacing mode comprises a DDI, DDIR, VVI, or VVIR pacing mode, and further wherein the DDI, DDIR, VVI, or VVIR second pacing mode has an associated programmed lower pacing rate;
• sensing circuitry operable to sense atrial and ventricular activity;
• and
• a pacing controller operable to switch from the DDD, DDDR, VDD, or VDDR first pacing mode to the DDI, DDIR, VVI, or VVIR second pacing mode, respectively, upon detecting a period of accelerated atrial arrhythmias based on information from the sensing circuitry, wherein the pacing controller is further operable to at least initially, upon switching from the first pacing mode to the second pacing mode, adjust the programmed lower pacing rate to an elevated adjusted lower rate, and further wherein the pacing controller is operable to decelerate the elevated adjusted lower rate towards a predetermined basic pacing rate that is as fast or faster than the programmed lower pacing rate during a deceleration period.