Dynamic bandwidth control in an implantable medical cardiac stimulator

A method for calibrating an implantable pacemaker having a dynamically adjustable band pass filter, said method using an external calibration device and comprising the steps of:

• (a) transmitting an electrogram waveform to said calibration device;
• (b) performing a frequency analysis on said electrogram waveform with said calibration device;
• (c) determining a frequency response suitably sensitive to said electrogram;
• (d) determining filter coefficients for implementing said frequency response;
• and
• (e) transmitting said filter coefficients from said calibration device to said implantable pacemaker.

A method for electrically stimulating a heart using an implantable pacemaker that includes a pacing circuit, a sense circuit including a dynamically adjustable band pass filter, and a logic and control unit, comprising the steps of:

• (a) operating said pacemaker in a first pacing mode with said band pass filter set to a first frequency response;
• (b) monitoring an electrogram;
• (c) switching said pacemaker to a second pacing mode upon detection of a first event in the electrogram;
• and
• (d) increasing the sensitivity of the sense circuit to said electrogram upon mode switching.

A medical system for monitoring the heart, comprising:

• an implantable medical device including a processor coupling together an atrial sense circuit having a dynamically adjustable band pass filter and a telemetry unit;
• and
• an external calibration device adapted to communicate to the implantable medical device;
• wherein said telemetry unit transmits atrial electrogram data to said calibration device;
• and wherein said calibration device determines a set of filter coefficients for dynamically adjusting said dynamically adjustable band pass filter to provide a frequency response that increases the medical device's sensitivity to said transmitted atrial electrogram data.