Decreasing IEGM hazards in time division multiplexed system
In one embodiment, a medical system includes a catheter interface comprising electrode lines configured to be electrically connected to respective electrodes of a catheter, and a signal generation apparatus configured to generate signal pulses, each of the signal pulses comprising a carrier frequency and having a non-rectangular signal envelope, the signal generation apparatus being configured to time multiplex the signal pulses among the electrode lines.
1 . A medical system, comprising:
a catheter interface comprising:
electrode lines electrically connected to respective electrodes of a catheter and body surface electrodes, the catheter being inserted into a cardiac chamber of a patient and the electrodes emitting signal pulses dedicated for sensing positions of each of the electrodes and concurrently sensing intracardiac electrogram (IEGM) signals; and
a signal generation apparatus generating the signal pulses, each of the signal pulses comprising a carrier frequency and having a non-rectangular signal envelope, the signal generation apparatus time multiplexing the signal pulses among the electrode lines; and
a position tracking system configured to sense the signal pulses on the body surface electrodes and track positions of each of the electrodes based on the signal pulses sensed,
wherein the electrodes of the catheter emit the signal pulses responsively to the time multiplexed signal pulses generated by the signal generation apparatus;
wherein the signal generation apparatus generates the non-rectangular signal envelope with a gradual increase in a peak-to-peak amplitude of the envelope over time to a maximum peak-to-peak amplitude and then after a given time period a gradual reduction in the envelope over time to a zero peak-to-peak amplitude, and
wherein the gradual increase in the peak-to-peak amplitude of the envelope is based on an error function (ERF), and the gradual reduction is based on a complementary error function (ERFC) thereby reducing or eliminating signal spikes in IEGM signals sensed currently with generating the signal pulses.
2 . The system according to claim 1 , wherein the signal generation apparatus further comprises a memory storing a digital signal pulse representation, processing circuitry and a digital-to-analog converter, the processing circuitry configured to retrieve the digital signal pulse representation from the memory and provide the digital signal pulse representation to the digital-to-analog converter, which converts the digital signal pulse representation into an analog signal including one of the signal pulses.
3 . The medical system of claim 1 further comprising an ablation energy generator, wherein the ablation energy generator is configured to conduct ablation energy to one or more of the electrodes, wherein the ablation energy generator generates one or more of radio frequency energy or pulsed field ablation energy configured for ablating tissue in the cardiac chamber.
4 . The medical system of claim 1 further comprising:
body surface electrocardiogram (ECG) electrodes mounted on skin of the patient and electrically coupled to the catheter interface;
wherein the catheter interface is further configured to receive and process ECG signals from the ECG electrodes concurrently with sensing the signal pulses and the IEGM signals; and
a display configured to display the ECG signals and the IEGM signals as processed.
5 . A computer-implemented method comprising:
generating signal pulses by a signal generation apparatus, each of the signal pulses comprising a carrier frequency and having a non-rectangular signal envelope; and
time multiplexing the signal pulses among electrode lines electrically connected to respective electrodes of a catheter, the catheter inserted into a cardiac chamber of a patient and the electrodes emitting the signal pulses responsively to the time multiplexed signal pulses generated by the signal generation apparatus,
sensing the signal pulses emitted by the electrodes on body surface electrodes mounted on skin of the patient;
tracking position of each of the electrodes based on the signal pulses sensed; and
sensing intracardiac electrogram (IEGM) signals on the electrodes concurrently with sensing the signal pulses among electrode lines,
wherein the non-rectangular signal envelope has a gradual increase in a peak-to-peak amplitude of the envelope over time to a maximum peak-to-peak amplitude and then after a given time period a gradual reduction in the envelope over time to a zero peak-to-peak amplitude, and
wherein the gradual increase in the peak-to-peak amplitude of the envelope is based on an error function (ERF), and the gradual reduction is based on a complementary error function (ERFC), thereby reducing or eliminating signal spikes in the IEGM signals.
6 . The method according to claim 5 , further comprising:
sensing electrocardiogram (ECG) signals from ECG electrodes mounted on the skin of the patient concurrently with sensing the IEGM signals and the signal pulses; and
displaying on a display device, activation sequences compiled from IEGM signals and the ECG signals.
7 . The method according to claim 5 , further comprising:
receiving electro-anatomical signals from the electrodes via the electrode lines; and
processing the received electro-anatomical signals.
8 . The method according to claim 5 , further comprising:
storing a digital signal pulse representation;
retrieving the stored digital signal pulse representation; and
converting the digital signal pulse representation into an analog signal including one of the signal pulses.