Leadless cardiac pacemaker triggered by conductive communication
A leadless cardiac pacemaker configured for implantation in electrical contact with a left ventricular cardiac chamber and configured for leadless triggered left-ventricular pacing for cardiac resynchronization therapy (CRT) in response to conducted signals from a pulse generator.
1. A method for communicating information between first and second implantable medical devices implanted within a patient, the method comprising:
generating a therapeutic electrical stimulation pulse using the first device, the stimulation pulse encoded with information to be communicated to the second device;
delivering the encoded therapeutic stimulation pulse to patient tissue in a first heart chamber;
detecting a far-field version of the therapeutic stimulation pulse within tissues of a second chamber of the patient's heart using the second device; and
decoding the detected pulse using the second device to extract the encoded information.
2. The method of claim 1 wherein the first implantable device is a primary cardiac pacemaker; and wherein the step of delivering the therapeutic stimulation pulse to patient tissue is performed to deliver an encoded cardiac pacing pulse to cardiac tissue with a pulse magnitude sufficient to depolarize a portion of cardiac tissue.
3. The method of claim 2 wherein the second implantable device is a secondary cardiac pacemaker.
4. The method of claim 1 wherein the stimulation pulse is encoded by the first device by modulating the shape of the stimulation pulse.
5. The method of claim 4 wherein the stimulation pulse is modulated to include a sequence of individual pulse portions collectively configured to encode the information.
6. The method of claim 5 wherein the individual pulse portions are collectively configured to encode the information digitally.
7. The method of claim 6 wherein relative spacing between the individual pulse portions of the stimulation pulse is modulated to digitally encode the information.
8. The method of claim 6 wherein relative width of the individual pulse portions of the stimulation pulse is modulated to digitally encode the information.
9. The method of claim 5 wherein individual pulse portions have durations each in the range of 15-30 microseconds (μs) and wherein the total pulse has a duration in the range of 0.2-2.0 milliseconds (ms).
10. An implantable cardiac stimulation system for delivering cardiac stimulation therapy to the heart of a patient, the system having first and second separately implanted devices, comprising:
an encodable pulse generator provided within the first device and operative to generate an encoded therapeutic electrical stimulation pulse for delivery to patient tissues in a first heart chamber, the pulse encoded with information to be communicated to the second device; and
an encodable pulse detector provided within the second device and operative to detect a far-field version of the encoded therapeutic stimulation pulse within patient tissues in a second chamber of the patient's heart and to decode the pulse to extract the encoded information.
11. An implantable cardiac stimulation system for delivering cardiac stimulation therapy to the heart of a patient, the system having first and second separately implanted devices, comprising:
means, provided within the first device, for generating an encoded therapeutic electrical stimulation pulse for delivery to patient tissues in a first chamber of the patient's heart, the pulse encoded with information to be communicated to the second device; and
means, provided within the second device, for detecting a far field version of the encoded therapeutic stimulation pulse within patient tissues in a second chamber of the patient's heart and for decoding the pulse to extract the encoded information.
12. The method of claim 3 wherein the primary cardiac pacemaker is equipped to generate pacing pulses for delivery to the right ventricle (RV); and wherein the step of delivering the encoded cardiac pacing pulse is performed to deliver the encoded pulse endocardially to the RV.
13. The method of claim 12 wherein the secondary cardiac pacemaker is an epicardial left ventricle (LV) satellite pacer equipped to sense electrical signals at the LV; and wherein the step of detecting the therapeutic stimulation pulse using the second device is performed to detect a far-field version in the LV of the encoded pacing pulse delivered to the RV.
14. The method of claim 13 further including the step, performed by the LV epicardial satellite pacer, of generating LV pacing pulses for delivery to the LV based on the encoded information.
15. The method of claim 14 wherein the stimulation pulse is encoded with information indicating whether LV pulses are to be delivered by the epicardial satellite pacer.