Hand shake for implanted medical device telemetry

• US 5,292,343 A
• Filed: 06/10/1992
• Issued: 03/08/1994
• Est. Priority Date: 01/22/1990
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Busacker, James W., Nichols, Lucy M., Dalluge, David E., Blanchette, Christine M., Wyborny, Paul B., Grevious, John J., Thompson, David L., Roline, Glenn M.
• Primary Examiner(s): Cohen, Lee S.
• Assistant Examiner(s): Parker, Marianne
• Application Number:
  US07/896,645
• Time in Patent Office: 636 Days
• Field of Search: 128/419 PT, 128/422, 128/419 PS, 128/419 D, 128/419 PG, 128/419 P, 128/419 R, 128/903, 128/420.6, 340/573, 340/502-505, 371/2.1, 371/4, 607/32, 607/60
• US Class Current: 607/32
• CPC Class Codes: A61N 1/3708 for power depletion
• CPC Class Codes: A61N 1/37211 Means for communicating with stimulators
• CPC Class Codes: A61N 1/3727 characterised by the modulation technique
• CPC Class Codes: A61N 1/378 Electrical supply
• CPC Class Codes: Y10S 128/903 Radio telemetry

Abstract

A method of and apparatus for telemetering both analog and digital data transcutaneously between an implantable medical device and an external receiver, such as between an external programmer and an implantable cardiac pacer. A damped carrier at 175 kilohertz is pulse position modulated by digital data. The data, along with synchronization and identification codes, are positioned into predefined ranges within predefined frames as measured by individual time periods. The data is uniquely identified by the position of a burst of the carrier within the predefined range. An automatically initiated hand shake protocol maintains the link over slight variations in programmer head position with an indicator notifying the operator when repositioning is required. Analog data may be transferred in digital form or alternatively transferred using phase modulation of the carrier bursts. A cyclic redundancy code is used for link error detection.

Claims

1. In a system employing an implantable medical device and an external device which communicates with said implantable medical device via means for transmission of a stream of data and means for receiving said stream of data, and further having means coupled to said transmission means for inserting a link maintenance message into said stream of data, and means coupled to said receiving means for recognizing said link maintenance message, wherein said recognizing means is further coupled to a means for replying to said link maintenance message with a reply message, and further having means coupled to said transmission means for responding to said reply message with a confirmation message, the improvement comprising:

(a) means coupled to said transmission means for recording an inoperative link in response to failure to receive said reply message within a predetermined period of time; and

(b) means coupled to said receiving means for recording an inoperative link in response to failure to receive said confirmation message within a second predetermined period of time.

2. A method of maintaining a transcutaneous information link comprising:

(a) establishing a transcutaneous information link;

(b) transferring an information link maintenance message message via said transcutaneous information link;

(c) receiving said information link maintenance message;

(d) returning an information link maintenance message reply message in response to said receiving said information link maintenance message;

(e) confirming said returned information link maintenance message reply message with a confirmation message;

(f) indicating failure to receive said confirmation message within a predetermined period of time; and

(g) recording an inoperative link in response to failure to receive said reply message within a second predetermined period of time;

3. A method according to claim 2 further comprising:

(h) recording an inoperative link in response to failure to receiver said confirmation message within a third predetermined period of time.