Cardiac pacemaker with triggered magnet modes

• US 5,529,578 A
• Filed: 10/20/1995
• Issued: 06/25/1996
• Est. Priority Date: 12/09/1993
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Struble, Chester
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US08/546,080
• Time in Patent Office: 249 Days
• Field of Search: 607/9, 607/14, 607/15, 607/17, 607/19, 607/29, 607/30, 607/27
• US Class Current: 607/29
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/37217 characterised by the communication link, e.g. acoustic or tactile

Abstract

An implantable pulse generator responsive to closure of a remotely actuable switch to operate in one or more triggered magnet modes, wherein intrinsic cardiac activity is continuously sensed. The pulse generator includes a timing mechanism for defining a predetermined triggered magnet mode interval. During triggered magnet mode operation, the pulse generator delivers pacing pulses at the end of each triggered magnet mode interval, provided that no intrinsic cardiac activity is sensed during the interval. Each time a stimulating pulse is delivered, the timing mechanism is reset and restarted to initiate another triggered magnet mode interval. The pulse generator is responsive to the sensing of intrinsic cardiac activity prior to expiration of a triggered magnet mode interval to deliver a non-competitive triggered stimulating pulse and to reset and restart the timing mechanism. In this way, competitive pacing and pacing during the vulnerable phase of a cardiac cycle is avoided. Upon discontinuance of switch closure, the pulse generator resumes operation in its previously programmed mode. Operation of the pulse generator in the triggered magnet mode does not interfere with other functions, such as threshold margin testing, battery depletion measurement, pace and sense threshold measurement, device interrogation and programming, and the like, normally associated with and performed during conventional magnet mode operation.

Claims

1. A pulse generator, implantable in a patient, comprising:

a means for providing power;

an output circuit, responsive to a triggering signal to generate an electrical stimulating pulse, said output circuit coupled to said means for providing power;

at least one conductive lead, coupled to said output circuit, said conductive lead to conduct said stimulating pulse from said output circuit to a patient'"'"'s heart and to conduct an electrical signal generated by a cardiac event from said patient'"'"'s heart to said pulse generator;

a sensing circuit, coupled to said conductive lead to sense an occurrence of a predetermined cardiac event and to issue a detection signal upon the sensing of said predetermined cardiac event;

a remotely actuable switch having an output terminal, said switch having means for asserting a mode control signal on said output terminal when said switch is actuated;

a control circuit, coupled to said output circuit, said sensing circuit, and to said remotely actuable switch output terminal, said control circuit having means for responding to assertion of said mode control signal to issue a series of said triggering signals wherein each two successive triggering signals in said series is separated in time by the lesser of;

(a) a fixed pacing time interval; and

(b) a time interval beginning with the first of said two successive triggering signals and ending with the issuance of said detection signal.

2. A pulse generator in accordance with claim 1, wherein said remotely-actuable switch is a magnetic reed switch.

3. A pulse generator in accordance with claim 1, said means for providing power comprises a battery coupled to said control circuit.

4. A pulse generator, implantable in a patient, comprising:

a means for providing power;

a ventricular output circuit, responsive to a ventricular triggering signal to generate a ventricular stimulating pulse, said ventricular output circuit coupled to said means for providing power;

an atrial output circuit, responsive to an atrial triggering signal to generate an atrial stimulating pulse, said atrial output circuit coupled to said means for providing power;

a ventricular conductor, coupled to said ventricular output circuit to conduct said ventricular stimulating pulse to a ventricle of said patient;

an atrial conductor, coupled to said atrial output circuit to conduct said atrial stimulating pulse to an atrium of said patient;

a sensing circuit, electrically coupled to said patient'"'"'s heart to sense an occurrence of a predetermined cardiac event and to issue a detection signal upon the sensing of said predetermined cardiac event;

a remotely actuable switch having an output terminal, said switch having means for asserting a mode control signal on an output terminal thereof when said switch is in a first position;

a control circuit, coupled to said ventricular output circuit, said atrial output circuit, said sensing circuit, and to said remotely-actuable switch, said control circuit responsive to said mode control signal to issue an alternating series of said atrial and ventricular triggering signals wherein an atrial triggering signal is issued a first predetermined time interval after each ventricular triggering signal, and wherein for each atrial triggering signal, the time interval between said atrial triggering signal and a subsequent ventricular triggering signal is the lesser of;

(a) a second predetermined time interval; and

(b) a time interval beginning with said atrial triggering signal and ending with the issuance of said detection signal.

5. A pulse generator in accordance with claim 4, wherein said remotely-actuable switch is a magnetic reed switch.

6. A pulse generator in accordance with claim 4, wherein means for providing power comprises a battery coupled to said control circuit.

7. A method of operating an implantable pulse generator responding to manual actuation of a mode control switch comprising:

(a) manually actuating a mode control switch;

(b) initiating a predetermined, fixed timing interval and detecting a cardiac event which occurs within the time of said predetermined, fixed timing interval;

(c) issuing a stimulating pulse immediately in response to said detected cardiac event which occurs within the time of said predetermined, fixed timing interval;

(d) if no cardiac event is detected in step (c), issuing said stimulating pulse upon expiration of said fixed timing interval; and

(e) repeating steps (b) through (d) so long as said mode control switch is actuated.

8. A method in accordance with claim 7, wherein said step of manually actuating a mode control switch comprises manually actuating a magnetically-actuated reed switch.

9. An implantable pulse generator comprising:

means for providing power;

means for generating an electrical stimulating pulse in response to a triggering signal, the means for generating coupled to the means for providing power;

means for electrically coupling the means for generating to a patient'"'"'s heart, the means for generating coupled to the means for electrically coupling;

means for sensing an occurrence of a predetermined cardiac event, the means for sensing issuing a detection signal upon sensing of the predetermined cardiac event, the means for sensing coupled to the means for electrically coupling, the means for sensing coupled to the means for generating; and

means for controlling the means for generating, the means for controlling switchable between a first mode and a second mode by a means for remotely switching, wherein in the first mode the means for controlling issues a series of triggering signals wherein each two successive triggering signals in the series is separated in time by the lesser of;

(a) a fixed pacing time interval; and

(b) a time interval beginning with the first of the two successive triggering signals and ending with the issuance of the detection signal.

10. An implantable pulse generator in accordance with claim 9, wherein the means for remotely switching comprises a magnetic reed switch.

11. An implantable pulse generator comprising:

a battery;

a generator emitting an electrical stimulating pulse in response to a triggering signal, the generator coupled to the battery;

a lead for coupling the generator to a patient'"'"'s heart, the generator coupled to the lead;

a sensor for sensing a predetermined cardiac event, the sensor issuing a detection signal upon the sensing of the predetermined cardiac event, the sensor coupled to the lead; and

a controller, the controller coupled to the generator, the controller coupled to the sensor, the controller switchable between a first mode and a second mode by a remotely switchable switch, wherein in the first mode the controller issues a series of triggering signals wherein each two successive triggering signals in the series are separated in time by the lesser of;

(a) a fixed pacing time interval; and

(b) a time interval beginning with the first of the two successive triggering signals and ending with the issuance of the detection signal.

12. An implantable pulse generator in accordance with claim 11, wherein the remotely switchable switch comprises a magnetic reed switch.