Ring-to-ring cardiac electrogram pacemaker

• US 5,265,602 A
• Filed: 07/13/1992
• Issued: 11/30/1993
• Est. Priority Date: 07/13/1992
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Vadnais, Kirk S., Anderson, Russell E., Reinke, James D., Hudrlik, Terrence R.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): MANUEL, GEORGE C
• Application Number:
  US07/912,455
• Time in Patent Office: 505 Days
• Field of Search: 128/419 PG, 128/419 P, 128/783, 128/786, 128/901, 128/696
• US Class Current: 607/9
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence

Abstract

A pacemaker having two bipolar leads, one atrial, one ventricular, each with TIP and RING electrodes, configured as for conventional bipolar pacing/sensing in both chambers. Switching circuitry in the pacemaker is operable to select from among various possible sensing configurations, including one configuration in which sensing is performed between the ring electrodes of the respective pacing/sensing leads. Pacing is preferably performed in a conventional unipolar configuration in each chamber, from the respective tip electrodes. The "ring-to-ring" EGM signal is applied to filtering and EGM amplifier circuitry, and then provided to a telemetry system for transmission to an external receiver. The ring-to-ring EGM signal possesses the high resolution properties of conventional intracardiac signals, and is relatively unaffected by the after-potentials and tissue polarization effects that arise when the same lead is used for pacing and sensing. Additionally, the ring-to-ring EGM signal is a composite of atrial and ventricular electrical signals, and thus has an appearance similar to that of surface ECGs.

Claims

1. An implantable cardiac pacemaker system, comprising:

a pulse generator, adapted to produce cardiac stimulating pulses;

a bipolar transvenous atrial pacing/sensing lead coupled to said pulse generator, said atrial lead having a first atrial conductor therein coupled to a tip electrode at a distal end of said lead and a second atrial conductor therein coupled to a ring electrode spaced apart from said tip electrode, said distal end of said lead disposed in a patient'"'"'s atrium such that electrical signals in said atrium are received by said atrial ring electrode and conducted by said first atrial conductor;

a bipolar transvenous ventricular pacing/sensing lead coupled to said pulse generator, said ventricular lead having a first ventricular conductor therein coupled to a tip electrode at a distal end of said lead and a second ventricular conductor therein coupled to a ring electrode spaced apart form said tip electrode, said distal end of said ventricular lead being disposed in the patient'"'"'s ventricle such that electrical signals in said ventricle are received by said ventricular ring electrode and conducted by said first ventricular conductor;

an EGM amplifier circuit having first and second inputs, adapted to produce an output signal corresponding to a difference between voltages applied to said first and second inputs;

switching circuitry, adapted to selectively couple said second atrial conductor to said first input of said EGM amplifier circuit and said second ventricular conductor to said second input of said EGM amplifier circuit, such that said atrial electrical signals are applied to said first EGM amplifier circuit input and said ventricular electrical signals are applied to said second EGM amplifier circuit input.

2. A pacemaker system in accordance with claim 1, further comprising:

a telemetry circuit, coupled to said EGM amplifier output and adapted to transmit said EGM amplifier output signal to an external receiver.

3. A pacemaker system in accordance with claim 1, further comprising an electrically conductive pacemaker canister, wherein said switching circuitry is further adapted to selectively couple said pulse generator to said second atrial conductor and said second ventricular conductor, such that said cardiac stimulating pulses are applied to said heart from said ventricular and atrial tip electrodes, said pacemaker canister adapted to serve as an indifferent electrode.

4. A pacemaker system in accordance with claim 1, wherein said EGM amplifier circuit further comprises filtering circuitry.

5. A method of cardiac pacing and sensing comprising the steps of:

(a) disposing a distal end of an atrial bipolar pacing and sensing lead with atrial tip and ring electrodes in a patient'"'"'s atrium;

(b) disposing a distal end of a ventricular bipolar pacing and sensing lead with ventricular tip and ring electrodes in a patient'"'"'s ventricle;

(c) coupling a proximal end of said atrial lead to an implanted pacemaker having a conductive canister;

(d) coupling a proximal end of said ventricular lead to said implanted pacemaker;

(e) applying electrical signals received by said atrial ring electrode to a first input of an EGM amplifier in said pacemaker;

(f) applying electrical signals received by said ventricular ring electrode to a second input of an EGM amplifier in said pacemaker;

(g) delivering atrial stimulating pulses to said atrium from said atrial tip electrode, said conductive pacemaker canister serving as an indifferent pacing electrode;

(h) delivering ventricular stimulating pulses to said ventricle from said ventricular tip electrode, said conductive pacemaker canister serving as an indifferent pacing electrode.