Implantable defibrillator system and method having successive changeable defibrillation waveforms

• US 5,531,764 A
• Filed: 04/14/1994
• Issued: 07/02/1996
• Est. Priority Date: 03/24/1992
• Status: Expired due to Term

• Current Assignee: Ela Medical S.A. (LivaNova Plc)
• Original Assignee: Angeion Corporation (Niterra Co., Ltd.)
• Inventors: Kroll, Mark W., Adams, Theodore P.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): Getzow, Scott M.
• Application Number:
  US08/227,563
• Time in Patent Office: 810 Days
• Field of Search: 607/5, 607/4, 607/6, 607/7, 607/8, 607/13
• US Class Current: 607/5
• CPC Class Codes: A61N 1/3906 characterised by the form of the shockwave
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An implantable defibrillator having programmable shock waveforms and paths where each successive waveform may be of a different shape and form, and delivered to and through an area of the human heart in a desired sequence. The shock waveforms can be delivered independently through certain areas of the heart or through different areas of the heart to the can electrode or to a patch electrode at a computed common time. Alternatively, a first shock waveform or set of shock waveforms can be delivered through one or more areas of the heart followed by a delivery of time sequenced delayed shock waveform or forms through specific areas of the heart to the can electrode or patch electrode.

Claims

1. An improved implantable defibrillator system adapted to be implanted in a human patient for producing a capacitive-discharge countershock, the implantable defibrillator system being a self-contained device including a capacitor system, a battery system, a switching system and a sensing system all of which are connected to and controlled by a programmable computer system having a memory for storing a plurality of physician programmable charging voltage parameters, one parameter for each countershock in a sequence of countershocks to be delivered to the human patient as part of a multiple-countershock therapy regimen, and computer programming stored in the memory and executing in the computer system that, in response to an initial cardiac arrhythmia in the human patient sensed by the sensing system, selectively charges the capacitor system from the battery system in accordance with a first of the charging voltage parameters stored in the memory for the multiple-countershock therapy regimen and then selectively discharges the capacitor system as a first of the sequence of multiple countershocks delivered through the switching system to a plurality of electrodes adapted to be implanted in the human patient, after which, in response to a continuing cardiac arrhythmia in the human patient sensed by the sensing system, selectively charges the capacitor system from the battery system in accordance with a second of the charging voltage parameters stored in the memory for the multiple-countershock therapy regimen and then selectively discharges the capacitor system as a second of the sequence of multiple countershocks, the improvement comprising:

a data structure located in the memory for defining a plurality of different possible waveforms and a plurality of different possible wavepaths for individual countershocks in the multiple-countershock therapy regimen by storing a plurality of sets of physician programmable waveform parameters in the data structure, a unique set of waveform parameters being associated with each countershock in the sequence of multiple countershocks, the waveform parameters including both wave phase information and wave path information such that each set of waveform parameters defines a selected one of the different possible waveforms and defines a selected one of the different possible wave paths definable in the data structure; and

computer programming stored in the memory and executing in the computer system that selectively charges and then discharges the capacitor system in accordance with a first one of the unique sets of waveform parameters stored in the data structure as a first countershock in the sequence of multiple countershocks and, in response to a continuing cardiac arrhythmia in the human patient sensed by the sensing system, selectively charges and discharges the capacitor system in accordance with a subsequent one of the unique sets of waveform parameters stored in the data structure as a subsequent countershock in the sequence of multiple countershocks,

such that the first and subsequent countershocks delivered by the implantable defibrillator system as part of the sequence of multiple countershocks can be independently programmed for different waveforms and wave paths.

2. An improved method of operating an implantable defibrillator system adapted to be implanted in a human patient for producing a capacitive-discharge countershock, the implantable defibrillator system being a self-contained device electrically connected to a plurality of electrodes adapted to be implanted in the human patient, the device including a capacitor system, a battery system, a switching system and a sensing system all of which are connected to and controlled by a programmable computer system having a memory and computer programming stored in the memory and executing in the computer system that performs the computer-implemented steps of:

(a) using the sensing system to sense a cardiac arrhythmia in the human patient;

(b) in response to the cardiac arrhythmia, selectively charging the capacitor system from the battery system in accordance with a first of a plurality of physician programmable charging voltage parameters stored in the memory for a first of a sequence of multiple countershocks;

(c) selectively discharging the capacitor system as the first of the sequence of multiple countershocks delivered through the switching system to the plurality of electrodes in accordance with a single set of physician programmable waveform parameters stored in the memory,

(d) using the sensing system to sense if the cardiac arrhythmia in the human patient has been converted;

(e) if the cardiac arrhythmia has not been converted, selectively charging the capacitor system from the battery system in accordance with a subsequent one of the plurality of physician programmable charging voltage parameters stored in the memory for a subsequent one of the sequence of multiple countershocks;

(f) selectively discharging the capacitor system as a subsequent one of the sequence of multiple countershocks delivered through the switching system to the plurality of electrodes in accordance with the same single set of physician programmable waveform parameters stored in the memory for the first of the sequence of multiple countershocks; and

(g) repeating steps (d)-(f) for other subsequent ones of the multiple countershocks until the cardiac arrhythmia has been converted or the entire sequence of multiple countershocks has been delivered,

wherein the improved method comprises implemented steps of;

storing in a data structure defined in the memory a plurality of sets of physician programmable waveform parameters, a unique set of waveform parameters for each countershock in the sequence of multiple countershocks, the waveform parameters including both wave phase information and wave path information such that each set of waveform parameters defines a selected one of a plurality of different possible waveforms and defines a selected one of a plurality of different possible wave paths definable in the data structure; and

selectively discharging the capacitor system in step (c) in accordance with a first one of the unique sets of waveform parameters stored in the data structure, and selectively discharging the capacitor system in step (f) in accordance with a subsequent one of the unique sets of waveform parameters stored in the data structure for each subsequent countershock in the sequence of multiple countershocks,

such that the first and subsequent countershocks delivered by the implantable defibrillator system as part of the sequence of multiple countershocks can be independently programmed for different waveforms and wave paths.

3. A method of operating an implantable cardioverter defibrillator system adapted to be implanted in a patient for delivering a sequence of capacitive-discharge countershocks to the heart of the patient as part of a multiple-countershock therapy regimen for treating a continuing cardiac arrhythmia in the patient, the implantable defibrillator system having a sensing system, a battery system and a capacitor system, all of which are connected to and controlled by a programmable computer having a memory, the method comprising the steps of:

(a) programming a first set of waveform parameters in the memory in the programmable computer to define a first countershock in the sequence of multiple countershocks, the first countershock having a waveform that is individually selected and programmed by a physician;

(b) programming at least one set additional set of waveform parameters in the memory in the programmable computer to define at least one subsequent countershock in the sequence of multiple countershocks, the subsequent countershock having a waveform that is independent of the waveform of the first countershock and that is individually selected and programmed by the physician;

(c) using the sensing system to sense a cardiac arrhythmia in the patient;

(d) in response to a cardiac arrhythmia, using the battery system to charge the capacitor system to delivery a first countershock to the patient;

(e) discharging the capacitor system in accordance with the first set of waveform parameters stored in the memory programmed in step (a) to deliver the first countershock to the patient;

(f) sensing whether the cardiac arrhythmia in the patient has been converted;

(g) if the cardiac arrhythmia has not been converted, using the battery system to recharge the capacitor system to deliver a subsequent countershock to the patient;

(h) discharging the capacitor system in accordance with a subsequent set of waveform parameters stored in the memory programmed in step (b) to deliver a subsequent countershock to the patient, the subsequent countershock having a waveform that is independent of the waveform of at least one other countershock in the sequence of multiple countershocks and that is individually programmed in step (b); and

(i) repeating steps (f)-(h) until the cardiac arrhythmia has been converted or the entire sequence of multiple countershocks has been delivered.

4. The method of claim 3, wherein:

step (a) further includes programming the memory in the programmable computer to define the set of waveform parameters for the first countershock as having a first wave path;

step (b) further includes programming the memory in the programmable computer to define the set of waveform parameters for a subsequent countershock as having a wave path that is independent of the wave path of at least one other countershock in the sequence of multiple countershocks;

step (e) further includes discharging the capacitor system in accordance with the first set of waveform parameters programmed in step (a) to deliver the first countershock having the wave path individually programmed in step (a); and

step (h) further includes discharging the capacitor system in accordance with the subsequent sets of waveform parameters programmed in step (b) to deliver a subsequent countershock having a wave path that is independent of the wave path of at least one other countershock in the sequence of multiple countershocks and that is individually programmed in step (b).

5. A self-contained implantable defibrillator system adapted to be implanted in a patient for producing a sequence of multiple capacitive-discharge countershocks to the heart of the patient as part of a multiple-countershock therapy regimen for treating a continuing cardiac arrhythmia in the patient, the system comprising:

a countershock delivery system for delivering the sequence of multiple countershocks to the patient, the countershock delivery system including a capacitor system and a battery system coupled with the capacitor system to charge the capacitor system;

a sensing system to detect a cardiac arrhythmia in the patient;

a programmable computer means, coupled with the countershock delivery system and with the sensing system, the programmable computer means including;

means for storing data defining the waveform of each countershock independently, such that each delivered countershock can be programmed to have a waveform different than and independent of the waveform of any other countershock in the sequence of multiple countershocks; and

means for directing delivery of each countershock in the sequence of multiple countershocks through the countershock delivery system in accordance with detection of a cardiac arrhythmia by the sensing system; and

means for delaying delivery of each subsequent countershock after the first countershock in the sequence of multiple countershocks until the sensing system detects if the cardiac arrhythmia in the patient has been converted in response to a previous countershock and the battery system has charged the capacitor system for delivery of the subsequent countershock.

6. The defibrillator system of claim 5, wherein the programmable computer means further comprises means for storing data defining the wave path of each countershock independently, such that each delivered countershock can be programmed to have a wave path different than and independent of the wave path of any other countershock in the sequence of multiple countershocks.