Adaptive shock delivery in an implantable cardiac stimulus device

• US 8,244,349 B2
• Filed: 01/30/2009
• Issued: 08/14/2012
• Est. Priority Date: 02/02/2008
• Status: Active Grant

• Current Assignee: Cameron Incorporated (Schlumberger NV)
• Original Assignee: Cameron Incorporated (Schlumberger NV)
• Inventors: Sanghera, Rick, Warren, Jay A.
• Primary Examiner(s): Gedeon, Brian T
• Application Number:
  US12/363,425
• Publication Number:
  US 20090198296A1
• Time in Patent Office: 1,292 Days
• Field of Search: 607/5
• US Class Current: 607/5
• CPC Class Codes: A61N 1/3686 configured for selecting the electrode configuration on a lead A61N1/3688 takes precedence
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

Methods and devices that are configured to deliver cardiac stimuli in a particular fashion. In an illustrative embodiment, a method is used wherein a first stimulus is delivered using a first polarity, and, if the first stimulus fails to successfully convert an arrhythmia, a second stimulus having a second polarity that is different from or opposite of the first polarity is then delivered. Subsequent stimuli, if needed, are delivered in a continuing alternating-polarity manner. The first polarity may be determined by observing whether successfully-converting stimulus has been delivered previously and, if so, the polarity of the most recent stimulus that resulted in successful conversion is used as the first polarity. In additional embodiments, electrode configuration may be changed instead of or in addition to polarity, following unsuccessful stimulus delivery. Devices configured to perform such methods are included in additional illustrative embodiments.

Claims

1. An implantable cardioverter-defibrillator (ICD) system including a lead system coupled to a canister, the canister housing operational circuitry, the ICD comprising:

a plurality of stimulus delivery electrodes consisting of a first electrode disposed on the lead system and a second electrode that takes the form of an electrically conductive surface that makes up all or a portion of the surface of the canister;

implantable operational circuitry coupled to the first and second electrodes such that first and second selectable stimulus delivery configurations are available for use by the operational circuitry;

the improvement comprising;

the operational circuitry being configured to determine whether stimulus is currently needed and if so, delivering the currently needed stimulus by;

determining whether a successful stimulus has previously been delivered; and

, if so, using a stimulus delivery configuration for a most recent successful stimulus delivery to deliver the currently needed stimulus;

otherwise delivering the currently needed stimulus using a predetermined stimulus delivery configuration chosen from the first and second configurations;

wherein;

the operational circuitry is configured to provide therapy as a biphasic waveform having first and second phases;

the first configuration uses the first electrode as the positive electrode during the first phase of the biphasic waveform and as the negative electrode during the second phase of the biphasic waveform; and

the second configuration uses the second electrode as the positive electrode during the first phase of the biphasic waveform and as the negative electrode during the second phase of the biphasic waveform.

2. The ICD system of claim 1 wherein the operational circuitry is configured such that:

if it is determined that a prior successful stimulus has been delivered, the operational circuitry selects an energy level for output stimulus equal to that used in the successful stimulus;

otherwise, the operational circuitry selects a predetermined energy level for output stimulus.

3. A method of treating a patient using an implantable cardioverter defibrillator (ICD) having a plurality of electrodes and operational circuitry configured to detect malignant arrhythmias;

the plurality of electrodes including a coil electrode disposed on a lead and an electrically conductive canister for the ICD, with the operational circuitry comprising therapy output circuitry including a first output and a second output, the therapy output circuitry being coupled to the electrically conductive canister and the coil electrode, wherein the operational circuitry is configured to enable only first and second configurations to deliver stimulus using the electrically conductive canister and the coil electrode;

the method comprising;

detecting, using the plurality of electrodes, a malignant arrhythmia and determining therapy is indicated;

a) determining whether a prior therapy has been delivered by the ICD to successfully convert a prior malignant arrhythmia and, if so, re-using whichever of the first configuration or the second configuration was used in delivering the successfully converting prior therapy to deliver therapy;

or

b) determining that no prior successful therapy has been delivered and using a predetermined therapy configuration chosen from the first and second configurations to deliver therapy;

determining whether the delivered therapy from one of steps a) or b) successfully converts the malignant arrhythmia and;

if the delivered therapy is successful, storing data relating to the configuration of the successful delivered therapy;

or

if the delivered therapy is not successful, delivering therapy by switching to the other of the first and second configurations and until therapy is successful or until a timeout occurs.

4. The method of claim 3 wherein the stimulus electrodes are disposed within a patient without contacting or entering the patient'"'"'s heart.

5. The method of claim 3 wherein if the delivered therapy is not successful, the method further comprises raising the energy level delivered by a subsequent therapy in addition to changing the electrode configuration.

6. A method of patient treatment comprising:

providing an implantable cardioverter-defibrillator (ICD) comprising a lead electrode assembly coupled to a canister that houses operational circuitry for the ICD, the lead electrode assembly including a stimulus electrode and the canister having a stimulus electrode for use in conjunction with the stimulus electrode on the lead electrode assembly, wherein the ICD is configured to define first and second therapy configurations using the stimulus electrode on the lead and the stimulus electrode on the canister, each configuration for delivering biphasic stimulus, such that in the first configuration the stimulus electrode on the lead electrode assembly is the positive electrode in the first phase of the biphasic stimulus and in the second configuration the stimulus electrode on the canister is the positive electrode in the first phase of the biphasic stimulus;

implanting the ICD into the patient such that the canister is disposed subcutaneously outside the patient'"'"'s ribcage and the lead electrode assembly does not contact or enter the patient'"'"'s heart;

the operational circuitry observing electrical cardiac activity of the patient to determine whether a malignant arrhythmia is occurring;

if a malignant arrhythmia is identified by the operational circuitry;

a) the operational circuitry preparing to deliver electrical therapy to the patient by charging a capacitor to an energy level chosen for therapy;

b) the operational circuitry observing whether a previous successful therapy delivery using one of the first therapy configuration or the second therapy configuration has occurred and, if so, the operational circuitry enabling a therapy configuration corresponding to the previous successful therapy delivery, otherwise the operational circuitry enabling a predetermined one of the first therapy configuration or the second therapy configuration chosen for initial therapy delivery;

c) the operational circuitry delivering therapy to the patient via the therapy delivery electrodes; and

d) if the malignant arrhythmia does not terminate in response to the delivered therapy, changing a configuration of the therapy delivery to the other of the first therapy configuration or the second therapy configuration which was not enabled in step (b) and delivering an additional therapy until;

therapy delivery succeeds in converting the malignant arrhythmia, at which point the method also includes storing the configuration of the therapy delivery that succeeds;

or

a timeout occurs and therapy delivery is terminated.