Lead system for use with an atrial defibrillator and method

• US 5,350,404 A
• Filed: 10/01/1993
• Issued: 09/27/1994
• Est. Priority Date: 04/12/1991
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: InControl, Inc. (Daikin Industries Ltd)
• Inventors: Alferness, Clifton A., Adams, John M., Kreyenhagen, Paul E.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): SCHAETZLE, KENNEDY
• Application Number:
  US08/130,308
• Time in Patent Office: 361 Days
• Field of Search: 607/5, 607/122, 607/4, 607/5, 128/642
• US Class Current: 607/5
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems
• CPC Class Codes: A61N 1/0563 specially adapted for defibrillation or cardioversion
• CPC Class Codes: A61N 1/3918 characterised by shock pathway, e.g. by electrode configuration
• CPC Class Codes: A61N 1/395 for treating atrial fibrillation
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock
• CPC Class Codes: A61N 2001/0585 Coronary sinus electrodes

Abstract

An implantable atrial defibrillator provides a pulse of defibrillating electrical energy to the atria of the heart in synchronism with sensed R waves in response to non-coincident sensing of an R wave at first and second areas of the heart. The defibrillating pulse is provided after a predetermined number of consecutive R waves are non-coincidently sensed to assure reliable synchronization. The atrial defibrillator is also operational in a marker mode wherein a number of synchronization marker pulses are delivered to the heart for detection on an externally generated electrocardiogram. The atrial fibrillation detector of the defibrillator is normally disabled and is activated when the sensed ventricular activity indicates a probability of atrial fibrillation to conserve a depletable power source. A plurality of lead systems are also described for use with the atrial defibrillator which reduce the quantity of electrical energy required to defibrillate the heart and ensure that the delivered atrial defibrillating electrical energy is substantially confined to the atria of the heart.

Claims

1. A device for monitoring activity of the heart and delivering cardioverting electrical energy to the atria of the heart, said device comprising:

storage means for storing said electrical energy;

atrial activity sensing means for sensing atrial activity of the heart;

electrical activation sensing means for sensing electrical activations of the heart;

a first lead including a first electrode and a second electrode, said first lead for disposing said first electrode within the right atrium of the heart and for disposing said second electrode within the coronary sinus beneath the left atrium of the heart, said first and second electrodes being coupled to said storage means for delivering said electrical energy to the atria of the heart and to said atrial activity sensing means for sensing atrial activity of the heart;

a second lead including first and second sensing electrodes, said second lead for disposing said first and second sensing electrodes within the right ventricle of the heart, said first and second sensing electrodes being coupled to said electrical activation sensing means for sensing electrical activations of the heart; and

said first and second leads being fully implantable beneath the skin of a patient.

2. A device as defined in claim 1 wherein said first lead is configured for being advanced through the right atrium and into the coronary sinus of the heart.

3. A device as defined in claim 2 wherein said first lead includes a preshaped bend in the region of said first lead within the coronary sinus for fixing said first lead within the coronary sinus.

4. A device as defined in claim 1 wherein said first electrode is further arranged for being disposed in the right atrial appendage of the heart.

5. A device as defined in claim 4 wherein said first lead further includes a preshaped portion in the region of said first lead within the right atrium for forcing said first electrode into the right atrial appendage.

6. A device as defined in claim 5 wherein said first lead is looped within the right atrium and wherein said first lead further includes a stiffened portion for forcing said first electrode against the inner wall of the right atrium.

7. A device as defined in claim 1 wherein said second lead further includes a third sensing electrode coupled to said electrical activation sensing means.

8. A device as defined in claim 7 wherein said second lead is arranged for disposing said third sensing electrode within the right ventricle of the heart.

9. A device as defined in claim 1 wherein said second electrode and a selected one of said first and second sensing electrodes are coupled to said electrical activation sensing means for sensing electrical activations of the heart between said second electrode and said selected one of said first and second sensing electrodes.

10. A method of monitoring activity of the heart of a patient and delivering cardioverting electrical energy to the atria of the heart of the patient, said method comprising the steps of:

providing storage means for storing electrical energy;

implanting said storage means beneath the skin of the patient;

providing lead means including first lead having first and second electrodes and a second lead including first and second sensing electrodes;

implanting said lead means beneath the skin of the patient including steps of disposing said first electrode within the right atrium of the heart, disposing said second electrode within the coronary sinus beneath the left atrium of the heart, and disposing said first and second sensing electrodes within the right ventricle of the heart;

coupling said first and second electrodes to said storage means;

sensing atrial activity of the heart between said first and second electrodes;

sensing electrical activations of the heart between said first and second sensing electrodes;

storing said electrical energy in said storage means; and

applying, through said first lead, at least a portion of said stored electrical energy between said first and second electrodes to deliver said cardioverting electrical energy to the atria of the heart.

11. A method as defined in claim 10 wherein said second lead includes a third sensing electrode and including the further steps of disposing said third sensing electrode within the right ventricle of the heart and sensing electrical activations of the heart with said first, second, and third sensing electrodes.

13. A method as defined in claim 10 including the further step of sensing said electrical activations of the heart between said second electrode and a selected one of said first or and second sensing electrodes.

14. A method as defined in claim 13 wherein said first electrode is disposed in the right atrial appendage of the heart.

15. A method as defined in claim 10 wherein said applying step includes applying said electrical energy in the form of a biphasic waveform having a pair equal duration phases and a total energy between 0.5 and 2.1 joules.

16. A method as defined in claim 15 wherein each of said phases has a duration between 2 and 4 milliseconds.

12. A method as defined in claim 12 wherein said first electrode is disposed in the right atrial appendage of the heart.

17. An implantable device for monitoring activity of the heart and delivering cardioverting electrical energy to the atria of the heart, said device comprising:

storage means for storing said electrical energy;

atrial activity sensing means for sensing atrial activity of the heart;

electrical activation sensing means for sensing electrical activations of the heart; and

lead means including a first electrode, a second electrode, a first sensing electrode, and a second sensing electrode for disposing said first electrode within the right atrium of the heart, for disposing said second electrode within the coronary sinus beneath the left atrium of the heart, and for disposing said first and second sensing electrodes within the right ventricle of the heart;

said first and second electrodes being coupled to said storage means for delivering said cardioverting electrical energy to the atria of the heart and to said atrial activity sensing means for sensing atrial activity of the heart;

said first and second sensing electrodes being coupled to said electrical activation sensing means for sensing electrical activations of the heart between said first and second sensing electrodes,

said second electrode and a selected one of said first and second sensing electrodes being coupled to said electrical activation sensing means for sensing electrical activations of the heart between said second electrode and said selected one of said first and second sensing electrodes, and

said lead means being fully implantable beneath the skin of a patient.