Method and apparatus for pacing patients with severe congestive heart failure

• US 5,700,283 A
• Filed: 11/25/1996
• Issued: 12/23/1997
• Est. Priority Date: 11/25/1996
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Salo, Rodney W.
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): LAYNO, CARL HERNANDZ
• Application Number:
  US08/754,932
• Time in Patent Office: 393 Days
• Field of Search: 607/17, 607/18, 607/23, 607/25
• US Class Current: 607/17
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36564 controlled by blood pressure
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay

Abstract

An implantable cardiac pacemaker especially designed for treatment of CHF includes an accelerometer for sensing heart sounds and processing circuitry for deriving from the heart sound information the mechanical AV delay of the patient'"'"'s heart. The pacemaker'"'"'s applied AV delay is then adjusted until the measured mechanical AV delay falls in a range of between 180 ms and 250 ms. Further optimization of the heart as a pump can then be achieved by incrementally adjusting the pacemaker'"'"'s applied AV delay interval until a point is reached where a measure of cardiac performance such as aortic pulse pressure is optimized.

Claims

1. A method of treating patients having congestive heart failure comprising the steps of:

(a) providing a dual-chamber cardiac pacemaker of the type having means for sensing atrial depolarization signals, means for sensing ventricular depolarization signals, means for generating ventricular stimulating signals, an accelerometer for sensing heart sounds and a programmable AV delay interval between the sensing of an atrial depolarizing signal and the sensing of a next succeeding ventricular depolarizing signal;

(b) deriving from the heart sounds a measure of an interval between the onset of atrial ejection and of aortic ejection in the patient'"'"'s heart; and

(c) adjusting the AV delay interval of the pacemaker until the interval measured in step (b) falls in the range of from about 180 ms to 250 ms.

2. The method as in claim 1 and further including the step of incrementally adjusting the programmable AV delay interval while measuring pulse pressure and for fixing the AV delay interval at a value corresponding to a maximum measured pulse pressure value.

3. A pacemaker for use in treating patients having congestive heart failure, comprising in combination:

(a) means for sensing atrial events;

(b) means for sensing ventricular events;

(c) means for generating ventricular stimulating pulses following a programmed AV delay interval;

(d) means in said pacemaker for determining a mechanical AV delay of a patient'"'"'s heart; and

(e) means for adaptively and incrementally setting the programmed AV delay interval until the mechanical AV delay interval falls in a range of from about 180 ms to about 250 ms.

4. A method of treating patients having congestive heart failure comprising the steps of:

(a) providing a dual-chamber cardiac pacemaker of the type having means for sensing atrial depolarization signals, means for sensing ventricular depolarization signals, means for generating ventricular stimulating signals, an accelerometer for sensing heart sounds and a programmable AV delay interval between the sensing of an atrial depolarizing signal and the sensing of a next succeeding ventricular depolarizing signal;

(b) obtaining from the accelerometer an integrated value of the heart sounds corresponding to total accelerometer energy; and

(c) adjusting the AV delay interval of the pacemaker until the total accelerometer energy is a minimum.