Cardiac resynchronization therapy for patients with right bundle branch block

• US 8,041,424 B2
• Filed: 07/31/2007
• Issued: 10/18/2011
• Est. Priority Date: 07/31/2007
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Corbucci, Giorgio
• Primary Examiner(s): Layno; Carl H
• Assistant Examiner(s): Stice; Paula J
• Application Number:
  US11/831,403
• Publication Number:
  US 20090036941A1
• Time in Patent Office: 1,540 Days
• Field of Search: 600508-514, 600/29, 600/547.119, 607/4, 607/9, 607 14- 19, 607 24- 25
• US Class Current: 607/9
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61B 7/023 for introduction into the body, e.g. into the oesophagus oesophageal ECG probes A61B5/285
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/36578 controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay
• CPC Class Codes: A61N 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36843 Bi-ventricular stimulation

Abstract

An implantable medical device and associated method deliver cardiac resynchronization therapy in a patient having right bundle branch block by measuring an interval between a right atrial depolarization and a first heart sound and selecting a right atrial-ventricular (AV) pacing interval in response to the measured interval. Pacing pulses are delivered to the right ventricle of a patient'"'"'s heart at the selected right AV pacing interval to synchronize the right ventricle with an intrinsic left ventricle depolarization.

Claims

1. A method for use in an implantable medical device for delivering cardiac resynchronization therapy in a patient having right bundle branch block, comprising:

measuring a first interval between a right atrial depolarization signal and a first heart sound signal;

selecting a right atrial-ventricular (AV) pacing interval in response to the measured first interval; and

delivering pacing pulses to a right ventricle of a heart at the selected right AV pacing interval;

further comprising;

measuring a second interval between the right atrial depolarization and a right ventricular depolarization;

delivering pacing pulses to the right ventricle at a plurality of test AV pacing intervals determined based on the second interval; and

assessing ventricular synchrony by determining a metric of ventricular synchrony for each of the plurality of test AV pacing intervals;

wherein selecting the right AV pacing interval further comprises determining an optimal right AV pacing interval by comparing the metric of ventricular synchrony for each of the plurality of test AV pacing intervals.

2. A method according to claim 1 wherein assessing ventricular synchrony comprises computing a third interval between the right ventricular depolarization and the first heart sound for each of the plurality of test AV pacing intervals.

3. A method according to claim 1 wherein assessing ventricular synchrony comprises measuring a cardiac electrogram characteristic for each of the plurality of test AV pacing intervals.

4. A method according to claim 3 wherein the cardiac electrogram characteristic is one of a QRS duration and a QT interval.

5. A method according to claim 1 wherein assessing ventricular synchrony comprises measuring a right ventricular pressure parameter for each of the plurality of test AV pacing intervals.

6. A method according to claim 5 wherein the right ventricular pressure parameter is one of a maximum dP/dt, an end diastolic pressure, and an estimated pulmonary artery pressure.

7. An implantable medical device to provide cardiac resynchronization therapy in a patient having right bundle branch block, the device comprising:

electrodes to detect electrical signals within a heart and deliver pacing pulses to the heart;

sensing circuitry for receiving the electrical signals from the electrodes;

pulse generating circuitry for generating the pacing pulses delivered by the electrodes;

a heart sound sensor; and

a processor coupled to the sensing circuitry, the pulse generating circuitry, and the heart sound sensor and configured to measure a first interval between a right atrial depolarization signal and a first heart sound signal, select a right atrial-ventricular (AV) pacing interval in response to the measured first interval; and

control the delivery of pacing pulses to a right ventricle of a heart at the selected right AV pacing interval, wherein the processor is further configured to;

measure a second interval between the right atrial depolarization signal and a sensed right ventricular depolarization signal;

control the delivery of pacing pulses to the right ventricle at a plurality of test AV pacing intervals determined based on the second interval; and

perform an assessment of ventricular synchrony by determining a metric of ventricular synchrony for each of the plurality of test AV pacing intervals;

wherein selecting the right AV pacing interval by the processor comprises comparing the metric of ventricular synchrony for each of the plurality of test AV pacing intervals.

8. A device according to claim 7 wherein the assessment of ventricular synchrony performed by the processor comprises computing a third interval between the right ventricular depolarization and the first heart sound for each of the plurality of test AV pacing intervals.

9. A device according to claim 7 wherein the assessment of ventricular synchrony performed by the processor comprises measuring a cardiac electrogram characteristic for each of the plurality of test AV pacing intervals.

10. A device according to claim 7 wherein the assessment of ventricular synchrony performed by the processor comprises measuring a right ventricular pressure parameter for each of the plurality of test AV pacing intervals.

11. A device according to claim 7 wherein the processor being further configured to:

determine a difference between the selected right AV pacing interval and a programmed interval,

adjust the selected AV pacing interval by the difference,

repeat the ventricular synchrony assessment to determine a next selected right AV pacing interval; and

adjust the next selected AV pacing interval by the difference.

12. A non-transitory computer-readable medium for storing a set of instructions which when implemented in an implantable medical device for delivering cardiac resynchronization therapy causes the device to:

measure a first interval between a right atrial depolarization signal and a first heart sound signal;

select a right atrial-ventricular (AV) pacing interval in response to the measured first interval;

deliver pacing pulses to a right ventricle of a heart at the right AV pacing interval;

measure a second interval between the right atrial depolarization and a right ventricular depolarization;

deliver pacing pulses to the right ventricle at a plurality of test AV pacing intervals determined based on the second interval; and

assess ventricular synchrony by determining a metric of ventricular synchrony for each of the plurality of test AV pacing intervals;

wherein selecting the right AV pacing interval further comprises determining an optimal right AV pacing interval by comparing the metric of ventricular synchrony for each of the plurality of test AV pacing intervals.