Method and system for treatment of neurocardiogenic syncope

• US 20030023279A1
• Filed: 07/27/2001
• Published: 01/30/2003
• Est. Priority Date: 07/27/2001
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Spinelli, Julio C., Zhu, Qingsheng
• Granted Patent: US 6,748,271 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• 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

Abstract

A method and apparatus for treating or preventing neurocardiogenic syncope is disclosed. Upon detection of bradycardia or a drop in blood pressure indicating the onset of syncope, electrostimulation pulses are delivered during the heart'"'"'s refractory period. The pulses are non-excitatory but increase myocardial contractility and thereby increase cardiac output.

Claims

1. A method for operating a cardiac rhythm management device, comprising:

sensing ventricular depolarizations and generating ventricular sense signals in accordance therewith;

detecting a ventricular bradycardia when a ventricular rate derived from a time interval between successive depolarizations in a ventricle is below a specified bradycardia limit value; and

,

delivering an electrostimulation pulse to the ventricle during a refractory period of the ventricle when bradycardia is detected to thereby increase the contractility of the ventricle.

2. The method of claim 1 wherein the electrostimulation pulse is delivered within a specified refractory time interval after a ventricular sense.

3. The method of claim 1 further comprising terminating delivery of electrostimulation pulses when the ventricular rate equals or exceeds the bradycardia limit value.

4. The method of claim 3 wherein the bradycardia limit value is increased to a hysteresis value when delivery of electrostimulation pulses is begun and returned to its previous non-hysteresis value when delivery of electrostimulation pulses is terminated.

5. The method of claim 1 further comprising alternating the delivery of electrostimulation pulses between different stimulation sites of the ventricle.

6. The method of claim 1 further comprising measuring a blood pressure and delivering an electrostimulation pulse only when the measured blood pressure is below a specified minimum value.

7. The method of claim 6 wherein the blood pressure is measured with an accelerometer.

8. The method of claim 6 further comprising adjusting the magnitude and/or duration of the stimulation pulses in accordance with the measured blood pressure.

9. The method of claim 1 further comprising deriving the ventricular rate from a moving average of intervals between successive ventricular senses.

10. The method of claim 1 further comprising:

pacing the ventricle upon expiration of an escape interval without receipt of a ventricular sense, the inverse of the escape interval being a lower rate limit; and

,

increasing the lower rate limit when bradycardia is detected.

11. A cardiac rhythm management device, comprising:

a sensing channel for sensing ventricular depolarizations and generating ventricular sense signals in accordance therewith;

a stimulation channel for delivering an electrostimulation pulse to a ventricle;

a controller for controlling the delivery of stimulation pulses to the ventricle;

wherein the controller is programmed to detect a ventricular bradycardia when a ventricular rate derived from a time interval between successive depolarizations in a ventricle is below a specified bradycardia limit value and to deliver a stimulation pulse during a refractory period of the ventricle when bradycardia is detected to thereby increase the contractility of the ventricle.

12. The device of claim 11 wherein the controller is programmed to deliver the electrostimulation pulse within a specified refractory time interval after a ventricular sense.

13. The device of claim 11 wherein the controller is programmed to terminate delivery of electrostimulation pulses when the ventricular rate equals or exceeds the bradycardia limit value.

14. The device of claim 13 wherein the controller is programmed to increase the bradycardia limit value to a hysteresis value when delivery of electrostimulation pulses is begun and return the bradycardia limit value to its previous non-hysteresis value when delivery of electrostimulation pulses is terminated.

15. The device of claim 11 wherein the controller is programmed to alternate the delivery of electrostimulation pulses between different stimulation sites of the ventricle.

16. The device of claim 11 further comprising means for measuring blood pressure and wherein the controller is programmed to measure a blood pressure and deliver an electrostimulation pulse only when the measured blood pressure is below a specified minimum value.

17. The device of claim 16 wherein the blood pressure measuring means is an accelerometer.

18. The device of claim 11 wherein the controller is programmed to adjust the magnitude and/or duration of the stimulation pulses in accordance with the measured blood pressure.

19. The device of claim 11 wherein the controller is programmed to derive the ventricular rate from a moving average of intervals between successive ventricular senses.

20. The device of claim 11 wherein the controller is programmed to:

pace the ventricle upon expiration of an escape interval without receipt of a ventricular sense, the inverse of the escape interval being the lower rate limit; and

,

increase the lower rate limit when bradycardia is detected.