Method and system for treatment of neurocardiogenic syncope

• US 8,024,040 B2
• Filed: 06/07/2004
• Issued: 09/20/2011
• Est. Priority Date: 07/27/2001
• Status: Expired due to Term

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Spinelli, Julio C., Zhu, Qingsheng
• Primary Examiner(s): Patel; Niketa I
• Assistant Examiner(s): HOLMES, REX R
• Application Number:
  US10/862,831
• Publication Number:
  US 20050021098A1
• Time in Patent Office: 2,661 Days
• Field of Search: 607 4- 5, 607/9, 607/17, 607/23, 607/2, 607/7, 607/14, 607/25, 607/28
• 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;

deriving a ventricular rate as a function of a plurality of time intervals between successive ventricular senses;

detecting a ventricular bradycardia when the derived ventricular rate is below a specified bradycardia limit value;

initiating delivery of one or more electrostimulation pulses to the ventricle while the ventricle is refractory when ventricular bradycardia is detected from the derived ventricular rate to thereby increase the contractility of the ventricle, wherein such electrostimulation pulses are timed to occur within a refractory interval following a ventricular sense or pace;

pacing 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

,

increasing the lower rate limit when bradycardia is detected.

2. The method of claim 1 further comprising delivering the electrostimulation pulse within the specified refractory time interval after each ventricular sense when bradycardia is detected.

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 further comprising increasing the bradycardia limit value to a hysteresis value when delivery of the electrostimulation pulses is begun and returning the bradycardia limit value to its previous non-hysteresis value when delivery of the electrostimulation pulses is terminated.

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

6. The method of claim 1 further comprising measuring a blood pressure and delivering the electrostimulation pulses 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 of the stimulation pulses in accordance with the measured blood pressure.

9. The method of claim 6 further comprising adjusting the duration of the stimulation pulses in accordance with the measured blood pressure.

10. A cardiac rhythm management device, comprising:

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

a pulse generator for delivering electrostimulation pulses to a ventricle through a stimulation channel;

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

wherein the controller is programmed to derive a ventricular rate as a function of a plurality of time intervals between successive ventricular senses, detect a ventricular bradycardia when the derived ventricular rate is below a specified bradycardia limit value, and initiate delivery of one or more stimulation pulses while the ventricle is refractory when ventricular bradycardia is detected from the derived ventricular rate to thereby increase the contractility of the ventricle, wherein such electrostimulation pulses are timed to occur within a refractory interval following a ventricular sense or pace; and

,

wherein the controller is configured 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 to increase the lower rate limit when bradycardia is detected.

11. The device of claim 10 wherein the controller is programmed to deliver the electrostimulation pulse within the specified refractory time interval after each ventricular sense when bradycardia is detected.

12. The device of claim 10 wherein the controller is programmed to terminate delivery of electrostimulation pulses when the ventricular rate equals or exceeds the bradycardia limit value.

13. The device of claim 12 further comprising specified hysteresis and non-hysteresis values for the bradycardia limit value and wherein the controller is programmed to increase the bradycardia limit value the hysteresis value when delivery of electrostimulation pulses is begun and return the bradycardia limit value to the non-hysteresis value when delivery of electrostimulation pulses is terminated.

14. The device of claim 10 further comprising a plurality of stimulation channels and wherein the controller is programmed to alternate the delivery of electrostimulation pulses between different stimulation channels.

15. The device of claim 10 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.

16. The device of claim 15 wherein the blood pressure measuring means is an accelerometer.

17. The device of claim 15 wherein the controller is programmed to adjust the magnitude of the stimulation pulses in accordance with the measured blood pressure.

18. The device of claim 15 wherein the controller is programmed to adjust the duration of the stimulation pulses in accordance with the measured blood pressure.