Cardiac pacing to induce heart rate variability

Details Cardiac pacing to induce heart rate variability Cardiac pacing to induce heart rate variability

1999-12-06

2001-06-26

Getzow, Scott M. (Department: 3737)

Surgery: light, thermal, and electrical application

Light, thermal, and electrical application

Electrical therapeutic systems

C600S513000

Reexamination Certificate

active

06253107

ABSTRACT:

BACKGROUND
Heart rate variability (“HRV”) is known to be associated with a healthy heart. Numerous clinical studies have shown that patients with higher levels of heart rate variability have an increased chance of survival. Heart rate variability encompasses both long term HRV and short term HRV. Long term HRV is primarily the result of circadian rhythms and activity associated with sleep and awake cycles. Short term HRV is primarily the result of faster acting physiologic responses to respiration and blood pressure control. It has been demonstrated in clinical studies that both short term and long term HRV are related to likelihood of survival.
The beneficial effects of short term HRV are believed to be related to its modulating effect on the cardiac muscle cells and its ability to disrupt or diminish the evolution of dangerous patterns of electrical activity. One such important pattern is the pattern of electrical alternation in the action potential of the cardiac cells. It has been recognized that, in many patients who are at higher risk for serious cardiac arrhythmias, there may emerge a pattern of local or regional alternation in the action potential. This pattern of alternation is not always present, but often emerges under conditions where the patient's heart experiences an increased demand due to an increased level of physical or mental stress.
The pattern of alternation is referred to as electrical alternans. Electrical alternans can often be measured at the body surface as a subtle beat-to-beat change in the repeating pattern of an electrocardiogram (ECG) waveform. Alternans can be indicative of electrical instability of the heart and increased susceptibility to sudden cardiac death. Alternans results in an ABABAB . . . pattern of variation of waveform shape between successive beats in an ECG waveform. An overview of electrical alternans is given by Rosenbaum, Albrecht and Cohen in “Predicting sudden cardiac death from T wave alternans of the surface electrocardiogram: promise and pitfalls.”,
Journal of Cardiovascular Electrophysiology,
Nov., 1996, Vol. 7(11), pages 1095-1111, which is incorporated by reference.
SUMMARY
In one general aspect, the invention provides a method of improving heart function by inducing heart rate variability through cardiac pacing. The method includes generating electrical pacing signals and applying the electrical pacing signals to a heart to improve heart function. The pacing signals are controlled to vary a heart rate during periods of less than five minutes in duration to induce beneficial heart rate variability.
Implementations may include one or more of the following features. For example, the beneficial heart rate variability may be controlled to result in decreased likelihood of cardiac arrhythmia. For example, a measure of electrical stability of the heart related to likelihood of cardiac arrhythmia may be generated and used in generating the pacing signals. The measure of electrical stability may be, for example, a measure of electrical alternans or a measure of blood pressure alternans. Generating the pacing signals may include modifying the pacing signals in response to changes in the measure.
The pacing signals also may be controlled to mimic physiologic patterns of heart rate variability. Alternatively, the pacing signals may be controlled using a measure of a physiologic process, such as, for example, cardiac electrical activity, respiration, or blood pressure regulation. The pacing signals also may be controlled using a measure of the average heart rate.
The beneficial heart rate variability may result in improved left ventricular function.
The pacing signals also may be controlled to decrease a level of blood pressure alternans.
The pacing signals may be controlled to vary the heart rate by more than 2 percent. For example, the pacing signals may be controlled to vary the heart rate by more than 2 percent during a period of less than one minute in duration, less than 30 seconds in duration, or less than 10 seconds in duration.
In another general aspect, the invention features assessing cardiac electrical stability by generating a measure of cardiac electrical alternans, generating a measure of blood pressure alternans, and assessing cardiac electrical stability using both the measure of cardiac electrical alternans and the measure of blood pressure alternans.
Other features and advantages will be apparent from the following description, including the drawings, and from the claims.


REFERENCES:
patent: 5143065 (1992-09-01), Adkins et al.
patent: 5312453 (1994-05-01), Shelton et al.
patent: 5560370 (1996-10-01), Verrier et al.
patent: 5645575 (1997-07-01), Stangl et al.
patent: 5733312 (1998-03-01), Schloss et al.
patent: 5749900 (1998-05-01), Schroeppel et al.

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