Evaluating a patient condition using autonomic balance information in implantable cardiac devices

Abstract

Systems and methods for evaluating a patient condition using autonomic balance information involve providing an implantable cardiac device that acquires a cardiac waveform from a patient. One or more characteristics associated with autonomic balance of the patient are detected and used to evaluate a patient condition, such as sleep onset, sleep stage, cardiac vulnerability over a predetermined duration, and sleep disordered breathing. Patient activity levels may be sensed and used to evaluate the patient's condition, such as for determining a level of systemic stress. Characteristics associated with the autonomic balance include calculating an LF / HF ratio waveform and / or determining one or more morphological features of the LF / HF ratio waveform. Coordination with a patient-external device may facilitate transmission of information about one or more of the cardiac waveform, the one or more characteristics associated with the autonomic balance, and a marked cardiac waveform.

Description

CLAIM OF PRIORITY[0001]This application is a continuation of and claims the benefit of priority under 35 U.S.C. §120 to U.S. patent application Ser. No. 11 / 168,614, filed on Jun. 28, 2005, which is hereby incorporated by reference herein in its entirety.FIELD OF THE INVENTION[0002]The present invention relates generally to implantable cardiac methods and systems, and more particularly to systems and methods for evaluating a patient condition using autonomic balance information.BACKGROUND OF THE INVENTION[0003]The human body functions through a number of interdependent physiological systems controlled through various mechanical, electrical, and chemical processes. The metabolic state of the body is constantly changing. For example, as exercise level increases, the body consumes more oxygen and gives off more carbon dioxide. The cardiac and pulmonary systems maintain appropriate blood gas levels by making adjustments that bring more oxygen into the system and dispel more carbon dioxid...

AI Technical Summary

Problems solved by technology

Autonomic imbalances and other disorders may affect the cardiovascular, respiratory, and other physiological systems.

Heart failure is an abnormality of cardiac function that causes cardiac output to fall below a level adequate to meet the metabolic demand of peripheral tissues.

Over time, the elasticity of the lung tissue is lost, and the lungs become distended, unable to expand and contract normally.

As the disease progresses, breathing becomes labored, and the patient grows progressively weaker.

Sleep disordered breathing is particularly prevalent and is associated with excessive daytime sleepiness, systemic hypertension, increased risk of stroke, angina, and myocardial infarction.

Disordered breathing can be particularly serious for patients concurrently suffering from cardiovascular deficiencies.

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