摘要:
A method and apparatus for discriminating between stable and unstable ventricular tachycardias based on a measurement of oxygen saturation. Reference values for average oxygen saturation level and of the pulsatile characteristic of the oxygen saturation level are taken while a patient is in a resting condition. Measurements of oxygen saturation are also taken in response to the detection of a high heart rate, and are compared to the reference measurements to discriminate between stable and unstable ventricular tachyarrhythmias. An unstable tachyarrhythmia is diagnosed if a tachycardia is diagnosed and the current oxygen saturation level is similar to the reference average oxygen saturation level or if the oxygen saturation as presently measured displays a decreased pulsatile characteristic as compared to the reference measurements. The discriminator is intended for use in conjunction with or as part of an automated cardioverter of the type capable of delivering differing therapies for termination of stable and unstable ventricular tachyarrhythmias, such as antitachycardia pacing, cardioversion and defibrillation.
摘要:
A method includes controlling a cardiac pacing rate of an implantable medical device (IMD) to control a heart rate of a patient and determining that the patient is in a resting state. The method further includes modifying the pacing rate of the IMD for N cardiac cycles in response to determining that the patient is in the resting state. N is an integer greater than 1. Modifying the pacing rate includes incrementally increasing the pacing rate for a first portion of the N cardiac cycles, and incrementally decreasing the pacing rate for a second portion of the N cardiac cycles.
摘要:
A medical device for determining a respiratory effort having a pressure sensor to sense pressure signals, a housing having system components positioned therein, and a microprocessor positioned within the housing, wherein the microprocessor detects an inspiration and an expiration in response to the pressure signals, detects a breath in response to the detected inspiration and the detected expiration, and determines the respiratory effort in response to the detected breath.
摘要:
A method of determining respiratory effort in a medical device in which pressure signals are sensed to generate corresponding sample points, an inspiration and an expiration are detected in response to the sensed pressure signals, a breath is detected in response to the detected inspiration and the detected expiration, and the respiratory effort is determined in response to the detected breath.
摘要:
A system and method for monitoring respiration including sensing a signal that varies with respiration, deriving a respiration parameter, applying criteria for detecting a respiration disturbance and determining one or more respiratory disturbance metrics. The system preferably includes an implantable sensor with an associated implantable medical device such that chronic respiration monitoring is possible. The implantable medical device may execute methods for detecting and measuring respiratory disturbances or may store data to be transferred to an external device for detecting and measuring respiratory disturbances. Respiratory disturbance detection may trigger a responsive action such as physiological data storage, a change in therapy delivery, or a clinician warning. Assessment of cardiac function may be made based on metrics of respiratory disturbances or a measure of circulatory delay time following detection of a respiratory disturbance.
摘要:
The present invention relates to methods and apparatus for detection and treatment of syncope in an implantable medical device, and particularly to detection of syncope as a function of a predetermined increase in one or more respiration parameter and drop in heart rate and optionally delivering a pacing therapy in response thereto. The onset of a syncopal episode is declared when the patient's respiration rate and/or tidal volume and/or minute ventilation increases by a predetermined increment or threshold and a heart rate drops below a threshold heart rate drop. The threshold heart rate drop is preferably established as a function of the change in the respiration parameter.
摘要:
A method includes controlling a cardiac pacing rate of an implantable medical device to control a heart rate of a patient and detecting inhalation and exhalation of the patient. The method further includes determining that the patient is in a resting state, and, in response to determining that the patient is in the resting state, incrementally increasing the pacing rate while exhalation of the patient is detected and incrementally decreasing the pacing rate while inhalation of the patient is detected.
摘要:
A method includes controlling a cardiac pacing rate of an implantable medical device (IMD) to control a heart rate of a patient and determining that the patient is in a resting state. The method further includes modifying the pacing rate of the IMD for N cardiac cycles in response to determining that the patient is in the resting state. N is an integer greater than 1. Modifying the pacing rate includes incrementally increasing the pacing rate for a first portion of the N cardiac cycles, and incrementally decreasing the pacing rate for a second portion of the N cardiac cycles.
摘要:
A system and method for filtering a pressure signal in a medical device in which a sensor terminal senses the pressure signal, an electrode terminal receives cardiac electrical signals, a signal filtering system filters the sensed pressure signal in response to a determined heart rate to generate a heart-rate dependent frequency response, and a microprocessor derives a respiration signal in response to the heart rate dependent frequency response, and determines metrics of hemodynamic function in response to the derived respiration signal.
摘要:
A system and method for monitoring in a patient includes producing sensor signals representative of a physiologic parameter associated with respiration. A periodic breathing cycle is detected based on the sensor signals. An output is produced as a function of the cycle length.