Hewlett-packard Company

Koninklijke Philips Corporation N.V.

Agilent Technologies, Inc.

A Dean Forbes

Eric D Helfenbein

Eric Helfenbein

Robert A Piety

In a cardiographic apparatus (), a plurality of electrodes () are configured for operative connection with a subject (). A cardiograph (') is connected with the plurality of electrodes to acquire cardiographic data. A respiratory gate () is configured to identify end expiration periods or other quiescent respiratory periods so as to generate a cardiographic dataset () limited to the identified end-expiration periods from cardiographic data acquired by the cardiograph at least during the identified end expiration periods.

Respiration-gated cardiography

A technique of detecting repeating patterns of anomalous intramyocardial Wenckebach electrical activity in a patient is provided. The method of the technique deals with determining the presence or absence of such intramyocardial anomaly by processing signals that are electrical potential signals which include a cardiac component and a respiratory component. The method includes estimating the respiratory component (preferably by a regression curve-fitting technique based on data of the electrical potential signals and data of respiratory signals), finding the difference between the electrical potential and the estimated respiratory component and based on this difference inferring the presence of absence of the intramyocardial anomaly. Preferably, a generalized inverse of a matrix representing Wenckebach basis functions reflecting Wenckebach phases and modes is used to act on a vector representing the difference between the electrical potential and the estimated respiratory component to determine whether any repeating intramyocardial electrical anomaly is present.

Intramyocardial anomalous activity detection by subtracting modeled

An apparatus for determining the respiratory effort of a patient is disclosed. The apparatus includes a device for acquiring electrocardiographic (ECG) signal (e.g., conventional electrocardiogram (ECG) signal) that contains pure cardiac signal and respiratory muscle tremor (RMT) signal. The apparatus also includes a processor for processing the ECG signal. The processor includes a filter to filter the ECG signal for reducing the cardiac signal, a device for determining a waveform representing the magnitude of the oscillations in the filtered ECG signal, and a mechanism for smoothing spikes in the waveform. The resulting waveform is related to the respiratory muscle tremor, which is related to the respiratory effort. The estimation of the respiratory effort is derived entirely from the ECG signal.

Apparatus and method for determining respiratory effort from muscle

An intramyocardial activity detector for detecting repeating patterns of irregular intramyocardial Wenckebach activity in the heart of a patient is provided. The apparatus includes a mechanism measuring electrocardiogram (ECG) signals from the body, a mechanism for measuring respiratory signals from the body, and a processor electrically associated with the two mechanisms means for measuring to determine the presence of intramyocardial Wenckebach activity of two or more phases. The processor calculates Wenckebach basis function strengths that indicate the presence of voltage in the measured ECG signals caused by repeating patterns of irregular intramyocardial Wenckebach activity via a relationship that describes the measured ECG signals as comprising Wenckebach input being additive to respiratory interference. In this relationship a nonsingular Wenckebach matrix W representing Wenckebach basis functions reflecting Wenckebach phases and a nonsingular interference matrix R act on the ECG signals to extract the Wenckebach input. The nonsingular interference matrix R based on the respiratory signals and the ECG signals of the patient represents how the measured ECG signals are related to the phases of the respiration. The Wenckebach basis function strengths are calculated in terms of the measured ECG signals, the nonsingular Wenckebach matrix W, and the nonsingular interference matrix R.

Intramyocardial Wenckebach activity detector

An electromagnetic shielding garment comprising amorphous alloy strips or strands woven together. The woven material or sheet can be reenforced by bonding it to a flexible material such as plastic. This garment is effective in shielding a patient from extraneous electromagnetic radiation to allow sensitive medical measurements to be taken with minimal interference.

Magnetic shielding garment for electro-biologic measurements

A compact, cardiac analyzer system provides for monitoring physiological indicators of rapid eye movement (REM) sleep, autonomic fluctuations and ischemia. When any of these 'indicators' is detected, a full complement of ECG data is recorded from a subject for subsequent analysis. In the absence of these indicators, only a minimal complement of ECG data is recorded. The system includes a first set of ECG electrode sets, from which the data are recorded only during REM sleep, extreme autonomic drive fluctuations, or ischemia, and a second set of ECG electrode sets, from which the data are constantly recorded. A set of electromagnetic interference sensors is used to assess environmental noise levels so that corrupted data can be rejected or purified. During REM sleep, autonomic drive fluctuations provide a setting for assessing the variability of fractionated potentials in subjects susceptible to sudden cardiac death. In addition, the muscle atonia characterizing REM sleep provides exceedingly low muscle tremor noise levels. Accordingly, cardiac activity is most thoroughly monitored when fluctuating fractionated potentials are most likely to occur and when tremor noise levels are most favorable for their detection. Data recording is minimized in the absence of the indicators, allowing for up to a 5:1 data reduction during a typical sleep cycle.

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Palo Alto, CA, United States of America

A Dean Forbes