Abstract: In a cardiographic apparatus (10), a plurality of electrodes (16) are configured for operative connection with a subject (14). A cardiograph (12, 12?, 12?) is connected with the plurality of electrodes to acquire cardiographic data. A respiratory gate (20, 22, 26, 36, 46, 50, 52, 54) is configured to identify end expiration periods or other quiescent respiratory periods so as to generate a cardiographic dataset (30) limited to the identified end-expiration periods from cardiographic data acquired by the cardiograph at least during the identified end expiration periods.

Abstract: In a cardiographic apparatus (10), a plurality of electrodes (16) are configured for operative connection with a subject (14). A cardiograph (12, 12?, 12?) is connected with the plurality of electrodes to acquire cardiographic data. A respiratory gate (20, 22, 26, 36, 46, 50, 52, 54) is configured to identify end expiration periods or other quiescent respiratory periods so as to generate a cardiographic dataset (30) limited to the identified end-expiration periods from cardiographic data acquired by the cardiograph at least during the identified end expiration periods.

Abstract: 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.

Abstract: 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.

Abstract: An apparatus and method for the filtering of signals collected during a period that includes a quiet ("signal-free") epoch and an event epoch is disclosed. The apparatus includes a means for generating electrical digitized signals of the event episode, memory for receiving and storing the digitized signals of the event episode, an event detector for determining the event epoch and the quiet epoch of the event episode in the digitized signals, a spectrum analyzer to analyze the power spectrum of the digitized signals of at least one event episode, an estimator to estimate electromagnetic interference (EMI) based on the digitized signals of the quiet epoch and the frequencies obtained in the spectral analysis; and a subtractor to subtract the estimated EMI from the digitized signals of the event epoch. The resulting signals are signals of the event epoch with reduced EMI.

Abstract: During sampling, a finite impulse response (FIR) filter separates a composite signal into two components, non-cardiac physiological phenomena and cardiac artifacts. The length of the filter window dynamically varies to produce an output signal in which the cardiac frequency and any associated harmonics are suppressed with a fixed delay. The FIR filter is applied to the patient signal and lags the patient signal by at least one interval between triggering events. When the present interval between triggering events passes by the filter window, the window length is gradually adjusted to have the same length as the next period such that the window length is centered between two adjacent triggering events. The difference between the present interval and the next interval is evenly distributed or subtracted across the filter window between centerings.