Abstract: A subject suspected of experiencing a myocardial infarction is monitored by applying sensors to the subject, where the sensors are configured to produce electrical signals representative of cardiac activity of the subject. Electrical signals are received from at least two of the sensors. The received signals then are processed to obtain a localized cardiac measure that is analyzed to determine whether the subject is experiencing a myocardial infarction.

Abstract: The invention relates to detecting leaks in a pipeline using enhanced methods of data sensing, digitally encoded transmission, and cross-correlation. A plurality of acoustic sensors are applied to the pipeline to sense a combination of signals from the leak and much greater quantities of noise. The sensed data is digitized at the sensor, encoded and digitally transmitted to a computerized base station. The encoded data from a plurality of sensors received at the base station is decoded, digitally filtered and cross-correlated. Enhanced methods of cross-correlation are performed to estimate the likely presence of a leak and the location and size of any leaks present. Participation in the leak detection procedure by an expert not present at the pipeline is facilitated by communication of data between the base station and a distant supervisory station.

Abstract: Abnormal cardiac activity in a patient may be detected by acquiring an electrocardiogram waveform associated with a first level of physiologic activity of the patient and an electrocardiogram waveform associated with a second, different level of physiologic activity of the patient. QRS complexes of the electrocardiogram waveforms are compared to identify an abnormal portion of the QRS complex of the electrocardiogram waveform associated with the second level of physiologic activity. The abnormal portion of the QRS complex is processed to detect abnormal physiologic activity.

Abstract: A localized cardiac measure, such as a localized measure of myocardial ischemia, is obtained by applying sensors to a subject, where the sensors are configured to produce electrical signals representative of cardiac activity of the subject. The subject's heart is then physiologically stressed by, for example, exercise stress testing, and electrical signals are received from at least two of the sensors. The received signals then are processed to obtain a localized cardiac measure.

Abstract: Noise is reduced from a received ECG signal representative of activity of the heart of a patient. A collection of beats from the ECG signal is selected and transformed into a multi-dimensional representation. A multi-dimensional filter function is applied to the multi-dimensional representation to enhance a signal-to-noise ratio of the collection of beats.

Abstract: Method and apparatus for analyzing electrocardiogram signals to ascertain any defects or abnormalities in heart activity. Sensed, orthogonal x, y and z input signals are processed to obtain QRS onset and then passed through first and second spectral filters having respective passbands of 70-200 hertz and 40-200 hertz in order to establish QRS offset and accurate determinations of RMS voltage values and (LAS) low amplitude signals in the terminal QRS portion of the ECG signal. A spectral filtering of the x, y and z input signals with 150-250 hertz bandpass window also allows determination of certain high frequency activity in the midportions of the QRS.

Abstract: Method and apparatus for analyzing ECG signal data for diagnostic purposes by performing an incrementally moving, short window FFT analysis to produce a set of spectral templates representative of the spectral frequency content of the ECG at each window position. The spectral templates may be displayed as a representation of a three dimensional surface or mathematically analyzed. The changes in the shape of the templates or surface with time represent a change in the spectrum, which are shown to be an indication of abnormalities in the heart.

Abstract: Method and apparatus for analyzing ECG signal data for diagnostic purposes by performing an incrementally moving, short window FFT analysis to produce a set of spectral templates representative of the spectral frequency content of the ECG at each window position. The spectral templates may be displayed as a representation of a three dimensional surface or mathematically analyzed. The changes in the shape of the templates or surface with time represent a change in the spectrum, which are shown to be an indication of abnormalities in the heart.