Abstract: A method for detecting heart beats is disclosed. A plurality of sensors are configured to receive a cardiac signal and another cardiac signal or a signal correlated with a noise source. A processor is configured to detect candidate peaks in a cardiac signal and select a subset of the candidate peaks for temporal correlation with features, such as peaks, in another cardiac signal or noise correlated signal. This relationship is quantified by a correlation measure. The correlation measure, in turn, influences the likelihood that a particular peak or sequence corresponds to a heartbeat. Candidate peaks that were not part of the correlation process may then be added to a sequence or sequences associated with the peaks subject to the correlation analysis. Sequences are scored according to quality and a final sequence is selected as possible heartbeats.

Abstract: Disclosed is a system for detecting pathophysiological cardiac conditions. The system comprises a diagnostic device that contains electronic circuitry that can detect a cardiac event such as an acute ischemia. The cardiac diagnostic device receives electrical signals from subcutaneous or body surface sensors. The cardiac diagnostic device includes a processor that computes QRS onset and offset points and fiducial points associated with T and U waves. The processor than baseline corrects the original signal/waveform by fitting a polynomial function to QRS offset points, and subtracting this function from the original waveform.

Abstract: A device for detecting cardiac ischemia is disclosed. The device includes a processor that is configured to distinguish between ventricularly paced beats and supraventricular beats. The processor applies different ischemia tests to the two different beat types, and generates alert when it detects ischemia. The processor collects and counts the ST segment deviation values for ventricularly paced beats for a pre-set time period. The processor then determines if the number of ventricularly paced beats is insufficient to perform ischemia detection. If so, then the processor collects ST deviation values for additional paced beats. When the processor determines that a sufficient number of ventricularly paced beats have been acquired, it identifies ischemic beats by the application of ischemia detection criteria to the ST deviation values of the collected ventricularly paced beats.

Abstract: A device for detecting a cardiac event is disclosed. Detection of an event is based on a test applied to a parameter whose value varies according to heart rate. Both the parameter value and heart rate (RR interval) values are filtered with an exponential average filter. The filtered parameter value and heart rate values are stored as separate datasets corresponding to particular body postures. Upper and lower boundary values and detection thresholds of the parameter are computed for each of the datasets. The test to detect the cardiac event depends on the heart rate and the difference between the parameter's value and a corresponding detection threshold.

Abstract: A method for detecting heart beats within a cardiac signal is disclosed. A cardiac signal is acquired and segmented. Peak detection is performed within each segment. A search within the detected peaks is performed to locate physiologically permissible peak sequences. A particular peak sequence is selected based on feature space criteria or interpeak temporal regularity criteria or both.

Abstract: A method for detecting acute ischemia is disclosed. The method comprises the steps of determining ST segment deviations and storing the results in heart rate based histograms. The histogram data is periodically analyzed to estimate a true range of ST deviation for a particular heart rate range. A current threshold for a heart rate range is set by estimating the true range of ST deviations within that bin, determining the median value of ST deviations within the range, and basing thresholds on the range and median value. The true range for a particular heart rate bin is estimated by locating ST deviation values between which reside a predetermined percentage of all ST deviation values collected for that bin.

Abstract: A device for detecting a cardiac event is disclosed. Detection of an event is based on a test applied to a parameter whose value varies according to heart rate. Both the parameter value and heart rate (RR interval) values are filtered with an exponential average filter. The filtered parameter value and heart rate values are stored as separate datasets corresponding to particular body postures. Upper and lower boundary values and detection thresholds of the parameter are computed for each of the datasets. The test to detect the cardiac event depends on the heart rate and the difference between the parameter's value and a corresponding detection threshold.

Abstract: A device for detecting a cardiac event is disclosed. Detection of an event is based on a test applied to a parameter whose value varies according to heart rate. Both the parameter value and heart rate (RR interval) are filtered with an exponential average filter. From these filtered values, the average change in the parameter and the RR interval are also computed with an exponential average filter. Before computing the average change in the parameter, large changes in the parameter over short times, which may be caused by body position shifts, are attenuated are removed, so that the average change represents an average of small/smooth changes in the parameter's value that are characteristic of acute ischemia, one of the cardiac events that may be detected. The test to detect the cardiac event depends on the heart rate, the difference between the parameter's value and its upper and lower normal values, and its average change over time, adjusted for heart rate changes.

Abstract: A heart monitor is disclosed. The monitor computes ST segment deviations and stores the results in heart rate based histograms. Periodically, the monitor analyzes the histogram data to determine a normal range of ST deviation for a particular heart rate range. The monitor computes heart rate dependent ischemia detection thresholds based on the upper and lower boundaries of the normal range. A current threshold for a heart rate range is set as a weighted average of the prior threshold and a provisional threshold based on recent data, thereby limiting the amount the actual detection threshold changes from period to period.

Abstract: A device for detecting cardiac ischemia is disclosed. The device includes a processor that is configured to distinguish between two different heart beats types such as ventricularly paced beats and supraventricular beats. The processor collects separate reference data for a first one of the beat types indicative of the normal values of a cardiac feature. The processor performs an ischemia test to beats of the first type by first checking whether valid reference data exists for that beat type. If so, the ischemia test is based on this reference data. If no valid reference data exists for the firs beat type, the processor applies an ischemia test that is not based on reference data for the first beat type.

Abstract: A device for detecting a cardiac event is disclosed. Detection of an event is based on a test applied to a parameter whose value varies according to heart rate. Both the parameter value and heart rate (RR interval) are filtered with an exponential average filter. From these filtered values, the average change in the parameter and the RR interval are also computed with an exponential average filter. Before computing the average change in the parameter, large changes in the parameter over short times, which may be caused by body position shifts, are attenuated are removed, so that the average change represents an average of small/smooth changes in the parameter's value that are characteristic of acute ischemia, one of the cardiac events that may be detected. The test to detect the cardiac event depends on the heart rate, the difference between the parameter's value and its upper and lower normal values, and its average change over time, adjusted for heart rate changes.

Abstract: A device for detecting a cardiac event is disclosed. Detection of an event is based on a test applied to a parameter whose value varies according to heart rate. Both the parameter value and heart rate (RR interval) are filtered with an exponential average filter. From these filtered values, the average change in the parameter and the RR interval are also computed with an exponential average filter. Before computing the average change in the parameter, large changes in the parameter over short times, which may be caused by body position shifts, are attenuated are removed, so that the average change represents an average of small/smooth changes in the parameter's value that are characteristic of acute ischemia, one of the cardiac events that may be detected. The test to detect the cardiac event depends on the heart rate, the difference between the parameter's value and its upper and lower normal values, and its average change over time, adjusted for heart rate changes.

Abstract: A heart monitor is disclosed. The monitor computes ST segment deviations and stores the results in heart rate based histograms. Periodically, the monitor analyzes the histogram data to determine heart rate dependent acute ischemia detection thresholds. If the statistical distribution associated with a heart rate range is insufficient, the threshold for that heart rate range is set as a function of the threshold for a neighboring heart rate range. Thresholds are also increased for heart rate ranges associated with statistical distributions that are sufficient but that have a relatively small number of entries.

Abstract: A heart monitor is disclosed. The monitor computes ST segment deviations and stores the results in heart rate based histograms. Periodically, the monitor analyzes the histogram data to determine a normal range of ST deviation for a particular heart rate range. The monitor computes heart rate dependent ischemia detection thresholds based on the upper and lower boundaries of the normal range.

Abstract: A method for detecting heart beats within a cardiac signal is disclosed. A cardiac signal is acquired and segmented. Peak detection is performed within each segment. A search within the detected peaks is performed to locate physiologically permissible peak sequences. A particular peak sequence is selected based on feature space criteria or interpeak temporal regularity criteria or both.

Abstract: A device for detecting cardiac ischemia is disclosed. The device includes a processor that is configured to distinguish between two different heart beats types such as ventricularly paced beats and supraventricular beats. The processor collects separate reference data for a first one of the beat types indicative of the normal values of a cardiac feature. The processor performs an ischemia test to beats of the first type by first checking whether valid reference data exists for that beat type. If so, the ischemia test is based on this reference data. If no valid reference data exists for the first beat type, the processor applies an ischemia test that is not based on reference data for the first beat type.

Abstract: A system for the detection of cardiac events occurring in a human patient. At least two electrodes are included in the system for obtaining an electrical signal from a patient's heart. An electrical signal processor is electrically coupled to the electrodes for processing the electrical signal. The system receives data regarding the patient's state (e.g. asleep, exercising). Patient state information is stored in a patient state array, thereby enabling the system to track the patient's state over time, and to select an appropriate test for detecting a cardiac event based on both past and present data regarding the patient's state.

Abstract: A system for the detection of cardiac events occurring in a human patient is disclosed to include at least two electrodes for obtaining an electrical signal from a patient's heart. At least two electrodes are included in the system for obtaining an electrical signal from a patient's heart. An electrical signal processor is electrically coupled to the electrodes for processing the electrical signal. The system determines the presence of a cardiovascular condition by applying a sliding scale rule to heart signal feature values. When the cardiovascular condition is ischemia, the ST segment may be analyzed. A sliding scale is applied to ST segment shifts such that when the magnitudes of ST segment shifts are relatively small, a larger number of beats is required to detect ischemia compared to the case when the magnitudes of ST shifts are large.

Abstract: A heart monitor is disclosed. The monitor computes ST segment deviations and stores the results in heart rate based histograms. Periodically, the monitor analyzes the histogram data to determine a normal range of ST deviation for a particular heart rate range. The monitor computes heart rate dependent ischemia detection thresholds based on the upper and lower boundaries of the normal range.

Abstract: A heart monitor is disclosed. The monitor computes ST segment deviations and stores the results in heart rate based histograms. Periodically, the monitor analyzes the histogram data to determine a normal range of ST deviation for a particular heart rate range. The monitor computes heart rate dependent ischemia detection thresholds based on the upper and lower boundaries of the normal range.