Angel Medical Systems Inc.

Lucent Technologies Inc.

Terraworx, Inc.

Steven R Johnson

David R Fischell

Jonathan Harwood

Robert E Fischell

Bruce Hopenfeld

Tim A Fischell

Michael Sasha John

Gerald Nykolak

Paul F Szajowski

David Keenan

Howard David Helms

Gerald Edward Tourgee

Frank J Peragine

Philip Joseph Lauriello

Stan Lumish

Dennis M Romain

Vibha Prakash Goel

Dominick J Imbesi

Joseph P Kunz

Bruce D Paulson

Dominick J Imbsei

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.

Acute ischemia detection based on parameter value range estimation

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.

Acute ischemia detection based on smoothed temporal thresholding

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.

Threshold adjustment schemes for acute ischemia detection

A method for tracking cardiac conditions is disclosed. An electrical signal from a patient's heart is sensed. A heart signal parameter value and an associated heart rate value are computed from the electrical signal. Based on the heart rate value, one of a plurality of histograms stored in a histogram memory is updated with the heart signal parameter value. After a data collection time period has elapsed, a statistical value of the heart signal parameter is computed from the selected histogram. A detection threshold for abnormal values of the heart signal parameter is then computed based on the statistical value.

Histogram based generation of cardiac state detection thresholds

Disclosed is a system for the detection of cardiac events that includes an implanted device called a cardiosaver, a physician's programmer and an external alarm system. The system is designed to provide early detection of cardiac events such as acute myocardial infarction or exercise induced myocardial ischemia caused by an increased heart rate or exertion. The system can also alert the patient with a less urgent alarm if a heart arrhythmia is detected. Using different algorithms, the cardiosaver can detect a change in the patient's electrogram that is indicative of a cardiac event within five minutes after it occurs and then automatically warn the patient that the event is occurring. To provide this warning, the system includes an internal alarm sub-system (internal alarm means) within the cardiosaver and/or an external alarm system (external alarm means) which are activated after the ST segment of the electrogram exceeds a preset threshold.

Means and method for the detection of cardiac events

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.

Acute ischemia detection based on parameter value range analysis

A heart monitor computes ST segment deviation as the difference in the value of an electrocardiogram signal at the ST and PQ points of a heartbeat. The ST point is found based on slope criteria and temporal criteria. The maximum (positive) slope of the QRS (maxQRS) is located. Within a preset window after the maxQRS point, the processor searches for a sample at which the second finite difference is less than a threshold that is a function of average QRS amplitude. If such a qualifying sample is found, the processor examines its location relative to the location of an adaptive window that is centered on a sample that is an adaptively determined distance from the peak of the R wave. If the qualifying point is within the adaptive window, it is chosen as the ST point. If the qualifying point is after the adaptive window, the ST point is set at the end of the adaptive window. Finally, if the qualifying point is before the adaptive window, the ST point is selected at the beginning of the adaptive window. The adaptive window is then updated according to an exponential average filter based upon the distance between the ST point and the R wave peak.

QRS onset and offset detection with adaptive temporal windowing

A physician's programmer for an implantable device is disclosed. The programmer includes a receiver for receiving wireless transmission data from the implantable heart monitor. A processor is configured to extract from the wireless transmission data ST-deviation histogram data as a function of heart rate. The histogram data for a particular heart rate range is shown on a display in the form of a bar chart. The histogram data for a plurality of heart rate ranges is shown in the form of a chart with multiple line plots.

Physician's programmer with ST-segment histogram display capability

A system for the detection of cardiac events occurring in a human patient is provided. 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 and a patient alarm means is further provided and electrically coupled to the electrical signal processor. The electrical signal is acquired in the form of electrogram segments, which are categorized according to heart rate, ST segment shift and type heart rhythm (normal or abnormal). Baseline electrogram segments are tracked over time.

System for detection of different types of cardiac events

A heart rate monitor generates an ST deviation time series by employing a recursive filter that is preferably an exponential average filter whose output is a weighted sum of the then existing ST time series value and current ST deviation values of analyzable beats. Beats are detected in segments of data. ST deviation is measured for analyzable beats. The ST deviation time series is updated only if certain criteria are met. A first criterion for updating the time series is that at least half of the beats within a segment must be normal sinus rhythm beats. A second criterion for updating the time series is that (i) the average RR interval of the segment is between &#xbe; and 1.5 times the average RR interval of the previous segment; or (ii) both (a) the number of abnormal beats in the current segment is less than 2, and (b) the number of premature ventricular contractions within the current segment is less than 2.

System and methods for the selective updating of heart signal parameter time series

Disclosed is a system for the detection of cardiac events (a guardian system) that includes an implanted device called a cardiosaver, a physician's programmer and an external alarm system. The system is designed to provide early detection of cardiac events such as acute myocardial infarction or exercise induced myocardial ischemia caused by an increased heart rate or exertion. The system can also alert the patient with a less urgent alarm if a heart arrhythmia is detected. Using one or more detection algorithms, the cardiosaver can detect a change in the patient's electrogram that is indicative of a cardiac event within five minutes after it occurs and then automatically warn the patient that the event is occurring. To provide this warning, the guardian system includes an internal alarm sub-system (internal alarm means) within the cardiosaver and/or an external alarm system (external alarm means). If the guardian system is put into a pacemaker, the algorithm can utilize a different analysis of the electrogram depending on whether or not the pacemaker is actually pacing the heart.

Implantable cardiac event detection device with an adaptive sleep state

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 median value of ST deviation. Subsequently, beats are excluded from the computation of the time series if their ST deviations both varies too far from the long term median value and varies too far from the then current time series value.

Parameter value rejection for a cardiac monitor

A system for cardiac event detection over varying time scales includes implanted electrical leads forming a portion of an implanted cardiotracker and external equipment including external alarm mechanisms and a physicians programmer. The cardiac event detection system monitors the degradation of a patient's cardiovascular condition from one or more causes. A processor computes the electrical signals of a heart signal parameter's average value over a time period for a multiplicity of heart rate ranges. The electrical signals are stored and information transmitted to external equipment.

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Fair Haven, NJ, United States of America

Steven R Johnson