117 results about "ST segment" patented technology

A cardiac stimulation device and method detect myocardial ischemia and provide a response for alleviating the ischemia. Myocardial ischemia is detected by identifying changes in the ST-segment of the intracardiac electrogram (EGM) sensed using large sensing electrode surfaces created by electrically coupling one or more cardiac electrodes or by using larger surface area shocking coils. Myocardial ischemia monitoring is performed when stimulation parameters are adjusted for increasing cardiac output, causing an increased metabolic demand to be placed on the myocardium itself. When myocardial ischemia is detected, stimulation parameters are re-adjusted to reduce the demand placed on the myocardium and thereby alleviate the ischemia.

Disclosed is a system for detecting pathophysiological cardiac conditions from a reduced number of extracardiac leads. A right side lead measures the electrical signal between the middle superior chest region over the heart and inferior right torso position. A left side lead measures the electrical signal between the left precordial chest region and an inferior left lateral or posterior torso position. The lead montage is preferably chosen so that, regardless of patient position (e.g. supine, upright), negative ST segments and / or T waves are used to detect right coronary or left circumflex ischemia. Also, in these positions, reduced slope of the final deflection in the QRS can be used to detect these types of ischemia. To detect transmural ischemia, the system examines changes in QRS slopes, ST segment, T wave and the difference between the J point and the PQ potentials. In addition, for transmural ischemia associated with the left anterior descending artery, a proxy for the propagation time across the front of the heart is examined by comparing QRS features of the right side lead with QRS features of the left side lead. Histogram profiles, trends, and statistical summaries, especially running averages, of all of the above mentioned features, corrected for heart rate, are maintained.

Techniques are described for detecting and distinguishing among ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. In one technique, these conditions are detected and distinguished based on an analysis of: the interval between the QRS complex and the peak of a T-wave (QTmax), the interval between the QRS complex and the end of a T-wave (QTend), alone or in combination with a change in ST segment elevation. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo / hyperglycemia can be properly distinguished from changes caused by cardiac ischemia. In another technique, hyperglycemia and hypoglycemia are predicted, detected and / or distinguished from one another based on an analysis of the amplitudes of P-waves, QRS-complexes and T-waves within the IEGM. Appropriate warning signals are delivered and therapy is automatically adjusted.

Techniques are described for detecting and distinguishing among ischemia, hypoglycemia or hyperglycemia based on intracardiac electrogram (IEGM) signals. In one technique, these conditions are detected and distinguished based on an analysis of: the interval between the QRS complex and the peak of a T-wave (QTmax), the interval between the QRS complex and the end of a T-wave (QTend), alone or in combination with a change in ST segment elevation. By exploiting QTmax and QTend in combination with ST segment elevation, changes in ST segment elevation caused by hypo / hyperglycemia can be properly distinguished from changes caused by cardiac ischemia. In another technique, hyperglycemia and hypoglycemia are predicted, detected and / or distinguished from one another based on an analysis of the amplitudes of P-waves, QRS-complexes and T-waves within the IEGM. Appropriate warning signals are delivered and therapy is automatically adjusted.

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.

An integrated physiological signal assessing device integrates electrical signal detecting technology and optical detecting technology to design a sensing interface module for simultaneously measuring ECG signals and PPG signals, and utilizes multiple algorithm processing methods to obtain ECG parameters, such as rhythm of a heart, ST segment, and QRS interval, as well as vascular parameters, such as vascular stiffness index (SI), vascular reflection index (RI), pulse wave velocity (PWV), and pulse oxygen saturation (SpO2), so as to simplify the conventional vascular functions measuring devices, easily understand physiological conditions of a subject, and helpfully apply on diagnosis and prevention of cardiovascular diseases.

Cardiac monitoring and / or stimulation methods and systems that provide one or more of monitoring, diagnosing, defibrillation, and pacing. Cardiac signal separation is employed to detect, monitor, track and / or trend ischemia using cardiac activation sequence information. Ischemia detection may involve sensing composite cardiac signals using implantable electrodes, and performing a signal separation that produces one or more cardiac activation signal vectors associated with one or more cardiac activation sequences. A change in the signal vector may be detected using subsequent separations. The change may be an elevation or depression of the ST segment of a cardiac cycle or other change indicative of myocardial ischemia, myocardial infarction, or other pathological change. The change may be used to predict, quantify, and / or qualify an event such as an arrhythmia, a myocardial infarction, or other pathologic change. Information associated with the vectors may be stored and used to track the vectors.

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. Based on the baseline adjusted signal and / or the above mentioned fiducial points, the processor then computes averages of various waveform feature values, including a QRS measure sensitive to QRS curvature, T wave timing measures, ST segment deviation (difference between signal amplitudes at QRS offset and onset and / or minimum amplitude between QRS offset and peak T wave); and T / U wave amplitudes. These averages are computed by exponential averaging. From the exponential averages, the processor computes an average of the change in the averages over time. Based on the averages and the change in the averages, the processor applies an ischemia test to determine a likelihood of ischemia.

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.

An implantable medical device system for detecting cardiac conditions such the long-term ischemic heart disease, an occlusion of a coronary artery by a thrombus or an impending as a myocardial infarction. The implantable medical device (IMD) system includes a sensor that outputs a blood flow rate signal representing a rate of blood flow through a coronary sinus of a patient's heart. An implantable medical device (IMD) includes a microcomputer circuit configured to analyze the blood flow rate signal and detect a cardiac condition as a function of the blood flow rate signal. The system can also includes an implantable lead that senses electrical activity from the patient's heart. The microcomputer circuit monitors an ST segment of the electrical activity signal and detects a cardiac condition as a function of blood flow rate signal in conjunction with the electrical activity signal.

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.

The present invention relates to a method for the prognosis of a vascular event in a patient suspected of being at risk for a vascular event, said patient presenting: - no elevation of the ST segment as seen on an electrocardiogram, and / or - a normal level of at least one myocardial necrosis marker, wherein the presence and / or levels of at least two different biochemical markers are measured in a biological sample of said patient, whereby the probability that the patient will experience a vascular event is deduced from the measured presence and / or levels of the biochemical markers such as MPO, sCD40L, IL-6, PaPP-A, CRP, D-dimer, troponin, and proBNP.

The invention provides an automatic classification method for ST-segment evaluation patterns in electrocardiograph (ECG) signals. The automatic classification method is characterized by comprising the following steps: collecting the lead ECG signals of a human body; classifying the ST-segment evaluation patterns in the ECG signals into horizontal type, upper inclined type, lower inclined type, concave type and convex type; utilizing the multi-scale analysis method of curvature scale space technology to position ST-segment and obtain the point corresponding to the maximum value of the absolute value of the curvature in the ST-segment, namely the maximum point of the bending degree of the ST-segment; according to the characteristic of the curvature, utilizing the maximum point of the bending degree in the ST-segment to judge the ST-segment evaluation patterns. By introduction of the curvature scale space method, the influence of noise is effectively reduced, the ST-segment evaluation patterns can be accurately identified, and the method has an important use value for early warning of myocardial ischemia.