Abstract: An implantable vagus nerve stimulation (VNS) system includes a sensor configured to measure ECG data for a patient, a stimulation subsystem configured to deliver VNS to the patient, and a control system configured to perform a heart rate variability analysis with the ECG data. In some aspects, performing the heart rate variability analysis includes measuring R-R intervals between successive R-waves for the ECG data measured during a stimulation period of VNS therapy and a baseline period of the VNS therapy, wherein the stimulation period comprises at least a portion of the ON period and the baseline period comprises at least a portion of the OFF period immediately preceding the ON period, and generating a plot of each R-R interval against an immediately successive R-R interval for each of the stimulation period and the baseline period configured to be displayed on a display.

Abstract: An implantable vagus nerve stimulation (VNS) system includes a sensor configured to measure ECG data for a patient, a stimulation subsystem configured to deliver VNS to the patient, and a control system configured to perform a heart rate variability analysis with the ECG data. In some aspects, performing the heart rate variability analysis includes measuring R-R intervals between successive R-waves for the ECG data measured during a stimulation period and a baseline period, plotting each R-R interval against an immediately preceding R-R interval for each of the stimulation period and the baseline period, and determining at least one of a standard deviation from an axis of a line perpendicular to an identity line for each of the stimulation period plot and the baseline period plot or a centroid of each of the stimulation period plot and the baseline period plot.

Abstract: Disclosed herein are example methods and systems for predicting efficacy of pacemakers or cardiac resynchronization therapy (CRT) devices prior to implantation in patients based on electrocardiogram (ECG) heterogeneity analysis. A method of determining or predicting efficacy of implanting a pacemaker or cardiac resynchronization therapy (CRT) device in a patient includes receiving a first set of electrocardiogram (ECG) signals associated with the patients heart from spatially separated leads, analyzing data from the first set of ECG signals, quantifying a spatio-temporal heterogeneity of the first set of ECG signals based on the analysis, and determining or predicting efficacy of implanting the pacemaker or cardiac re-synchronization therapy (CRT) device in the patient based on the quantified spatio-temporal heterogeneity.

Abstract: A method and system for high-throughput detection of coronary artery stenosis observes trends in abnormal or pathologic morphology of the electrocardiogram (ECG). A first set of ECG signals is monitored from a patient. A baseline measurement is generated from the monitored first set of ECG signals to contain nonpathologic ECG morphologies in each lead. A second set of ECG signals is monitored from the patient and a second mean measurement during or after stress is generated from the second set of ECG signals. A residuum signal is generated for each lead based on the baseline measurement and the second mean measurement. The residuum signals are averaged across the leads for each timepoint. T-wave heterogeneity is quantified based on the generated residuum signals and the averaged residuum signal at each timepoint, and used to detect coronary artery stenosis.

Abstract: An implantable vagus nerve stimulation (VNS) system includes a sensor configured to measure ECG data for a patient, a stimulation subsystem configured to deliver VNS to the patient, and a control system configured to perform a heart rate variability analysis with the ECG data. In some aspects, performing the heart rate variability analysis includes measuring R-R intervals between successive R-waves for the ECG data measured during a stimulation period and a baseline period, plotting each R-R interval against an immediately preceding R-R interval for each of the stimulation period and the baseline period, and determining at least one of a standard deviation from an axis of a line perpendicular to an identity line for each of the stimulation period plot and the baseline period plot or a centroid of each of the stimulation period plot and the baseline period plot.

Abstract: A method and system for high-throughput prediction of the onset of heart arrhythmias observes trends in abnormal or pathologic morphology of the electrocardiogram (ECG). A first set of ECG signals is monitored from a patient. A baseline measurement is generated from the monitored first set of ECG signals to contain nonpathologic ECG morphologies in each lead. A second set of ECG signals is monitored from the patient and a second baseline measurement is generated from the second set of ECG signals. A residuum signal is generated for each lead based on the baseline measurement and the second baseline measurement. The residuum signals are averaged across the leads. R-wave heterogeneity, T-wave heterogeneity, P-wave heterogeneity, or ST-segment heterogeneity or other indicators of arrhythmia risk or myocardial ischemia are quantified based on the generated residuum signals and the averaged residuum signal.

Abstract: A method and system for high-throughput prediction of the onset of heart arrhythmias observes trends in abnormal or pathologic morphology of the electrocardiogram (ECG). A first set of ECG signals is monitored from a patient. A baseline measurement is generated from the monitored first set of ECG signals to contain nonpathologic ECG morphologies in each lead. A second set of ECG signals is monitored from the patient and a second baseline measurement is generated from the second set of ECG signals. A residuum signal is generated for each lead based on the baseline measurement and the second baseline measurement. The residuum signals are averaged across the leads. R-wave heterogeneity, T-wave heterogeneity, P-wave heterogeneity, or ST-segment heterogeneity or other indicators of arrhythmia risk or myocardial ischemia are quantified based on the generated residuum signals and the averaged residuum signal.

Abstract: A method and system for predicting the onset of heart arrhythmias more accurately observes trends in abnormal or pathologic morphology of the electrocardiogram (ECG). A first set of ECG signals is monitored from a patient. A baseline measurement is generated from the monitored first set of ECG signals to contain nonpathologic ECG morphologies in each lead. A second set of ECG signals is monitored from the patient and the baseline measurement is subtracted from the second set of ECG signals on a beat-to-beat basis. Afterwards, a residuum signal is generated for each lead based on the subtraction. R-wave heterogeneity, T-wave heterogeneity, P-wave heterogeneity, or ST-segment heterogeneity or other indicators of arrhythmia risk or myocardial ischemia are quantified based on the generated residuum signals.

Abstract: A method and system for predicting the onset of heart arrhythmias more accurately observes trends in abnormal or pathologic morphology of the electrocardiogram (ECG). A first set of ECG signals is monitored from a patient. A baseline measurement is generated from the monitored first set of ECG signals to contain nonpathologic ECG morphologies in each lead. A second set of ECG signals is monitored from the patient and the baseline measurement is subtracted from the second set of ECG signals on a beat-to-beat basis. Afterwards, a residuum signal is generated for each lead based on the subtraction. R-wave heterogeneity, T-wave heterogeneity, P-wave heterogeneity, or ST-segment heterogeneity or other indicators of arrhythmia risk or myocardial ischemia are quantified based on the generated residuum signals.

Abstract: A method and kit for accessing the pericardial space take advantage of the fact that the right auricle is a thin-walled, low-pressure structure which can be readily penetrated without damaging the pericardium or the epicardium. The method includes the step of passing a guide catheter through a selected peripheral vein to establish a transvenous route to the right auricle of the heart. An infusion guide wire and a leading guide wire are passed through the guide catheter and into the right auricle so that a distal end of the leading guide wire is positioned against a wall of the right auricle. The leading guide wire is located within a lumen of the infusion guide wire and protrudes outward, preferably about 2 mm, from a distal end of the infusion guide wire. The wall of the right auricle is then pierced with the distal end of the leading guide wire. After the wall of the right auricle is pierced, at least one of the infusion guide wire and the leading guide wire are advanced into the pericardial space.

Abstract: A method and kit for accessing the pericardial space take advantage of the fact that the right auricle is a thin-walled, low-pressure structure which can be readily penetrated without damaging the pericardium or the epicardium. The method includes the step of passing a guide catheter through a selected peripheral vein to establish a transvenous route to the right auricle of the heart. An infusion guide wire and a leading guide wire are passed through the guide catheter and into the right auricle so that a distal end of the leading guide wire is positioned against a wall of the right auricle. The leading guide wire is located within a lumen of the infusion guide wire and protrudes outward, preferably about 2 mm, from a distal end of the infusion guide wire. The wall of the right auricle is then pierced with the distal end of the leading guide wire. After the wall of the right auricle is pierced, at least one of the infusion guide wire and the leading guide wire are advanced into the pericardial space.

Abstract: A system and method for quantifying alternation in the T-wave and ST segment of an ECG signal receives a digitized ECG signal (i.e., ECG data) for processing. The ECG data are used to calculate an odd median complex for the odd beats in the ECG data and an even median complex for the even beats in the ECG data. The odd median complex and the even median complex are then compared to obtain an estimate of the amplitude of beat-to-beat alternation in the ECG signal. Prior to calculation of the even and odd median complexes, the ECG data are filtered. Filtering of the ECG data involves low pass filtering the ECG data to remove high frequency noise, applying a baseline wander removal filter to the ECG data to remove low frequency artifacts, removing arrhythmic beats from the ECG data, and eliminating noisy beats from the ECG data. The filtered data are more suitable for calculation of an accurate estimate of alternation.

Abstract: A method for placing various types of catheters into the pericardial space takes advantage of the fact that the right auricle is a thin-walled, low-pressure structure which can be readily penetrated without damaging the pericardium or the epicardium. A guide catheter is passed through a selected peripheral vein to establish a transvenous route to the right auricle of the heart. A needle catheter is then passed through the guide catheter and into the right auricle so that a distal end of the needle catheter is positioned against a wall of the right auricle. The wall of the right auricle is then pierced with the needle catheter. A guide wire is advanced through the needle catheter and into the pericardial space. Once in position, the guide wire can be used as a conduit over which a desired catheter may be introduced for performing a specific medical procedure.

Abstract: The non-invasive, dynamic tracking and diagnosing of cardiac vulnerability to ventricular fibrillation involves analysis of both cardiac electrical stability and the influence of autonomic activity. The magnitude of alternation in an electrocardiogram is indicative of cardiac electrical stability. Alternans are made manifest by applying a physiologic stress such as exercise or behavioral stress to a subject.

Abstract: A method for determining the sleep state of a patient includes monitoring heart rate variability of the patient and determining sleep state based on the heart rate variability. The method also may include monitoring the frequency of eyelid movements and making the sleep state determination based also on the frequency of eyelid movements. A method for determining respiratory pattern includes monitoring heart rate variability by receiving heart beat signals and determining respiratory pattern from the strength of the signals. A home-based, wearable, self-contained system determines sleep-state and respiratory pattern, and assesses cardiorespiratory risk, of a patient based on the frequency of eyelid movements, the frequency of head movements, and heart rate variability of the patient.

Abstract: A method and an apparatus for the non-invasive, dynamic tracking and diagnosing of cardiac vulnerability to ventricular fibrillation are disclosed. T-wave alternans and heart rate variability are simultaneously evaluated. T-wave alternation is an absolute predictor of cardiac electrical stability. Heart rate variability is a measure of autonomic influence, a major factor in triggering cardiac arrhythmias. By simultaneously analyzing both phenomena, the extent and cause of cardiac vulnerability can be assessed.

Abstract: A method and apparatus for predicting cardiac electrical instability simultaneously assesses T-Wave Alternans and QT Interval Dispersion. T-wave alternation is an excellent predictor of cardiac electrical instability but can be influenced by mechano-electrical coupling. Thus, a measure of alternation has a high degree of sensitivity but a low degree of specificity. The low specificity of alternation is addressed by simultaneously analyzing QT interval dispersion. Dispersion is not a measure of excitable stimulus and is not sensitive to mechano-electrical coupling. The resulting combination of alternans and dispersion yields an accurate predictor of cardiac electrical instability caused by intrinsic factors.

Abstract: A method and apparatus for predicting susceptibility to sudden cardiac death simultaneously assessing cardiac electrical stability and autonomic influence. Cardiac electrical stability is assessed by analyzing at least one of a beat-to-beat alternation in a T-wave of an ECG of a patient's heart and dispersion of repolarization in the ECG of the patient's heart. Autonomic influence on the patient's heart is assessed by analyzing at least one of a magnitude of heart rate variability in the ECG of the patient's heart and baroreceptor sensitivity.

Abstract: A method for placing various types of catheters into the pericardial space takes advantage of the fact that the right auricle is a thin-walled, low-pressure structure which can be readily penetrated without damaging the pericardium or the epicardium. The method avoids surgical trauma and the risks of general anesthesia and infection. A catheter is guided downstream through one of the venae cavae to the right atrium. Once inside the right atrium, the catheter is passed into the right auricle. The wall at the apex of the right auricle is then pierced to gain access to the pericardial space. The method can be used, for example, to provide electrical stimuli to the heart (e.g., for pacing, cardioversion, and defibrillation), to pick-up an ECG signal, to deliver pharmacologic agents to the heart, to improve vascularization, to remove pericardial fluid for analysis or pericardiocentesis, or to inject a radio-labelled or echo-sensitive dye into the pericardial space for precision fluid imaging.

Abstract: A method and apparatus for the non-invasive, dynamic tracking and diagnosing of cardiac vulnerability to ventricular fibrillation are disclosed. T-wave alternans and heart rate variability are simultaneously evaluated. T-wave alternation is an absolute predictor of cardiac electrical instability. Heart rate variability is a measure of autonomic influence, a major factor in triggering cardiac arrythmias. By simultaneously analyzing both phenomena, the extent and cause of cardiac vulnerability can be assessed. The method includes the following steps. An ECG signal is sensed from a heart. The T-wave portions of the ECG signal are analyzed to estimate an amplitude of beat-to-beat alternation. The amplitude of beat-to-beat alternation represents cardiac electrical instability. The R-R intervals are analyzed to estimate a magnitude of a high frequency component of heart rate variability and to estimate a magnitude of a low frequency component of heart rate variability.