Abstract: A system and method for treating an arrhythmia in a heart are provided. The system includes an electronic control unit configured to monitor movement of one or more position sensor over a period of time. The position sensors may, for example, comprise electrodes or coils configured to generate induced voltages and currents in the presence of electromagnetic fields, The positions sensors are in contact with portions of heart tissue and changes in position are representative of motion of that tissue. The electronic control unit is further configured to generate an indicator, responsive to the movements of the sensors over the period of time, of a characteristic of the heart affected by delivery of ablation energy to heart tissue. In this manner, the effectiveness and safety of cardiac tissue ablation for treatment of the arrhythmia can be assessed and a post-ablation therapy regimen determined.

Abstract: A system and method for treating an arrhythmia in a heart are provided. The system includes an electronic control unit configured to monitor movement of one or more position sensor over a period of time. The position sensors may, for example, comprise electrodes or coils configured to generate induced voltages and currents in the presence of electromagnetic fields. The positions sensors are in contact with portions of heart tissue and changes in position are representative of motion of that tissue. The electronic control unit is further configured to generate an indicator, responsive to the movements of the sensors over the period of time, of a characteristic of the heart affected by delivery of ablation energy to heart tissue. In this manner, the effectiveness and safety of cardiac tissue ablation for treatment of the arrhythmia can be assessed and a post-ablation therapy regimen determined.

Abstract: In specific embodiments, a method to monitor left atrial pressure and/or intra-thoracic fluid volume of a patient, comprises (a) monitoring posture of the patient using a posture sensor implanted within the patient, and (b) using portions of an impedance signal, obtained using implanted electrodes, to monitor the left atrial pressure and/or intra-thoracic fluid volume of the patient. Each portion of the impedance signal used to monitor the left atrial pressure and/or intra-thoracic fluid volume of the patient corresponds to a period after which the patient has maintained a predetermined posture for at least a predetermined period of time, and during which the patient has remained in the predetermined posture.

Abstract: An exemplary method includes positioning a lead in a patient where the lead has a longitudinal axis that extends from a proximal end to a distal end and where the lead includes an electrode with an electrical center offset from the longitudinal axis of the lead body; measuring electrical potential in a three-dimensional potential field using the electrode; and based on the measuring and the offset of the electrical center, determining lead roll about the longitudinal axis of the lead body where lead roll may be used for correction of field heterogeneity, placement or navigation of the lead or physiological monitoring (e.g., cardiac function, respiration, etc.). Various other methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary method includes positioning a lead in a patient where the lead has a longitudinal axis that extends from a proximal end to a distal end and where the lead includes an electrode with an electrical center offset from the longitudinal axis of the lead body; measuring electrical potential in a three-dimensional potential field using the electrode; and based on the measuring and the offset of the electrical center, determining lead roll about the longitudinal axis of the lead body where lead roll may be used for correction of field heterogeneity, placement or navigation of the lead or physiological monitoring (e.g., cardiac function, respiration, etc.). Various other methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary method includes positioning a lead in a patient where the lead has a longitudinal axis that extends from a proximal end to a distal end and where the lead includes an electrode with an electrical center offset from the longitudinal axis of the lead body; measuring electrical potential in a three-dimensional potential field using the electrode; and based on the measuring and the offset of the electrical center, determining lead roll about the longitudinal axis of the lead body where lead roll may be used for correction of field heterogeneity, placement or navigation of the lead or physiological monitoring (e.g., cardiac function, respiration, etc.). Various other methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary method includes positioning a lead in a patient where the lead has a longitudinal axis that extends from a proximal end to a distal end and where the lead includes an electrode with an electrical center offset from the longitudinal axis of the lead body; measuring electrical potential in a three-dimensional potential field using the electrode; and based on the measuring and the offset of the electrical center, determining lead roll about the longitudinal axis of the lead body where lead roll may be used for correction of field heterogeneity, placement or navigation of the lead or physiological monitoring (e.g., cardiac function, respiration, etc.). Various other methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary method includes positioning a lead in a patient where the lead has a longitudinal axis that extends from a proximal end to a distal end and where the lead includes an electrode with an electrical center offset from the longitudinal axis of the lead body; measuring electrical potential in a three-dimensional potential field using the electrode; and based on the measuring and the offset of the electrical center, determining lead roll about the longitudinal axis of the lead body where lead roll may be used for correction of field heterogeneity, placement or navigation of the lead or physiological monitoring (e.g., cardiac function, respiration, etc.). Various other methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary method includes positioning a lead in a patient where the lead has a longitudinal axis that extends from a proximal end to a distal end and where the lead includes an electrode with an electrical center offset from the longitudinal axis of the lead body; measuring electrical potential in a three-dimensional potential field using the electrode; and based on the measuring and the offset of the electrical center, determining lead roll about the longitudinal axis of the lead body where lead roll may be used for correction of field heterogeneity, placement or navigation of the lead or physiological monitoring (e.g., cardiac function, respiration, etc.). Various other methods, devices, systems, etc., are also disclosed.

Abstract: An exemplary method includes positioning a lead in a patient where the lead has a longitudinal axis that extends from a proximal end to a distal end and where the lead includes an electrode with an electrical center offset from the longitudinal axis of the lead body; measuring electrical potential in a three-dimensional potential field using the electrode; and based on the measuring and the offset of the electrical center, determining lead roll about the longitudinal axis of the lead body where lead roll may be used for correction of field heterogeneity, placement or navigation of the lead or physiological monitoring (e.g., cardiac function, respiration, etc.). Various other methods, devices, systems, etc., are also disclosed.

Abstract: Diastolic function is monitored within a patient using a pacemaker or other implantable medical device. In one example, the implantable device uses morphological parameters derived from the T-wave evoked response waveform as proxies for ventricular relaxation rate and ventricular compliance. In particular, the magnitude of the peak of the T-wave evoked response is employed as a proxy for ventricular compliance. The maximum slew rate of the T-wave evoked response following its peak is employed as a proxy for ventricular relaxation. A metric is derived from these proxy values to represent diastolic function. The metric is tracked over time to evaluate changes in diastolic function. In other examples, specific values for ventricular compliance and ventricular relaxation are derived for the patient based on the T-wave evoked response parameters.

Abstract: In specific embodiments, a method to monitor pulmonary edema of a patient, comprises (a) detecting, using an implanted posture sensor, when a posture of the patient changes from a first predetermined posture to a second predetermined posture, (b) determining an amount of time it takes an impedance signal to achieve a steady state after the posture of the patient changes from the first predetermined posture to the second predetermined posture, where the impedance signal is obtained using implanted electrodes and is indicative of left atrial pressure and/or intra-thoracic fluid volume of the patient, and (c) monitoring the pulmonary edema of the patient based on the determined amount of time it takes the impedance signal to achieve the steady state after the posture of the patient changes from the first predetermined posture to the second pre-determined posture.

Abstract: Techniques are provided for use with an implantable medical device for detecting and assessing heart failure and for controlling cardiac resynchronization therapy (CRT) based on impedance signals obtained using hybrid impedance configurations. The hybrid configurations exploit right atrial (RA)-based impedance measurement vectors and/or left ventricular (LV)-based impedance measurement vectors. In one example, current is injected between the device case and a ring electrode in the right ventricle (RV) or RA. RA-based impedance values are measured along vectors between the device case and an RA electrode. LV-based impedance values are measured along vectors between the device case and one or more electrodes of the LV. Heart failure and other cardiac conditions are detected and tracked using the measured impedance values. CRT delay parameters are also optimized based impedance.

Abstract: Systems and methods are provided for detecting the orientation and/or movement of a patient having an implantable cardiac stimulation device and evaluating whether a change in the patient's cardiac activity can be at least in part due to a change in the patient's orientation. In one particular embodiment, signals from an orientation sensor and/or a pressure sensor are evaluated to determine static positional orientation of the patient and determine based on the static orientation whether the patient's cardiac activity is abnormal.

Abstract: A method for use in an implantable medical device comprises the steps of monitoring respiration with an amplifier having a gain, generating a moving apneic threshold based on recent respiration cycles, accumulating differences between amplitudes of respiration cycles and the moving apnea detection threshold and comparing the accumulated differences against an apnea detection threshold to detect the onset of an episode of apnea. The method further comprises measuring respiration levels upon detecting the onset of apnea, confirming the episode of apnea based upon the respiration levels measured upon detecting the onset of apnea; and adjusting one of the gain of the amplifier and the apnea detection threshold so that the time from the detection of onset of apnea to the time of confirmation of the episode of apnea is within a predetermined time range following the detection of the onset of apnea.

Abstract: A medical device is provided that comprises a lead assembly. The lead assembly includes at least one intra-cardiac (IC) electrode, an extra-cardiac (EC) electrode and a subcutaneous remote-cardiac (RC) electrode. The IC electrode is configured to be located within the heart. The EC electrode is configured to be positioned proximate to at least one of a superior vena cava (SVC) and a left ventricle (LV) of a heart. The RC electrode is configured to be located remote from the heart. An extra-cardiac impedance (ECI) module is configured to measure extra-cardiac impedance along an ECI vector between the EC and RC electrodes to obtain ECI measurements. An arrhythmia monitoring module is configured to declare a potential atrial arrhythmia to be an atrial arrhythmia based on the hemodynamic performance determined from the ECI measurements. The hemodynamic performance assessment module is further enabled to compare a current ECI pattern with a prior baseline ECI waveform.

Abstract: A method of filtering respiration noise from a localization signal includes acquiring a localization signal from at least one position measurement sensor within a localization field and acquiring an acceleration signal for at least one localization field generator (e.g., a patch electrode). A displacement signal for the field generator is calculated, for example by integrating the acceleration signal twice, and transformed into the frequency domain in order to calculate a fractional power indicative of patient respiration. The fractional power can then be compared to a threshold value, and the localization signal can be filtered if the fractional power exceeds the threshold value. Alternatively, the acquired acceleration signal can be used to gate collection of data points from the localization signal.

Abstract: Adaptively creating a table of optimal, patient-specific atrioventricular (AV) delays for a an implantable medical device (IMD) begins as the IMD detects the patient entering a target heart rates within a defined range of elevated heart rates. On detection, the device begins testing AV delays by pacing the heart at a number of different AV delays. The IMD selects the optimal AV delay based on a comparison of measurements of cardiac output obtained during each delay's test pacing period. The optimal AV delay corresponds to the one which resulted in the highest cardiac output. The device selects this optimal AV delay and stores it in an AV delay table on the device. The process continues as the device detects the patient entering the other target heart rates in order to complete the table.

Abstract: Methods for monitoring a patient's level of B-type natriuretic peptide (BNP), and implantable cardiac systems capable of performing such methods, are provided. A ventricle is paced for a period of time to provoke a ventricular evoked response, and a ventricular intracardiac electrogram (IEGM) indicative of the ventricular evoked response is obtained. Based on the ventricular IEGM, there is a determination of at least one ventricular evoked response metric (e.g., ventricular evoked response peak-to-peak amplitude, ventricular evoked response area and/or ventricular evoked response maximum slope), and the patient's level of BNP is monitored based on determined ventricular evoked response metric(s). Based on the monitored level's of BNP, the patients heart failure (HF) condition and/or risks and/or occurrences of certain events (e.g., an acute HF exacerbation and/or an acute myocardial infarction) can be monitored.

Abstract: An exemplary method includes selecting multiple electrodes located in a patient; acquiring position information during one or more cardiac cycles for the multiple electrodes where the acquiring includes using each of the electrodes for measuring one or more electrical potentials in an electrical localization field established in the patient; calculating one or more vector metrics based on the acquired position information for one or more vectors, each vector defined by two of the multiple electrodes; and analyzing the one or more vector metrics to assess cardiac performance during the one or more cardiac cycles. Various other methods, devices, systems, etc., are also disclosed.