Abstract: Systems and methods include differential diagnosis for acute heart failure to provide treatment to a patient including determining whether the patient has cardiac volume overload, determining whether the patient has decreased abdominal venous system volume, and providing the appropriate treatment in response to the determinations. A multi-sensor system may be used to determine cardiac volume and abdominal venous system volume. Fluid redistribution treatment may be provided when cardiac volume overload is accompanied by a decrease in abdominal venous system volume. Fluid accumulation treatment may be provided when cardiac volume overload is not accompanied by a decrease in abdominal venous system volume.

Abstract: Systems and methods include differential diagnosis for acute heart failure to provide treatment to a patient including determining whether the patient has cardiac volume overload, determining whether the patient has decreased abdominal venous system volume, and providing the appropriate treatment in response to the determinations. A multi-sensor system may be used to determine cardiac volume and abdominal venous system volume. Fluid redistribution treatment may be provided when cardiac volume overload is accompanied by a decrease in abdominal venous system volume. Fluid accumulation treatment may be provided when cardiac volume overload is not accompanied by a decrease in abdominal venous system volume.

Abstract: The exemplary systems and methods may monitor one or more signals to be used to assess the hemodynamic status of a patient. The one or more signals may be used to calculate, or determine, a plurality of pulse transit times. The plurality of pulse transit times may be used to determine hemodynamic status values that may be indicative of a patient's aggregate hemodynamic status.

Abstract: The exemplary systems and methods may monitor one or more signals to be used to assess the hemodynamic status of a patient. The one or more signals may be used to calculate, or determine, a plurality of pulse transit times. The plurality of pulse transit times may be used to determine hemodynamic status values that may be indicative of a patient's aggregate hemodynamic status.

Abstract: A system and method for determining mean pulmonary arterial pressure (MPAP) using a pressure sensor located within a ventricle of a heart, and a signal indicative of cardiac electrical activity such as an electrocardiogram (EGM) signal. The pressure may be sensed within the right and/or left ventricle using an implanted pressure sensor. The sensed pressure may be used to determine the Ventricular Systolic Pressure (VSP) and an estimated Pulmonary Arterial Diastolic pressure (ePAD). The VSP, ePAD, and time intervals associated with systole and diastole may then be used to obtain an MPAP that closely approximates mean pulmonary arterial pressure measured using a sensor located in the pulmonary artery.

Abstract: An implantable stimulator and monitor measures a group of heart failure parameters indicative of the state of heart failure employing EGM signals, measures of blood pressure including absolute pressure P, developed pressure (DP=systolic P−diastolic P), and/or dP/dt, and measures of heart chamber volume (V) over one or more cardiac cycles. These parameters include: (1) relaxation or contraction time constant tau (&tgr;); (2) mechanical restitution (MR), i.e., the mechanical response of a heart chamber to premature stimuli applied to the heart chamber; (3) recirculation fraction (RF), i.e., the rate of decay of PESP effects over a series of heart cycles; and (4) end systolic elastance (EES), i.e., the ratios of end systolic blood pressure P to volume V. These heart failure parameters are determined periodically regardless of patient posture and activity level.

Abstract: Medical device data is transferred using a universal adaptor between an implanted medical device and hospital monitoring systems. The universal adaptor is an interface compatible with various built-in hospital monitoring network comprised of equipment from a variety of manufacturers. The universal adaptor includes a telemetry circuitry, a calibration system for atmospheric pressure and an analog interface. The calibration system relates to barometric correction and includes an external pressure reference system.

Abstract: An implantable stimulator and monitor measures a group of heart failure parameters indicative of the state of heart failure employing EGM signals, measures of blood pressure including absolute pressure P, developed pressure (DP=systolic P−diastolic P), and/or dP/dt, and measures of heart chamber volume (V) over one or more cardiac cycles. These parameters include: (1) relaxation or contraction time constant tau (&tgr;); (2) mechanical restitution (MR), i.e., the mechanical response of a heart chamber to premature stimuli applied to the heart chamber; (3) recirculation fraction (RF), i.e., the rate of decay of PESP effects over a series of heart cycles; and (4) end systolic elastance (EES), i.e., the ratios of end systolic blood pressure P to volume V. These heart failure parameters are determined periodically regardless of patient posture and activity level.

Abstract: An implantable stimulator and monitor measures a group of heart failure parameters indicative of the state of heart failure employing EGM signals, measures of blood pressure including absolute pressure P, developed pressure (DP=systolic P−diastolic P), and/or dP/dt, and measures of heart chamber volume (V) over one or more cardiac cycles. These parameters include: (1) relaxation or contraction time constant tau (&tgr;); (2) mechanical restitution (MR), i.e., the mechanical response of a heart chamber to premature stimuli applied to the heart chamber; (3) recirculation fraction (RF), i.e., the rate of decay of PESP effects over a series of heart cycles; and (4) end systolic elastance (EES), i.e., the ratios of end systolic blood pressure P to volume V. These heart failure parameters are determined periodically regardless of patient posture and activity level.

Abstract: An implantable stimulator and monitor measures a group of heart failure parameters indicative of the state of heart failure employing EGM signals, measures of blood pressure including absolute pressure P, developed pressure (DP=systolic P−diastolic P), and/or dP/dt, and measures of heart chamber volume (V) over one or more cardiac cycles. These parameters include: (1) relaxation or contraction time constant tau (&tgr;); (2) mechanical restitution (MR), i.e., the mechanical response of a heart chamber to premature stimuli applied to the heart chamber; (3) recirculation fraction (RF), i.e., the rate of decay of PESP effects over a series of heart cycles; and (4) end systolic elastance (EES), i.e., the ratios of end systolic blood pressure P to volume V. These heart failure parameters are determined periodically regardless of patient posture and activity level.

Abstract: A system and method for determining mean pulmonary arterial pressure (MPAP) using a pressure sensor located within a ventricle of a heart, and a signal indicative of cardiac electrical activity such as an electrocardiogram (EGM) signal. The pressure may be sensed within the right and/or left ventricle using an implanted pressure sensor. The sensed pressure may be used to determine the Ventricular Systolic Pressure (VSP) and an estimated Pulmonary Arterial Diastolic pressure (ePAD). The VSP, ePAD, and time intervals associated with systole and diastole may then be used to obtain an MPAP that closely approximates mean pulmonary arterial pressure measured using a sensor located in the pulmonary artery.

Abstract: Medical device data is transferred using a universal adaptor between an implanted medical device and hospital monitoring systems. The universal adaptor is an interface compatible with various built-in hospital monitoring network comprised of equipment from a variety of manufacturers. The universal adaptor includes a telemetry circuitry, a calibration system for atmospheric pressure and an analog interface. The calibration system relates to barometric correction and includes an external pressure reference system.

Abstract: A physiologic rate responsive pacer which alters the pacer's escape interval in response to the patient's respiratory minute ventilation derived from the electromyogram of selected respiratory muscle groups. The directly detected electromyogram (EMG) signal is amplified and band passed filtered, processed to remove any electrocardiogram (ECG) or pacing impulse signal, full-wave rectified, processed to develop a moving time average signal from which the peak, the maximal slope, and the average slope of the EMG moving time average may be calculated and processed in conjunction with the inspiratory and expiratory times between successive slope detections of the moving time average EMG to develop a rate control signal representative of minute ventilation.

Abstract: A physiologic rate responsive pacer which alters the pacer's escape interval in response to the patient's respiratory minute ventilation derived from the electromyogram of selected respiratory muscle groups. The directly detected electromyogram (EMG) signal is amplified and band passed filtered, processed to remove any electrocardiogram (ECG) or pacing impulse signal, full-wave rectified, processed to develop a moving time average signal from which the peak, the maximal slope, and the average slope of the EMG moving time average may be calculated and processed in conjunction with the inspiratory and expiratory times between successive slope detections of the moving time average EMG to develop a rate control signal representative of minute ventilation.

Abstract: A dual chamber pacemaker system and method are provided for HOCM and like pacing therapy, with the feature of searching or scanning values of AV escape interval to define an optimized value at about the longest AV escape interval value consistent with full capture in response to a delivered ventricular pace pulse. In a preferred embodiment of the invention, the system and method sense and process FFRS signals derived from the atrial lead and otherwise, and obtain therefrom a characteristic which is evaluated for a determination of optimized AV escape interval. In one specific embodiment, the time durations between delivered ventricular pacing pulses and resulting FFRS signals are analyzed as a function of AV escape interval, and the optimized AV escape interval is chosen at about the longest AV escape interval corresponding to the longest such time duration, i.e., at about the knee of the FFRS time duration vs. AV escape interval curve.

Abstract: A pacemaker capable of automatically adjusting the sensitivity of its sense amplifier to electrical cardiac signals is disclosed. In one embodiment, a pacemaker having a pressure sensor disposed on the distal end of its pacing/sensing lead counts the number of pressure events and electrical events which occur during an autosensitivity timing period. If the number of electrical events exceeds the number of pressure events by more than a predetermined margin, the sense amplifier's sensitivity threshold is decreased. If the number of electrical events does not exceed the number of pressure events by more than the predetermined margin, the sense amplifier's sensitivity threshold is increased. In another embodiment, the pacemaker maintains a running average of the peak voltages of sensed electrical events over a predetermined history period.

Abstract: A method and apparatus for providing an enhanced capability of detecting and gathering electrical cardiac signals via an array of relatively closely spaced subcutaneous electrodes (located on the body of an implanted device) which may be employed with suitable switching circuits, signal processors, and memory to process the electrical cardiac signals between any selected pair or pairs of the electrode array in order to provide a leadless, orientation insensitive means for receiving the electrical signal from the heart.

Abstract: An implantable physiologic device, e.g., a multi-programmable, microprocessor based cardiac pacemaker, is provided with data storage and transmission capabilities for transmitting out certain current operating parameters and sensed events and for storing counted events for transmission of counts, histograms and real-time clock data out on command. The device preferably comprises a rate responsive cardiac pacemaker for providing an optimized pacing rate of stimulation pulses as a function of at least one selected rate control parameter. Each rate control parameter has a value which varies as a function of changes in a patient's physiologic demand and includes a sensor system for sensing the rate control parameter value and for providing a sensor output representative thereof.

Abstract: A pacemaker capable of automatically adjusting the activity threshold setting of its activity sensor signal processing circuitry to its optimal value is disclosed. In one embodiment, the pacemaker maintains a running average of zero activity time and a cumulative summation of zero activity time over a predetermined history period. Periodically, the pacemaker computes a time difference between the running average of zero activity time and the cumulative summation of zero activity time, and adjusts the activity threshold of the activity sensor signal processing circuitry according to this computation. By basing the adjustment of activity threshold on a long-term average of zero activity time, the effects of cycle-to-cycle variation in sensed zero activity time are minimized. In another embodiment, the pacemaker periodically computes a time difference between a preprogrammed margin value and the cumulative summation of zero activity time.

Abstract: A post-extrasystolic potentiation (PESP) cardiac pacing energy stimulator for applying paired and/or triggered pacing stimulation pulses to the right atrium and/or ventricle incorporating one or more sensors, such as a venous oxygen saturation, ventricular, atrial, or arterial blood pressure, or intracardiac or systemic blood flow sensor, and signal processing circuitry for controlling the frequency of or number of heart cycles between periodic delivery of triggered or paired pacing to induce PESP for the treatment of congestive heart failure or other cardiac dysfunctions. Preferably, a first sensor, e.g., a ventricular or arterial blood pressure or flow sensor, is employed to monitor the performance of the heart, and develop a cardiac performance index (CPI) and a second sensor, e.g., an oxygen saturation sensor positioned in the coronary sinus, is employed to monitor cardiac muscle stress and develop a cardiac stress index (CSI) to balance performance and stress.