Abstract: An implantable device monitors and treats heart failure, pulmonary edema, and hemodynamic conditions and in some cases applies therapy. In one implementation, the implantable device applies a high-frequency multi-phasic pulse waveform over multiple-vectors through tissue. The waveform has a duration less than the charging time constant of electrode-electrolyte interfaces in vivo to reduce intrusiveness while increasing sensitivity and specificity for trending parameters. The waveform can be multiplexed over multiple vectors and the results cross-correlated or subjected to probabilistic analysis or thresholding schemata to stage heart failure or pulmonary edema. In one implementation, a fractionation morphology of a sensed impedance waveform is used to trend intracardiac pressure to stage heart failure and to regulate cardiac resynchronization therapy. The waveform also provides unintrusive electrode integrity checks and 3-D impedancegrams.

Abstract: In a method and a device for determining the posture of a patient, a bio-impedance measurement device, having a number of electrodes configured to interact with the patient in a number of different electrode configurations, is operated to initiate a patient posture determining session by measuring an impedance value of the patient with the electrodes in at least one configuration among the number of configurations. A reference impedance value from among a number of stored reference impedance values for the at least one configuration is selected. The number of stored reference impedance values are respectively associated with different postures of the patient, and the posture associated with the selected reference impedance value represents a candidate posture. The measured impedance value is compared with the selected reference impedance value, thereby obtaining a comparison result.

Abstract: In an implantable heart monitoring device and a monitoring method, an impedance is measured across at least part of an atrium, such that variation of the impedance is related to the volume change of the atrium. Values are stored at different occasions that indicate the rate of change of the measured impedance. The stored values are determined such that, when the device is used in a living being, the variation of the stored values will be related to the variation of the speed with which the atrium is filled with blood during the atrial diastole.

Abstract: An implantable device monitors and treats heart failure, pulmonary edema, and hemodynamic conditions and in some cases applies therapy. In one implementation, the implantable device applies a high-frequency multi-phasic pulse waveform over multiple-vectors through tissue. The waveform has a duration less than the charging time constant of electrode-electrolyte interfaces in vivo to reduce intrusiveness while increasing sensitivity and specificity for trending parameters. The waveform can be multiplexed over multiple vectors and the results cross-correlated or subjected to probabilistic analysis or thresholding schemata to stage heart failure or pulmonary edema. In one implementation, a fractionation morphology of a sensed impedance waveform is used to trend intracardiac pressure to stage heart failure and to regulate cardiac resynchronization therapy. The waveform also provides unintrusive electrode integrity checks and 3-D impedancegrams.

Abstract: An implantable medical device has an impedance determiner for determining a cardiogenic impedance signal based on electric signals sensed by connected electrodes. A parameter calculator processes the impedance signal to calculate an impedance parameter representative of the cardiogenic impedance in connection with the diastolic phase of a heart cycle. This parameter is then employed by the device for monitoring acute decompensated heart failure status of a subject.

Abstract: Implantable heart stimulator connectable to an electrode arrangement has a pulse generator adapted to deliver stimulation pulses to a heart of a subject; an impedance measurement unit adapted monitor at least one heart chamber of the heart of the subject to measure the impedance in the at least one monitored heart chamber for generating an impedance signal corresponding to the measured impedance. The impedance signal is applied to a processor where the signal is processed, according to specified criteria, and a fractionation index value is determined represented by the curve length of the impedance signal during a predetermined measurement period. The fractionation index value is a measure of different degrees of mechanical dyssynchrony of the heart.

Abstract: In a method and implantable medical device for ventricular tachyarrhythmia detection and classification, upon detection of a ventricular tachyarrhythmia based on an electrocardiogram signal, cardiogenic impedance data representative of ventricular volume dynamics are collected and used for classifying the detected tachyarrhythmia as stable or unstable. In the latter case but typically not in the former case, defibrillation shocks or other forms of therapy are applied to combat the unstable ventricular tachyarrhythmia.

Abstract: An implantable cardiac device has a heart stimulator for electrically stimulating the heart of a patient, detector that measures a physiologic parameter that is affected by the status of a cardiovascular disease associated with sympathetic activation, a signal processor that determines at least one of a low frequency, LF, and a very low frequency, VLF, Mayer wave component in the measured parameter, and analyzer that automatically analyzes the determined Mayer wave component in relation to a predetermined reference value to determine the status of the cardiovascular disease. The detector is a cardio-mechanical parameter detector that measures, as said physiologic parameter, a mechanical change in at least one of the four chambers of the heart. In a corresponding method for monitoring the status of a cardiovascular disease associated with sympathetic activation of a patient having an implantable electric heart stimulator a physiologic parameter affected by the cardiac disease is measured.

Abstract: In a method and an apparatus for creating hemodynamic sensor signal templates using an implantable medical device connectable to a patient heart activity of the patient is sensed in order to identify a paste or sensed sequence of events of a heart cycle. Hemodynamic sensor signals for consecutive heart cycles are sensed and the sensed hemodynamic sensor signals for consecutive heart cycles are stored. The sensed sensor signals are classified dependent on at least one predetermined heart event sequence condition. A template may be created using the classified sensor signals.

Abstract: An implantable medical device has an impedance determiner for determining a cardiogenic impedance signal based on electric signals sensed by connected electrodes. A parameter calculator processes the impedance signal to calculate an impedance parameter representative of the cardiogenic impedance in connection with the diastolic phase of a heart cycle. This parameter is then employed by the device for monitoring acute decompensated heart failure status of a subject.

Abstract: An implantable medical apparatus for detecting diastolic heart failure, DHF, has a DHF determining device for determining at least one DHF parameter for detecting a DHF state of the heart of a patient. The DHF includes circuitry for determining, as the DHF parameter, the time duration of a predetermined phase of diastole. A pacemaker has such an apparatus and a control unit that optimizes pacing therapy and pacemaker settings depending on the determined time duration. A corresponding method of detecting diastolic heart failure, DHF, includes determining at least one DHF parameter for detecting a DHF state of the heart of a patient. As the DHF parameter, the time duration of a predetermined phase of diastole is determined.

Abstract: In a method and device for detecting the intake of food in a subject at least one parameter related to the blood flow and/or perfusion of a blood vessel and/or an organ in the digestive system of a patient is monitored by a sensor attached to, or in, a blood vessel or organ of the digestive system. The value of each monitored parameter is analyzed and may be used to control the activity of a gastric stimulator.

Abstract: Implantable heart stimulator connectable to an electrode arrangement has a pulse generator adapted to deliver stimulation pulses to a heart of a subject; an impedance measurement unit adapted monitor at least one heart chamber of the heart of the subject to measure the impedance in the at least one monitored heart chamber for generating an impedance signal corresponding to the measured impedance. The impedance signal is applied to a processor where the signal is processed, according to specified criteria, and a fractionation index value is determined represented by the curve length of the impedance signal during a predetermined measurement period. The fractionation index value is a measure of different degrees of mechanical dyssynchrony of the heart.

Abstract: In an implantable heart monitoring device and a monitoring method, an impedance is measured across at least part of an atrium, such that variation of the impedance is related to the volume change of the atrium. Values are stored at different occasions that indicate the rate of change of the measured impedance. The stored values are determined such that, when the device is used in a living being, the variation of the stored values will be related to the variation of the speed with which the atrium is filled with blood during the atrial diastole.

Abstract: In a device and method for a medical implant for monitoring progression of heart failure in a human heart, an activity sensor provides information related to the activity level of a patient and an oxygen sensor provides information related to the level of oxygen content in venous blood. A determined level of venous oxygen content at a determined activity level is obtained, and that level of venous oxygen content is compared to stored values at a corresponding activity level. The result of the comparison is used as a basis for determining a degree of heart failure.

Abstract: In a method and implantable medical device for ventricular tachyarrhythmia detection and classification, upon detection of a ventricular tachyarrhythmia based on an electrocardiogram signal, cardiogenic impedance data representative of ventricular volume dynamics are collected and used for classifying the detected tachyarrhythmia as stable or unstable. In the latter case but typically not in the former case, defibrillation shocks or other forms of therapy are applied to combat the unstable ventricular tachyarrhythmia.

Abstract: An implantable cardiac device has a heart stimulator for electrically stimulating the heart of a patient, detector that measures a physiologic parameter that is affected by the status of a cardiovascular disease associated with sympathetic activation, a signal processor that determines at least one of a low frequency, LF, and a very low frequency, VLF, Mayer wave component in the measured parameter, and analyzer that automatically analyzes the determined Mayer wave component in relation to a predetermined reference value to determine the status of the cardiovascular disease. The detector is a cardio-mechanical parameter detector that measures, as said physiologic parameter, a mechanical change in at least one of the four chambers of the heart. In a corresponding method for monitoring the status of a cardiovascular disease associated with sympathetic activation of a patient having an implantable electric heart stimulator a physiologic parameter affected by the cardiac disease is measured.

Abstract: The present invention relates to a method for determining the posture of a patient. The method comprises the steps of: initiating (50, 52) a patient posture determining session by performing an electrical bio-impedance measurement session in at least one of a number of different electrode configurations in order to measure an impedance value for the at least one configuration; obtaining reference impedance values (54) stored in advance for the at least one configuration and for at least one potential posture of the patient; comparing (54) the measured impedance value for the at least one configuration with corresponding stored reference impedance values for at least one potential posture of the patient; and determining (56) the present posture of the patient by using results from the comparison between measured impedance values and the stored reference impedance values.

Abstract: A method, an implantable medical device, and a computer-readable medium encoded with programming instructions allow monitoring of a hematocrit value and an SvO2 level of a patient, making use of at least one medical lead connected to an implantable medical device that carries an optical sensor module that measures at least one hematocrit value and at least one SvO2 value using at least first, second and third light radiation wavelengths, by determining a present hematocrit value from at least one of the measured hematocrit values and determining a present SvO2 value from at least one of the measured SvO2 values, and determining a patient status by evaluating the present hematocrit value and the present SvO2 value, to allow a change in the patient status to be identified.

Abstract: In a method for detecting a change of a condition of a patient using an implantable medical device being connectable to the patient in at least one electrode configuration, at least one impedance measurement session is initiated to obtain at least one impedance value corresponding to an impedance of whole blood of the patient. At least one relative or absolute value of an amount of hematocrit in the blood of the patient is calculated using the at least one impedance value. A present hematocrit level is determined dependent on the at least one hematocrit value, with a change of the condition being derived from the present hematocrit level of the patient.