摘要:
An implantable medical device has a pressure sensing arrangement to measure right ventricular pressure of a heart including a pressure sensor adapted to be positioned in the right ventricle of the heart, to measure the pressure and to generate a pressure signal in response to the measured pressure. The pressure sensing arrangement also has a pressure signal processor and a timing unit. The processor determines from the pressure signal, using diastolic timing signals from the timing unit based on the pressure signal identifying the diastolic phase, a diastolic pressure signal representing the ventricular pressure only during the diastolic phase of the heart cycle.
摘要:
In a cardiac assist device and method, a microphone is placed in contact with the epicardium of the heart of a patient, and heart and lung sounds are simultaneously detected at the placement location of the microphone. The heart and lung sounds are automatically analyzed to set an appropriate cardiac therapy for the patient.
摘要:
The present invention provides methods for detecting phrenic nerve stimulation. A pacing module is instructed to deliver pacing pulses having a predetermined pulse amplitude and/or width within the refractory period of the left ventricle. The pacing pulses are repeatedly delivered during a number of cardiac cycles and wherein the pacing pulses are delivered at different delays relative to an onset of the refractory period of the left ventricle in different cardiac cycles. Impedance signals are measured in time windows synchronized with the delivery of pacing pulses in the refractory period of the left ventricle using at least one electrode configuration. At least one impedance signal is gathered from each time window, aggregated impedance signals are created using the impedance signals from the different time windows, and the aggregated impedance signals are analyzed to detect PNS.
摘要:
CRT settings for an implantable medical device are determined by applying pacing pulses to heart chambers of a scheme of different combinations of interchamber delays. A respective width parameter value representing an R or P wave width is determined for each such delay combination based on an ECG representing signal and the width parameter values are employed to estimate a parametric model defining the width parameter as a function of interchamber delays. Candidate interchamber delays that minimize the width parameter are determined from the parametric model and employed to determine optimal CRT settings. The technique provides an efficient way of finding optimal CRT settings when multiple pacing sites are available in a heart chamber.
摘要:
CRT settings for an implantable medical device are determined by applying pacing pulses to heart chambers of a scheme of different combinations of interchamber delays. A respective width parameter value representing an R or P wave width is determined for each such delay combination based on an ECG representing signal and the width parameter values are employed to estimate a parametric model defining the width parameter as a function of interchamber delays. Candidate interchamber delays that minimize the width parameter are determined from the parametric model and employed to determine optimal CRT settings. The technique provides an efficient way of finding optimal CRT settings when multiple pacing sites are available in a heart chamber.
摘要:
A rate-responsive heart stimulator with a variable stimulation interval contains a measurement device which generates a measurement signal corresponding to the volume of blood in a heart during the blood-filling phase (diastole) and a comparator which compares the measurement signal with a defined threshold value corresponding to a defined degree of blood filling. The comparator generates a control signal when the measurement signal reaches the threshold value, the control signal representing the time elapsing since the last stimulation pulse, and controlling the heart stimulator's stimulation interval.
摘要:
The present invention provides implantable medical devices for detecting phrenic nerve stimulation. A pacing module is configured to deliver pacing pulses having a predetermined pulse amplitude and/or width within the refractory period of the left ventricle. The pacing pulses are repeatedly delivered during a number of cardiac cycles, and the pacing pulses are delivered at different delays relative to an onset of the refractory period of the left ventricle in different cardiac cycles. An impedance measurement module is configured to measure impedance signals in time windows synchronized with the delivery of pacing pulses in the refractory period of the left ventricle. A phrenic nerve stimulation, PNS, detection module is configured to gather at least one impedance signal from each time window, create aggregated impedance signals using the impedance signals from the different time windows, and analyze the aggregated impedance signals to detect PNS.
摘要:
A pacemaker has control circuits contained in an enclosure and a lead containing an electrical conductor connected to an electrode for delivering electrical stimulation pulses to a heart. The stretching of a wall in the ventricle, corresponding to adequate filling of the ventricle in the heart, is determined in order to identify a time of emitting the stimulation pulses. This stretching is measured indirectly by measurement of pressure in the ventricle using a pressure sensor disposed near the lead in the ventricle. The signal from the sensor is supplied via the lead to circuitry in the enclosure, wherein the signal is amplified and is supplied to an edge detector, which detects an increasing or positive edge of the signal. The edge detector compares the incoming signal with a threshold value, and when the pressure indicated by the signal increases so as to exceed the threshold value, the edge detector supplies a signal to the control circuit which, in turn, triggers the emission of a stimulation pulse from a pulse generator, with or without a delay. The aforementioned stretching can also be measured using a strain gauge or a distance sensor attached to the ventricle wall.
摘要:
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.
摘要:
An implantable heart stimulating device has a stimulation pulse generator that emits stimulation pulses at an adjustable stimulation rate, an activity sensor that emits an activity signal in response to detected activity of the patient, and a physiological parameter sensor that generates a physiological sensor signal in response to a detected physiological parameter. The activity and physiological sensor signals are supplied to a control arrangement that sets the stimulation rate for the stimulation pulse generator by executing a stimulation rate algorithm dependent on those signals. In the stimulation rate algorithm, if the physiological signal indicates an emotional stress on the part of the patient, the stimulation rate is increased to an adjustable emotional stress rate level, and if no increase in the activity signal occurs during a predetermined time period following the stimulation rate increase, the stimulation rate is decreased.