Abstract: An implantable medical device lead having a flow measurement sensor mounted thereon is provided with a capsule mounted proximate to the sensor. The capsule is used to house electrical circuitry corresponding to the sensor in order to prevent impedance on conductors of the lead, which gradually decreases over chronic periods, from directly affecting signal transmission between the sensor and the electrical circuitry. The electrical circuitry includes a charge amplifier used for processing signals from the sensor. In some cases, the amplifier can be initially calibrated and periodically tuned so as to have consistent functioning with the sensor over chronic periods.

Abstract: An implantable medical device lead having a flow measurement sensor mounted thereon is provided with a capsule mounted proximate to the sensor. The capsule is used to house electrical circuitry corresponding to the sensor in order to prevent impedance on conductors of the lead, which gradually decreases over chronic periods, from directly affecting signal transmission between the sensor and the electrical circuitry. The electrical circuitry includes a charge amplifier used for processing signals from the sensor. In some cases, the amplifier can be initially calibrated and periodically tuned so as to have consistent functioning with the sensor over chronic periods.

Abstract: An ultrasound method and medical devices using same provide for various techniques of sampling blood flow velocity, e.g., at several sampling rates. To minimize the energy required for ultrasound monitoring, pulsed Doppler signal packages provided by a pulsed ultrasound circuit are switched in such a way that the repetition rate is the lowest possible and yet sufficiently high to be able to record the blood flow velocity within the heart. For example, an ultrasound circuit may be activated only within a part of the cardiac cycle designated as the Doppler Measurement Interval (DMI); the ultrasound circuit may be switched between an on state and an off state during the DMI; and/or the ultrasound circuit may also be switched on and off in different sampling modes: detection mode and measurement mode (e.g., using different sampling rates).

Abstract: An ultrasound method and medical devices using same provide for various techniques of sampling blood flow velocity, e.g., at several sampling rates. To minimize the energy required for ultrasound monitoring, pulsed Doppler signal packages provided by a pulsed ultrasound circuit are switched in such a way that the repetition rate is the lowest possible and yet sufficiently high to be able to record the blood flow velocity within the heart. For example, an ultrasound circuit may be activated only within a part of the cardiac cycle designated as the Doppler Measurement Interval (DMI); the ultrasound circuit may be switched between an on state and an off state during the DMI; and/or the ultrasound circuit may also be switched on and off in different sampling modes: detection mode and measurement mode (e.g., using different sampling rates).

Abstract: A compact computer pointing device without moving parts detects the movement of objects, typically an operator's hand, in a detection area at a pre-selected height above the device. In an ultrasonic embodiment, the device includes two ultrasonic transmitter-receivers mounted at an appropriate position on the computer housing or keyboard. These transmitter-receivers use the Doppler effect to sense the vector velocity of objects moving in front of them. In an optical embodiment, the device consists of two optical emitters-receivers mounted at an appropriate position on the computer housing or keyboard. These emitter-receivers sense the vector velocity of objects moving in front of by cross-correlating the light reflected from the object with the incident light. In both the ultrasonic and the optical embodiment, the velocity vector thus determined is used to generate signals for corresponding movement of a pointer on the computer display.

Abstract: An implantable detection and therapy device allow prediction of the vasovagal syncope for use in administering therapy to a subject, the therapy including pacing pulses or drug delivery, or a combination thereof. The detection and therapy device includes a sensor which obtains blood flow velocity data or blood pressure data either in the area of the tricuspid valve or in the superior vena cava. The data are utilized in a control unit to identify the occurrence of venous pooling, which is recognized by the occurrence of a sudden reduction of the peak values of blood flow velocity waves or blood pressure waves. If this sudden reduction of the blood flow velocity waves or blood pressure waves is preceded by a sudden increase in the sinus heartbeat rate, the reduction is identified as being caused by venous pooling. The sudden increase in sinus heartbeat rate is caused by the increased sympathetic activity preceding the vasovagal syncope.

Abstract: A method and system for therapy of cardiac arrythmias is provided which uses a directional electric field applied via ablation electrode for cardiac ablation together with an ultrasonic imaging system including an ultrasonic marking transducer mounted fixedly in the vicinity of the ablation electrode and having ultrasonic sensitivity characteristics either in the same direction as the ablation field or in some other direction determined by a certain defined angle relative to the direction of the ablation field.

Abstract: An intracardiac blood flow velocity measurement device has a catheter adapted to be inserted through a blood vessel into the heart, at least two electrodes made of two different biocompatible materials mounted on the catheter at a detecting position which is located in a selected detecting area when the catheter is inserted into the heart for detecting blood flow velocity, with at least one of the electrodes being formed as a polarizable electrode and being disposed in the detecting position, and another of the electrodes being located on the catheter at an axially spaced distance from the polarizable electrode. Variation in an over-voltage or in a galvanic voltage is detected, and is used as a blood flow velocity signal.

Abstract: A blood flow velocity measurement device is devised where there exist such entities within the fluid which are detectable when axially flowing (passing by) an appropriate detector of known and well defined dimensions mounted onto a catheter. The entities produced for instance by a generator, when flowing by the detector, induced a known single response, the response bearing direct correlation to the flow velocity, in the form of direct reciprocity to the velocity and direct proportion to the length of the sensitive length of the detector. Autocorrelation of the function obtained by the overlap and pile-up of successive events is calculated and from the characteristic points in the autocorrelation function the axial velocity is inferred. The measurement is best when the probing beam is perpendicular to the flow.

Abstract: A system and method for regulation of pacing signals, and more particularly for regulation of an atrioventricular interval in a cardiac electrotherapy system based on measurement of blood flow velocity profiles. More particularly, a diastolic blood flow filling wave and an atrial blood flow filling wave are determined and a time delay between peaks of the two waves and/or a superimposition velocity of the two waves relative to one another are utilized for the regulation. The regulation preferably occurs by comparing the measured time delay to a desired time delay or desired superimposition velocity, and the result of the comparison is then employed for regulating the pacing, or regulating the atrio-ventricular interval.

Abstract: A cardiac electrotherapy system has flow velocity measurement capability for measuring a velocity of blood flow at a region of a tricuspid valve of a heart. A pacing system is provided which outputs a pacing electrical signal to the heart. A control unit which is responsive to a measured flow velocity from the flow velocity measurement unit detects heart irregularities and controls electrical pacing signals to the heart. In detecting heart irregularities, peak flow velocity waveforms are detected and analyzed. The flow velocity measurement employs a Doppler ultrasonic transducer which is mounted on a cardiac pacing lead in spaced relation to a pacing electrode at a distal end of the lead. When the pacing lead is inserted in the heart, the pacing electrode is placed at an apex of the right ventricle and the piezoelectric Doppler transducer is positioned at or near the tricuspid valve. The flow velocity transducer is preferably formed as an annular piezo body having associated electrodes.

Abstract: A device for measuring blood flow in the vicinity of a catheter implanted within the vascular vessel or the heart uses hydrodynamic principles. The device has two transducers mounted at the exterior surface of the catheter spaced from each other. One of the transducers has a protrusion in the form of a hydrofoil profile, and the other transducer presents a substantially flat surface at the exterior of the catheter. The transducer having the hydrofoil profile generates a signal due to the quasi-static pressure acting on the transducer as well as due to the drag force acting on the transducer caused by the blood flow. The other transducer generates a signal solely due to the quasi-static pressure. The transducers can either be connected with opposite polarity, or their respective signals can be subtracted in a differential amplifier, so that a signal proportional to the axial flow velocity is obtained.

Abstract: A cardiac electrotherapy system has flow velocity measurement capability for measuring a velocity of blood flow at a region of a tricuspid valve of a heart. A pacing system is provided which outputs a pacing electrical signal to the heart. A control unit which is responsive to a measured flow velocity from the flow velocity measurement unit detects heart irregularities and controls electrical pacing signals to the heart. In detecting heart irregularities, peak flow velocity waveforms are detected and analyzed. The flow velocity measurement employs a Doppler ultrasonic transducer which is mounted on a cardiac pacing lead in spaced relation to a pacing electrode at a distal end of the lead. When the pacing lead is inserted in the heart, the pacing electrode is placed at an apex of the right ventricle and the piezoelectric Doppler transducer is positioned at or near the tricuspid valve. The flow velocity transducer is preferably formed as an annular piezo body having associated electrodes.

Abstract: Cardiac ultrasonically marked leads produced by mounting one or more piezoelectric marker transducers into the leads and connecting the transducers by electrical conductors to appropriate electronic circuits which, upon reception of the scanner ultrasonic signals by the marker transducers, generate appropriate electrical signals which localize unambiguously the marker transducers in an ultrasonic echographic image, thereby permitting guiding of pacing leads and detection of their malfunctions.

Abstract: The hollow cylindrical wall of the catheter is composed of flexible, electrically insulating, ultrasonically transparent material. Embedded therein are spaced tubular-shaped ultrasonic piezoelectric transducers which substantially surround the lumen. The transducers receive signals from the imaging transducer on the body surface and serve to establish catheter location within the body during a diagnostic procedure. Electrical connector leads from the transducers are embedded in the wall and connected to a signal processor which provides an output for incorporation into the display of an echocardiograph image display system.