초록 ▼

An apparatus and method for performing multi-chamber anti-tachycardia pacing (ATP) in response to a tachycardia that is of particular use in an implantable cardiac stimulation device. The expected benefits of such a multi-chamber ATP include improved hemodynamic performance and the ability to termin

An apparatus and method for performing multi-chamber anti-tachycardia pacing (ATP) in response to a tachycardia that is of particular use in an implantable cardiac stimulation device. The expected benefits of such a multi-chamber ATP include improved hemodynamic performance and the ability to terminate the tachycardia sooner. Embodiments of the present invention use an intrinsic chamber activation sequence and associated interchamber time delays, preferably automatically detected during a period of time when a pathologic tachycardia is not present, to treat a pathologic tachycardia should it occur. Such a device monitors two or more chambers of the patient's heart, i.e., the controlled chambers, and in the event a tachycardia is detected, the device determines the chamber which originated the tachycardia. The device then calculates anti-tachycardia pacing (ATP) cycle lengths, typically as percentages of the detected tachycardia cycle length of the chamber where the tachycardia originated, and begins pacing the controlled chambers according to the intrinsic chamber activation sequence and interchamber delays (initially synchronized relative to a cardiac signal from the chamber which originated the tachycardia) at the ATP cycle lengths for a predefined period or until the tachycardia ends. Optionally, embodiments of the present invention may additionally include a hemodynamic sensor and may adaptively alter the activation sequence and/or interchamber time delays in response to feedback from the hemodynamic sensor.

대표청구항 ▼

An apparatus and method for performing multi-chamber anti-tachycardia pacing (ATP) in response to a tachycardia that is of particular use in an implantable cardiac stimulation device. The expected benefits of such a multi-chamber ATP include improved hemodynamic performance and the ability to termin

An apparatus and method for performing multi-chamber anti-tachycardia pacing (ATP) in response to a tachycardia that is of particular use in an implantable cardiac stimulation device. The expected benefits of such a multi-chamber ATP include improved hemodynamic performance and the ability to terminate the tachycardia sooner. Embodiments of the present invention use an intrinsic chamber activation sequence and associated interchamber time delays, preferably automatically detected during a period of time when a pathologic tachycardia is not present, to treat a pathologic tachycardia should it occur. Such a device monitors two or more chambers of the patient's heart, i.e., the controlled chambers, and in the event a tachycardia is detected, the device determines the chamber which originated the tachycardia. The device then calculates anti-tachycardia pacing (ATP) cycle lengths, typically as percentages of the detected tachycardia cycle length of the chamber where the tachycardia originated, and begins pacing the controlled chambers according to the intrinsic chamber activation sequence and interchamber delays (initially synchronized relative to a cardiac signal from the chamber which originated the tachycardia) at the ATP cycle lengths for a predefined period or until the tachycardia ends. Optionally, embodiments of the present invention may additionally include a hemodynamic sensor and may adaptively alter the activation sequence and/or interchamber time delays in response to feedback from the hemodynamic sensor. a cavity of the housing; an actuator lever supported on an upper surface of the housing by a cantilever plate spring, a top end of the actuator lever being extended to a housing side, said actuator lever including a hole which controls a moving range of the lever, the hole being provided at a position facing the housing side for fitting to a protrusion of the housing side; a piston provided between and connecting the actuator lever and the microswitch; and an elastic membrane for sealing the piston. 6. A limit switch comprising: a housing; a non-contact type microswitch provided inside a cavity of the housing; an actuator lever supported on an upper surface of the housing by a cantilever plate spring; a piston provided between and connecting the actuator lever and the microswitch; an elastic membrane for sealing the piston, and a compression coil spring insertably mounted between the piston and a mounting board of the microswitch for supporting the piston and opposing an urging force of the elastic membrane. 7. The limit switch according to claim 6, wherein the mounting board of the microswitch includes an external thread on an outer periphery thereof for screwing to an internal thread provided on a hole of the housing. 8. The limit switch according to claim 7, wherein the mounting board of the microswitch is rotatable so as to move a position of the piston relative to the actuator lever by a screw mechanism and to adjust a distance of an operating position for the actuator lever relative to a free position of the microswitch. 9. The limit switch according to claim 1, including a filler material inside the cavity to seal the microswitch so that the limit switch is water resistant. 10. A limit switch comprising: a housing including an aperture extending therethrough and opening at one end into a cavity in the housing and opening at the other end outwardly from a side wall of said housing; an actuator secured to said housing and positioned adjacent the aperture at the side wall of said housing; a microswitch secured to said housing and positioned in the cavity; a piston disposed in and extending the entire length of the aperture, said piston having a first end for contacting said microswitch in the cavity and a second end protruding from the aperture for contacting said actuator; and an elastic membrane positioned about a portion of the second end of said piston and sealing the aperture at the side wall of said housing, wherein said piston transfers physical movement of said adjacent actuator toward said microswitch. 11. The limit switch according to claim 10, wherein said actuator comprises an actuator lever secured at one end to the side wall of the housing by a cantilever spring plate. 12. The limit switch according to claim 10, including a filler material located inside the cavity to seal the microswitch so that the limit switch is water resistant. F2/HI, CCl2F2/HI, and CBrClF2/HI mixtures". Gauthier et al., (Appl. Phys. B. 28, 2, (1982)). Month unavailable. "Efficient Production of 13C2F4in the Infrared Laser Photolysis of CHClF2". Evseev et al., (Appl. Phys. B 36, 93, 1985; Sov. J. Quantum Electron, 18, 385, 1988)). Month unavailable. "Highly Selective and Efficient Multiphoton Dissociation of Polyatomic Molecules in Multiply-Frequency IR-Laser Fields". Evseev et al., (Appl. Phys. B 36, 93, 1985; Sov. J. Quantum Electron, 18, 385, (1988)). Month unavailable. "Laser Separation of Carbon Isotopes by Two-Frequency Dissocoation of Freons". R. 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