Rate-adaptive pacing

Atrium Atrium Triggered Rate Adaptive Pacing... 

Mond H. and Barold SS Dual chamber, rate-adaptive pacing in patients with paroxysmal supraventricular tachyarrhythmias Protective measures for rate control. PACE 1993 16 2168-2185. 

Rate-adaptive pacing was developed to provide a heart rate response to meet the metabolic needs of the patient with chronotropic incompetence. For the patient in sinus rhythm, DDDR pacing provides an adequate heart rate with atrial pacing at rates that may exceed the maximal sinus rates. For the patient in chronic atrial fibrillation, VVIR pacing provides an adequate heart rate response with ventricular pacing. 

Rate-adaptive pacing relies on the performance of sensors to provide input to the pacemaker regarding the appropriate heart rate for the activity. An algorithm then converts the sensor data to a specific heart rate response. Currently available sensor systems are so-called open loop because an external algorithm must be apphed to the sensor data to determine an appropriate heart rate. A closed-loop system would internally regulate the heart rate response based on the sensor data without requiring adjustment of an external algorithm. 

Candinas R, Jakob M, Buckingham TA, et al. Vibration, acceleration, gravitation, and movement activity controlled rate adaptive pacing during treadmill exercise testing and daily life activities. PACE 1997 20 1777-1786. 

Tse HE, Sin CW, Lee KL, Fan K, Chan HW, Tang MO, Tsang V, Lee SW, Lau CP. The incremental benefit of rate-adaptive pacing on exercise performanee during cardiac resynchronization therapy. J Am CoU Cardiol 2005 46 2292-7. 

Positions and description I. Chamber(s) paced II. Chamber(s) sensed III. Pacemaker response IV. Rate adaptive and programming features V. Antiarrhythmic pacing, cardioversion, and defibrillator functions... 

There are number of strategies to promote ventricular pacing in sinus rhythm. Rate-adaptive AV delay is generally employed in order to promote ventricular pacing. Negative AV hysteresis is used to promote ventricular pacing by shortening the AV interval when intrinsic conduction is detected in the AV interval. 

Faerestrand S, Ohm O-J, Stangeland L, et al. Long-term chnical performance of a central venous oxygen satnration sensor for rate adaptive cardiac pacing. PACE 1994 17 1355-1372. 

If the procedure is to proceed in a smooth and expeditious fashion, careful preoperative planning is essential. The first such decision is whether the patient requires a single-chamber or dual-chamber pacemaker. As a rule, if the patient has intact atrial function, every effort is made to preserve atrial and ventricular relationships. Single-chamber ventricular pacing is usually reserved for the patient with chronic atrial fibrillation or atrial paralysis. A device is selected with acceptable size, longevity, and progranunability. If the heart is chronotropically incompetent, a device that offers some form of rate adaptation... 

Lau CP, Tai YT, Fong PC, Li IP, Chung EL. Atrial arrhythmia management with sensor controlled atrial refractory period and automatic mode switching in patients with minute ventilation sensing dual chamber rate adaptive pacemakers. Pacing Clin Electrophysiol. 1992 15 1504-1514. 

Lau W, Corcoran SJ, Mond HG. Pacemaker tachycardia in a minute ventilation rate-adaptive pacemaker induced by electrocardiographic monitoring. Pacing Clin Electrophysiol 2006 29 438 40. 

Common pacemakers stimulate the heart with a fixed rate. For the benefit of the patient, it is desirable to adjust the cardiac output to the physiological state of the patient. Among other factors, the physiological condition of a patient is influenced by body motion, posture, metabolism, ambient conditions, and emotional states. It is the objective of advanced pacemaker systems to adjust cardiac output by either altering the cardiac stroke volume or the cardiac rate. The regulation of stroke volume is refined by its inherent limited range. Current activities focus on rate-adaptive heart pacing systems. Cardiac... 

Source Bernstein, A.. Daubert J.. Fletcher R. et al. 2002. The revised NASPE/BPEG generic code for antibradycardia, adaptive-rate, and multisite pacing. PACE 23 260-64. 

Takt time The interval that sets the pace of production to match the rate of customer demand. It is the heartbeat of the lean production system. The term is derived from the German expression for a metronome beat. (Adapted from APICS Dictionary, lOtb edition )... 

A temperature sensor has also been used clinically for adaptive rate pacing. As exercise continues, the body temperature rises in a nonlinear manner. Cooler blood returns from the extremities with the onset of activity, resulting in a fall in core temperature. Algorithms using temperature as a sensor must consider these phenomena and respond appropriately. 

Ruiter J, Heemels JP, Kee K, et al. Adaptive rate pacing controlled by the right ventricnlar preejection interval clinical experience with a physiological pacing system. PACE 1992 15 886-894. 

Metallocene catalysts have been successfully adapted to all commercial polyethylene processes. Recently, companies have begun to join forces to avoid patent disputes as well as to accelerate the pace of commercialization. Joint ventures between Exxon and Union Carbide (Univation Technologies) and between Dow and BP were formed to leverage popular process technologies (variants of fluidized-bed gas-phase reactor systems) to expand the market for metallocene catalysts and products. The Dow-Union Carbide merger of 2001 could greatly influence the rate of technology dissemination. 

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