Pacing and clinical electrophysiology : PACE
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Pacing Clin Electrophysiol · Jun 2005
Clinical TrialCerebral oxygenation during defibrillator threshold testing of implantable cardioverter defibrillators.
The induction of ventricular fibrillation (VF) during defibrillator threshold testing of implantable cardioverter defibrillators (ICD) provokes global cerebral hypoperfusion and impaired oxygen delivery. Limited data are available on the neurophysiological effects of defibrillator threshold testing. Near infrared spectroscopy (NIRS) can noninvasively measure changes in specific chromophores, which reflect cerebral oxygenation at the intravascular and mitochondrial levels. We performed a prospective trial using NIRS to analyze cerebral cortical oxygenation during defibrillator threshold testing. ⋯ Our results suggest that impaired oxygen delivery during induced VF and VT does not affect oxygen availability at the cellular intra-mitochondrial level.
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Pacing Clin Electrophysiol · Jun 2005
ReviewDevelopment of implantable devices for continuous ambulatory monitoring of central hemodynamic values in heart failure patients.
Care and management of patients with congestive heart failure (CHF) is a major health-care challenge. The value of acute hemodynamic data in assessing heart failure has been questioned in some studies, while more intensive hemodynamic monitoring has been reported to improve patient care in others. A series of patient studies are reported here that were conducted to identify device requirements and verify the feasibility of continuous hemodynamic monitoring in CHF patients and devices for remote transfer and use of these data. ⋯ Development of implantable technology to measure several hemodynamic variables in ambulatory CHF patients is feasible. External instrumentation needed to remotely acquire data from the implanted devices has been verified. The potential to eliminate the uncertainties associated with the use of acute, invasive hemodynamics and the ability to evaluate long-term ambulatory hemodynamic patterns is provided. These findings set the stage for determining the potential clinical value of these systems in impacting the care of chronic CHF patients.
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Pacing Clin Electrophysiol · Jun 2005
Electromagnetic interference of implantable unipolar cardiac pacemakers by an induction oven.
Induction ovens have been reported to exert electromagnetic interference on implanted cardiac pacemakers. In an attempt to quantitatively investigate the electromagnetic interference caused by an induction oven on implantable unipolar cardiac pacemakers, we measured the distribution profile of the magnetic field intensity, both with and without a pan on the induction oven. We also performed the inhibition test and asynchronous test using four kinds of pacemakers housed in the standardized Irnich human body model, and measured the maximal distance from the induction oven up to which the interference occurred. ⋯ Thus, the safe distance from an induction oven of a patient with an implanted cardiac pacemaker is considered to be 50 cm or more. In conclusion, in the pan-detection mode of the oven in the absence of a pan, the distribution profile of the magnetic field intensity peaked at the center of the cooking plate, and during the induction heating of a pan placed on the oven, it peaked at the circular edge of the pan. The induction oven asynchronized or generated pulses in implantable unipolar cardiac pacemakers up to a maximal distance of 34 cm from the induction oven.