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Determination of the optimal match between defibrillation energy delivered by an internal cardiac defibrillator (ICD) and the characteristics of abnormal waveforms (VF or VT) will likely improve countershock success and, therefore, patient survivability.
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Determination of the optimal match between defibrillation energy delivered by an internal cardiac defibrillator (ICD) and the characteristics of abnormal waveforms (VF or VT) will likely improve countershock success and, therefore, patient survivability. • ICD optimization will improve implant viability and performance while increasing device longevity, improving patient comfort and minimizing treatment expense. http://www.sadadadoksadoksx.com/accomplishments/icd.mov
The frequency characteristics of VF and VT waveforms have been shown to correlate to abnormal global activation patterns. • Those patterns, in turn, have been shown to require specific electrical cardioversion intensities and compositions in order to transform VF and VT into sinus rhythm.
This study asses the correlation between the minimum defibrillation energy (MDE)and the dominant frequency (DF), which is a parameter that characterizes the power distribution. Dominant Frequency Median Frequency or • The purpose of this study was to design and test a computer-controlled collection and processing station that is capable of extracting pertinent electrical information from a heart in VT or VF. Frequency at the Half-Power Point
The system developed collects, digitizes and stores electrical data from the heart (i.e., ECG) during controlled and monitored cardiac challenges. • Electrical data from as many as 16 channels are collected using LabVIEW™ 6.1 in concert with a DAQcard 700 ADC. • The DF is plotted as a function of time to characterize the changes that occur duringVF in the globally ischemic heart and during reperfusion. • Signals are cataloged and displayed,segmented into 5sec epochs, decomposed via the FFT and subjected to power spectral analyses.
cross power spectra with ensemble averaging - computation of the energy in the frequency distribution of two different electrical signals • power characterization – computation of the total, peak, and median power • bispectra – computation of the frequency distribution of the ECG exhibiting nonlinear behavior • Parameters extracted, cataloged and evaluated include: • quartiles – computation of the distribution of the power into bands of the frequencies • quadratic phase coupling – a measure of the degree to which specific frequencies interact to produce a third • magnitude squared coherence – a measure of the degree of synchrony between two electrical signals
In the future, ICDs will continue to evolve into increasingly sophisticated cardiac rhythm management devices. The ICD is no longer simply a safeguard against VF since it has been shown to be effective inmanaging bradycardias and VT. • ICDs may be used to predict and prevent arrhythmias in addition to managing them when they do. • To enhance ICD function, our system will be used to develop more complex analysis algorithms to identify appropriate therapeutic rhythm maneuvers.
Mr. Randal T Cole • Dr. Stephen R Quint • Dr. Timothy A Johnson • Dr. Henry Frierson for RES Grant Support