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University of Pittsburgh

Lawrence Duane Sherman

Clifton W Callaway

James John Menegazzi

A defibrillation system for use in treatment of ventricular fibrillation includes at least one sensor to measure heart rhythm; at least one applicator to apply a defibrillation pulse to a patient; and at least one processor in communication with the sensor and the applicator to determine a first value related to the rate of change of a leading edge of a lagged phase space reconstruction of ventricular fibrillation heart rhythm measured over a period of time.

Devices, systems and methods for characterization of ventricular fibrillation and for treatment of ventricular fibrillation

A computationally efficient method of determining the duration of ventricular fibrillation and the probability of successful defibrillation by analyzing an electrocardiogram using the logarithm of the absolute value of the autocorrelation function over a range of lags is disclosed. The method is particularly well suited for use in currently available defibrillators. The method is used in conjunction with frequency based measures, such as the angular velocity, to provide markedly improved accuracy in determining ventricular fibrillation duration, to indicate appropriate therapies to be delivered, and to assess the quality of ventricular fibrillation.

Methods and devices to characterize the probability of successful defibrillation and determine treatments for ventricular fibrillation

A method of determining a state of ventricular fibrillation from a waveform, includes: performing calculations on the Fourier transform of the waveform voltage values by using the quotient of the power in a high frequency band and of the power in a low frequency band; and determining the state of ventricular fibrillation by relating this ratio to the state of ventricular fibrillation. A defibrillation system for use in treatment of ventricular fibrillation includes at least one sensor to measure heart rhythm and at least one applicator to apply a defibrillation shock to a patient. The system further includes at least one processor which is adapted to calculate the ratio and also to obtain user input regarding survival of subgroups and average response times in the user's domain which allows calculation of an estimated maximum overall survival and selection of an optimum threshold for the ratio measure based on this maximum. The system further includes a user interface system in operative connection with the processor to provide information related to the ratio to a user.

Methods and devices to guide therapy for ventricular fibrillation based on waveform analysis and survival benefit analysis

A defibrillator, which selectively delivers a defibrillation pulse to a patient, includes electrodes adapted for placement on the patient, a monitoring circuit for providing an electrocardiogram (ECG) of the patient, and a defibrillation pulse generator having an energy store for delivering a defibrillation pulse. A switch in electrical communication with the ECG monitoring circuit and the defibrillation pulse generator selectively electrically connects the monitoring circuit and the defibrillation pulse generator to the electrodes. A microprocessor is in electrical communication with the monitoring circuit, the defibrillation pulse generator, and the switch. The microprocessor causes the switch to electrically connect the monitoring circuit to the electrodes in order to provide the ECG of the patient. The microprocessor also determines a scaling exponent for the patient from the ECG thereof. The microprocessor further compares the scaling exponent to a predetermined value and selectively causes the switch to electrically connect the defibrillation pulse generator to the electrodes in order that the energy store delivers the defibrillation pulse to the patient.

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Bellevue, WA, United States of America

Lawrence Duane Sherman