Abstract: The present technology describes various embodiments of systems and methods for analyzing electrocardiograms to detect ventricular fibrillation. In several embodiments, systems for detecting ventricular fibrillation can be implemented without interrupting cardiopulmonary resuscitation. In one embodiment, a method of identifying a cardiac rhythm in a person includes recording an electrocardiogram signal of the person and stratifying the signal. A signal having a parameter value within a pre-determined range is categorized as a shockable ventricular fibrillation signal while a signal having a parameter value outside the pre-determined range is categorized as a non-shockable signal.

Abstract: 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.

Abstract: 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.

Abstract: The powered tubing cutter is a hand held, mechanical device driven by a motor for cutting tubing/piping. The device comprises a housing, a drive plate, a main drive shaft, a cutting assembly having a cutting blade, a cam plate and a chain drive secured to a motor housing, having a handle, by a mounting bracket. The chain drive is powered by the motor, which causes the main drive shaft to rotate. The cutting assembly is pivotally secured to a pin on the main drive shaft. The pipe/tube to be cut is placed into the hole in the center of the housing and the main drive shaft. As the cutting assembly rotates with the main drive shaft the cam plate forces the cutting blade into cutting engagement with the tube/pipe.