Recognition Algorithm And The Discussion On The Implementation Of Low-energy Defibrillation. The Aed

Ventricular Fibrillation(VF) is the most malignant arrhythmia.Most cases of ventricular fibrillation occur out of the hospital.These patients often die because they fail to obtain treatments in time.The emergence of Automatic External Defibrillator(AED) makes it possible to treat these patients in time.To make the AEDs easy to use by the public who is not familiar with emergency treatment and ECG analysis,it is critical to have an accurate shockable rhythm recognition algorithm.The American Heart Association (AHA) divides the cardiac rhythms into three categories:Shockable Rhythm (ShR),Non-Shockable Rhythm(NShR) and Intermediate Rhythm.High sensitivity for ShR and high specificity for NShR are required for the shockable rhythm recognition algorithm in AEDs.Focusing on the design of novel feature algorithm with excellent performance of classification and short calculation time,this article proposes several measurements for the Normalized Isoelectric Potential,two measuments for the shadow variability and two measurements for the slope variability.To test and compare the performances among different algorithms fairly,the MIT Database,the CU Database and the VF Database,which are widely accepted in the field of AED algorithms researches,are used as the testing data sets in this article.And the area under the ROC curve(AUC) is selected as the main performance evaluation parameter.The HILB algorithm and the Largest Lyapunov Index algorithm that were reported by other researchers, two algorithms using shadow variability,two algorithms using slope variability and several measurements for the Normalized Isoelectric Potential that are proposed in this article,have all been tested.The results show that the algorithms using shadow variability and the algorithms using slope variability give a better performance and need less calculation time,and they exceed the performance required by the AHA's recommendations.Besides,in order to make the results in this article able to be used better by the other researchers,the test condition is conformed to that condition used by the other works in this research field.The defibrillation method using electrical shock has shortcomings in the clinical uses,and decreasing the shock energy will help to overcome these shortcomings.If energy is reduced while defibrillation success rate is insured,there would be less damage to the body,and patients would suffer less.Besides,the service life of the batteries in ICD can be prolonged.Therefore,the research of low energy defibrillate method is of great meaning.Based on the fact that the body can be considered as an impedance conductor to a medium or low frequency current,this article supposes that the relation between defibrillation threshold and total pulse width in the condition of semi-external defibrillation is similar to the relation between the stimulation threshold and stimulation duration in the condition of tissue stimulation.And the result that the minimum energy threshold occurs at the chronaxie can be concluded from the relation between the stimulation threshold and stimulation duration. So this article supposes ulteriorly that there is a proper total pulse width at which the minimum energy threshold for external/ semi-external defibrillation.To prove these supposes,7 animal trials were carried out based on BTE waveform.With the analysis of the data got in the trials, the article concludes that the relation of the pulse duration versus the threshold for the semi-external defibrillation is similar to the relation of the pulse duration versus the threshold for the cardiac muscle tissue, and compared to the 5ms+1ms+5ms waveform,the 3ms+1ms+3ms waveform needs lower threshold of both electric quantity and energy and needs similar threshold of voltage meanwhile.Finally,this article proposes design scheme and development results of AED device that can be used in the animal trials to validate algorithms and to research low energy defibrillation method.That's also the attempts to develop AED with independent intellectual property.