Обзор методов автоматической диагностики сердечной аритмии для принятия решений о необходимости проведения дефибрилляции

Ventricular fibrillation is considered the most common cause of sudden cardiac arrest. The fibrillation, and ventricular tachycardia often preceding it, are cardiac rhythms that may respond to emergency electroshock therapy and return to normal sinus rhythm when diagnosed early after cardiac arrest with the restoration of adequate cardiac pumping function. However, manually checking ECG signals on the existence of a pattern of such arrhythmias is a risky and time-consuming task in stressful situations and practically impossible in the absence of a qualified medical specialist. Therefore, systems of the computer classification of arrhythmias with the function of making a decision on the necessity of electric cardioversion with the parameters of a high-voltage pulse calculated adaptively for each patient are widely used for the automatic diagnosis of such conditions. This paper discusses methods of analyzing the electrocardiographic signal taken from the electrodes of an external automatic or semi-automatic defibrillator in order to make a decision on the necessity for defibrillation, which are applicable in the embedded software of automatic and semiautomatic external defibrillators. The paper includes an overview of applicable filtering techniques as well as subsequent algorithms for extracting, classifying and compressing features for the ECG signal.  Lipchak D. A., Chupov A. A. Methods of Signal Analysis for Automatic Diagnosis of Shockable Cardiac Arrhythmias: A Review. Ural Radio Engineering Journal. 2021;5(4):380–409. (In Russ.) DOI: 10.15826/ urej.2021.5.4.004. Фибрилляция желудочков сердца считается наиболее часто встречающейся причиной внезапной остановки сердца. Такая фибрилляция и часто предшествующая ей желудочковая тахикардия – это ритмы сердца, которые могут реагировать на экстренную электрошоковую терапию и вернуться к нормальному синусовому ритму при ранней диагностике после остановки сердца с восстановлением адекватной насосной функции сердца. Однако ручная проверка сигналов ЭКГ на наличие паттерна такой аритмии является сложной аналитической задачей, требующей немедленного принятия решения в стрессовой ситуации, практически невыполнимой в отсутствие квалифицированного медицинского специалиста. Поэтому для автоматической диагностики острых состояний широкое применение получили системы компьютерной классификации аритмий с функцией принятия решения о необходимости проведения электрокардиотерапии с параметрами высоковольтного импульса, вычисленного адаптивно для каждого пациента. В данной работе рассмотрены методы анализа электрокардиографического сигнала, снимаемого с электродов наружного автоматического или полуавтоматического дефибриллятора, с целью принятия решения о необходимости оказания дефибрилляции, применимые во встроенном программном обеспечении автоматических и полуавтоматических внешних дефибрилляторов. Работа включает обзор применимых методов фильтрации, а также последующих алгоритмов извлечения, классификации и сжатия характерных признаков для сигнала ЭКГ.  Липчак Д. А., Чупов А. А. Обзор методов автоматической диагностики сердечной аритмии для принятия решений о необходимости проведения дефибрилляции. Ural Radio Engineering Journal. 2021;5(4):380–409. DOI: 10.15826/urej.2021.5.4.004.

Methods of Signal Analysis for Automatic Diagnosis of Shockable Cardiac Arrhythmias: A Review

Ventricular fibrillation is considered the most common cause of sudden cardiac arrest. Ventricular fibrillation, and ventricular tachycardia often preceding it, are cardiac rhythms that can respond to emergency electroshock therapy and return to normal sinus rhythm when diagnosed early after cardiac arrest with the restoration of adequate cardiac pumping function. However, manually checking ECG signals for the presence of a pattern of such arrhythmias is a risky and time- consuming task in stressful situations and practically impossible in the absence of a qualified medical specialist. Therefore, for the automatic diagnosis of such conditions, systems for the computer classification of arrhythmias to decide on the need for electric cardioversion with the parameters of a high-voltage pulse, calculated adaptively for each patient, are widely used. This paper discusses methods for analyzing the electrocardiographic signal taken from external automatic or semi-automatic defibrillator electrodes to decide the need for defibrillation, which is applicable in the embedded software of automatic, semi-automatic external defibrillators. The paper includes an overview of applicable filtering techniques and subsequent algorithms for extracting, classifying, and compressing features for the ECG signal. Both advantages and disadvantages are discussed for the studied algorithms. © 2022 IEEE.Russian Foundation for Basic Research, РФФИ, (20-37-90037)The reported study is funded by RFBR according to research project No. 20-37-90037

Methods of Signal Analysis for Automatic Diagnosis of Shockable Cardiac Arrhythmias: A Review

Поступила: 19.12.2021. Принята в печать: 18.01.2022.Received: 19.12.2021. Accepted: 18.01.2022.Фибрилляция желудочков сердца считается наиболее часто встречающейся причиной внезапной остановки сердца. Такая фибрилляция и часто предшествующая ей желудочковая тахикардия – это ритмы сердца, которые могут реагировать на экстренную электрошоковую терапию и вернуться к нормальному синусовому ритму при ранней диагностике после остановки сердца с восстановлением адекватной насосной функции сердца. Однако ручная проверка сигналов ЭКГ на наличие паттерна такой аритмии является сложной аналитической задачей, требующей немедленного принятия решения в стрессовой ситуации, практически невыполнимой в отсутствие квалифицированного медицинского специалиста. Поэтому для автоматической диагностики острых состояний широкое применение получили системы компьютерной классификации аритмий с функцией принятия решения о необходимости проведения электрокардиотерапии с параметрами высоковольтного импульса, вычисленного адаптивно для каждого пациента. В данной работе рассмотрены методы анализа электрокардиографического сигнала, снимаемого с электродов наружного автоматического или полуавтоматического дефибриллятора, с целью принятия решения о необходимости оказания дефибрилляции, применимые во встроенном программном обеспечении автоматических и полуавтоматических внешних дефибрилляторов. Работа включает обзор применимых методов фильтрации, а также последующих алгоритмов извлечения, классификации и сжатия характерных признаков для сигнала ЭКГ.Ventricular fibrillation is considered the most common cause of sudden cardiac arrest. The fibrillation, and ventricular tachycardia often preceding it, are cardiac rhythms that may respond to emergency electroshock therapy and return to normal sinus rhythm when diagnosed early after cardiac arrest with the restoration of adequate cardiac pumping function. However, manually checking ECG signals on the existence of a pattern of such arrhythmias is a risky and time-consuming task in stressful situations and practically impossible in the absence of a qualified medical specialist. Therefore, systems of the computer classification of arrhythmias with the function of making a decision on the necessity of electric cardioversion with the parameters of a high-voltage pulse calculated adaptively for each patient are widely used for the automatic diagnosis of such conditions. This paper discusses methods of analyzing the electrocardiographic signal taken from the electrodes of an external automatic or semi-automatic defibrillator in order to make a decision on the necessity for defibrillation, which are applicable in the embedded software of automatic and semiautomatic external defibrillators. The paper includes an overview of applicable filtering techniques as well as subsequent algorithms for extracting, classifying and compressing features for the ECG signal

Detection of shockable heart rhythms with convolutional neural networks : Based on ECG spectrograms

Purpose Automated feature extraction combined with deep learning has had and continues to have a strong impact on the improvement and implementation of pattern recognition driven by machine learning. Systems without prior expertise about a problem but with the ability to iteratively learn strategies to solve problems, tend to outperform concepts of manual feature engineering in vari-ous fields. In ECG data analysis as well as in other medical domains, models based on manual feature extraction are tedious to develop, require scientific expertise, and are oftentimes not easily adaptive to variations of the problem to be solved. This work aims to examine automated feature extraction and classification of ECG data, specifically of shockable heart rhythms, with convolu-tional neural networks and residual neural networks. The precise and rapid determination of shockable cardiac conditions is a decisive step to improve the chances of survival for patients having a sudden cardiac arrest. Conventional, commercially available automated external defib-rillators (AEDs) deploy algorithms based on manual feature extraction. Approximately 1 out of 10 shockable conditions is not recognized by the AED. Consequently, strategies for improvement need to be explored. Methods 125 ECG recordings from four annotated cardiac arrhythmia databases (American Heart Association Database, Creighton University Tachyarrhythmia Database, MIT-BIH Arrhythmia Da-tabase, MIT-BIH Malignant Ventricular Arrhythmia Database) with a duration of 30 mins or 8 mins (Creighton University Tachyarrhythmia Database) per recording were processed. Shockable con-ditions are identified as ventricular tachycardia, ventricular fibrillation, and ventricular flutter. The 1 channel ECG recordings (modified limb lead II) were normalized to 250 Hz sampling frequency, high-pass filtered (1 Hz cutoff and 0.85 filter steepness), second order Butterworth low-pass fil-tered (30 Hz cutoff), and notch filtered at 50 Hz. Consistent wavelet transformation with 5 octaves, 20 voices per octave, and a time bandwidth product parameter of 50 was applied to generate greyscale spectrogram representations of the ECG data (pixel value range from 0 to 255). The recordings were segmented into 3 s segments. Data augmentation around the borders of shock-able episodes and along shockable episodes was carried out to create balanced datasets con-sisting of 60340 samples. 45% of samples in the balanced dataset contain shockable rhythms with more than 60% temporal prevalence within each sample. Conventional convolutional neural networks and residual neural networks with varying architectures and hyperparameter settings were trained and evaluated on balanced datasets (train/val/test: 70/15/15). The approach focused on examining a broader range of parameter settings and model architectures rather than optimiz-ing a specific configuration. The best performing model was evaluated in a 5-fold cross-validation. Exemplarily, a leave-one-subject-out cross-validation was deployed with 3 randomly chosen re-cordings, with the constraints that each subject must come from a different database and contain a different shockable condition. Results and Conclusion The best performing model was a residual neural network with 96 residual blocks. The 5-fold cross-validation results on average in an accuracy of 0.987, a sensitivity of 0.992 on shock-able rhythms, and a specificity of 0.984 for non-shockable rhythms on the test sets. The ROC AUC score is 0.998 on average. The 3-fold leave-one-subject-out cross-validation reaches on average an accuracy of 0.984, a sensitivity of 0.984, and a specificity of 0.980. The ROC AUC score reaches 0.997 on average. The analysis of misclassified segments reveals that the classi-fier performs less accurately on border segments containing a shockable and at least one non-shockable rhythm. While the test set contains 4.73% border segments, the set of misclassified samples includes 11.29% border segments. The label distributions of the test set and the set of misclassified samples show that segments annotated as “not defined” (ND) and “ventricular fibril-lation or flutter” (VF-VFL) are significantly more prevalent in the set of misclassified samples. Histogram analysis, referring to the mean pixel intensity of the spectrograms, indicates that the classifier works less accurately on spectrograms with mean pixel values below 2 (practically flat-line signals or signals with very small amplitude). The results indicate that it is possible to improve the analysis of ECG data by deploying automated feature detection combined with artificial neural networks. The methods presented in this work are not restricted to the detection of shockable cardiac arrhythmias, they likewise em-phasize the potential of machine learning in the domain of biosignal analysis and correlated med-ical data. In the next step, the approach needs to be verified on a broader database. The tech-nology can even help create more comprehensive databases of clinical ECG data by supporting automated annotation

Seinale prozesaketan eta ikasketa automatikoan oinarritutako ekarpenak bihotz-erritmoen analisirako bihotz-biriketako berpiztean

Tesis inglés 218 p. -- Tesis euskera 220 p.Out-of-hospital cardiac arrest (OHCA ) is characterized by the sudden loss of the cardiac function, andcauses around 10% of the total mortality in developed countries. Survival from OHCA depends largelyon two factors: early defibrillation and early cardiopulmonary resuscitation (CPR). The electrical shock isdelivered using a shock advice algorithm (SAA) implemented in defibrillators. Unfortunately, CPR mustbe stopped for a reliable SAA analysis because chest compressions introduce artefacts in the ECG. Theseinterruptions in CPR have an adverse effect on OHCA survival. Since the early 1990s, many efforts havebeen made to reliably analyze the rhythm during CPR. Strategies have mainly focused on adaptive filtersto suppress the CPR artefact followed by SAAs of commercial defibrillators. However, these solutionsdid not meet the American Heart Association¿s (AHA) accuracy requirements for shock/no-shockdecisions. A recent approach, which replaces the commercial SAA by machine learning classifiers, hasdemonstrated that a reliable rhythm analysis during CPR is possible. However, defibrillation is not theonly treatment needed during OHCA, and depending on the clinical context a finer rhythm classificationis needed. Indeed, an optimal OHCA scenario would allow the classification of the five cardiac arrestrhythm types that may be present during resuscitation. Unfortunately, multiclass classifiers that allow areliable rhythm analysis during CPR have not yet been demonstrated. On all of these studies artefactsoriginate from manual compressions delivered by rescuers. Mechanical compression devices, such as theLUCAS or the AutoPulse, are increasingly used in resuscitation. Thus, a reliable rhythm analysis duringmechanical CPR is becoming critical. Unfortunately, no AHA compliant algorithms have yet beendemonstrated during mechanical CPR. The focus of this thesis work is to provide new or improvedsolutions for rhythm analysis during CPR, including shock/no-shock decision during manual andmechanical CPR and multiclass classification during manual CPR