Background. Currently, psoriasis is the most common skin disease, its prevalence reaches 5% and this pathology often occurs together with arterial hypertension. Both arterial hypertension and psoriasis contribute to the remodeling of the cardiovascular system. As is known, myocardial remodeling is a substrate for electrical instability of the myocardium. Objective. The aim of the study was to study the parameters of the signal-averaged electrocardiogram in men with stage 2 arterial hypertension with concomitant vulgar psoriasis in the progressive stage, and to evaluate the parameters of the signal-averaged electrocardiogram against the background of psoriasis therapy. A total of 86 men with stage 2 arterial hypertension with a progressive stage of vulgar psoriasis with a severe and moderate course were examined. Signal-averaged ECG was recorded before psoriasis therapy was prescribed and after 6 months of systemic and topical psoriasis therapy. Results. A statistically significant moderate positive correlation was found between the severity of psoriasis vulgaris (according to the PASI index) and such an SU-ECG indicator as the duration of the filtered QRS complex (r = 0.32; p = 0.005), a statistically significant weak negative correlation of the PASI index with the root-mean-square amplitude of the last 40 ms of the filtered QRS complex (r = -0.27; p = 0.012). Patients with severe psoriasis had more pronounced changes in cardiac electrophysiology, in the form of more frequent recording of late ventricular potentials χ2 = 4.07; p = 0.044, a longer duration of the filtered QRS complex (p = 0.01). Systemic and topical therapy of concomitant psoriasis in patients with arterial hypertension leads to a decrease in the frequency of recording late ventricular potentials, and in patients who had severe psoriasis before the start of treatment, late potentials were recorded significantly more often after 6 months of therapy (χ2 = 3.88; p = 0.049) than in patients with initially moderate-severe psoriasis.

The paper considers the actual problem of improving neural network models for the classification of cardiovascular pathologies by compressing the information contained in electrocardiographic (ECG) signals. Due to the active implementation of artificial intelligence in medical diagnostics, the study focuses on creating a reduced ECG feature vector that allows for a significant reduction in training data volume without losing important diagnostic information. The research is dedicated to the development of an autoencoder model with a specialized architecture that combines convolutional and fully connected layers, attention layers, residual connections, and a symmetric structure with shared weights. This approach enables not only to compress the input multichannel signal but also to form a latent space from which the signal can be restored or used as a feature vector for classification. In the proposed autoencoder architecture, the latent representation is combined with the layer weight vector into a single reduced vector that contains information about both the shape and the structural features of the ECG signal. The model was trained using a composite loss function, which allows for balancing between signal reconstruction quality and classification accuracy. To evaluate the model, several alternative dimensionality reduction methods were used, including downsampling, transformation to Frank's orthogonal leads, calculation of a resultant vector, and principal component analysis (PCA). A number of alternative dimensionality reduction methods were used to test the model: reduction of the sampling frequency; transformation to Frank orthogonal derivations; calculation of the resulting vector; principal component analysis (PCA). All methods were tested on the PTB-XL dataset, which contains 12-lead ECG recordings with a wide range of cardiovascular pathologies. The effectiveness of the reduced feature vector was assessed using two models—a convolutional neural network (EcgNet) and a fully connected network with two hidden layers. The analysis of the results showed that, on average, classification accuracy using the reduced vector decreased by only 2% for EcgNet and increased by 3–6% for the fully connected network, indicating preservation of diagnostic information even with a high compression ratio of 25. In contrast, traditional dimensionality reduction methods such as PCA and orthogonal transformation showed a significant deterioration in classification quality (up to –16%). While downsampling to 75 Hz significantly reduces data volume, it also leads to the loss of high-frequency information critical for detecting ischemia and arrhythmias. Particular attention is given to ventricular and atrial late potentials, which are low-amplitude and high-frequency in nature. The constructed reduced feature vector preserved the informative characteristics of these classes, resulting in improved classification accuracy compared to traditional dimensionality reduction methods. Thus, the developed reduced feature vector demonstrates the ability to retain diagnostic information under significant ECG data compression, achieving a balance between computational efficiency, classification accuracy, and application versatility. The obtained results suggest that the use of the proposed reduced feature vector may serve as a promising solution for compact and efficient systems for automated ECG analysis, particularly in mobile or computing-limited systems, while also enabling faster development and testing of new neural network models for diagnostics.

Aim. To investigate clinical manifestations, phenotypic variants, genetic features, and outcomes in children with arrhythmogenic cardiomyopathy (ACM).Methods. The study group consisted of 24 patients (< 18 years of age) with ACM, who were under observation from 2011 to 2024. The median age at ACM diagnosis was 13 years [12-15]. The following data were analyzed: complaints and medical history, laboratory parameters (biochemical markers of inflammation and serum myocardial damage mar­ kers, NT-proBNP levels), electrocardiogram, Holter monitoring, echocardiography results, cardiac magnetic resonance imaging, selective coronary angiography, histological and molecular genetic studies. The median follow-up duration for ACM patients was 27 months [16.5-38].Results. All patients were unrelated probands. All children presented with asymptomatic ventricular arrhythmias (VA) as the initial manifestation of the disease, 23 (95.8%) patients had complaints: palpitations in 21 (87.5%) children, syncope in 14 (58.3%) children, heart failure symptoms in 12 (50.0%), and isolated chest pain in 4 (16.7%) patients. 5 (20.8%) children had a “hot” phase. Analysis of arrhythmic data revealed several features of ACM in childhood: VAs were polymorphic, daily VA density was less than 20% at the time of diagnosis, presence of late ventricular potentials in most patients, and several criteria from the «repolarization abnormalities» group had low informativeness. During follow-up, 9 (37.5%) children had the right-dominant ACM, 7 (29.9%) had ACM with left ventricle involvement, and 8 (33.3%) had biventricular form. Desmosomal mutations were found in 16 children (66.7%), non-desmosomal gene variants in 8 patients (33.3%).Conclusion. It has been shown that ACM can manifest at an early age and is associated with the development of arrhythmic events and/or severe heart failure. Increasing awareness among physicians about the early onset of ACM is crucial for timely treatment of heart failure, prevention of sudden cardiac death, and family screening.

Arrhythmogenic cardiomyopathy/right ventricular dysplasia is a rarely diagnosed hereditary cardiomyopathy that seldom debuts in the prepubertal period. Therefore, its diagnosis at this ages certain difficulties. We present a clinical case of this disease, which we have been observing for 6 years. The first symptoms of the disease in a thirteen years old teenager were ventricular premature beats that detected during a routine electrocardiographic examination. The presence of deep negative T waves in leads V1–V3 on the ECG, the presence of stress induced of polymorphic ventricular tachycardia, the appearance of additional markers of electrical instability of the myocardium during Holter monitoring (heart rate turbulence, microvolt alternans) and ventricular late potentials made it possible to suspect and then confirm a rare cardiomyopathy – arrhythmogenic cardiomyopathy during an MRI examination of the heart. The antiarrhythmic therapy allowed stabilizing the patient’s condition. However, at the age of 18, the disease progressed with inadequate intake of drugs, episodes of loss of consciousness appeared, and a cardioverter defibrillator was implanted in the patient. The presented case of observation of a patient with cardiomyopathy, rare for the pediatric population, with a progressive unfavorable course of the disease, the use of modern diagnostic methods made it possible to identify the unfavorable nature of arrhythmia, quickly make a diagnosis and prescribe therapy that prevented the development of syncopal episodes in childhood.

BackgroundThe diagnostic role of signal‐averaged ECG (SAECG) in arrhythmogenic right ventricular cardiomyopathy (ARVC) has lately been questioned. We assessed the value of SAECG‐derived late ventricular potentials (LP) in ARVC diagnosis and its association with disease manifestations.Methods and ResultsPatients with definite ARVC diagnosis or genotype‐positive family members who underwent SAECG were included in register‐based observational study (n=357, mean age 41 years, 47% female, 43% probands). LP and terminal activation duration (TAD) were defined by Task Force Criteria 2010. We assessed the association of TAD and LP with structural RV abnormalities and ventricular tachycardia (VT), defined as sustained VT, appropriate implantable cardioverter‐defibrillator shock, aborted cardiac arrest, or sudden cardiac death, at diagnosis. LP were documented in 210 patients (59%) and abnormal TAD in 66 patients (18%). Each of the SAECG parameters was significantly associated with definite ARVC diagnosis in receiver‐operator characteristics curve analysis with area under the curve between 0.67 and 0.74. Exclusion of SAECG from diagnostic workup led to reclassification of 37 patients (16%) from definite to borderline ARVC (13 probands, 9 of whom had prevalent VT). Ninety patients (25%) had history of VT. LP, but not TAD, were associated with VT (adjusted odds ratio [ORadj], 2.42 [95%CI, 1.07–5.48]). LP had lower specificity (72% versus 97%) but higher sensitivity (71% versus 25%) for association with RV structural abnormalities than TAD.ConclusionsIn the Nordic ARVC cohort SAECG‐derived LP are associated with VT and structural RV abnormalities and were critical for ascertainment of ARVC diagnosis in 16% of patients with narrow QRS complexes, including 8% of all probands.

Разработка устройств, которые могут эффективно анализировать электрокардиосигналы (ЭКС), является актуальной задачей. Особенно это касается задачи расширения функционала. Например, в настоящий момент отсутствуют одноканальные устройства, направленные на оценку поздних потенциалов желудочков (ППЖ) сердца – низкоамплитудных составляющих с прогностической ценностью. Цель данной работы – проанализировать возможность регистрации ППЖ в ЭКС по одному отведению. ЭКС по отведению Z выбраны для данной работы. Для более точного анализа применена процедура сглаживания сигналов, а также разработан вспомогательный алгоритм корреляционной обработки на основе коэффициента корреляции 0,97÷0,99. Стандартным методом обнаружено 46 случаев ППЖ, предлагаемым алгоритмом – 80 случаев. Вероятность правильного принятия решения при тестировании алгоритма превысила 73 %. Предложенный алгоритм может обнаруживать ППЖ в ЭКС по отведению Z. Результаты могут быть полезны для разработки одноканального анализатора ЭКС. Introduction. The development of devices capable of effectively analyzing electrocardiosignals (ECS) is a relevant and significant task, particularly in enhancing their functionality. Currently, there are no single-channel devices that can evaluate ventricular late potentials (VLPs)—low-amplitude components with predictive value. The aim of this study is to assess the feasibility of detecting VLPs in ECS recorded using a single lead. Materials and methods. For this study, Z-lead ECS signals were selected. A total of 271 signals were analyzed using two approaches: the standard method for detecting VLPs (Simson’s method) and a modified version of this method adapted for Z-lead ECS (the proposed algorithm). To improve analysis accuracy, smoothing techniques and an additional correlation-based processing algorithm were applied. Results. The standard approach detected VLPs in 46 cases, whereas the proposed algorithm identified 80 cases. This may indicate a potential advantage of the proposed algorithm, particularly since the analyzed signals exhibited characteristics associated with myocardial infarction. The probability of a correct decision when testing the algorithm exceeded 73%. Conclusion.The proposed algorithm effectively detects VLPs in Z-lead ECS. These findings may contribute to the development of single-channel ECS analyzers.

Sudden cardiac death (SCD) represents a critical acute cardiovascular event characterized by rapid onset of cardiac and respiratory arrest, posing a significant threat to patients due to its high fatality rate. Monitoring indices related to SCD using wearable devices holds profound implications for preemptive measures aimed at reducing the incidence of such life-threatening events. Hence, this study proposed a predictive algorithm for SCD leveraging single-lead electrocardiogram (ECG) signals featuring low signal-to-noise ratios. Initially, simulated electrode motion artifact noise was introduced to ideal ECG signals to emulate the signal conditions with low signal-to-noise ratios encountered in everyday scenarios. To meet the criteria of simplicity and cost-effectiveness required for wearable devices, the analysis focused exclusively on single-lead signals. The proposed algorithm in this study employed a lightweight machine learning approach to extract 12-dimensional features encompassing ventricular late potentials, T-wave electrical alternation, and corrected QT intervals from the signal. The algorithm achieved an average prediction accuracy of 93.22% within 30 min prior to SCD onset, and 95.43% when utilizing a normal sinus rhythm database as a control, demonstrating robust performance. Additionally, a comprehensive Sudden Cardiac Death Index (SCDI) was devised to quantify the risk of SCD, formulated by integrating pivotal two-dimensional features contributing significantly to the algorithm. This index effectively distinguishes high-risk signals indicative of SCD from normal signals, thereby offering valuable supplementary insights in clinical settings.

Psoriasis and arterial hypertension are often observed in men of working age. Biologically active molecules such as insulin-like growth factor, vascular endothelial growth factor (VEGF), etc. play a significant role in the pathogenesis of these diseases. These factors contribute to cardiac remodeling, which is one of the arrhythmogenic substrates. The aim of the study was a comprehensive assessment of electrical cardiac parameters in male patients suffering from arterial hypertension affected by psoriasis vulgaris. Materials and Methods. The study was conducted in 2021–2023. It involved 110 male patients undergoing outpatient treatment for stage 2 arterial hypertension. Their average age was 52.4±6.9 years. The patients were divided into 2 groups: Group 1 (comparison) – 50 patients with arterial hypertension; Group 2 (control) – 60 patients with hypertension and psoriasis vulgaris in the progressive moderate severity stage (PASI index between 10 and 20). Results. In males with arterial hypertension affected by psoriasis vulgaris, late ventricular potentials were statistically significantly more common (33 %) compared to those with arterial hypertension without psoriasis (16 %) (χ²=4.32; p=0.048). In patients with both arterial hypertension and psoriasis, a greater number of local peaks in the ventricular complex along all Frank orthogonal leads were registered in spectral-temporal mapping of the QRS complex. Conclusion. The concomitant psoriasis vulgaris in males with arterial hypertension negatively effects the parameters of cardiac electrical remodeling.

Introduction: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder characterised by progressive fibrosis predominantly of the right ventricular (RV) myocardium, resulting in life-threatening arrhythmias and heart failure. The diagnosis is challenging due to a wide spectrum of clinical symptoms. The important role of ECG was covered in the current diagnostic criteria. The role of the epsilon wave (EW) is still under discussion. Aim: The aim of the study was to examine a potential association between the EW and late ventricular potentials (LPs) in ARVC patients (pts). The correlation between RV dilatation or dysfunction and LPs/EW was also analysed. Methods: The ARVC group consisted of 81 pts (53 men, aged 20-78 years) fulfilling 2010 International Task Force Criteria. 12-lead ECG, LPs, Holter, and ECHO were performed in all pts. The presence of EW was analysed in ECG by 3 investigators. LPs were detected by signal-averaged ECG (SAECG). SAECG was considered positive for LPs when at least two of the three following criteria were met: (1) the filtered QRS duration (fQRS) ≥ 114 msec; (2) the duration of the final QRS fragment in which low-amplitude signals lower than 40 μV are recorded (LAS-40 > 38 msec); and (3) the root mean square amplitude of the last 40 milliseconds of the fQRS complex (RMS-40 < 20 μV). The results were compared with a reference group consisting of 53 patients with RV damage in the course of atrial septum defect (ASD) or Ebstein's Anomaly (EA). Results: In the ARVC group, a significant relationship was observed between the occurrence of EW and the presence of LPs. EW was more common in the LP+ than in the LP- patients (48.1% vs. 6.9%, p < 0001; OR 12.5; 95% CI [2.691-58.063]). In ARVC pts, RVOT > 36 mm, RVIT > 41 mm, and RV S' < 9 cm/s were observed significantly more often in the LPs+ than in the LPs- group (OR [95% CI]: 8.3 [2.9-1.5], 6.4 [2.2-19.0] and 3.6 [1.1-12.2], respectively). In the ARVC group, any of fQRS > 114 ms, LAS > 38 ms, and RMS < 20 μV were significantly more frequent in EW+ pts. In multivariate analysis, the independent factors of the EW were LAS-40 and RV S'. In the LPs- subgroup, RVOT > 36 mm was more frequent in ASD/EA than in ARVC (70.4% vs. 25%, p = 0.002). Similarly, in the LPs- subgroup, RVIT > 41 mm was encountered more frequently in ASD/EA than in ARVC (85.2% vs. 48.3%, p = 0.004). Conclusions: In ARVC, there is an association between EW and LPs, with both probably resulting from the same process of fibrofatty substitution of the RV myocardium. Although RV dilatation is common in ASD and EA, it does not correlate with LPs.

Background and Objectives: Chronic heart failure (CHF) caused by ischemic heart disease (IHD) is the leading cause of death worldwide and presents significant health challenges. Effective management of IHD requires prevention, early detection, and treatment to improve patient outcomes. This study aims to expand the diagnostic utility of various 24 h Holter ECG parameters, such as T-wave alternans (TWA), late ventricular potentials (LVPs), and heart rate variability (HRV) in patients with CHF caused by IHD. Additionally, we seek to explore the association between these parameters and other comorbid conditions affecting the prognosis of CHF patients. Materials and Methods: We conducted a prospective case-control study with 150 patients divided into two subgroups: 100 patients with CHF caused by IHD, and 50 patients in the control group. Data included medical history, physical examination, laboratory tests, echocardiography, and 24 h Holter monitoring. Results: Our comparative analysis demonstrated that both TWA and LVPs were significantly higher in patients with CHF compared to the control group (p < 0.01), indicating increased myocardial electrical vulnerability in CHF patients. Both time and frequency-domain HRV parameters were significantly lower in the CHF group. However, the ratio of NN50 to the total count of NN intervals (PNN50) showed a borderline significance (p = 0.06). While the low-frequency (LF) domain was significantly lower in CHF patients, the high-frequency (HF) domain did not differ significantly between groups. Acceleration and deceleration capacities were also significantly altered in CHF patients. Categorizing CHF patients by left ventricular ejection fraction (LVEF) revealed that the mean of the 5-min normal-to-normal intervals over the complete recording (SDNN Index) was significantly higher in patients with LVEF ≥ 50% compared to those with CHF with reduced EF and CHF with mildly reduced EF (p < 0.001), whereas the other HRV parameters showed no significant differences among the groups. Conclusions: Holter ECG parameters can become a reliable tool in the assessment of patients with CHF. The integration of multiple Holter ECG parameters, such as TWA, LVPs, and HRV, can significantly enhance the diagnostic assessment of CHF caused by IHD. This comprehensive approach allows for a more nuanced understanding of the patient's condition and potential outcomes.

В работе представлен алгоритм регистрации информативных низкоамплитудных составляющих электрокардиосигналов для одноканального портативного анализатора. В качестве искомых составляющих рассмотрены поздние потенциалы желудочков сердца. Их наличие означает возникновение проблем с функционированием сердца в будущем с высокой вероятностью. В настоящий момент одноканальные устройства обнаружения потенциалов желудочков сердца отсутствуют, поэтому разработка таких устройств и программных алгоритмов, нацеленных на обнаружение потенциалов желудочков сердца, является актуальной задачей. Стандартный метод обнаружения потенциалов желудочков сердца – метод Симсона – основан на анализе сигналов по трём отведениям: X, Y, Z и в данной работе метод Симсона применён к сигналам, зарегистрированным только по отведению X. Научной новизной данной работы является разработка алгоритма обнаружения потенциалов желудочков сердца и оценкой всех их параметров в сигналах по отведению X. Тестирование алгоритма показало, что вероятность правильного принятия решения оценки потенциалов желудочков сердца превышает 80 %, что подчёркивает возможность эффективного решения поставленной задачи. Результаты работы могут быть использованы для разработки одноканальных анализаторов электрокардиосигналов в сферах телемедицины и безопасности водителей транспортных средств. Introduction. Ventricular late potentials (VLPs) are low-amplitude potentials located at the terminal part of the QRS complex in electrocardiogram (ECG) signals. The presence of VLPs indicates a high probability of heart function deviations. Currently, no single-channel devices are available to detect VLPs. Therefore, designing devices and developing algorithms to detect VLPs is a topical task. The aim of this research is to analyze the feasibility of registering VLPs using single-lead ECG signals. Materials and methods. X-lead signals were selected for this study. A total of 271 signals were analyzed using MATLAB. Preliminary estimates to detect VLPs were performed using the standard Simson method, which analyzes X-, Y-, and Z-lead signals through coherent accumulation and averaging of heartbeat signals to increase the signal-to-noise ratio. This study proposes analyzing only X-lead signals using the same method. Results. According to the standard method, 46 signals had VLPs. Using the proposed algorithm, 61 signals were detected to have VLPs. The probability of a correct decision when testing the algorithm exceeded 80%. Conclusion. The proposed algorithm can detect VLPs in X-lead signals. The results of this study will be useful in designing single-channel ECG analyzers with enhanced functionality.

The latest technologies of long-term ECG registration improve detection of rhythm and conduction disturbances, as well as comprehensively assess autonomic regulation of heart rhythm. Objective. To identify the advantages of long-term telemetric ECG monitoring for 72 hours (TMM72 ECG) for recording arrhythmic events, episodes of conduction disturbances, as well as for evaluating the parameters of electrical instability in patients with myocardial infarction (MI). Material and methods. The study included 114 ICU patients aged 58 (52; 62) years with MI. TMM72 Nehb 3-lead (A, D, I) ECG was performed using the ASTROCARD®-TELEMETRY telemetry complex for 72 hours from the 4th day after MI. We assessed frequent and paired supraventricular premature contractions, supraventricular tachycardia (SVT), ventricular arrhythmias Lown—Wolf grade ≥3, sinoatrial and atrioventricular (SA- and AV-) blockages, paroxysms of atrial fibrillation. Chronotropic load (CL), heart rate variability (HRV), heart rate turbulence (HRT), microvolt alternation of T wave (MAT), late ventricular potentials (LVPs), and QT interval variance were evaluated. The transmitted data were analyzed at the end of each day of monitoring, and then we estimated certain time intervals (24, 48 and 72 hours). Results. The number of patients with frequent supraventricular premature contractions increased by 13.1% (p=0.04), paired supraventricular premature contractions by 22.7% (p=0.001) and SVT by 21% (p=0.003) compared to standard 24-hour ECG monitoring. Ventricular premature contractions Lown—Wolf grade ≥3 were registered in 65 patients (57%) that is 1.6 times higher compared to standard 24-hour ECG monitoring (p=0.031). SA- and AV- blockages grade 2 were 2 times more common (p=0.044). Impaired HRT was detected in 32.5% and 15.8% of cases, respectively (p=0.06). The number of patients with MAT increased by 14.9% (p=0.021) after 72 hours of continuous monitoring. CL Sa demonstrated total decrease from 1.07 (0.26; 3.8) on the first day to 0.94 (0.26;4.2) (p=0.022) by the end of TMM72 ECG. HRV parameters positively changed by the end of monitoring: TotP — by 46% (p=0.001), ULfP — by 47% (p=0.001), LfP — by 43% (p=0.001), HfP — by 37% (p=0.001), L/H increased by 49% (p=0.001). Conclusion. TMM72 ECG significantly improves detection of clinically significant rhythm and conduction disorders. This method is valuable for comprehensive assessment of autonomic regulation of heart rhythm and markers of myocardial electrical instability in early period after MI.

Abstract Introduction Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder characterised by progressive fibrosis predominantly of the right ventricular (RV) myocardium resulting in life-threatening arrhythmias and heart failure. The diagnosis is challenging due to a wide spectrum of clinical symptoms. The important role of ECG was covered in the current diagnostic criteria. The role of epsilon wave (EW) is still under discussion. Aim The aim of the study was to correlate the presence of EW with late ventricular potentials (LPs) in ARVC patients (pts). The correlation between RV dilatation /dysfunction and LPs/EW was also analysed. Methods The ARVC group consisted of 81 pts (53 men, aged 20-78 years) fulfilling 2010 International Task Force Criteria. 12-lead ECG, LPs, Holter, ECHO were performed in all pts. The presence of EW, defined as low-amplitude deflection observed between the end of the QRS complex and the onset of the T wave was analysed in ECG by 3 investigators. LPs were defined as low-amplitude, high-frequency waveforms at the end of the QRS complex on signal-averaged ECG (SAECG). SAECG was considered positive for LPs when at least two of the three following criteria were met: filtered QRS duration (fQRS) &amp;gt;114 ms, root-mean-square voltage in the terminal 40 ms (RMS 40) &amp;lt;20 uV, or low amplitude (&amp;lt;40 µV) signal (LAS 40) duration &amp;gt;38 ms. The results were compared with a reference group consisting of 53 pts with RV damage in the course of atrial septum defect (ASD) (29 pts, 8 men, aged 22-80 years) or Ebstein Anomaly (EA) (24 pts, 11 men, aged 23-55 years). Results In the ARVC group, a significant relationship was observed between the occurrence of EW and the presence of LPs. EW was more common in LP+ than in LP- patients (48.1% vs 6.9%, p&amp;lt;0001; OR 12.5). In ARVC a relationship was also found between the presence of LPs and increased RV inflow tract (RVIT) and RV outflow tract (RVOT) dimensions, as well as a reduced RV S' wave value. RVOT &amp;gt;36 mm, RVIT &amp;gt;41 mm and RV S’ &amp;lt;9 cm/s were observed significantly more often in the LPs+ than in LPs- group (OR: 8.3, 6.4 and 3.6, respectively). In the ARVC group, any of fQRS &amp;gt;114 ms, LAS &amp;gt;38 ms, and RMS &amp;lt;20 uV were significantly more frequent in EW+ pts. In multivariate analysis, the only independent factor of the EW was fQRS (OR: 1.043 [1.020-1.067], p&amp;lt;0.001; AUC: 0.852). In the LPs- subgroup, RVOT &amp;gt;36 mm was more frequent in ASD/EA than in ARVC (70.4% vs 25%, p=0.002). Similarly, in the LPs- subgroup, RVIT &amp;gt;41 mm was encountered more frequently in ASD/EA than in ARVC (85.2% vs 48.3%, p=0.004). Conclusions In ARVC, there is an association between EW and LPs, with both probably resulting from the same process of fibrofatty substitution of the RV myocardium. Although RV dilatation is common in ASD and EA, it does not correlate with LPs, possibly due to a lower degree of fibrosis in ASD/EA compared to ARVC.

Abstract. Introduction. Current technological progress and advances in electronics and medical equipment allow reaching unprecedented heights in the detection of various arrhythmic conditions, while such conditions can be observed directly at the time of their occurrence. Nevertheless, there is an issue related to predicting life-threatening conditions that may lead to cardiac arrest causing sudden cardiac death. We should also note some difficulties in timely predicting myocardial infarction. Therefore, it is necessary to develop new or implement the existing technologies that allow ensuring high susceptibility and specificity toward these disorders. Aim. To study the potential of high-frequency electrocardiography regarding identifying additional criteria for myocardial ischemia and informing about the possible development of cardiac arrhythmia. Materials and Methods. Methodological approaches: We searched for and analyzed sources in the NCBI and eLibrary databases and in Google Scholar using the following keywords: Advanced ECG, High Frequency ECG, and HF ECG ischaemia. The search was filtered for the years 1930-2022. Publications containing only summaries, abstracts, or duplicated information were excluded from the analysis. Thus, this present descriptive review includes generalized and systematized data from 50 sources, encompassing current clinical trials, reports, and systematic reviews. Results and Discussion. High-frequency electrocardiography is the most promising method in terms of the qualities required for a technique to register such disorders. When forming a cardiogram, the high-frequency electrocardiography method has three stages: 1) Registration of high-frequency electrical cardiac potentials; 2) signal amplification due to the computational performance to enhance the resolution; and 3) signal averaging through mathematical computations and further filtering the necessary sectors of the electrocardiogram. Combining the stages presented above allows registering low-amplitude signals, which would be impossible when using standard electrocardiography techniques. Low-amplitude signals provide important diagnostic information in risk stratification regarding life-threatening cardiovascular diseases. Detecting delayed myocardium depolarization potentials, ventricular late potentials, and atrial late potentials is an important task in identifying these pathologic conditions. Conclusions. Over thirty years, the high-frequency electrocardiography technique has been frequently studied and tested in various countries, such as the USA, Israel, Spain, Italy, South Korea, Japan, Russia, Austria, and Great Britain. These studies have proven the advantage of this method over the standard method of recording the electrical potentials of heart. This paper presents information on the studies and the facts proving the efficacy of the high-resolution electrocardiography technique.

This article is aimed at analyzing and improving the methods of preprocessing ECG signals for the task of detecting low-amplitude regular components. This study analyzed the main advantages and disadvantages of existing ECG signal preprocessing methods for the detection of late ventricular and atrial potentials. Based on this analysis, a cardiac cycle averaging method was proposed in order to increase the accuracy of detection of late potentials by various algorithms and improve the quality of preprocessing of the ECG signal aimed at detection of low-amplitude components. The main feature of the proposed method is the division of a large number of cardiocycles for averaging into smaller aggregates (epochs), and the subsequent application of linear matrix decomposition to suppress irregular inclusions. Also, when dividing into epochs, it can be used overlapping. It can reduce the difference between epochs, and increase the number of cardiocycles for averaging. The use of this approach allows to minimize irregular inclusions in the ECG signal and increase the accuracy of the selection of low-amplitude late potentials. In addition, the division into epochs and overlapping makes possible to avoid blurring of low-amplitude high-frequency components during averaging as a result of heart rate variability, as well as to improve the quality of averaging with a reduced number of cardiocycles. To test the proposed method, various approaches were used to assess the ECG signal preprocessing. Mostly, we compared the cardiac cycles obtained as a result of different averaging algorithms and the proposed method with the template. To test the averaging method, an artificial ECG signal was developed with existing noise, late ventricular and atrial potentials, heart rate variability, and a high-amplitude component that occurs at a random location every two heartbeats. The template cardiac cycle was obtained from the original artificial signal without any distortion or noise. Firstly, we visually compared and evaluated different averaging methods with the template. Secondly, we calculated the similarity metrics of the late potentials on the averaged cardiac cycle with the late potentials on the template signal. Based on these metrics, the curves of dependence of the similarity values on the amplitude of late potentials on the ECG signal were calculated. Thirdly, we evaluated the impact of the proposed averaging method on the classification results of various machine learning algorithms on real ECG signals with available late potentials. The overall testing result showed that the proposed averaging method is able to reproduce the morphology of low-amplitude regular components by 10-30% more accurately and improve the classification accuracy by 5-12%.

PO-02-228 ASSOCIATION BETWEEN SIGNAL-AVERAGED ECG INDICES AND RV STRUCTURAL ABNORMALITIES IN PATIENTS WITH ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY: INSIGHTS FROM NORDIC ARVC REGISTER

PO-05-135 SIGNAL-AVERAGED ECG IN THE NORDIC ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY REGISTRY: ASSOCIATION WITH PREVALENT LIFE-THREATENING ARRHYTHMIAS AND ASCERTAINMENT OF CLINICAL DIAGNOSIS.

Background: Ventricular late potentials (VLPs) are low amplitude, high frequency signals which are remarkable non-invasive electrocardiographic markers of myocardial tissue damage which can be used to identify ventricular arrhythmias in hypertensive patients with left ventricular hypertrophy (LVH). There are significant confounding factors which affect the association of LVH with VLPs in hypertensive patients. Noteworthy among these are gender, age, body surface area (BSA) and smoking. This study was planned to observe the effect of these confounders on VLPs in hypertensive patients with LVH. Methods: The study was conducted in Department of Cardiac Electrophysiology, Armed Forces Institute of Cardiology, Rawalpindi from Nov 2019 to Nov 2020. This was a cohort retrospective study in which 64 patients with systemic arterial hypertension on the basis of LVH were divided into two equal groups. Patients meeting inclusion criteria were selected for Signal-Averaged ECG (SAECG). Results: Out of 64 patients, 49 (76.6%) were males and 15 (23.4%) were females. The overall mean age was 60±11.80 years. To rule out the effect of probable confounders (gender, age, BSA, and smoking) which predominantly affects VLPs in hypertensive patients with LVH, logistic regression was applied. Significance of association of LVH with VLPs increased from 0.01 to 0.03 reflecting that confounder, i.e., age, gender, BSA, and smoking were actually having a negative effect on association of VLPs with LVH. Conclusion: None of the confounders were associated with VLPs reflecting negative effect on association for the two variables of interest. Pak J Physiol 2023;19(1):3-4

В статье предложена теоретическая методика оценки вектора ЭДС сердца, на основе которой разработана скорректированная система отведения для задач анализа низкоамплитудных сигналов сердца. С использованием математического моделирования подтверждена корректность предложенной методики и показано, что скорректированная система отведения позволяет повысить отношение сигнал/шум за счёт уменьшения влияния электрических сигналов других органов на электрокардиосигнал, а следовательно, повысить достоверность выявления поздних потенциалов желудочков сердца в автоматических анализаторах аритмий. Introduction. The identification and analysis of low amplitude potentials (LAPs) of the heart on the electrocardiosignal (ECG) is essential for the development of heart monitors. One of the LAPs types are ventricular late potentials (VLPs). The Simson’s method has been most widely used for the detection of VLPs in heart monitors. This method relies significantly on the signal to noise ratio. In the ECG, processing noise, in addition to noise from devices, includes noise produced by other organs and tissues. One of the directions in solving this challenge is improving the signal-to-noise ratio taking into account the impact of other organs and tissues on the signal. The goal of the work. Improving ECG signal-to-noise ratio taking into account the impact of other organs and tissues to enhance the accuracy of detection of VLPs. Fundamentals of Surface Electric Potentials on the Human Body. The baseline for analyzing LAPs is the amplitude of the EMF vector. However, measuring this in a non-invasive manner is not possible, so it is determined through potentials taken from the surface of the human body. The amplitude of these potentials is greatly influenced by the distance between the lead point and the EMF source, and in the human body, there are numerous organs with their own electrical activity. As a result, selecting an appropriate lead system is crucial in reducing noise levels. Selection and Modification of the Lead System. In diagnosing VLPs, the Frank lead system and the orthogonal lead system proposed by Dekhtyar, G.Ya. are the most commonly used methods. After conducting a comprehensive analysis of lead systems, this research proposes a modified orthogonal lead system in which all pairs of electrode application points are equidistant from the heart. Evaluation of the Proposed Lead System. The proposed modified lead system was evaluated for its efficiency in comparison to the Frank system. Through theoretical analysis, it was found that the components of the EMF vector in the proposed lead system are one and a half times larger than in the Frank system. To validate this result, mathematical modeling was conducted using the Altair Feko software to simulate heart signal propagation within the human body. The results of the simulation showed that the components of the EMF vector in the proposed bipolar lead system are indeed one and a half times larger than in the Frank system. Conclusion. The proposed theoretical method enables an accurate description of the EMF vector. Additionally, the proposed modified lead system enhances the signal-to-noise ratio for detecting VLPs in heart monitors by minimizing the effect of electrical signals from other organs. This leads to a more accurate detection of VLPs in automatic arrhythmia analyzers.

Beta thalassemia major (TM) is a common hereditary disease in Indonesia. Iron overload due to regular transfusion may induce myocardial iron deposition leading to electrophysiological dysfunction and functional disorders of the heart. Ventricular arrhythmia is one of the most common causes of sudden cardiac death in thalassemia patients. This cross-sectional study of 62 TM patients aged 10-32 years in Cipto Mangunkusumo General Hospital was done to assess their electrophysiological properties and heart rate variability, including 24- hour Holter monitoring, signal averaged electrocardiogram (SAECG) for detection of ventricular late potential (VLP), and determination of heart rate variability (HRV). We also assessed their 12-lead ECG parameters, such as P wave, QRS complex, QT/ QTc interval, QRS dispersion, and QT/ QTc dispersion. Iron overload was defined by T2-star magnetic resonance (MR-T2*) values of less than 20 ms or ferritin level greater than 2500 ng/mL. Subjects were grouped accordingly. There were significant differences of QTc dispersion (p = 0.026) and deceleration capacity (p = 0.007) between MR-T2* groups. Multivariate analysis showed an inverse correlation between QTc dispersion and MR-T2* values. There was a proportional correlation between heart rate deceleration capacity in the low MR-T2* group (p = 0.058) and the high ferritin group (p = 0.007). No VLPs were detectable in any patients. In conclusion, prolonged QTc dispersion and decreased heart rate deceleration capacity were significantly correlated with greater odds of iron overload among patients with Thalassemia major.