Ventricular Late Potentials Research Articles

Sudden Cardiac Death Risk Prediction Based on Noise Interfered Single-Lead ECG Signals

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.

ELECTRICAL CARDIAC REMODELING IN MEN WITH ARTERIAL HYPERTENSION AFFECTED BY PSORIASIS VULGARIS

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.

Correlation between Epsilon Wave and Late Potentials in Arrhythmogenic Right Ventricular Cardiomyopathy-Do Late Potentials Define the Epsilon Wave?

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.

Enhancing Comprehensive Assessments in Chronic Heart Failure Caused by Ischemic Heart Disease: The Diagnostic Utility of Holter ECG Parameters.

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.

Correlation between epsilon wave and late potentials in arrythmogenic right ventricular cardiomyopathy. Do late potentials define the epsilon wave?

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.

ЭЛЕКТРОКАРДИОГРАФИЯ ВЫСОКОГО РАЗРЕШЕНИЯ В КЛИНИЧЕСКОЙ ПРАКТИКЕ

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.

The Method of Preprocessing of ECG Signals for Detection of Atrial and Ventricular Late Potentials

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

The value of signal-averaged ECG (SAECG) derived ventricular late potentials (LP) as a minor depolarization criterion of arrhythmogenic right ventricular cardiomyopathy (ARVC) has been debated. Another criterion from the same category, terminal activation duration (TAD>55 ms), is obtained from standard V1 ECG lead, which makes it easier for use. However little data exist regarding the relationship between structural right ventricular (RV) ARVC substrate, LP and TAD. We aimed to explore the association between structural and functional RV abnormalities assessed using cardiac magnetic resonance (CMR), SAECG parameters, and abnormal TAD. Patients with definite ARVC diagnosis or genotype-positive family members who were recruited in the Nordic ARVC Registry with SAECG and CMR were included (n=268, mean age 42±16 years, female 46%, probands 49%). RV end-diastolic volume index (RVEDVI), RV ejection fraction (RVEF), and late gadolinium enhancement (LGE) presence were assessed. RV was defined as enlarged if RVEDVI > 100 ml/m2 for men and 90 ml/m2 for women. RVEF was considered reduced if lower than 45%. SAECG components were assessed using TFC2010 definitions: filtered QRS duration (fQRSd)>114 ms, duration of terminal low-amplitude QRS signal below 40 μV (LAS40)> 38 ms and root-mean-square voltage of the terminal 40 ms (RMS40)< 20 μV. An abnormal value of any one or more of these indexes was considered as the presence of LP. We assessed sensitivity and specificity of the SAECG indexes and TAD for association with abnormal RVEF, LGE and/or RVEDVI. C-statistics was used to assess the association between each of SAECG parameters as continuous variables and RV abnormalities. All 3 SAECG indexes were significantly associated with RV structural abnormalities using c-statistics (Table), each of them characterized by higher specificity and lower sensitivity than LP. TAD demonstrated high specificity but poor sensitivity in prediction of RV structural abnormalities. LP had lower specificity, but much higher sensitivity for association with RV structural and functional abnormalities than TAD. In a large cohort of patients with definite ARVC or genotype-positive family members SAECG indexes appear to have lower specificity for detection of structural and functional RV abnormalities compared to TAD, however its sensitivity far exceeds the one of the TAD and supports SAECG value as an ECG indicator of RV substrate.

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.

In arrhythmogenic right ventricular cardiomyopathy (ARVC), minor depolarization criteria by TFC2010 include ventricular late potentials (LP) assessed using signal-averaged ECG (SAECG) and terminal activation duration (TAD). TAD is measured from a standard V1 lead, which favors its use in clinical practice, however its ability to fully replace LP in ARVC workup is not clear. 1. To assess the association between TAD and LP and the prevalence of life-threatening ventricular arrhythmias in patients with ARVC. 2. To assess diagnostic impact of SAECG by characterizing the subgroup of patients, who would not have received definite ARVC diagnosis if LP were not considered. Patients with definite ARVC or genotype-positive family members who underwent SAECG were included (n=358, 47% women, age 41±16 years, 43% probands, 67% definite ARVC). LP and TAD were defined according to TFC2010 criteria. TFC score was calculated by assigning 2 points for major and 1 for minor criterium. Ventricular tachycardia (VT) was defined as sustained VT, aborted cardiac arrest or appropriate ICD shock. Logistic regression adjusted for clinical covariates was used to test association of TAD and LP with prevalent VT. In a subgroup of patients with TFC score 4, i.e. minimally required for diagnosis, patients who would be reclassified into borderline category if LP not considered (LP-dependent, n=38) were compared with those who had TFC score 4 regardless of LP (LP-independent, n=30) in terms of proband status, prevalence of imaging criteria and VT. LP were found in 209 patients (58%); TAD in 65 (18%); 90 patients had prevalent VT (25%). LP was associated with prevalent VT (OR=2.5 95%CI 1.2-5.3; Sensitivity 84%, Specificity 50%) while TAD was not (OR=1.6 95%CI 0.7-3.6; Sensitivity 32%, Specificity 87%). In the LP-dependent group, 9 of 14 (64 %) probands had prevalent VT, 7 (50%) survived cardiac arrest and 4 (29%) were genotype-positive. Clinical characteristics did not demonstrate significant differences between LP-dependent and LP-independent subgroups. LP is independently associated with VT and is more sensitive than TAD in identification of patients with prevalent VT. LP were critical for ascertainment of ARVC diagnosis required for initiation of family screening in 9% probands. Although the diagnostic impact of LP varies depending on SAECG availability, our data support its use as a sensitive non-invasive diagnostic tool.

PLAUSIBLE CONFOUNDING FACTORS INFLUENCING ASSOCIATION OF LEFT VENTRICULAR HYPERTROPHY WITH VENTRICULAR LATE POTENTIALS IN HYPERTENSIVE PATIENTS

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

Electrophysiological properties and heart rate variability of patients with thalassemia major in Jakarta, Indonesia.

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.

ЭМПАГЛИФЛОЗИН В ЛЕЧЕНИИ ПАЦИЕНТОВ С ХРОНИЧЕСКОЙ СЕРДЕЧНОЙ НЕДОСТАТОЧНОСТЬЮ, ЕГО ВЛИЯНИЕ НА ЖЕЛУДОЧКОВЫЕ НАРУШЕНИЯ РИТМА

The study aims to assess empagliflozin affecting ventricular dysrhythmia and late potential of ventricles in patients with chronic heart failure with low etiology ejection fraction. The study included 35 male patients (61.7 ± 11.2 years old) who received standard therapy, followed by 10 mg empagliflozin in 6 months. The examination included echocardioscopy, 12-leads electrocardiography, signal-averaged electrocardiography, and daily electrocardiography monitoring. 10 mg empagliflozin added to the standard therapy provided for a statistically significant decrease in the number of single premature heart beats by 67.7 % (p = 0.001), in the episodes of unstable ventricular tachycardia by 74.5 % (p = 0.001), in the frequency of late ventricular potential by 31 % (Chisquare = 5.51; р = 0.019), and for a statistically insignificant trend to ejection fraction increase (p &gt; 0.05).

Parameters Of Myocardial Electrical Instability In Patients After Myocardial Infarction Comorbid With A Novel Coronavirus Infection (COVID-19)

Objective — This article aims to assess parameters of myocardial electrical instability and arrhythmic events in patients after myocardial infarction (MI), with and without ST-segment elevation, comorbid/noncomorbid with a novel coronavirus infection (COVID-19) using a long-term electrocardiographic (ECG) monitoring. Methods — The study included 64 subjects: 25 (39%) patients with MI comorbid with COVID-19 (MI+C group) and 39 (61%) patients with MI noncomorbid with a novel coronavirus infection (MI group). The mean age of patients was 54.3±6.8 years. A long-term ECG monitoring for 97.4 (95% CI 77.9-115.2) hours was performed with Astrocard®-Telemetry system (Meditek JSC, Russia), starting from the 4th day of MI. Rhythm and conduction disorders, along with ischemic episodes were recorded; an analysis of ventricular late potentials, heart rate turbulence, and QT dispersion was carried out. Results — There were no differences in the frequency of delayed afterdepolarizations in MI and MI+C groups: 15-28% and 18-33% of patients, respectively. An analysis of turbulence parameters did not reveal statistically significant differences between the groups. Such arrhythmic events as frequent supraventricular extrasystole and life-threatening arrhythmias (ventricular extrasystole of grade 4A and higher sensu B. Lown and M. Wolf) were recorded significantly more often in the MI+C group than in the MI group: 48% vs. 20.5% (p=0.021) and 24% vs. 5.1% (p=0.026), respectively. Conclusion — The novel coronavirus infection (COVID-19) exacerbates myocardial electrophysiological heterogeneity in the acute cardiovascular event and is associated with an increase in clinically significant arrhythmic events.

Evaluation of the efficacy of signal-averaged electrocardiogram testing in the cardiac assessment of beta-thalassemia major patients

BackgroundMore than 70% of thalassemia’s major mortality is due to the cardiac complications of this syndrome, mostly consequent to myocardial Iron overload; therefore, evaluation of such complications is of utmost importance. T2*MRI is used to assess hepatic and myocardial Iron load in thalassemia patients, which is not always available. Signal-Averaged Electrocardiography is a rather easy method of evaluating major thalassemia patients regarding their risk for sudden cardiac death.Methods and materialsIn this cross-sectional study, 48 patients with thalassemia major underwent evaluation with electrocardiography, signal-averaged electrocardiography, echocardiography, T2*MRI, and ferritin level. The association of the existence of ventricular late potentials in SAECG and other cardiac variables was evaluated. Moreover, the association between myocardial and hepatic Iron load and cardiac characteristics was assessed.Results48 patients with a mean age of 30.31 ± 7.22 years old entered the study. 27 (56.3%) of the patients had ventricular late potentials, which were associated with myocardial dry Iron weight (P = 0.011). Nonspecific ST-T changes and premature atrial and ventricular contractions were seen more frequently in patients with late potentials (P = 0.002, 0.031, and 0.031, respectively). Patients with higher myocardial and hepatic Iron loads had longer QTc in their 12-lead surface electrocardiograms.ConclusionPatients with ventricular late potentials assessed by SAECG had a higher myocardial Iron load. Higher myocardial Iron load is associated with higher cardiac complications in patients with beta-thalassemia major; therefore, SAECG can be used as a screening test for cardiac complications in beta-thalassemia major patients.

An efficient machine learning based ventricular late potential detection and classification technique for cardiac healthcare

SUMMARYCardiovascular diseases (CVD) are a major cause of death worldwide each year, with myocardial infarction (MI) accounting for the highest percentage of deaths. The rate of mortality can be reduced if electrical homogeneity of the cardiac tissue is detected early. The presence of the ventricular late potential (VLP) at the conclusion of the QRS complex and the start of the ST segment of the electrocardiogram (ECG) signal indicates a violation. Existing research use a wavelet‐based decomposition of the ECG signal for VLP detection, which is a multistage process. The use of empirical mode decomposition (EMD) to automatically distinguish normal ECG signal and signal with the presence of VLP is proposed in this work. Furthermore, utilizing machine learning classifiers, this research aims to enable automated diagnosis of cardiac arrhythmia. Intrinsic mode functions (IMF) are amplitude and frequency modulated waves that result from the decomposition of ECG using the EMD. Each IMF's peak amplitudes, spectral entropy, and mean of the ECG in the EMD are retrieved and used as input features for various machine learning techniques (ML). According to simulation findings, the bagging classifier achieves accuracy and specificity of 98.93% and 98.62%, respectively, while the AdaBoost classifier based on machine learning technique achieves sensitivity of 99.84%. The observed performance is considered to be the best when compared to existing approaches.

Research progress on the predictive value of electrocardiographic indicators in the diagnosis and prognosis of children with vasovagal syncope.

Neurally mediated syncope (NMS) is a common type of syncope in children in clinical practice, among which vasovagal syncope (VVS) is the most frequent. In recent years, more and more studies have been carried out to assess the diagnosis and prognosis of VVS. The electrocardiographic indicators such as heart rate variability (HRV), QT dispersion (QTd), P-wave dispersion (Pd), ventricular late potentials (VLP), deceleration ability of heart rate (DC), etc., are easy to obtain and inexpensive. With the help of electrocardiographic indicators, the diagnostic procedure and individualized treatment strategies of pediatric VVS can be optimized. This article reviews the value of electrocardiographic indicators in the diagnosis and prognosis of children with VVS.

Capabilities of long-term ECG monitoring in patients with myocardial infarction: the longer, the better?

Background. In modern cardiology, 24-hour electrocardiogram (ECG) monitoring has a high diagnostic value, but this method has a number of disadvantages in detecting episodes of unstable life-threatening arrhythmias. An increase in ECG monitoring duration allows expanding the possibilities of diagnosing life-threatening arrhythmias.Objective. To study the possibilities of long-term ECG monitoring (48–120 hours) in the detection of life-threatening arrhythmic events and parameters of myocardial electrical instability in patients with ST-segment elevation myocardial infarction (STEMI).Design and methods. The study included 71 STEMI patients. All patients from the 4th day of STEMI underwent multi-day ECG monitoring in 3 leads using a telemetric ECG recording complex with an average recording duration of 90.4 ± 30.2 hours. The analysis of episodes of myocardial ischemia, rhythm and conduction disturbances, turbulence and heart rate variability, late ventricular potentials and dispersion of the QT interval within 5 days was carried out.Results. Long-term monitoring allowed detecting high-grade ventricular extrasystoles. Analysis of episodes of myocardial ischemia in the postinfarction period revealed significant differences in the data of 120h-ECG monitoring in comparison with 24h-ECG. Multiday ECG monitoring made it possible to detect dysfunction of the autonomic regulation of cardiac activity in patients 2 times more often.Conclusion. A comprehensive assessment of the possibilities of multi-day ECG monitoring is a promising direction in predicting severe arrhythmias in patients in the postinfarction period.

Factors of Cardiovascular Risk in Drivers of Locomotive Crews of Railway Transport with Ventricular Arrhythmias

AIM: This study aimed to assess cardiovascular risk factors in drivers and assistant drivers of railway engine crews with ventricular rhythm disorders.&#x0D; MATERIALS AND METHODS: The study included 120 patients aged 39 to 61 years (mean age M SD: 50.4 4 years), who were distributed into two groups with and without ventricular rhythm disorders. All participants underwent 12-lead daily ECG monitoring with assessment of noninvasive markers of myocardial electrical instability (circadian profile, QT interval, late ventricular potentials, T-wave alternation, rhythm variability). Traditional factors of cardiovascular risk, the employment period in the profession, and the level of personal and situational anxiety on Spielbergers state-trait anxiety inventory (STAI) were evaluated.&#x0D; RESULTS: In Group 1, in comparison with Group 2, significant differences were revealed in the duration of the PQ interval (during the day and at night) and the indicators of late ventricular potentials (RMS 40 and TotQRSF). When analyzing risk factors, elevated indices of total blood cholesterol were registered in both groups, and the risk on the SCORE scale was at a moderate level. In the group of workers with ventricular rhythm disorders, higher indicators of total blood cholesterol and the frequency of smoking and alcohol consumption were established. In individuals with ventricular rhythm disorders, a significant relationship was detected between the number of registered single monomorphic ventricular extrasystoles and the age of the employee (r = 0.3, р 0.05), and blood pressure level (r = 0.3, р 0.05), and the relationship between the level of anxiety and the registration of single supraventricular extrasystoles was established (r = 0.3, р 0.05). In the Group 2, a significant correlation was revealed between the number of registered single supraventricular extrasystoles and age (r = 0.2, р 0.05), the employment period in the profession of a driver (r = 0.2, р 0.05), the blood pressure level (r = 0.2, р 0.05), and the level of anxiety on the STAI (r = 0.3, р 0.05).&#x0D; CONCLUSIONS: Drivers of railway engine crews with ventricular rhythm disorders are characterized by a higher level of total blood cholesterol and a higher frequency of smoking and alcohol consumption. They have significant changes in the duration of the PQ interval (during the day and at night) and indicators of late ventricular potentials (RMS 40 and TotQRSF) according to Holter monitoring. The relationship of the number of ventricular rhythm disorders with age and the office values of systolic and diastolic blood pressure is noted in drivers of engine crews of railway transport.

Survey results of the STOPSTORM consortium about stereotactic arrhythmia radioablation in Europe

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Horizon 2020 research and innovation programme Background/Introduction In patients with structural heart disease (SHD), ventricular tachycardia (VT) plays a decisive role in sudden cardiac death. VT patients are often treated with antiarrhythmic medication and catheter ablation. For refractory VTs, STereotactic Arrhythmia Radioablation (STAR) delivered to the underlying VT substrate has recently been introduced and showed promising results for otherwise untreatable patients. [1] Purpose The purpose of the STOPSTORM consortium is to harmonize and optimize STAR across Europe. It consists of 31 members including 24 electrophysiology and 22 radiation oncology departments performing or participating in STAR throughout eight European countries. To obtain initial overview of organization, equipment, procedures, experiences, and quality levels for STAR, a detailed survey was circulated among STOPSTORM members. Methods The survey included questions for electrophysiology (18 questions), radiation oncology (24 questions) and medical physics (23 questions). The survey was the first step for accreditation of the centres and therefore mandatory for all consortium members. Results All centres participating in STOPSTORM completed the survey. 16 centres performed a total of 84 STAR treatments until May 2021 and 11 centres already participate in clinical trials for STAR. Annual number of VT ablations in SHD: less than 20 (17%), 20-50 (50%), 50-100 (21%), more than 100 (12%) and epicardial: less than 20 (71%), 20-50 (17%), n/s (12%). An overview of the availability of a clinical program for catheter ablation of ventricular arrhythmia with certification of the respective national cardiology society and the practice of general quality audits for ablation is given in figure 1. Participation in multicentre clinical trials in cardiology/EP were indicated by 19 departments (79%). Target volume definition is based on invasive electroanatomical mapping during VT (96%), pace mapping (75%), reduced voltage areas (63%) and/or late ventricular potentials (75%). Half of the centres includes the clinical VT substrate, while the other half includes the whole arrhythmogenic substrate. Non-invasive surface ECG mapping has so far found little application: used clinically (13%), research purposes (8%) and evaluation (4%). Stereotactic Body Radiotherapy experience (&amp;gt; 10 years: 82%, &amp;gt; 200 p.a.: 59%) is high. In all but one clinic, a dose of 25 Gy in a single fraction is applied. The prescription method, planning technique and inhomogeneity in the target volume, however, varies greatly. All departments perform patient-specific plan verifications for STAR, but with various evaluation criteria. Conclusion Experience in STAR within the STOPSTORM consortium is adequate, while the survey shows areas of harmonization and optimization need for substrate mapping, target delineation, dosimetry and quality assurance which will be addressed in the STOPSTORM project work-packages.

Поздние потенциалы желудочков у детей школьного возраста с сахарным диабетом I типа

Purpose — to study the indicators characterizing the ventricular late potentials (VLP) in schoolchildren with type I diabetes mellitus (TIDM). Materials and methods. 120 children aged 6–17 years were examined (56 — primary school age (6–11 years old), 64 children — senior school age (12–17 years old)). Of which at the age of 6–11 years old: 36 — with TIDM main group I, 20 healthy children (control group I). Of children 12–17 years old, 44 children were with TIDM — main group II, 20 healthy children were included in the control group II. In each age main group рatients with TIDM were divided into 2 subgroups depending on the duration of the disease: subgroup A — 39 patients (22 — primary school age, 17 — senior school age) with diabetes duration 1–3 years and subgroup B — 41 patients (14 и 27 retrospectively) with diabetes duration 4 years or more. All children underwent registration of VLP by high$resolution ECG. The following parameters were calculated: duration of the filtered QRS complex (TotORS, ms), the duration of the low$amplitude (up to 40 μV) part of the signal at the end of the QRS complex (LAS40, ms), the rms amplitude of oscillations in the last 40 ms of the ORS complex (RMS40, μV), as well as the ratio TotQRS / RMS40. The obtained results were processed on the basis of Microsoft Office Excel 2007 spreadsheets using the Statistica 7.0 package for Windows. Results. When analyzing the indicators, it was found that children with diabetes in comparison with healthy children had differences that could be interpreted as signs of lifespan (increase in TotORS, LAS40 and TotQRS / RMS40 ratio, decrease in RMS40 values). Such changes with varying degrees of reliability were recorded in all age groups, and were more pronounced in subgroups B, both in children 6–11 years old, and in patients 12–17 years old. This speaks in favor of the aggravation of the disturbance in the electrical stability of the myocardium as the duration of the disease increases. Conclusions. Thus, the data obtained indicate that children with type I diabetes have foci of delayed fragmented activity due to the electrophysiological heterogeneity of the myocardium. The presence of such foci is recognized as an independent prognostic factor for the risk of fatal arrhythmias, which poses the task of the specialists involved in the management of these patients with the early detection of VLP in order to prevent life$threatening conditions. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local ethics committee of all participating institutions. The informed consent of the patient was obtained for conducting the studies. No conflict of interest was declared by the authors. Key words: type I diabetes mellitus, children, ventricular late potentials, cardiac autonomic neuropathy.