Conventional Electrocardiography Research Articles

EASI monitoring in ventricular tachycardia, an alternative to conventional electrocardiography?

Abstract Background 12-lead electrocardiogram (ECG) is the gold standard for detecting ventricular arrhythmias. In cardiac critical care units (UCC), monitoring systems are used to detect transient events such as arrhythmias or ST-segment acute changes. The discomfort caused in the patient by the need for 10 electrodes to obtain the 12 leads continuously means that complete monitoring is not routine. The EASI monitoring system, based on vector electrocardiography, is an alternative that uses only 5 electrodes (4 thoracic and 1 ground) and theoretically allows obtaining a complete standard ECG. Objectives The main endpoint of this study was to evaluate the diagnostic accuracy of the EASI monitoring system in patients with ventricular tachycardia (VT), compared with conventional ECG. Methods Seven cases of patients admitted to the CCU due to episodes of VT are presented. The patients were monitored with the EASI system upon arrival, and the conventional ECG and the one derived from the EASI system were taken simultaneously for VT events for comparison. The 4 electrodes of the EASI system were placed, as recommended, on the sternal manubrium (S), lower sternum at the level of the 5th intercostal space (E), at the level of the 5th intercostal space, and on the right and left midclavicular lines (I and A). Results Analysing case by case, the axis of the tachycardia was similar in 5 patients, being able to assess the origin of the tachycardia in them. In 2 patients it was different. These cases of patients that differ, one episode has its origin in the right ventricular outflow tract (endocardial) and the other in the area of the left ventricular summit (epicardial). Two patients with different tachycardias and no cardiac characteristics in common. Figure 1. Conclusions EASI monitoring is a feasible alternative for monitoring patients in the CCU, which could give us reliable information (compared with standard ECG) with limitations in some cases in which the cardiac axis differs. For patients admitted for arrhythmic events, a better characterization of the differences would be interesting in order to optimize its use.

Detection of myocardial infarction using Shannon energy envelope, FA-MVEMD and deterministic learning

Myocardial infarction (MI) poses a significant clinical challenge, necessitating expeditious and precise detection to mitigate potentially fatal outcomes. Current MI diagnosis predominantly relies on electrocardiography (ECG); however, it is fraught with limitations, including inter-observer variability and a reliance on expert interpretation. This study introduces an automated MI detection framework that capitalizes on hybrid signal processing methodologies and deterministic learning theory. The initial step involves the extraction of the Shannon energy envelope (SEE) and its derivative from a single-lead ECG. Integration of the SEE into the ECG’s phase portrait provides a means to capture the underlying nonlinear system dynamics. Subsequently, the application of fast and adaptive multivariate empirical mode decomposition (FA-MVEMD) yields discriminative features originating from the most energetically dominant intrinsic mode components (IMFs) within the SEE. Profound dissimilarities are discernible between ECG signals recorded from healthy subjects and those afflicted with MI. In the subsequent phase, deterministic learning theory, implemented through neural networks, is employed to facilitate the classification of ECG signals into two distinct groups. The method’s efficacy is meticulously evaluated using the PTB diagnostic ECG database, resulting in a noteworthy average classification accuracy of 99.21%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\%$$\\end{document} within a tenfold cross-validation framework. In summation, the findings affirm that the proposed features not only complement conventional ECG attributes but also align closely with the underlying dynamics of the ECG system, ultimately fortifying the automatic detection of MI. The imperative requirement for early and accurate MI diagnosis is addressed through our approach, offering a robust and dependable means to fulfill this pivotal clinical need.

SleepMI: An AI-based screening algorithm for myocardial infarction using nocturnal electrocardiography

Myocardial infarction (MI) is a common cardiovascular disease, the early diagnosis of which is essential for effective treatment and reduced mortality. Therefore, novel methods are required for automatic screening or early diagnosis of MI, and many studies have proposed diverse conventional methods for its detection. In this study, we aimed to develop a sleep-myocardial infarction (sleepMI) algorithm for automatic screening of MI based on nocturnal electrocardiography (ECG) findings from diagnostic polysomnography (PSG) data using artificial intelligence (AI) models. The proposed sleepMI algorithm was designed using representation and ensemble learning methods and optimized via dropout and batch normalization. In the sleepMI algorithm, a deep convolutional neural network and light gradient boost machine (LightGBM) models were mixed to obtain robust and stable performance for screening MI from nocturnal ECG findings. The nocturnal ECG signal was extracted from 2,691 participants (2,331 healthy individuals and 360 patients with MI) from the PSG data of the second follow-up stage of the Sleep Heart Health Study. The nocturnal ECG signal was extracted 3 h after sleep onset and segmented at 30-s intervals for each participant. All ECG datasets were divided into training, validation, and test sets consisting of 574,729, 143,683, and 718,412 segments, respectively. The proposed sleepMI model exhibited very high performance with precision, recall, and F1-score of 99.38%, 99.38%, and 99.38%, respectively. The total mean accuracy for automatic screening of MI using a nocturnal single-lead ECG was 99.387%. MI events can be detected using conventional 12-lead ECG signals and polysomnographic ECG recordings using our model.

An Energy-Efficient ECG Processor Based on HDWT and a Hybrid Classifier for Arrhythmia Detection

Cardiac arrhythmia (CA) is a severe cardiac disorder that results in a significant number of fatalities worldwide each year. Conventional electrocardiography (ECG) devices are often unable to detect arrhythmia symptoms during patients’ hospital visits due to their intermittent nature. This paper presents a wearable ECG processor for cardiac arrhythmia (CA) detection. The processor utilizes a Hilbert transform-based R-peak detection engine for R-peak detection, a Haar discrete wavelet transform (HDWT) unit for feature extraction, and a Hybrid ECG classifier that combines linear methods and Non-Linear Support Vector Machines (NLSVM) classifiers to distinguish between normal and abnormal heartbeats. The processor is fabricated by the CMOS 110 nm process with an area of 1.34 mm2 and validated with the MIT_BIH Database. The whole design consumes 4.08 μW with an average classification accuracy of 97.34%.

Fully automatic screening for atrial fibrillation using a photoplethysmography based wristband and a novel smart infrastructure

Abstract Background Atrial Fibrillation (AF) is the leading cause of stroke, and its prevalence is expected to rise. While early detection is crucial in preventing thromboembolic events, its often asymptomatic and paroxysmal nature makes it challenging to capture using conventional electrocardiography (ECG). Photoplethysmography (PPG) enabled devices, such as smartwatches, allow continuous monitoring of the heart rhythm and accurate screening for AF. Purpose In this study, we aimed to build an IT-infrastructure for fully automated screening of AF in hospitalised patients at risk using a PPG-based wrist worn wearable device. Methods We conducted an investigator-initiated, prospective, clinical trial to evaluate the performance of a PPG-based wristband coupled to an automatic data process device hub in hospitalised patients. Participants with a CHA2DS2-VASc score of two or higher and no prior history of AF were eligible for the study. Consenting participants received a wristband with a built-in PPG sensor to be worn during the entire hospital stay. Data from the wristband was automatically transmitted, stored, analysed and visualised. When absolute arrhythmia (AA) was detected in the PPG signal, a subsequent seven-day Holter ECG was performed to confirm the diagnosis. Results A total of 346 patients were included in the analysis (age 72 ± 10 years; 175 females (50.6%); mean CHA2DS2-VASc score of 3.5 ± 1.3). No data was lost in the process. The mean monitoring time was 4.3 ± 4.4 days, 45.9% was evaluable. In twelve patients (3.5%, CI: 1.5% - 5.4%) absolute arrhythmia (AA) was detected in the PPG-signal. The mean screening time until first detection of AA was 14.7 ± 16.8 hours. The highest detection rate was observed within the first 24 hours of screening (p = 0.004) (Figure 1). The AA burden per hour was 1.9 times greater during the night (22:00 - 06:00) compared to the day (p = 0.003) (Figure 2). Of the 346 patients, 304 (87.9%) were compliant in wearing the wristband for the entire hospitalisation. In nine patients a Holter ECG was recorded, no AF was identified. Conclusions We successfully established an infrastructure for automated AF screening in hospitalised patients using wrist-worn PPG devices, enabling real-time visualisation of incoming data and facilitating therapeutic interventions with minimal delay. To our knowledge this is the first hospital to implement a fully automated AF screening infrastructure based on PPG devices. In a population at risk, AA was identified in 3.5% of all patients. The high compliance rate of the wearable device further supports its feasibility and utility in clinical practice.Figure 1:Time to first detection of AAFigure 2:Total AA burden per hour

EASI Monitoring: An Alternative to Conventional Electrocardiography in the Recording of Ventricular Tachycardia

This study compares the EASI monitoring setting with the conventional 12-lead electrocardiogram (ECG) in patients experiencing ventricular tachycardia (VT) episodes. The results revealed that the EASI monitoring setting demonstrated a VT morphology that closely resembled that of the conventional ECG in the majority of cases. This finding suggests that EASI monitoring could serve as a valuable alternative in situations where obtaining a conventional ECG is either risky or not feasible.

Clinical and prognostic significance of left ventricular dysfunction predictors in patients with ventricular ectopy and without structural heart disease

Aim. To determine the predictors of left ventricular dysfunction in patients with ventricular ectopic beats without structural heart disease.Material and Methods. We modeled ventricular ectopy in rats through early afterdepolarization (aconitine-induced arrhythmia) and delayed afterdepolarization (adrenaline arrhythmia). In addition, we modeled ventricular ectopy in rabbits and cats by delayed afterdepolarization (barium chloride-induced and strophanthin arrhythmias, respectively) and also modeled ventricular ectopy in dogs by re-entry hydrogen peroxide-induced arrhythmia. In addition to conventional electrocardiography parameters, we analyzed pre-ectopic interval, its variability, and the internal deviation index. Further, the study included 514 patients aged 16 to 34 years (mean 21.2 ± 0.2 years), and the number of premature ventricular contractions (PVCs) per day of observation ranged from 6,157 to 37,254 (mean 19,706 ± 656 PVCs). We registered the same parameters as in experimental arrhythmias but calculated them separately for mono- and polymorphic, left and right ventricular out-flow tract arrhythmias. The duration of follow-up of patients was up to 10 years. The endpoint was the detection or absence of cardiovascular and/or extracardiac pathology.Results. We recorded polymorphic PVCs and early monomorphic PVCs when modeling ventricular arrhythmias by the mechanism of delayed post-depolarization and early post-depolarization, respectively. Both early and late monomorphic PVCs were documented when inducing ventricular arrhythmias by re-entry. When modeling hydrogen peroxide-induced and strophanthin arrhythmias, we observed significantly higher values of PVC-QRS complex and ventricular arrhythmia internal deviation index in comparison with aconitine-induced arrhythmia. Favourable outcome was registered in 50.97% of patients, whilst coronary artery disease, arterial hypertension, and mitral valve prolapse were documented in 7.98%, 16.73% and 2.92% patients. The rest of the patients had gastrointestinal diseases. In patients with favourable outcome, the signs of monomorphic PVCs correlated with those revealed during the modeling of ventricular ectopy by early afterdepolarization (r = 0.92), whereas those signs of polymorphic PVCs correlated with those observed at barium chloride-induced delayed afterdepolarization (r = 0.94). In patients with CAD, signs of PVCs correlated with those registered during re-entry hydrogen peroxide-induced arrhythmia (r = 0.93), Finally, in patients with arterial hypertension and mitral valve prolapse signs of PVCs correlated with those documented at strophanthin-(r = 0.92) and adrenaline-induced delayed afterdepolarization (r = 0.89). In these patients, the values for both monomorphic and polymorphic PVCs, ventricular arrhythmia internal deviation index, duration of PVC-QRS complex and PVC-QRS/QRSaverage did not exceed 0.42 units, 149 ms and 1,44 units, respectively. The development of coronary artery disease and arterial hypertension well correlated with an increase in ventricular arrhythmia internal deviation index ≥ 0.56 units and QRS complex duration ≥ 157 ms. Mitral valve prolapse was associated with the duration of the QRS complex ≥ 159 ms of polymorphic PVCs.Conclusion. In patients with ventricular ectopy but without structural heart disease, an increase in the values of ventricular arrhythmia internal deviation index and the duration of PVC-QRS complex was ≥ 0.48 units and 149 ms, respectively, associated with the development of cardiovascular pathology. Development of coronary artery disease and hypertension correlated with ventricular arrhythmia internal deviation index ≥ 0.56 units, and QRS complex duration ≥ 157 ms in monomorphic and polymorphic PVCs, whereas development of mitral valve prolapse correlated QRS complex duration ≥ 159 ms in polymorphic PVCs.

Ultra-High-Resolution Electrocardiography Enables Earlier Detection of Transmural and Subendocardial Myocardial Ischemia Compared to Conventional Electrocardiography.

The sensitivity of exercise ECG is marginally sufficient for the detection of mild reduction of coronary blood flow in patients with early coronary atherosclerosis. Here, we describe the application of a new technique of ECG registration/analysis-ultra-high-resolution ECG (UHR ECG)-for early detection of myocardial ischemia (MIS). The utility of UHR ECG vs. conventional ECG (C ECG) was tested in anesthetized rats and pigs. Transmural MIS was induced in rats by the ligation of the left coronary artery (CA). In pigs, subendocardial ischemia of a variable extent was produced by stepwise inflation of a balloon within the right CA, causing a 25-100% reduction of its lumen. In rats, a reduction in power spectral density (PSD) in the high-frequency (HF) channel of UHR ECG was registered at 60 s after ischemia (power 0.81 ± 0.14 vs. 1.25 ± 0.12 mW at baseline, p < 0.01). This was not accompanied by any ST segment elevation on C ECG. In pigs, PSD in the HF channel of UHR ECG was significantly decreased at a 25% reduction of CA lumen, while the ST segment on C ECG remained unchanged. In conclusion, UHR ECG enabled earlier detection of transmural MIS compared to C ECG. PSD in the HF channel of UHR ECG demonstrated greater sensitivity in the settings of subendocardial ischemia.

Abstract P3144: A Deep Neural Network Algorithm For Accurate Detection Of Brugada Syndrome Features In Electrocardiograms

Brugada Syndrome (BrS) is a rare but potentially fatal cardiac condition that is difficult to diagnose due to the elusive nature of its characteristic ECG pattern. The diagnosis of BrS requires identification of a specific electrocardiographic (ECG) pattern, which often appears only upon administration of sodium-channel blockers. Here, we present a deep neural network (DNN) algorithm that accurately detects BrS features in ECGs without the need for a drug challenge. We trained and validated the DNN on two independent cohorts of patients who were enrolled in electrophysiological studies for BrS diagnosis. The internal prospective validation cohort included 370 subjects, and the multicenter external validation cohort included 110 subjects from three other medical institutions in Italy. All subjects who did not present a spontaneous type 1 ECG underwent an ajmaline drug challenge to aid in confirming a BrS diagnosis. We found that the DNN approach classified ECGs for BrS with a sensitivity of 79.6%, specificity of 93.6%, accuracy of 88.4%, and area under the curve (AUC) of 0.934±0.027 in the validation cohorts. The DNN model also detected BrS with 100% accuracy in all cases in which a patient presented the spontaneous type 1 pattern. Our results demonstrate that a multivariate machine-learning algorithm can accurately detect the features of BrS in a conventional ECG without the challenge of a sodium-channel blocker. The computer-assisted analysis of digital ECG traces from current electrocardiographs might help physicians recognize patients affected by this disease. In conclusion, we have developed an advanced deep learning algorithm that can accurately detect BrS features in ECGs. Our results demonstrate that the DNN approach could be an effective tool to improve the diagnosis of BrS and potentially prevent sudden cardiac death in affected individuals.

Skin‐Adherent Elastomer‐Hydrogel Patch for Continuous 12‐Lead Cardiac Ambulatory Monitoring during Physical Activities

AbstractContinuous electrocardiography (ECG) monitoring is a necessity to prevent the sudden occurrence of cardiac events and premature death. Wearable bioelectronics provides the opportunity to realize noninvasive 12‐lead ambulatory monitoring for cardiovascular disease (CVD) detection and diagnosis. This work introduces a 12‐lead ECG patch that eliminates the issues associated with compliance, skin damage, and user‐discomfort encountered in conventional ECG sensors. The patch is safe, stretchable, and skin‐adherent with an adaptable design that allows for user‐friendly ECG monitoring. These can be attributed to the unique 3‐bridge patch structure, embedded liquid metal circuitry, and the wet‐adhesive polyacrylamide‐polydopamine‐tannic acid (PAM‐PDA‐TA) hydrogel. The hydrogel displays improved wet adhesiveness and biosafety for long‐term usage on deforming skin. The patch can acquire clean and consistent ECG signals with a higher signal‐to‐noise (SNR) ratio compared to commercial electrodes during both static and dynamic monitoring. The outstanding performance of the patch ascertains its potential for daily continuous ECG monitoring and remote diagnosis.

Clinical trial report: the electrocardiographic response to ajmaline provocation in healthy subjects

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation The Robert Lancaster Memorial Fund sponsored by McColl’s Research Group Background The electrocardiographic (ECG) response to diagnostic ajmaline provocation (AP) testing has been studied extensively in clinical cohorts. However, the healthy ECG response has not been described. We undertook a trial examining ECG changes in response to AP in a cohort of systematically recruited asymptomatic Caucasian healthy subjects with no family history of sudden death and normal baseline ECG and echocardiogram. Methods Applicants responded to a national recruitment advertisement and completed an online medical questionnaire. Those fulfilling inclusion criteria were invited to undergo further evaluation with eligible subjects undergoing a diagnostic ajmaline challenge (1mg/kg, max. 100mg over 5 minutes). A continuous ECG was recorded in the standard and high right precordial lead (HRPL) position. Automated analysis of conventional and novel ECG measurements were made at baseline and at peak drug effect, which was defined as the point of maximum QRS duration (excluding precordial leads). Results One hundred healthy Caucasian subjects underwent AP. The mean age was 26.84 years (SD ± 8.01 years) and 52% were male. A drug induced type 1 Brugada pattern (DI-T1BP) was observed in 3/100 (3%) of the cohort. We performed a paired comparison of ECG measures at baseline versus peak drug effect (Table 1). AP had a similar effect on global QRS duration and global PR interval, with both increasing by 28%, mean ∆ 25.66ms and mean ∆ 43.36ms respectively. Changes in S wave parameters in lead II were pronounced, with a 97% increase in S wave duration and a 101% increase in S wave negative amplitude. ST-J point elevation in the anterior, inferior, and lateral regions was comparable, with a 57%, 51% and 57% increase in ST-J amplitude respectively. AP had a greater effect on cardiac conduction in females compared to males (Table 2). In contrast, changes in STJ point amplitude and combined and segmented QRST segment area were greater in males. Conclusion The healthy ECG response to AP elicits a pronounced effect on cardiac conduction, more so in females compared to males, whilst changes in STJ point amplitude and QRST area were greater in male subjects. The DI-T1BP is part of the healthy response to AP.

High Density Body Surface Potential Mapping with Conducting Polymer-Eutectogel Electrode Arrays for ECG imaging.

Electrocardiography imaging (ECGi) is a non-invasive inverse reconstruction procedure which employs body surface potential maps (BSPM) obtained from surface electrode array measurements to improve the spatial resolution and interpretability of conventional electrocardiography (ECG) for the diagnosis of cardiac dysfunction. ECGi currently lacks precision, which has prevented its adoption in clinical setups. The introduction of high-density electrode arrays could increase ECGi reconstruction accuracy but is not attempted before due to manufacturing and processing limitations. Advances in multiple fields have now enabled the implementation of such arrays which poses questions on optimal array design parameters for ECGi. In this work, a novel conducting polymer electrode manufacturing process on flexible substrates is proposed to achieve high-density, mm-sized, conformable, long-term, and easily attachable electrode arrays for BSPM with parameters optimally selected for ECGi applications. Temporal, spectral, and correlation analysis are performed on a prototype array demonstrating the validity of the chosen parameters and the feasibility of high-density BSPM, paving the way for ECGi devices fit for clinical application.

PO-03-200 THE RESPONSE TO AJMALINE PROVOCATION IN HEALTHY SUBJECTS

The electrocardiographic (ECG) response to diagnostic ajmaline provocation (AP) testing has been studied extensively in clinical cohorts. However, the healthy ECG response has not been described. We undertook a trial examining ECG changes in response to AP in a cohort of systematically recruited asymptomatic Caucasian healthy subjects with no family history of sudden death and normal baseline ECG and echocardiogram. Applicants responded to a national recruitment advertisement and completed an online medical questionnaire. Those fulfilling inclusion criteria were invited to undergo further evaluation with eligible subjects undergoing a diagnostic ajmaline challenge (1mg/kg, max. 100mg over 5 minutes). A continuous ECG was recorded in the standard and high right precordial lead (HRPL) position. Automated analysis of conventional and novel ECG measurements were made at baseline and at peak drug effect, which was defined as the point of maximum QRS duration (excluding precordial leads). One hundred healthy Caucasian subjects underwent AP. The mean age was 26.84 years (SD ± 8.01 years) and 52% were male. A drug induced type 1 Brugada pattern (DI-T1BP) was observed in 3/100 (3%) of the cohort. We performed a paired comparison of ECG measures at baseline versus peak drug effect (Table 1). AP had a similar effect on global QRS duration and global PR interval, with both increasing by 28%, mean delta 25.66ms and mean delta 43.36ms respectively. Changes in S wave parameters in lead II were pronounced, with a 97% increase in S wave duration and a 101% increase in S wave negative amplitude. ST-J point elevation in the anterior, inferior, and lateral regions was comparable, with a 57%, 51% and 57% increase in ST-J amplitude respectively. AP had a greater effect on cardiac conduction in females compared to males (Figure 1). In contrast, changes in STJ point amplitude and combined and segmented QRST segment area were greater in males. The healthy ECG response to AP elicits a pronounced effect on cardiac conduction, more so in females compared to males, whilst changes in STJ point amplitude and QRST area were greater in male subjects. A DI-T1BP is part of the healthy response to AP.Tabled 1Table 1. Paired analysis of baseline and peak ajmaline effect ECG characteristicsECG CharacteristicsMean at baseline (SD)Mean at Peak Ajmaline Effect (SD)Mean Delta = peak - baseline (SD)% ChangeP value*Global QRS duration ms90.42 (10.59)116.06 (12.06)25.66 (11.98)28.38<0.01Global T wave duration ms210.48 (24.96)225.48 (25.53)15.00 (20.53)7.13<0.01Global PR interval ms153.14 (19.45)196.50 (25.10)43.36 (17.27)28.31<0.01Global QT interval ms408.66 (33.03)414.38 (23.70)5.72 (18.62)1.40<0.01Global RR interval ms958.39 (197.57)813.98 (130.64)-144.41 (154.18)-15.06<0.01Global P wave duration ms102.74 (10.82)121.78 (13.58)19.04 (15.38)18.53<0.01Precordial Tpeak to Tend interval ms75.39 (27.28)81.88 (29.30)6.49 (39.29)8.610.07Precordial QRS duration ms85.59 (8.89)107.69 (11.10)22.10 (8.34)25.82<0.01Precordial T wave duration ms174.48 (24.53)199.81 (26.12)25.33 (26.33)15.00<0.01Anterior STJ amplitude uV47.97 (31.20)75.55 (48.44)27.58 (27.70)57.49<0.01Inferior STJ amplitude uV24.06 (21.97)36.46 (36.96)12.40 (26.33)51.54<0.01Lateral STJ amplitude uV34.45 (21.15)54.33 (30.79)19.89 (18.84)57.74<0.01Precordial QRS area mv/ms-409.59 (242.18)-613.71 (367.56)-204.12 (183.69)48.78<0.01Precordial QRST area mv/ms1481.06 (508.03)1838.87 (681.75)357.82 (278.89)24.32<0.01Precordial T wave area mv/ms483.66 (394.14)606.11 (453.04)122.45 (225.60)25.00<0.01Precordial STJ to Tpeak area mv/ms505.59 (230.36)543.71 (228.57)38.12 (103.28)8.00<0.01Precordial Tpeak to Tend area mv/ms258.31 (110.68)311.07 (147.60)52.76 (74.02)19.23<0.01S wave duration in lead I ms21.53 (15.55)36.01 (19.35)14.48 (14.07)67.25<0.01S wave duration in lead II ms17.34 (14.50)34.24 (20.33)16.90 (14.13)97.46<0.01S wave amplitude in lead I uV-189.09 (172.35)-290.47 (234.30)-110.38 (120.50)61.29<0.01S wave amplitude lead II uV-147.23 (197.92)-298.25 (255.25)-150.02 (155.93)101.89<0.01Inferior J wave amplitude uV43.31 (92.62)25.69 (57.06)-17.62 (68.55)-40.680.01Lateral J wave amplitude uV19.65 (41.36)10.18 (30.62)-9.47 (42.11)-48.190.03Anterior J wave amplitude uV0.77 (4.41)2.31 (7.42)1.55 (6.42)201.290.02 Open table in a new tab

Intervention in the Timeliness of Two Electrocardiography Types for Patients in the Emergency Department With Chest Pain: Randomized Controlled Trial.

BackgroundIn the emergency department (ED), the result obtained using the 12-lead electrocardiography (ECG) is the basis for diagnosing and treating patients with chest pain. It was found that performing ECG at the appropriate time could improve treatment outcomes. Hence, a wearable ECG device with a timer can ensure that the findings are continuously recorded.ObjectiveWe aimed to compare the time accuracy of a single-patch 12-lead ECG (SP-ECG) with that of conventional ECG (C-ECG). We hypothesized that SP-ECG would result in better time accuracy.MethodsAdult patients who visited the emergency room with chest pain but were not in shock were randomly assigned to one of the following 2 groups: the SP-ECG group or the C-ECG group. The final analysis included 33 (92%) of the 36 patients recruited. The primary outcome was the comparison of the time taken by the 2 groups to record the ECG. The average ages of the participants in the SP-ECG and C-ECG groups were 63.7 (SD 18.4) and 58.1 (SD 12.4) years, respectively.ResultsWith a power of 0.95 and effect sizes of 0.05 and 1.36, the minimum number of samples was calculated. The minimum sample size for each SP-ECG and C-ECG group is 15.36 participants, assuming a 20% dropout rate. As a result, 36 patients with chest pain participated, and 33 of them were analyzed. The timeliness of SP-ECG and C-ECG for the first follow-up ECG was 87.5% and 47.0%, respectively (P=.74). It was 75.0% and 35.2% at the second follow-up, respectively (P=.71).ConclusionsContinuous ECG monitoring with minimal interference from other examinations is feasible and essential in complex ED situations. However, the precision of SP-ECG has not yet been proved. Nevertheless, the application of SP-ECG is expected to improve overcrowding and human resource shortages in EDs, though more research is needed.Trial RegistrationClinicalTrials.gov NCT04114760; https://clinicaltrials.gov/ct2/show/NCT04114760

Improved evaluation of left ventricular hypertrophy using the spatial QRS-T angle by electrocardiography

Electrocardiographic (ECG) signs of left ventricular hypertrophy (LVH) lack sensitivity. The aim was to identify LVH based on an abnormal spatial peaks QRS-T angle, evaluate its diagnostic performance compared to conventional ECG criteria for LVH, and its prognostic performance. This was an observational study with four cohorts with a QRS duration < 120 ms. Based on healthy volunteers (n = 921), an abnormal spatial peaks QRS-T angle was defined as ≥ 40° for females and ≥ 55° for males. In other healthy volunteers (n = 461), the specificity of the QRS-T angle to detect LVH was 96% (females) and 98% (males). In patients with at least moderate LVH by cardiac imaging (n = 225), the QRS-T angle had a higher sensitivity than conventional ECG criteria (93–97% vs 13–56%, p < 0.001 for all). In clinical consecutive patients (n = 783), of those who did not have any LVH, 238/556 (43%) had an abnormal QRS-T angle. There was an association with hospitalization for heart failure or all-cause death in univariable and multivariable analysis. An abnormal QRS-T angle rarely occurred in healthy volunteers, was a mainstay of moderate or greater LVH, was common in clinical patients without LVH but with cardiac co-morbidities, and associated with outcomes.

Preoperative P-wave parameters and risk of atrial fibrillation after cardiac surgery: a meta-analysis of 20201 patients.

OBJECTIVESTo evaluate the role of P-wave parameters, as defined on preprocedural electrocardiography (ECG), in predicting atrial fibrillation after cardiac surgery [postoperative atrial fibrillation (POAF)].METHODSPubMed, Cochrane library and Embase were searched for studies reporting on P-wave parameters and risk of POAF. Meta-analysis of P-wave parameters reported by at least 5 different publications was performed. In case of receiver operator characteristics (ROC-curve) analysis in the original publications, an ROC meta-analysis was performed to summarize the sensitivity and specificity.RESULTSThirty-two publications, with a total of 20 201 patients, contributed to the meta-analysis. Increased P-wave duration, measured on conventional 12-lead ECG (22 studies, Cohen’s d = 0.4, 95% confidence interval: 0.3–0.5, P < 0.0001) and signal-averaged ECG (12 studies, Cohen’s d = 0.8, 95% confidence interval: 0.5–1.2, P < 0.0001), was a predictor of POAF independently from left atrial size. ROC meta-analysis for signal-averaged ECG P-wave duration showed an overall sensitivity of 72% (95% confidence interval: 65–78%) and specificity of 68% (95% confidence interval: 58–77%). Summary ROC curve had a moderate discriminative power with an area under the curve of 0.76. There was substantial heterogeneity in the meta-analyses for P-wave dispersion and PR-interval.CONCLUSIONSThis meta-analysis shows that increased P-wave duration, measured on conventional 12-lead ECG and signal-averaged ECG, predicted POAF in patients undergoing cardiac surgery.

Experience with automated ECG interpretation in intraventricular conduction disturbances

In 2019, a new document called “National Guidelines. Functional Testing” was issued recommending the use of conventional electrocardiography terms for the description of intraventricular conduction disturbances associated with atrioventricular bundle branch blocks. The article describes the experience with the use of international ECG diagnoses of intraventricular conduction disturbances generated at an automated workplace of a functional testing specialist at P.V. Mandryka Central Military Clinical Hospital of the Ministry of Defense of the Russian Federation. ECG interpretation in patients with bundle branch blocks was based on the ACC/AHA Guidelines for Ambulatory ECG (2009), which proved to be of practical importance and clearly demonstrated the functions of the bundle of His branches and fascicles.

Deep-learning model for screening sepsis using electrocardiography

BackgroundSepsis is a life-threatening organ dysfunction and a major healthcare burden worldwide. Although sepsis is a medical emergency that requires immediate management, screening for the occurrence of sepsis is difficult. Herein, we propose a deep learning-based model (DLM) for screening sepsis using electrocardiography (ECG).MethodsThis retrospective cohort study included 46,017 patients who were admitted to two hospitals. A total of 1,548 and 639 patients had sepsis and septic shock, respectively. The DLM was developed using 73,727 ECGs from 18,142 patients, and internal validation was conducted using 7774 ECGs from 7,774 patients. Furthermore, we conducted an external validation with 20,101 ECGs from 20,101 patients from another hospital to verify the applicability of the DLM across centers.ResultsDuring the internal and external validations, the area under the receiver operating characteristic curve (AUC) of the DLM using 12-lead ECG was 0.901 (95% confidence interval, 0.882–0.920) and 0.863 (0.846–0.879), respectively, for screening sepsis and 0.906 (95% confidence interval (CI), 0.877–0.936) and 0.899 (95% CI, 0.872–0.925), respectively, for detecting septic shock. The AUC of the DLM for detecting sepsis using 6-lead and single-lead ECGs was 0.845–0.882. A sensitivity map revealed that the QRS complex and T waves were associated with sepsis. Subgroup analysis was conducted using ECGs from 4,609 patients who were admitted with an infectious disease, and the AUC of the DLM for predicting in-hospital mortality was 0.817 (0.793–0.840). There was a significant difference in the prediction score of DLM using ECG according to the presence of infection in the validation dataset (0.277 vs. 0.574, p < 0.001), including severe acute respiratory syndrome coronavirus 2 (0.260 vs. 0.725, p = 0.018).ConclusionsThe DLM delivered reasonable performance for sepsis screening using 12-, 6-, and single-lead ECGs. The results suggest that sepsis can be screened using not only conventional ECG devices but also diverse life-type ECG machines employing the DLM, thereby preventing irreversible disease progression and mortality.

User Perceptions and Experiences of a Handheld 12-Lead Electrocardiographic Device in a Clinical Setting: Usability Evaluation.

BackgroundCardiac arrhythmias are a leading cause of death. The mainstay method for diagnosing arrhythmias (eg, atrial fibrillation) and cardiac conduction disorders (eg, prolonged corrected QT interval [QTc]) is by using 12-lead electrocardiography (ECG). Handheld 12-lead ECG devices are emerging in the market. In tandem with emerging technology options, evaluations of device usability should go beyond validation of the device in a controlled laboratory setting and assess user perceptions and experiences, which are crucial for successful implementation in clinical practice.ObjectiveThis study aimed to evaluate clinician and patient perceptions and experiences, regarding the usability of a handheld 12-lead ECG device compared to a conventional 12-lead ECG machine, and generalizability of this user-centered approach.MethodsInternational Organization for Standardization Guidelines on Usability and the Technology Acceptance Model were integrated to form the framework for this study, which was conducted in outpatient clinics and cardiology wards at Westmead Hospital, New South Wales, Australia. Each patient underwent 2 ECGs (1 by each device) in 2 postures (supine and standing) acquired in random sequence. The times taken by clinicians to acquire the first ECG (efficiency) using the devices were analyzed using linear regression. Electrocardiographic parameters (QT interval, QTc interval, heart rate, PR interval, QRS interval) and participant satisfaction surveys were collected. Device reliability was assessed by evaluating the mean difference of QTc measurements within ±15 ms, intraclass correlation coefficient, and level of agreement of the devices in detecting atrial fibrillation and prolonged QTc. Clinicians’ perceptions and feedback were assessed with semistructured interviews based on the Technology Acceptance Model.ResultsA total of 100 patients (age: mean 57.9 years, SD 15.2; sex: male: n=64, female n=36) and 11 clinicians (experience acquiring ECGs daily or weekly 10/11, 91%) participated, and 783 ECGs were acquired. Mean differences in QTc measurements of both handheld and conventional devices were within ±15 ms with high intraclass correlation coefficients (range 0.90-0.96), and the devices had a good level of agreement in diagnosing atrial fibrillation and prolonged QTc (κ=0.68-0.93). Regardless of device, QTc measurements when patients were standing were longer duration than QTc measurements when patients were supine. Clinicians’ ECG acquisition times improved with usage (P<.001). Clinicians reported that device characteristics (small size, light weight, portability, and wireless ECG transmission) were highly desired features. Most clinicians agreed that the handheld device could be used for clinician-led mass screening with enhancement in efficiency by increasing user training. Regardless of device, patients reported that they felt comfortable when they were connected to the ECG devices.ConclusionsReliability and usability of the handheld 12-lead ECG device were comparable to those of a conventional ECG machine. The user-centered evaluation approach helped us identify remediable action to improve the efficiency in using the device and identified highly desirable device features that could potentially help mass screening and remote assessment of patients. The approach could be applied to evaluate and better understand the acceptability and usability of new medical devices.

A New Index in the Follow-Up of Arrhythmia of Coronavirus Disease-2019 (COVID-19) Patients Receiving Hydroxychloroquine and Azithromycin Therapy; Index of Cardiac Electrophysiological Balance

Objective: Index of cardiac electrophysiological balance (iCEB) is a relatively new electrocardiographic (ECG) parameter that shows the balance between ventricular depolarization and repolarization, thus providing more information than other conventional ECG parameters such as QT and corrected QT (cQT) intervals. This study aimed to evaluate the condition of iCEB with the treatment of hydroxychloroquine and azithromycin used in COVID-19 patients. Method: The study was designed as cross-sectional and descriptive. Sixty three (52 male, 28.4 ± 10.7 years) COVID-19 patients with mild symptoms who received hydroxychloroquine and azithromycin treatment between 30 March and 30 June 2020 were included in the study. iCEB and corrected iCEB (iCEBc) values were calculated by dividing the respective QT and cQT intervals by the QRS duration. Results: In the study group, the mean PR, QRS, QT and cQT intervals were similar between groups. While heart rate was significantly higher before treatment, iCEB and iCEBc increased significantly after treatment. Conclusions: Our study did not observe a significant difference in QT and cQT intervals with hydroxychloroquine and azithromycin treatment in COVID-19. Still, there was a significant increase in the iCEB and iCEBc. We believe that the cardiac electrophysiological balance index can be used to monitor arrhythmias in patients undergoing short-term treatment at COVID -19.