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Background: Manually derived electrocardiographic (ECG) parameters were not associated with mortality in mechanically ventilated COVID‐19 patients in earlier studies, while increased high‐sensitivity cardiac troponin‐T (hs‐cTnT) and N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) were. To provide evidence for vectorcardiography (VCG) measures as potential cardiac monitoring tool, we investigated VCG trajectories during critical illness. Methods: All mechanically ventilated COVID‐19 patients were included in the Maastricht Intensive Care Covid Cohort between March 2020 and October 2021. Serum hs‐cTnT and NT‐proBNP concentrations were measured daily. Conversion of daily 12‐lead ECGs to VCGs by a MATLAB‐based script provided QRS area, T area, maximal QRS amplitude, and QRS duration. Linear mixed‐effect models investigated trajectories in serum and VCG markers over time between non‐survivors and survivors, adjusted for confounders. Results: In 322 patients, 5461 hs‐cTnT, 5435 NT‐proBNP concentrations and 3280 ECGs and VCGs were analyzed. Non‐survivors had higher hs‐cTnT concentrations at intubation and both hs‐cTnT and NT‐proBNP significantly increased compared with survivors. In non‐survivors, the following VCG parameters decreased more when compared to survivors: QRS area (−0.27 (95% CI) (−0.37 to −0.16, p <.01) μVs per day), T area (−0.39 (−0.62 to −0.16, p <.01) μVs per day), and maximal QRS amplitude (−0.01 (−0.01 to −0.01, p <.01) mV per day). QRS duration did not differ. Conclusion: VCG‐derived QRS area and T area decreased in non‐survivors compared with survivors, suggesting that an increase in myocardial damage and tissue loss play a role in the course of critical illness and may drive mortality. These VCG markers may be used to monitor critically ill patients. [ABSTRACT FROM AUTHOR]

Background: The prognosis of Duchenne muscular dystrophy (DMD) is poor once it develops to the stage of cardiac impairment. Recent studies have demonstrated that electrocardiogram (ECG), which consists of general ECG and vectorcardiogram (VCG), retains an extremely powerful role in the assessment of patients with reduced left ventricular (LV) systolic dysfunction. However, data regarding VCG recordings in DMD and its prognostic value for reduced left ventricular ejection fraction (LVEF) of DMD have never been reported. This study aims to describe the characteristics of VCG in children with DMD and to explore the predictive value of VCG for reduced LVEF in children with DMD. Methods: A total of 306 patients with a known diagnosis of DMD confirmed by the genetic test were retrospectively enrolled at our hospital between August 2018 and August 2022. This resulted in a total study group of 486 VCG recordings. Among them, 75 DMD patients who underwent cardiac magnetic resonance (CMR) later after one year follow-up were prospectively enrolled. The trend of VCG parameters of DMD patients across the different age span were compared with age-matched normal children. Concordance statistic analysis was further performed to assess the validity of VCG parameters in predicting the occurrence of reduced LVEF in patients with DMD. Results: DMD patients have a significantly higher heart rate, R waves in V1, QRS loop percentage in the right anterior quadrant in the horizontal plane (horizontal quadrant II) and QRS loop percentage in the anterior superior quadrant in the sagittal plane (sagittal quadrant IV) than normal children. Concordance statistic (C-statistic) showed an area under the curve of quadrant IV in the sagittal plane of baseline was 0.704. The receiver operating characteristic (ROC) curve shows that quadrant IV in the sagittal plane of 7.57% was the optimal cutoff with a sensitivity of 53.3% and a specificity of 88.3% for predicting reduced LVEF in DMD patients. Conclusions: Our study firstly showed that QRS loop percentage in the right anterior quadrant in the horizontal plane (horizontal quadrant II) and QRS loop percentage in the anterior superior quadrant in the sagittal plane (sagittal quadrant IV) could be abnormal in DMD boys as early as before 5 years old. Evaluation of the myocardium by VCG in the early age to predict possible cardiac systolic dysfunction may have important implications for the ongoing management of DMD boys. [ABSTRACT FROM AUTHOR]

Congenital short QT syndrome is a very low prevalence inherited primary arrhythmia syndrome first reported in 2000 by Gussak et al., who described two families with a short QT interval, syncope, and sudden cardiac death. In 2004, Ramon Brugada et al. identified the first genetic type of this entity. To date, a total of nine genotypes have been described. The diagnosis is easy from the electrocardiogram (ECG), not only due to the short QT duration, but also based on other aspects covered in this review. During 24-h Holter monitoring, paroxysmal atrial fibrillation spontaneously converting to sinus rhythm may be found. Even though the T wave may appear symmetric on the ECG, the T loop of the vectorcardiogram confirms that the T wave is constantly asymmetric due to the presence of dashes closer to each other in the efferent branch. In this review, we also describe the minus-plus T wave sign that we have described in a previously published article. In addition to congenital causes, we briefly highlight the existence of numerous acquired causes of short QT interval. [ABSTRACT FROM AUTHOR]

Objective To investigate the value of vectorcardiography in the diagnosis of abnormal cardiac electrical activity in hypertension, and to analyze the influencing factors of early cardiac target organ damage. Methods 80 cases in the Department of Cardiovascular of Kunming Municipal Hospital of Traditional Chinese Medicine from January 2022 to February 2023, were selected.Cardiac structural abnormalities were excluded by ultrasound cardiogram. The detection of abnormal ventricular depolarization and repolarization indexes was compared between electrocardiogram and vectorcardiogram. 80 cases were divided into normal group (n = 40) and abnormal group (n = 40) according to the results of vectorcardiogram, the related influencing factors of early cardiac damage were compared between the two groups, and the indicators with statistical significance were included in the binary Logistic regression analysis to screen out the independent influencing factors of early heart damage. Results Vectorcardiogram was superior to ECG in detecting abnormal ventricular repolarization indexes (P < 0.05), and there was no significant difference in detecting abnormal depolarization indexes between the two groups (P > 0.05). There were significant differences between the normal group and the abnormal group in age, regular medication, family history, diabetes, 24 h average systolic blood pressure ( 24 h SBP), daytime average systolic blood pressure (DSBP), night average systolic blood pressure (NSBP), blood pressure load, morning blood pressure, and pulse pressure (P < 0.05). Binary Logistic regression analysis showed, that age [OR (95%CI) = 0.891, 0.998] and NSBP [OR ( 95%CI) = 1.018, 2.10], family history [OR ( 95% CI) = 0.029, 0.499], diabetes [OR = 0.042 ( 95%CI), 0.916] were the independent influencing factors of early cardiac damage in hypertension. Conclusion Vectorcardiogram is an effective method to detect early cardiac target organ damage in hypertension. [ABSTRACT FROM AUTHOR]

Abstract Background Manually derived electrocardiographic (ECG) parameters were not associated with mortality in mechanically ventilated COVID‐19 patients in earlier studies, while increased high‐sensitivity cardiac troponin‐T (hs‐cTnT) and N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) were. To provide evidence for vectorcardiography (VCG) measures as potential cardiac monitoring tool, we investigated VCG trajectories during critical illness. Methods All mechanically ventilated COVID‐19 patients were included in the Maastricht Intensive Care Covid Cohort between March 2020 and October 2021. Serum hs‐cTnT and NT‐proBNP concentrations were measured daily. Conversion of daily 12‐lead ECGs to VCGs by a MATLAB‐based script provided QRS area, T area, maximal QRS amplitude, and QRS duration. Linear mixed‐effect models investigated trajectories in serum and VCG markers over time between non‐survivors and survivors, adjusted for confounders. Results In 322 patients, 5461 hs‐cTnT, 5435 NT‐proBNP concentrations and 3280 ECGs and VCGs were analyzed. Non‐survivors had higher hs‐cTnT concentrations at intubation and both hs‐cTnT and NT‐proBNP significantly increased compared with survivors. In non‐survivors, the following VCG parameters decreased more when compared to survivors: QRS area (−0.27 (95% CI) (−0.37 to −0.16, p

3DQRSarea is a strong marker for cardiac resynchronization therapy and can be obtained by taking the (i) summation or the (ii) difference of the areas subtended by positive and negative deflections in X, Y, Z vectorcardiographic electrocardiogram (ECG) leads. We correlated both methods with the instantaneous‐absolute‐3D‐voltage‐time‐integral (VTIQRS‐3D). 3DQRSarea consistently underestimated the VTIQRS‐3D, but the summation method was a closer and more reliable approximation. The dissimilarity was less apparent in left bundle branch block (r2 summation.996 vs. difference.972) and biventricular paced ECGs (r2.996 vs..957) but was more apparent in normal ECGs (r2.988 vs..653). [ABSTRACT FROM AUTHOR]

Introduction: Measurement of the spatial ventricular gradient (SVG), spatial QRST angles, and other vectorcardiographic measures of myocardial electrical heterogeneity have emerged as novel risk stratification methods for sudden cardiac death and other adverse cardiovascular events. Prior studies of normal limits of these measurements included primarily young, healthy, White volunteers, but normal limits in older patients are unknown. The influence of race and body mass index (BMI) on these measurements is also unclear. Methods: Normal 12‐lead electrocardiograms (ECGs) from a single center were identified. Patients with abnormal cardiovascular, pulmonary, or renal history (assessed by International Classification of Disease [ICD‐9/ICD‐10] codes) or abnormal cardiovascular imaging were excluded. The SVG and QRST angles were measured and stratified by age, sex, and race. Multivariable linear regression was used to assess the influence of age, BMI, and heart rate (HR) on these measurements. Results: Among 3292 patients, observed ranges of SVG and QRST angles (peak and mean) differed significantly based on sex, age, and race. Sex differences attenuated with increasing age. Men tended to have larger SVG magnitude (60.4 [46.1–77.8] vs. 52.5 [41.3–65.8] mv*ms, p <.0001) and elevation, and more anterior/negative SVG azimuth (−14.8 [−25.1 to −4.3] vs. 1.3 [−9.8 to 10.5] deg, p <.0001) compared to women. Men also had wider QRST angles. Observed ranges varied significantly with BMI and HR. SVG and QRST angle measurements were robust to different filtering bandwidths and moderate fiducial point annotation errors, but were heavily affected by changes in baseline correction. Conclusions: Age, sex, race, BMI, and HR significantly affect the range of SVG and QRST angles in patients with normal ECGs and no known cardiovascular disease, and should be accounted for in future studies. An online calculator for prediction of these "normal limits" given demographics is provided at https://bivectors.github.io/gehcalc/. [ABSTRACT FROM AUTHOR]

AimsVentricular activation patterns can aid clinical decision-making directly by providing spatial information on cardiac electrical activation or indirectly through derived clinical indices. The aim of this work was to derive an atlas of the major modes of variation of ventricular activation from model-predicted 3D bi-ventricular activation time distributions and to relate these modes to corresponding vectorcardiograms (VCGs). We investigated how the resulting dimensionality reduction can improve and accelerate the estimation of activation patterns from surface electrogram measurements.Methods and resultsAtlases of activation time (AT) and VCGs were derived using principal component analysis on a dataset of simulated electrophysiology simulations computed on eight patient-specific bi-ventricular geometries. The atlases provided significant dimensionality reduction, and the modes of variation in the two atlases described similar features. Utility of the atlases was assessed by resolving clinical waveforms against them and the VCG atlas was able to accurately reconstruct the patient VCGs with fewer than 10 modes. A sensitivity analysis between the two atlases was performed by calculating a compact Jacobian. Finally, VCGs generated by varying AT atlas modes were compared with clinical VCGs to estimate patient-specific activation maps, and the resulting errors between the clinical and atlas-based VCGs were less than those from more computationally expensive method.ConclusionAtlases of activation and VCGs represent a new method of identifying and relating the features of these high-dimensional signals that capture the major sources of variation between patients and may aid in identifying novel clinical indices of arrhythmia risk or therapeutic outcome.

Providing reliable detection of QRS complexes is key in automated analyses of electrocardiograms (ECG). Accurate and timely R-peak detections provide a basis for ECG-based diagnoses and to synchronize radiologic, electrophysiologic, or other medical devices. Compared with classical algorithms, deep learning (DL) architectures have demonstrated superior accuracy and high generalization capacity. Furthermore, they can be embedded on edge devices for real-time inference. 3D vectorcardiograms (VCG) provide a unifying framework for detecting R-peaks regardless of the acquisition strategy or number of ECG leads. In this article, a DL architecture was demonstrated to provide enhanced precision when trained and applied on 3D VCG, with no pre-processing nor post-processing steps. Experiments were conducted on four different public databases. Using the proposed approach, high F1-scores of 99.80% and 99.64% were achieved in leave-one-out cross-validation and cross-database validation protocols, respectively. False detections, measured by a precision of 99.88% or more, were significantly reduced compared with recent state-of-the-art methods tested on the same databases, without penalty in the number of missed peaks, measured by a recall of 99.39% or more. This approach can provide new applications for devices where precision, or positive predictive value, is essential, for instance cardiac magnetic resonance imaging. [ABSTRACT FROM AUTHOR]

Background: The prognosis of Duchenne muscular dystrophy (DMD) is poor once it develops to the stage of cardiac impairment. Recent studies have demonstrated that electrocardiogram (ECG), which consists of general ECG and vectorcardiogram (VCG), retains an extremely powerful role in the assessment of patients with reduced left ventricular (LV) systolic dysfunction. However, data regarding VCG recordings in DMD and its prognostic value for reduced left ventricular ejection fraction (LVEF) of DMD have never been reported. This study aims to describe the characteristics of VCG in children with DMD and to explore the predictive value of VCG for reduced LVEF in children with DMD., Methods: A total of 306 patients with a known diagnosis of DMD confirmed by the genetic test were retrospectively enrolled at our hospital between August 2018 and August 2022. This resulted in a total study group of 486 VCG recordings. Among them, 75 DMD patients who underwent cardiac magnetic resonance (CMR) later after one year follow-up were prospectively enrolled. The trend of VCG parameters of DMD patients across the different age span were compared with age-matched normal children. Concordance statistic analysis was further performed to assess the validity of VCG parameters in predicting the occurrence of reduced LVEF in patients with DMD., Results: DMD patients have a significantly higher heart rate, R waves in V1, QRS loop percentage in the right anterior quadrant in the horizontal plane (horizontal quadrant II) and QRS loop percentage in the anterior superior quadrant in the sagittal plane (sagittal quadrant IV) than normal children. Concordance statistic (C-statistic) showed an area under the curve of quadrant IV in the sagittal plane of baseline was 0.704. The receiver operating characteristic (ROC) curve shows that quadrant IV in the sagittal plane of 7.57% was the optimal cutoff with a sensitivity of 53.3% and a specificity of 88.3% for predicting reduced LVEF in DMD patients., Conclusions: Our study firstly showed that QRS loop percentage in the right anterior quadrant in the horizontal plane (horizontal quadrant II) and QRS loop percentage in the anterior superior quadrant in the sagittal plane (sagittal quadrant IV) could be abnormal in DMD boys as early as before 5 years old. Evaluation of the myocardium by VCG in the early age to predict possible cardiac systolic dysfunction may have important implications for the ongoing management of DMD boys., Competing Interests: The authors declare no conflict of interest., (Copyright: © 2024 The Author(s). Published by IMR Press.)

Coronary artery disease (CAD) is among the leading causes of death worldwide. Initial studies require an electrocardiogram stress test often followed by cardiac imaging procedures. However, conventional indices still show insufficient diagnostic performance. We propose quaternion methods to evaluate abnormal alterations during ventricular depolarization and repolarization. Assessment was conducted during a Bruce protocol treadmill stress test and after the end of the exercise. We developed an algorithm to automatically determine the beginning and end of exercise and then, computed the angular and linear velocities. Statistical analysis for feature selection and classification between ischaemic and non-ischaemic patients was used. The most significant markers were maximum linear velocity during ventricular depolarization (p < 5E-9) and maximum angular velocity during the second half of the repolarization loop (p < 5E-16). The latter reached sensitivity / specificity pair of 78 / 92 (AUC 0.89). A linear classifier showed a trend of reduction in cardiac vector velocity in at-risk patients after the end of exercise. The sensitivity / specificity pair reached was 86 / 100. Trajectory deviations of depolarization / repolarization loops that result from ischaemia effects, could be responsible for the observed reduction in dynamic changes during exercise. Further studies could provide non-invasive complementary tools to detect CAD risk. [ABSTRACT FROM AUTHOR]

Background: The electrocardiogram (ECG) is a powerful tool for differential diagnosis among a group of pathologies with different therapeutic approaches/prognoses, the so-called J-wave syndrome. The vectorcardiogram (VCG) can be used as a complementary method to the ECG in several dubious electrocardiographic alterations.Objective: We carried out a VCG analysis after conceiving and measuring a novel parameter (JT-distance) that allows diagnosis of the Brugada ECG pattern.Methods: A retrospective cohort study selected ninety-six ECGs with J-point elevation in V1/V2, ECG superior leads and VCGs, all performed on the same day. A new VCG measurement by Frank method (JT-distance) was conceived and designed in transverse and right sagittal planes by 3 lines drawn 1) at the final third of the QRS loop, comprehending the J-point; 2) at the initial portion of the T loop; 3) a parallel of the J-point line at the beginning of the T loop. JT measure was determined by the distance between parallels. A validation cohort was established in a new sample of thirty-five patients.Results: JT-distance ≥1.5 mm (tranverse plane) and JT-distance >1.25 mm, in the sagittal plane, differentiated Brugada type-1 from Brugada type-2, early repolarization and others, with 95% sensitivity and 68% specificity. JT-distance <1.5 mm (transverse plane) and JT >1.25 mm (sagittal plane) had 100% sensitivity and 85% specificity for Brugada type-1 diagnosis. A validation cohort showed very similar Cohen's kappa levels (0.65 and 0.77, test and validation cohorts, respectively), with overlapping 95% confidence intervals.Conclusions: The novel vectorcardiogram measurement (JT-distance) presented a new diagnostic criterion to identify Brugada pattern. Nevertheless, prospective studies should be performed by other centers to confirm these findings. [ABSTRACT FROM AUTHOR]

Wilson assumed that the ventricular gradient (VG) is independent of the ventricular activation order. This paradigm has often been refuted and was never convincingly corroborated. We sought to validate Wilson’s concept by intra-individual comparison of the VG of sinus beats and ectopic beats, thus assessing the effects of both altered ventricular conduction (caused by the ectopic focus) and restitution (caused by ectopic prematurity). We studied standard diagnostic ECGs of 118 patients with accidental extrasystoles: normally conducted supraventricular ectopic beats (SN, N = 6) and aberrantly conducted supraventricular ectopic beats (SA, N = 20) or ventricular ectopic beats (V, N = 92). In each patient, we computed the VG vectors of the predominant beat, VGp→, of the ectopic beat, VGe→, and of the VG difference vector, ΔVGep→, and compared their sizes. VGe→ of the SA and V ectopic beats were significantly larger than VGp→ (53.7 ± 25.0 vs. 47.8 ± 24.6 mV∙ms, respectively; p < 0.001). ΔVGep→ were three times larger than the difference of VGe→ and VGp→ (19.94 ± 9.76 vs. 5.94 mV∙ms, respectively), demonstrating differences in the VGp→ and VGe→ spatial directions. The amount of ectopic prematurity was not correlated with ΔVGep→, although the larger VG difference vectors were observed for the more premature (

Providing reliable detection of QRS complexes is key in automated analyses of electrocardiograms (ECG). Accurate and timely R-peak detections provide a basis for ECG-based diagnoses and to synchronize radiologic, electrophysiologic, or other medical devices. Compared with classical algorithms, deep learning (DL) architectures have demonstrated superior accuracy and high generalization capacity. Furthermore, they can be embedded on edge devices for real-time inference. 3D vectorcardiograms (VCG) provide a unifying framework for detecting R-peaks regardless of the acquisition strategy or number of ECG leads. In this article, a DL architecture was demonstrated to provide enhanced precision when trained and applied on 3D VCG, with no pre-processing nor post-processing steps. Experiments were conducted on four different public databases. Using the proposed approach, high F1-scores of 99.80% and 99.64% were achieved in leave-one-out cross-validation and cross-database validation protocols, respectively. False detections, measured by a precision of 99.88% or more, were significantly reduced compared with recent state-of-the-art methods tested on the same databases, without penalty in the number of missed peaks, measured by a recall of 99.39% or more. This approach can provide new applications for devices where precision, or positive predictive value, is essential, for instance cardiac magnetic resonance imaging.

Summary: The paper aims to develop a universally implementable efficient test for testing homogeneity of mean directions of several independent hyper‐spherical populations. Conventional tests are valid only under highly concentrated and/or large‐size groups. Focusing on the popular Langevin distribution on a d‐hyper‐sphere, the present work extends the very recent results for the circular case. The hurdle of the nuisance non‐location‐scale concentration parameter κ is overcome through a variant of the integrated likelihood ratio test (ILRT), yielding a simple and elegant test statistic. Analytically, second‐order accurate asymptotic chi‐squared distribution of ILRT is established. Extensive simulation study demonstrates that ILRT uniformly outperforms its peers, notably under highly dispersed groups, which is precisely the target parametric region, and is robust under a large class of alternate distributions. Five real‐life data analyses from diverse disciplines, including the emerging field of vectorcardiography and a novel application to compositional data analysis in the context of drug development, illustrate applications of the findings. [ABSTRACT FROM AUTHOR]

Objective: Vectorcardiographic (VCG) global electrical heterogeneity (GEH) metrics showed clinical usefulness. We aimed to assess the reproducibility of GEH metrics.Methods: GEH was measured on two 10-s 12‑lead ECGs recorded on the same day in 4316 participants of the Multi-Ethnic Study of Atherosclerosis (age 69.4 ± 9.4 y; 2317(54%) female, 1728 (40%) white, 1138(26%) African-American, 519(12%) Asian-American, 931(22%) Hispanic-American). GEH was measured on a median beat, comprised of the normal sinus (N), atrial fibrillation/flutter (S), and ventricular-paced (VP) beats. Spatial ventricular gradient's (SVG's) scalar was measured as sum absolute QRST integral (SAIQRST) and vector magnitude QT integral (VMQTi).Results: Two N ECGs with heart rate (HR) bias of -0.64 (95% limits of agreement [LOA] -5.68 to 5.21) showed spatial area QRS-T angle (aQRST) bias of -0.12 (95%LOA -14.8 to 14.5). Two S ECGs with HR bias of 0.20 (95%LOA -15.8 to 16.2) showed aQRST bias of 1.37 (95%LOA -33.2 to 35.9). Two VP ECGs with HR bias of 0.25 (95%LOA -3.0 to 3.5) showed aQRST bias of -1.03 (95%LOA -11.9 to 9.9). After excluding premature atrial or ventricular beat and two additional beats (before and after extrasystole), the number of cardiac beats included in a median beat did not affect the GEH reproducibility. Mean-centered log-transformed values of SAIQRST and VMQTi demonstrated perfect agreement (Bias 0; 95%LOA -0.092 to 0.092).Conclusion: GEH measurements on N, S, and VP median beats are reproducible. SVG's scalar can be measured as either SAIQRST or VMQTi.Significance: Satisfactory reproducibility of GEH metrics supports their implementation. [ABSTRACT FROM AUTHOR]

The angle between theQRSandTvectors reflects the consistency or inconsistency of the processes of de- and repolarization of the ventricles of the heart and is considered one of the indicators of global electrical heterogeneity of myocardium. In recent years, the prognostic value of theQRS-Tangle has been demonstrated in relation to total and cardiovascular mortality, both in the population and in various groups of patients. The mechanisms of this phenomenon are not completely clear. The review analyses studies published over the past five years on the relationship between theQRS-Tangle and mortality, as well as coronary heart disease and heart failure. Possible mechanisms for increasing theQRS-Tangle are discussed. Data are given on the use of theQRS-Tangle in diagnostic and prognostic scales, including in combination with other indicators of global electrical heterogeneity of myocardium.

Introduction: Left bundle branch pacing (LBBP) is a rapidly growing conduction system pacing technique. However, little is known regarding the electrophysiological characteristics of different types of LBBP. We aimed to evaluate the electrophysiological characteristics and anatomic lead location with pacing different branches of the left bundle branch.Methods: Consecutive bradycardia patients with successful LBBP were enrolled and classified into groups according to the paced electrocardiogram and the lead location. Electrocardiogram, pacing properties, vectorcardiogram, and lead tip location were analyzed.Results: Ninety-one patients were enrolled, including 48 with the left bundle trunk pacing (LBTP) and 43 with the left bundle fascicular pacing (LBFP). The paced QRS duration in the LBTP group was significantly shorter than that in the LBFP group (108.1 ± 9.9 vs. 112.9 ± 11.2 ms, p = 0.03), with a more rightward QRS transition zone (p = 0.01). The paced QRS area in the LBTP group was similar to that during intrinsic rhythm (35.1 ± 15.8 vs. 34.7 ± 16.6 μVs, p = 0.98), whereas in the LBFP group, the paced QRS area was significantly larger compared to intrinsic rhythm (43.4 ± 15.8 vs. 35.7 ± 18.0 μVs, p = 0.01). The lead tip site for LBTP was located in a small fan-shaped area with the tricuspid valve annulus summit as the origin, whereas fascicular pacing sites were more likely in a larger and more distal area.Conclusions: Pacing the proximal left bundle main trunk produced better electrical synchrony compared with pacing the distal left bundle fascicles. A visualization technique can facilitate achieving LBTP.

Objective. Even though the electrocardiogram (ECG) has potential to be used as a monitoring or diagnostic tool for fetuses, the use of non-invasive fetal ECG is complicated by relatively high amounts of noise and fetal movement during the measurement. Moreover, machine learning-based solutions to this problem struggle with the lack of clean reference data, which is difficult to obtain. To solve these problems, this work aims to incorporate fetal rotation correction with ECG denoising into a single unsupervised end-to-end trainable method. Approach. This method uses the vectorcardiogram (VCG), a three-dimensional representation of the ECG, as an input and extends the previously introduced Kalman-LISTA method with a Kalman filter for the estimation of fetal rotation, applying denoising to the rotation-corrected VCG. Main results. The resulting method was shown to outperform denoising auto-encoders by more than 3 dB while achieving a rotation tracking error of less than 33 ∘ . Furthermore, the method was shown to be robust to a difference in signal to noise ratio between electrocardiographic leads and different rotational velocities. Significance. This work presents a novel method for the denoising of non-invasive abdominal fetal ECG, which may be trained unsupervised and simultaneously incorporates fetal rotation correction. This method might prove clinically valuable due the denoised fetal ECG, but also due to the method's objective measure for fetal rotation, which in turn might have potential for early detection of fetal complications., (Creative Commons Attribution license.)

Aims: Despite the highest prevalence of stroke, obesity, and diabetes across races/ethnicities, paradoxically, Hispanic/Latino populations have the lowest prevalence of atrial fibrillation and major Minnesota code-defined ECG abnormalities. We aimed to use Latent Profile Analysis in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) population to obtain insight into epidemiological discrepancies., Methods and Results: We conducted a cross-sectional analysis of baseline HCHS/SOL visit. Global electrical heterogeneity (GEH) was measured as spatial QRS-T angle (QRSTa), spatial ventricular gradient azimuth (SVGaz), elevation (SVGel), magnitude (SVGmag), and sum absolute QRST integral (SAIQRST). Statistical analysis accounted for the stratified two-stage area probability sample design. We fitted a multivariate latent profile generalized structural equation model adjusted for age, sex, ethnic background, education, hypertension, diabetes, smoking, dyslipidaemia, obesity, chronic kidney disease, physical activity, diet quality, average RR' interval, median beat type, and cardiovascular disease (CVD) to gain insight into the GEH profiles. Among 15 684 participants (age 41 years; 53% females; 6% known CVD), 17% had an increased probability of likely abnormal GEH profile (QRSTa 80 ± 27°, SVGaz -4 ± 21°, SVGel 72 ± 12°, SVGmag 45 ± 12 mVms, and SAIQRST 120 ± 23 mVms). There was a 23% probability for a participant of being in Class 1 with a narrow QRSTa (40.0 ± 10.2°) and large SVG (SVGmag 108.3 ± 22.6 mVms; SAIQRST 203.4 ± 39.1 mVms) and a 60% probability of being in intermediate Class 2., Conclusion: A substantial proportion (17%) in the Hispanic/Latino population had an increased probability of altered, likely abnormal GEH profile, whereas 83% of the population was resilient to harmful risk factors exposures., Competing Interests: Conflict of interest: none declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Background: The segment of the latest mechanical contraction (LMC) does not always overlap with the site of the latest electrical activation (LEA). By integrating both mechanical and electrical dyssynchrony, this proof-of-concept study aimed to propose a new method for recommending left ventricular (LV) lead placements, with the goal of enhancing response to cardiac resynchronization therapy (CRT)., Methods: The LMC segment was determined by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) phase analysis. The LEA site was detected by vectorcardiogram. The recommended segments for LV lead placement were as follows: (1) the LMC viable segments that overlapped with the LEA site; (2) the LMC viable segments adjacent to the LEA site; (3) If no segment met either of the above, the LV lateral wall was recommended. The response was defined as ≥15% reduction in left ventricular end-systolic volume (LVESV) 6-months after CRT. Patients with LV lead located in the recommended site were assigned to the recommended group, and those located in the non-recommended site were assigned to the non-recommended group., Results: The cohort comprised of 76 patients, including 54 (71.1%) in the recommended group and 22 (28.9%) in the non-recommended group. Among the recommended group, 74.1% of the patients responded to CRT, while 36.4% in the non-recommended group were responders (P = .002). Compared to pacing at the non-recommended segments, pacing at the recommended segments showed an independent association with an increased response by univariate and multivariable analysis (odds ratio 5.00, 95% confidence interval 1.73-14.44, P = .003; odds ratio 7.33, 95% confidence interval 1.53-35.14, P = .013). Kaplan-Meier curves showed that pacing at the recommended LV lead position demonstrated a better long-term prognosis., Conclusion: Our findings indicate that pacing at the recommended segments, by integrating of mechanical and electrical dyssynchrony, is significantly associated with an improved CRT response and better long-term prognosis., (Copyright © 2024 American Society of Nuclear Cardiology. All rights reserved.)

Background: Myocardial electrical heterogeneity is critical for normal cardiac electromechanical function, but abnormal or excessive electrical heterogeneity is proarrhythmic. The spatial ventricular gradient (SVG), a vectorcardiographic measure of electrical heterogeneity, has been associated with arrhythmic events during long-term follow-up, but its relationship with short-term inducibility of ventricular arrhythmias (VAs) is unclear., Objective: This study was designed to determine associations between SVG and inducible VAs during electrophysiology study., Methods: A retrospective study was conducted of adults without prior sustained VA, cardiac arrest, or implantable cardioverter-defibrillator who underwent ventricular stimulation for evaluation of syncope and nonsustained ventricular tachycardia or for risk stratification before primary prevention implantable cardioverter-defibrillator implantation. The 12-lead electrocardiograms were converted into vectorcardiograms, and SVG magnitude (SVGmag) and direction (azimuth and elevation) were calculated. Odds of inducible VA were regressed by logistic models., Results: Of 143 patients (median age, 69 years; 80% male; median left ventricular ejection fraction [LVEF], 47%; 52% myocardial infarction), 34 (23.8%) had inducible VAs. Inducible patients had lower median LVEF (38% vs 50%; P < .0001), smaller SVGmag (29.5 vs 39.4 mV·ms; P = .0099), and smaller cosine SVG azimuth (cosSVGaz; 0.64 vs 0.89; P = .0007). When LVEF, SVGmag, and cosSVGaz were dichotomized at their medians, there was a 39-fold increase in adjusted odds (P = .002) between patients with all low LVEF, SVGmag, and cosSVGaz (65% inducible) compared with patients with all high LVEF, SVGmag, and cosSVGaz (4% [n = 1] inducible). After multivariable adjustment, SVGmag, cosSVGaz, and sex but not LVEF or other characteristics remained associated with inducible VAs., Conclusion: Assessment of electrical heterogeneity by SVG, which reflects abnormal electrophysiologic substrate, adds to LVEF and identifies patients at high and low risk of inducible VA at electrophysiology study., Competing Interests: Disclosures D.B.K. and J.W.W. previously served on an advisory board for HeartcoR Solutions. T.R.M.: consulting/speaking for Abbott and Biosense; research support from LuxMed. A.L.: speaking for Abbott and Biosense. A.D.: consulting/speaking for Abbott, Biosense, and Biotronik; research support from Abbott, Biosense, and Medtronic. All other authors report no conflicts of interest., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Myocardial infarction (MI) occurs due to the decrease in the blood flow into one part of the heart, and it further causes damage to the heart muscle. The 12-channel electrocardiogram (ECG) has been widely used to detect and localize MI pathology in clinical studies. The vectorcardiogram (VCG) is a 3-channel recording system used to measure the heart's electrical activity in sagittal, transverse, and frontal planes. The VCG signals have advantages over the 12-channel ECG to localize posterior MI pathology. Detection and localization of MI using VCG signals are vital in clinical practice. This paper proposes a multi-channel multi-scale two-stage deep-learning-based approach to detect and localize MI using VCG signals. In the first stage, the multivariate variational mode decomposition (MVMD) decomposes the three-channel-based VCG signal beat into five components along each channel. The multi-channel multi-scale VCG tensor is formulated using the modes of each channel of VCG data, and it is used as the input to the deep convolutional neural network (CNN) to classify MI and normal sinus rhythm (NSR) classes. In the second stage, the multi-class deep CNN is used for the categorization of anterior MI (AMI), anterior-lateral MI (ALMI), anterior-septal MI (ASMI), inferior MI (IMI), inferior-lateral MI (ILMI), inferior-posterior-lateral (IPLMI) classes using MI detected multi-channel multi-scale VCG instances from the first stage. The proposed approach is developed using the VCG data obtained from a public database. The results reveal that the approach has obtained the accuracy, sensitivity, and specificity values of 99.58%, 99.18%, and 99.87%, respectively, for MI detection. Moreover, for MI localization, we have obtained the overall accuracy value of 99.86% in the second stage for our proposed network. The proposed approach has demonstrated superior classification performance compared to the existing VCG signal-based MI detection and localization techniques. [ABSTRACT FROM AUTHOR]

The outcome in the Brugada syndrome (BrS) is more benign in female than in male individuals. However, outcome could be adversely affected by sinus node dysfunction (SND). Long sinus pauses indicate an overlap between the phenotypes of BrS and SND. We present a 29-year-old woman with syncopal episodes at rest since adolescence. [ABSTRACT FROM AUTHOR]

The aim of the work is to compare vectorcardiographic (VCG) variables - spatial QRS-T angle and electrocardiographic ventricular gradient (VG) with echocardiography (EchoCG) data in patients with idiopathic pulmonary hypertension (IPH) and chronic thromboembolic pulmonary hypertension (CTEPH). Materials and methods. In 40 patients with IPH and 40 patients with CTEPH at the age of 45±12 years, systolic pulmonary artery pressure (SPAP); the sizes of heart chambers, parameters of RV systolic and diastolic function were evaluated with EchoCG. The QRS-T and VG angles were calculated on the VCG, derived from 12-lead digital ECG. Results. In all patients SPAP was greater than 40 mm Hg (mean 83±18 mm Hg), EchoCG data indicated hypertrophy and dilatation of RV, its systolic and diastolic function; dilatation of the right atrium (RA). Prognostically unfavorable changes in EchoCG were observed: the presence of pericardial effusion in 35 (44%) patients, RA area greater than 26 cm2 in 18 (23%) patients; TAPSE less than 1.5 cm in 37 (46%) patients. EchoCG and VCG variables had statistically significant differences in patients with III-IV functional class in comparison with I-II functional class. Statistically significant moderate correlations between VCG and EchoCG variables were revealed. VCG variables allowed to separate patient groups with the presence and absence of prognostically unfavorable changes in EchoCG with sensitivity from 54 to 78% and specificity from 66 to 87%. Conclusion. In patients with IPH and CTEPH, changes of QRS-T angle and VG correlate with SPAP, the size of RV and RA, parameters of RV systolic and diastolic function. The possibility of the use of QRS-T angle and VG for the detection of patients with prognostically unfavorable echocardiographic changes in the general group of patients with IPH and CTEPH has been shown.

Objective　To evaluate the application value of vectorcardiogram （VCG） in the diagnosis of left ventricular abnormalities in the early stage of hypertension. Methods　The electrocardiogram （ ECG），VCG and ultrasonic cardiogram （ UCG） of 76 patients with essential hypertension at the same visit or during same hospitalization period were retrospectively analyzed. The initial vector and spatial maximum vector of VCG were used as the indicators of left ventricular abnormality，as well as the interventricular septum，left ventricular posterior wall and left ventricular end-diastolic diameter of UCG. The positive detection of the two were compared; and the detection of VCG and ECG in abnormal left ventricular electrical activity was compared. Results　The detection rate of VCG in left ventricular abnormality was 55.3%，which was significantly higher than that of UCG （38.2%，P < 0.05）.The positive rate of VCG in abnormal left ventricular electrical activity was 88.2%，which was significantly higher than that of ECG （ 71.1%，P < 0.01） . Using VCG as the standard， ECG missed diagnosis of abnormal indicators of left ventricular electrical activity: 18 T-ring abnormalities， 4 left ventricular high voltage， and 3 branch block. Conclusion　VCG has certain diagnostic advantages for early left ventricular abnormality in hypertension， especially for early detection of ventricular repolarization abnormality. Combined application with UCG can improve the positive detection rate of early left ventricular abnormality. [ABSTRACT FROM AUTHOR]

Objective To explore the clinical value of vectorcardiogram (VCG) in the diagnosis of left ventricular hypertrophy (LVH). Methods A total of 94 hypertensive patients with LVH diagnosed by VCG were enrolled in our study, and their cardiac ultrasound and related clinical data were retrospectively analyzed. They were divided into normal group and LVH group (abnormal group) according to left ventricular weight index. The VCG and related clinical indexes were compared between the two groups. Results ln the abnormal group, VCG indexes arc higher than those in the normal group (P < 0. 05); those indexes include left direction force, transverse plane QRS loop voltage, frontal plane QRS loop voltage, QRS loop maximum space vector, QRS loop starting right vector voltage, QRS loop starting right forward vector voltage, T ring abnormality, QRS loop orientation, etc. The two groups are significantly varied in clinical indexes such as the duration of hypertension and regular use of anti-hypertensive drugs (P < 0. 05). However, there is no significant difference in the complicating of diabetes between the two groups (P > 0. 05). Conclusion VCG indicators including QRS loop starling vector, QRS loop voltage, T ring and QRS loop orientation have diagnostic value for LVH; long course of hypertension and irregular intake of antihypertensive drugs arc important clinical factors for LVH. [ABSTRACT FROM AUTHOR]

Objective To investigate the clinical application value of vectorcardiogram (VCG) in the diagnosis of complete right bundle branch block (CRBBB) . Methods A total of 134 patients with CRBBB diagnosed by VCG and ECG were selected and divided into normal cardiac structure group (normal group) and abnormal cardiac structure group (abnormal group ) according to the results of cardiac echocardiography. The clinical data and VCG indexes were compared between the two groups. Results Comparison between the two groups reveals that indexes including the abnormal rate of T ring length-width ratio, the abnormal rate of QRS loop voltage to T ring voltage ratio (R/T), QRS loop duration and QRS loop space maximum vector (QRS loop voltage) in the abnormal group are significantly higher than those in the normal group (P < 0. 05). However, there is no significant difference in age, gender, body mass index (BMl), QRS loop operating direction and T ring voltage between the two groups (P >0. 05 ). Conclusion The clinical significance of CRBBB can be preliminarily evaluated combined with VCG analysis indexes. [ABSTRACT FROM AUTHOR]

Objective To compare the detection rate, sensitivity and specificity of two diagnostic critcria in the diagnosis of left anterior fascicular block ( LAFB) . The two diagnostic criteria were separately proposed in a book named "Clinical arrhythmology" and "2019 AHA/ ACCF/ HRS recommendations for the standardization and interpretation of the electrocardiogram", namely diagnostic criterion 1 and 2, respectively. Methods A retrospective study was carried out on routine ECGs with QRS axis between -45° and - 90° in our hospital. Those individuals with inferior and lateral wall myocardial infarction, ventricular pre-excitation, complete right bundle branch block, and ventricular hypertrophy were excluded. Taking vectorcardiogram ( VCG) diagnostic criterion as a standard, the detection rate, sensitivity and specificity of the two ECG diagnostic methods for LAFB were analyzed. Results A total of 3503 cases arc involved from which VCG detects 1137 cases(32. 46%), diagnostic criterion 1 detects 1376 cases(39. 28%), and diagnostic criterion 2 detects 2431 cases( 69.40%) . The sensitivity and specificity of diagnostic criterion 1 are separately 59.37% and 70.37% while those of diagnostic criterion 2 are 87.25% and 39. 18%, respectively. The specificity of diagnostic criterion 1 is significantly higher than that of diagnostic criterion 2 (P< 0.05), however, the detection rate and sensitivity of the latter is significantly higher(P< 0.05). Conclusion The diagnostic criterion 2 is more suitable for pure LAFB screening because of its higher detection rate and sensitivity. [ABSTRACT FROM AUTHOR]

Objective The electrocardiogram and vectorcardiogram were synchronously collected by stereo electrocardiograph using Wilson and Frank dual-lead system to timely detect and diagnose left anterior branch block.Methods The case of left anterior branch block with clinical manifestations and well-defined by vectorcardiogram were selected. Results Vectorcardiogram of 4 patients with left anterior branch block showed that the starting vector of frontal QRS ring was located at the lower right or left side,while the maximum vector shifted to the upper left. The main feature of the ring is that it ran counter-clockwise and expanded to the upper left quadrant.Conclusion Vectorcardiogram is superior to electrocardiogram in the diagnosis of left anterior branch block. In the practical work,we should adopt the principle of complementary advantages of ECG and vectorcardiogram to well serve the clinic. The combination of the two methods can improve the accuracy of diagnosis [ABSTRACT FROM AUTHOR]

Heart diseases alter the rhythmic behaviors of cardiac electrical activity. Recent advances in sensing technology bring the ease to acquire space-time electrical activity of the heart such as vectorcardiogram (VCG) signals. Recurrence analysis of successive heartbeats is conducive to detect the disease-altered cardiac activities. However, conventional recurrence analysis is more concerned about homogeneous recurrences, and overlook heterogeneous types of recurrence variations in VCG signals (i.e., in terms of state properties and transition dynamics). This paper presents a new framework of heterogeneous recurrence analysis for the characterization and modeling of disease-altered spatiotemporal patterns in multi-channel cardiac signals. Experimental results show that the proposed approach yields an accuracy of 96.9%, a sensitivity of 95.0%, and a specificity of 98.7% for the identification of myocardial infarctions. The proposed method of heterogeneous recurrence analysis shows strong potential to be further extended for the analysis of other physiological signals such as electroencephalogram (EEG) and electromyography (EMG) signals towards medical decision making. [ABSTRACT FROM AUTHOR]

Background: In the prehospital triage of patients presenting with symptoms suggestive of acute myocardial ischemia, reliable myocardial ischemia detection in the electrocardiogram (ECG) is pivotal. Due to large interindividual variability and overlap between ischemic and nonischemic ECG-patterns, incorporation of a previous elective (reference) ECG may improve accuracy. The aim of the current study was to explore the potential value of serial ECG analysis using subtraction electrocardiography.Methods: SUBTRACT is a multicenter retrospective observational study, including patients who were prehospitally evaluated for acute myocardial ischemia. For each patient, an elective previously recorded reference ECG was subtracted from the ambulance ECG. Patients were classified as myocardial ischemia cases or controls, based on the in-hospital diagnosis. The diagnostic performance of subtraction electrocardiography was tested using logistic regression of 28 variables describing the differences between the reference and ambulance ECGs. The Uni-G ECG Analysis Program was used for state-of-the-art single-ECG interpretation of the ambulance ECG.Results: In 1,229 patients, the mean area-under-the-curve of subtraction electrocardiography was 0.80 (95%CI: 0.77-0.82). The performance of our new method was comparable to single-ECG analysis using the Uni-G algorithm: sensitivities were 66% versus 67% (p-value > .05), respectively; specificities were 80% versus 81% (p-value > .05), respectively.Conclusions: In our initial exploration, the diagnostic performance of subtraction electrocardiography for the detection of acute myocardial ischemia proved equal to that of state-of-the-art automated single-ECG analysis by the Uni-G algorithm. Possibly, refinement of both algorithms, or even integration of the two, could surpass current electrocardiographic myocardial ischemia detection. [ABSTRACT FROM AUTHOR]

Objective To investigate the performance of vectorcardiogram(VCG) and electrocardiogram（ECG） on left septal fascicular block(LSFB).MethodsA total of 34 cases of VCG with LSFB in ECG examination were compared and analyzed.Results There were 34 cases of LSFB that meet the VCG diagram Nakaya stan-dard: In 8 cases, the maximum QRS loop vectors were from 45°-67° in the cross section(H) , and the forward-vector occupied (64.62±6.37)% of the total area; in 26 cases, the maximum QRS loop vectors were from 30°-44° in the cross section(H), and the forward-vector occupied (71.32±8.18)% of the total area. In 12 cases, the cross sections(H) were oriented in the right-front side(35.29%) with time of (11.88±1.14) ms; in 22 cases, the cross section(H) were oriented in the left-front side (64.71%);all the QRS ring were operated in counterclockwise. Among the 34 cases of ECG, 15 cases showed R/S>1 on V1-V3 lead(44.12%); 15 cases showed R/S>1 on V1 lead(44.12%); 31 cases showed R/S>1 on V2 lead(91.18%); 33 cases showed R/S>1 on lead V3(97.06%); 31 cases showed RV2> RV6>1(91.18%); 33 cases showed no Q wave on lead Ⅰ(97.06%),27 cases showed no Q waves on lead V5 and V6(79.41%).Conclusion The diagnosis of LSFB in VCG diagram is simple and easy. It shows better advantages in electrophysiological examination while combined VCG with ECG. [ABSTRACT FROM AUTHOR]

Electrocardiographic (ECG) and vectorcardiographic (VCG) analyses are used to diagnose current cardiovascular disease and for risk stratification for future adverse cardiovascular events. With increasing use of digital ECGs, research into novel ECG/VCG parameters has increased, but widespread computer-based ECG/VCG analysis is limited because there are no currently available, open-source, and easily customizable software packages designed for automated and reproducible analysis. We present BRAVEHEART, an open-source, modular, customizable, and easy to use software package implemented in the MATLAB programming language, for scientific analysis of standard 12-lead ECGs acquired in a digital format. BRAVEHEART accepts a wide variety of digital ECG formats and provides complete and automatic ECG/VCG processing with signal denoising to remove high- and low-frequency artifact, non-dominant beat identification and removal, accurate fiducial point annotation, VCG construction, median beat construction, customizable measurements on median beats, and output of measurements and results in numeric and graphical formats. The BRAVEHEART software package provides easily customizable scientific analysis of ECGs and VCGs. We hope that making BRAVEHART available will allow other researchers to further the field of ECG/VCG analysis without having to spend significant time and resources developing their own ECG/VCG analysis software and will improve the reproducibility of future studies. Source code, compiled executables, and a detailed user guide can be found at http://github.com/BIVectors/BRAVEHEART. The source code is distributed under the GNU General Public License version 3. • BRAVEHEART is open-source software for processing electrocardiograms (ECGs) and vectorcardiograms (VCGs) for research purposes. • BRAVEHEART provides complete and automatic ECG/VCG processing with output of measurements in numeric and graphical formats. • BRAVEHEART's modular design allows easy addition of new ECG formats or ECG/VCG measurements with minimal need for coding. • Large ECG datasets can be processed automatically in parallel, and poor quality ECGs can be flagged for review. • Source code and documentation are available at http://github.com/BIVectors/BRAVEHEART under the GNU GPL version 3. [ABSTRACT FROM AUTHOR]

Myocardial infarction (MI) occurs due to the decrease in the blood flow into one part of the heart, and it further causes damage to the heart muscle. The 12-channel electrocardiogram (ECG) has been widely used to detect and localize MI pathology in clinical studies. The vectorcardiogram (VCG) is a 3-channel recording system used to measure the heart’s electrical activity in sagittal, transverse, and frontal planes. The VCG signals have advantages over the 12-channel ECG to localize posterior MI pathology. Detection and localization of MI using VCG signals are vital in clinical practice. This paper proposes a multi-channel multi-scale two-stage deep-learning-based approach to detect and localize MI using VCG signals. In the first stage, the multivariate variational mode decomposition (MVMD) decomposes the three-channel-based VCG signal beat into five components along each channel. The multi-channel multi-scale VCG tensor is formulated using the modes of each channel of VCG data, and it is used as the input to the deep convolutional neural network (CNN) to classify MI and normal sinus rhythm (NSR) classes. In the second stage, the multi-class deep CNN is used for the categorization of anterior MI (AMI), anterior-lateral MI (ALMI), anterior-septal MI (ASMI), inferior MI (IMI), inferior-lateral MI (ILMI), inferior-posterior-lateral (IPLMI) classes using MI detected multi-channel multi-scale VCG instances from the first stage. The proposed approach is developed using the VCG data obtained from a public database. The results reveal that the approach has obtained the accuracy, sensitivity, and specificity values of 99.58%, 99.18%, and 99.87%, respectively, for MI detection. Moreover, for MI localization, we have obtained the overall accuracy value of 99.86% in the second stage for our proposed network. The proposed approach has demonstrated superior classification performance compared to the existing VCG signal-based MI detection and localization techniques.

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This paper takes three patients definitely diagnosed with left bundle branch block (LBBB) for case study. Their routine electrocardiogram (ECG) and vectorcardiogram (VCG) were synchronously recorded. On the VCGs of two patients with true LBBB, the starting vector was oriented in the left-front side with forward vector reduced; 20-ms vector was oriented in the left-rear side operating in the form of an 8-character shape; the central and terminal parts of the ring operated slowly. In one patient with left ventricular hypertrophy complicating branch-type complete LBBB (false LBBB), the starting vector was oriented in the right-front side, 20-ms vector was still left-front oriented, and the amplitude of the maximal vector of QRS loop significantly increased. Combined with the patients' clinical medical histories, VCG was found highly valuable in diagnosing true LBBB and made explanation of the additional ECG diagnostic criteria of true LBBB become possible. [ABSTRACT FROM AUTHOR]

Patients with Brugada syndrome (BrS) can show a leftward deviation of the frontal QRS-axis upon provocation with sodium channel blockers. The cause of this axis change is unclear. In this study, we aimed to determine (1) the prevalence of this left axis deviation and (2) to evaluate its cause, using the insights that could be derived from vectorcardiograms. Hence, from a large cohort of patients who underwent ajmaline provocation testing (n = 1430), we selected patients in whom a type-1 BrS-ECG was evoked (n = 345). Depolarization and repolarization parameters were analyzed for reconstructed vectorcardiograms and were compared between patients with and without a >30° leftward axis shift. We found (1) that the prevalence of a left axis deviation during provocation testing was 18% and (2) that this left axis deviation was not explained by terminal conduction slowing in the right ventricular outflow tract (4th QRS-loop quartile: +17 ± 14 ms versus +13 ± 15 ms, nonsignificant) but was associated with a more proximal conduction slowing (1st QRS-loop quartile: +12[8;18] ms versus +8[4;12] ms, p < 0.001 and 3rd QRS-loop quartile: +12 ± 10 ms versus +5 ± 7 ms, p < 0.001). There was no important heterogeneity of the action potential morphology (no difference in the ventricular gradient), but a left axis deviation did result in a discordant repolarization (spatial QRS-T angle: 122[59;147]° versus 44[25;91]°, p < 0.001). Thus, although the development of the type-1 BrS-ECG is characterized by a terminal conduction delay in the right ventricle, BrS-patients with a left axis deviation upon sodium channel blocker provocation have an additional proximal conduction slowing, which is associated with a subsequent discordant repolarization. Whether this has implications for risk stratification is still undetermined.

Background: Many variants of the spatial QRS-T angle (QRS-Ta) are in use. We aimed to identify the best QRS-Ta for all-cause mortality prediction among different variants.Methods: 6667 individuals from the Inter99 General Population Study were followed for a median of 12.7 years. Vectorcardiograms were calculated using the Kors and Inverse Dower matrices. The QRS-Ta was calculated using both mean and peak vectors of the QRS- and T-loops. Hazard ratios (HR) for abnormal QRS-Tas were calculated using a Cox's Proportional Hazard Model.Results: The highest HR and largest AUC for all-cause mortality was obtained with the Kors matrix and the mean vector (HR = 2.2, 95% confidence interval: [1.38;3.43] p < 0.001, in men). There was interaction with the orientation of the QRS-T plane.Conclusion: For optimal prediction of all-cause mortality, the mean vectors in the QRS- and T-loops of the Kors-derived vectorcardiogram should be used. QRS-T plane orientation affects mortality prediction. [ABSTRACT FROM AUTHOR]

Objective To timely identify and diagnose old inferior posterolateral myocardial infarction complicating left anterior fascicular block on synchronously recorded electrocardiogram! EGG) and vectorcardiogram ( VCG) by the Wilson & Frank dual lead system with three-dimensional electrocardiography. Methods We selected and analyzed the VCGs with typical features of definitely diagnosed old inferior posterolateral myocardial infarction complicating left anterior fascicular block. The changes of VCGs were observed. Results The vectorcardiographies features of three cases coincided with vectoreardiographie diagnostic criteria of old inferior posterolateral myocardial infarction complicating left anterior fascicular block. Conclusion VCG has high diagnostic value for old inferior posterolateral myocardial infarction complicating left anterior fascicular block. [ABSTRACT FROM AUTHOR]

Purpose: Implantable cardioverter-defibrillators (ICDs) improve survival of systolic heart failure (HF) patients who are at risk of sudden cardiac death (SCD). We recently showed that electrocardiographic (ECG) global electrical heterogeneity (GEH) is independently associated with SCD in the community-dwelling cohort and developed GEH SCD risk score. The Global Electrical Heterogeneity and Clinical Outcomes (GEHCO) study is a retrospective multicenter cohort designed with two goals: (1) validate an independent association of ECG GEH with sustained ventricular tachyarrhythmias and appropriate ICD therapies and (2) validate GEH ECG risk score for prediction of sustained ventricular tachyarrhythmias and appropriate ICD therapies in systolic HF patients with primary prevention ICD.Methods: All records of primary prevention ICD recipients with available data for analysis are eligible for inclusion. Records of ICD implantation in patients with inherited channelopathies and cardiomyopathies are excluded. Raw digital 12-lead pre-implant ECGs will be used to measure GEH (spatial QRST angle, spatial ventricular gradient magnitude, azimuth, and elevation, and sum absolute QRST integral). The primary endpoint is defined as a sustained ventricular tachyarrhythmia event with appropriate ICD therapy. All-cause death without preceding sustained ventricular tachyarrhythmia with appropriate ICD therapy will serve as a primary competing outcome. The study will draw data from the academic medical centers.Results: We describe the study protocol of the first multicenter retrospective cohort of primary prevention ICD patients with recorded at baseline digital 12-lead ECG.Conclusion: Findings from this study will inform future trials to identify patients who are most likely to benefit from primary prevention ICD.Trial Registration: URL: http://www.clinicaltrials.gov . Unique identifier: NCT03210883. [ABSTRACT FROM AUTHOR]

Advanced sensing and internet of things bring the big data, which provides an unprecedented opportunity for data-driven knowledge discovery. However, it is common that a large number of variables (or predictors, features) are involved in the big data. Complex interdependence structures among variables pose significant challenges on the traditional framework of predictive modeling. This paper presents a new methodology of self-organizing network to characterize the interrelationships among variables and cluster them into homogeneous subgroups for predictive modeling. Specifically, we develop a new approach, namely nonlinear coupling analysis to measure variable-to-variable interdependence structures. Further, each variable is represented as a node in the complex network. Nonlinear-coupling forces move these nodes to derive a self-organizing topology of the network. As such, variables are clustered into sub-network communities. Results of simulation experiments demonstrate that the proposed method not only outperforms traditional variable clustering algorithms such as hierarchical clustering and oblique principal component analysis, but also effectively identifies interdependent structures among variables and further improves the performance of predictive modeling. Additionally, real-world case study shows that the proposed method yields an average sensitivity of 96.80% and an average specificity of 92.62% in the identification of myocardial infarctions using sparse parameters of vectorcardiogram representation models. The proposed new idea of self-organizing network is generally applicable for predictive modeling in many disciplines that involve a large number of highly-redundant variables. [ABSTRACT FROM AUTHOR]