Body Surface Potential Mapping Research Articles

CineECG analysis of body surface potential mapping performed in preclinical and clinical plakophilin-2-variant carriers

Abstract Background/introduction Pathogenic variation of the plakophilin-2 (PKP2) gene is associated with arrhythmogenic cardiomyopathy (ACM). Disease manifestation in PKP2-pathogenic variant (PV) carriers differs greatly. Early detection of disease is crucial and could be of benefit in the risk stratification of this population. 67-lead body surface potential mapping (BSPM) could offer more insight into subtle electrical abnormalities. CineECG is a novel tool which can provide an estimation of the average pathway of ventricular activation based on the BSPM-signals, and could be of added value in the detection of electrical abnormalities. Purpose This study aimed to analyze 67-lead BSPM data with CineECG to ascertain the electrical activation pathway in PKP2-PV carriers and to compare these to the normal CineECG. Methods Ten PKP2-PV carriers underwent 67-lead BSPM. Six carriers were without definite ACM diagnosis (preclinical); no Task Force Criteria (TFC) were met apart from the identification of the pathogenic PKP2-variant. The other four carriers were all diagnosed with definite ACM (symptomatic). The average location and direction of ventricular activation was determined with CineECG, resulting in a CineECG trajectory throughout the ventricles. These results were compared to the normal CineECG trajectory, which was established in a previous study with normal ECG’s from the PTB-XL database. A CineECG trajectory that deviated more than 15% from the normal trajectory was considered abnormal. Additionally, to further determine the added diagnostic value of BSPM and CineECG beyond the standard 12-lead ECG, the 12-lead ECG’s were evaluated for abnormalities by three different ECG-experts. Results Expert evaluation of the 12-lead ECG showed that all preclinical PKP2-PV carriers had a normal ECG (no TFC and no other abnormalities such as abnormal electrical heart axis, pathological Q-waves or low voltage). In the symptomatic carriers, all ECG’s showed either presence of TFC or conduction abnormalities. Of the ten PKP2-PV carriers, eight exhibited an abnormal CineECG trajectory. In the preclinical group, four out of six carriers had an abnormal activation trajectory, while all symptomatic carriers had an abnormal CineECG trajectory. Conclusions Through CineECG analysis of 67-lead BSPM, abnormal ventricular activation was identified in the majority of PKP2-PV carriers. Notably, abnormal activation was observed in four out of six preclinical PKP2-PV carriers while the standard 12-lead ECG showed no abnormalities. Future research in a larger group, which also includes follow-up data, is warranted to determine whether these results are an indication of early signs of disease.Figure 1

High-resolution repolarization changes preceding short-coupled ectopy in idiopathic ventricular fibrillation, and effects of quinidine

Abstract Background Idiopathic ventricular fibrillation (VF) is linked to early repolarization, increased repolarization heterogeneity, and (short-coupled) premature ventricular complexes (PVCs). Quinidine, an antiarrhythmic drug with class-IA and -III effects, reduces the occurrence of PVCs and VF, but its effects on repolarization have not yet been studied at the whole-heart level in idiopathic-VF patients. Purpose To study dynamic changes in repolarization preceding short-coupled PVCs using noninvasive electrocardiographic imaging (ECGI) in a patient with idiopathic VF, and the antiarrhythmic effects of quinidine. Methods ECGI was performed during sinus rhythm in a 61-year-old male with an ICD (secondary prevention; 2.5 mg nebivolol daily) two days after recurrent idiopathic VF (Fig. A). This was done 1) at baseline, 2 minutes before short-coupled ectopy ("baseline"); 2) at baseline, 10 seconds before the short-coupled PVC ("pre PVC"); and 3) at 2 hours after start of quinidine 200 mg ("on-quinidine"). The ECGI procedure consisted of a 224-electrode body surface potential map and a contrast-enhanced CT scan to obtain torso and heart geometries. After reconstruction of epicardial unipolar electrograms (UEGs), local activation and repolarization times (ATs and RTs) were derived from UEGs by assessing the steepest downslope of the QRS complex and steepest upslope of the T waves, respectively, of 10-second signal-averaged beats. AT and RT duration (first to last AT or RT) were assessed. Results At baseline, QRS duration and QT interval measured 107 ms and 343 ms, respectively, on the standard 12-lead ECG. ECGI-derived epicardial AT duration was 72 ms, and RT histogram span 92 ms. The coupling interval of the PVC that triggered VF in the ICD readout was 340 ms (Fig. A). During 44 minutes of ECGI, 157 short-coupled PVCs from the moderator-band region were recorded (Fig. B; no tachycardia or VF). Just prior to a PVC, epicardial early repolarization at the PVC origin decreased by 26 ms (star in Figs. C-E), and the RT histogram broadened to 109 ms (Fig. E). While on-quinidine, (25 minutes; QRS duration 107 ms, QT interval 419 ms), epicardial repolarization was prolonged (Fig. C/D), also at the site of abnormal impulse formation. Quinidine had increased the epicardial AT duration to 79 ms, and RT histogram span to 133 ms. PVCs were completely suppressed. The patient remained free of sustained arrhythmias while on-quinidine. Conclusion(s) In this case of short-coupled idiopathic VF, epicardial early repolarization shortened momentarily prior to abnormal impulse formation. We found dynamic substrate-trigger characteristics that likely facilitate reentrant excitation. Quinidine prolonged the duration of epicardial activation and repolarization, suppressing the ectopy and VF recurrence.

3D Printed PEDOT:PSS-based Conducting and Patternable Eutectogel Electrodes for Machine Learning on Textiles

The proliferation of medical wearables necessitates the development of novel electrodes for cutaneous electrophysiology. In this work, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is combined with a deep eutectic solvent (DES) and polyethylene glycol diacrylate (PEGDA) to develop printable and biocompatible electrodes for long-term cutaneous electrophysiology recordings. The impact of printing parameters on the conducting properties, morphological characteristics, mechanical stability and biocompatibility of the material were investigated. The optimised eutectogel formulations were fabricated in four different patterns —flat, pyramidal, striped and wavy— to explore the influence of electrode geometry on skin conformability and mechanical contact. These electrodes were employed for impedance and forearm EMG measurements. Furthermore, arrays of twenty electrodes were embedded into a textile and used to generate body surface potential maps (BSPMs) of the forearm, where different finger movements were recorded and analysed. Finally, BSPMs for three different letters (B, I, O) in sign-language were recorded and used to train a logistic regressor classifier able to reliably identify each letter. This novel cutaneous electrode fabrication approach offers new opportunities for long-term electrophysiological recordings, online sign-language translation and brain-machine interfaces.

Nonlocal based FISTA network for noninvasive cardiac transmembrane potential imaging

Objective. The primary aim of our study is to advance our understanding and diagnosis of cardiac diseases. We focus on the reconstruction of myocardial transmembrane potential (TMP) from body surface potential mapping. Approach. We introduce a novel methodology for the reconstruction of the dynamic distribution of TMP. This is achieved through the integration of convolutional neural networks with conventional optimization algorithms. Specifically, we utilize the subject-specific transfer matrix to describe the dynamic changes in TMP distribution and ECG observations at the body surface. To estimate the TMP distribution, we employ LNFISTA-Net, a learnable non-local regularized iterative shrinkage-thresholding network. The coupled estimation processes are iteratively repeated until convergence. Main results. Our experiments demonstrate the capabilities and benefits of this strategy. The results highlight the effectiveness of our approach in accurately estimating the TMP distribution, thereby providing a reliable method for the diagnosis of cardiac diseases. Significance. Our approach demonstrates promising results, highlighting its potential utility for a range of applications in the medical field. By providing a more accurate and dynamic reconstruction of TMP, our methodology could significantly improve the diagnosis and treatment of cardiac diseases, thereby contributing to advancements in healthcare.

Body Surface Potential Mapping during Ventricular Depolarization in Athletes with Prolonged PQ Interval after Exercise.

Prolongation of the PQ interval, generally associated with an atrioventricular conduction delay, may be related to changes in intraventricular impulse spreading. To assess, using body surface potential mapping (BSPM), the process of ventricular depolarization in athletes with prolonged PQ intervals at rest and after exercise. The study included 7 cross-country skiers with a PQ interval of more than 200 ms (Prolonged-PQ group) and 7 with a PQ interval of less than 200 ms (Normal-PQ group). The BSPM from 64 unipolar torso leads was performed before (Pre-Ex) and after the bicycle exercise test (Post-Ex). Body surface equipotential maps were analyzed during ventricular depolarization. The significance level was 5%. Compared to Normal-PQ athletes, the first and second periods of the stable position of cardiac potentials on the torso surface were longer, and the formation of the "saddle" potential distribution occurred later, at Pre-Ex, in Prolonged-PQ athletes. At Post-Ex, the Prolonged-PQ group showed a shortening of the first and second periods of stable potential distributions and a decrease in appearance time of the "saddle" phenomenon relative to Pre-Ex (to the values near to those of the Normal-PQ group). Additionally, at Post-Ex, the first inversion of potential distributions and the total duration of ventricular depolarization in Prolonged-PQ athletes decreased compared to Pre-Ex and with similar values in Normal-PQ athletes. Compared to Normal-PQ athletes, the second inversion was longer at Pre-Ex and Post-Ex in Prolonged-PQ athletes. Prolonged-PQ athletes had significant differences in the temporal characteristics of BSPM during ventricular depolarization both at rest and after exercise as compared to Normal-PQ athletes.

Correlation of the Left Ventricular Systolic Dysfunction and Ventricular Depolarization in a Post-Infarction Model of Chronic Heart Failure.

The body surface potential mapping of the heart during the period of ventricular depolarization and the inotropic function of the ventricles were studied in rats under conditions of a translational model of post-infarction chronic heart failure developed by us. We revealed a statistically significant (p<0.001) correlation between the left-ventricular ejection fraction and the values of the maximum positive and negative extrema of the cardioelectric field on the body surface of rats with post-infarction chronic heart failure caused by anterior transmural myocardial infarction. The calculated linear regression equations have high predictive efficiency, which makes it possible to use the amplitude characteristics of the heart cardioelectric field as a marker of the development of chronic heart failure.

Body Surface Potential Mapping in Highly Trained Athletes during Ventricular Depolarization

Body Surface Potential Mapping in Highly Trained Athletes during Ventricular Depolarization

A method for noninvasive beat-by-beat visualization of His bundle signals.

Invasive recording of His bundle signals (HBS) in electrophysiological study (EPS) is important in determining HV interval, the time taken to activate the ventricles from the His bundle. Noninvasive surface measurements of HBS are attempted by averaging typically 100-200 cardiac cycles of ECG time series in body surface potential mapping (BSPM) and in magnetocardiography (MCG) which records weak cardiac magnetic fields by highly sensitive detectors. However, noninvasive beat-by-beat extraction of HBS is challenged by ramp-like atrial signals and noise in PR segment of the cardiac cycle. By making use of a signal-averaged trace showing prominent HBS as a guide trace, we developed a method combining interval-dependent wavelet thresholding (IDWT) and signal space projection (SSP) technique to eliminate artifacts from single beats. The method was applied on MCG recorded on 21 subjects with known HV intervals based on EPS and noninvasive signal-averaging, including five subjects with BSPM recorded subsequently. The method was also applied on stress-MCG of a subject featuring autonomic dynamics. HBS could be extracted from 19 out of 21 subjects by signal-averaging whose timing differed from EPS between -8 and 11 ms as tested by 2 observers. HBS in single beats were seen as aligned patterns in inter-beat contours and were appreciable in stress-MCG and conspicuous than BSPM. The performance of the method was evaluated on simulated and measured MCG to be adequate if the signal-to-noise ratio was at least 20 dB. These results suggest the use of this method for noninvasive assessments on HBS.

Body surface potential mapping detects early disease onset in plakophilin-2-pathogenic variant carriers.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive inherited cardiac disease. Early detection of disease and risk stratification remain challenging due to heterogeneous phenotypic expression. The standard configuration of the 12 lead electrocardiogram (ECG) might be insensitive to identify subtle ECG abnormalities. We hypothesized that body surface potential mapping (BSPM) may be more sensitive to detect subtle ECG abnormalities. We obtained 67 electrode BSPM in plakophilin-2 (PKP2)-pathogenic variant carriers and control subjects. Subject-specific computed tomography/magnetic resonance imaging based models of the heart/torso and electrode positions were created. Cardiac activation and recovery patterns were visualized with QRS- and STT-isopotential map series on subject-specific geometries to relate QRS-/STT-patterns to cardiac anatomy and electrode positions. To detect early signs of functional/structural heart disease, we also obtained right ventricular (RV) echocardiographic deformation imaging. Body surface potential mapping was obtained in 25 controls and 42 PKP2-pathogenic variant carriers. We identified five distinct abnormal QRS-patterns and four distinct abnormal STT-patterns in the isopotential map series of 31/42 variant carriers. Of these 31 variant carriers, 17 showed no depolarization or repolarization abnormalities in the 12 lead ECG. Of the 19 pre-clinical variant carriers, 12 had normal RV-deformation patterns, while 7/12 showed abnormal QRS- and/or STT-patterns. Assessing depolarization and repolarization by BSPM may help in the quest for early detection of disease in variant carriers since abnormal QRS- and/or STT-patterns were found in variant carriers with a normal 12 lead ECG. Because electrical abnormalities were observed in subjects with normal RV-deformation patterns, we hypothesize that electrical abnormalities develop prior to functional/structural abnormalities in ARVC.

Localization of the ventricular pacing site from BSPM and standard 12-lead ECG: a comparison study

Inverse ECG imaging methods typically require 32–250 leads to create body surface potential maps (BSPM), limiting their routine clinical use. This study evaluated the accuracy of PaceView inverse ECG method to localize the left or right ventricular (LV and RV, respectively) pacing leads using either a 99-lead BSPM or the 12-lead ECG. A 99-lead BSPM was recorded in patients with cardiac resynchronization therapy (CRT) during sinus rhythm and sequential LV/RV pacing. The non-contrast CT was performed to localize precisely both ECG electrodes and CRT leads. From a BSPM, nine signals were selected to obtain the 12-lead ECG. Both BSPM and 12-lead ECG were used to localize the RV and LV lead, and the localization error was calculated. Consecutive patients with dilated cardiomyopathy, previously implanted with a CRT device, were enrolled (n = 19). The localization error for the RV/LV lead was 9.0 [IQR 4.8–13.6] / 7.7 [IQR 0.0–10.3] mm using the 12-lead ECG and 9.1 [IQR 5.4–15.7] / 9.8 [IQR 8.6–13.1] mm for the BSPM. Thus, the noninvasive lead localization using the 12-lead ECG was accurate enough and comparable to 99-lead BSPM, potentially increasing the capability of 12-lead ECG for the optimization of the LV/RV pacing sites during CRT implant or for the most favorable programming.

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.

Detection of brief atrial fibrillation in continuous 12-lead ECG recordings using an algorithm for computerized resting ECG interpretation combined with convolutional neural network for reducing false detections

Existing criteria recommended by ACC/ESC for identifying patients with ST elevation myocardial infarction (STEMI) from the 12-lead ECG perform with high specificity (SP), but low sensitivity (SE). In our previous studies, we found that the SE of ischemia detection can be markedly improved without any loss of SP by calculating, from the 12-lead ECG, ST deviation in 3 “optimal” vessel-specific leads (VSLs). Our original VSLs, based on ΔST body-surface potential maps (BSPMs), have been modified by using the more appropriate J-point BSPMs at peak ischemia (without subtraction of pre-occlusion distributions). The aim of the present study was to compare the performance of these new VSLs with that achieved by the STEMI criteria used in current practice.Two independent datasets of 12-lead ECGs were used: the STAFF III dataset acquired during ischemic episodes caused by balloon inflation in LAD (n = 35), RCA (n = 47), and LCx (n = 17) coronary arteries, and the Glasgow dataset comprising admission 12-lead ECGs of 116 patients who were hospitalized for chest pain and underwent contrast-enhanced cardiac MRI that confirmed AMI in 58 patients (50%).We found that, in the STAFF III dataset, the detection of ischemic state by the STEMI criteria attained SE/SP of 60/97%, whereas SE/SP values of VSLs were 72/98%. In the Glasgow dataset, STEMI criteria yielded SE/SP of 43/98%, whereas the VSLs improved SE/SP to 60/98%. The most significant increase in diagnostic performance appeared in patients with LCx coronary artery occlusion: in STAFF III data (n = 17) SE achieved by STEMI criteria was improved by the VSLs from 35% to 71%; in Glasgow data (n = 12) SE of 31% achieved by STEMI criteria was improved by the VSLs to 69%.In our study population, existing ACC/ESC STEMI criteria complemented by the new VSLs yielded much improved sensitivity of ischemia detection without any detrimental effect on specificity. This finding needs to be corroborated on a larger chest-pain patient population with typical prevalence of acute ischemia presented to the emergency rooms.

Novel non-invasive ECG imaging method based on the 12-lead ECG for reconstruction of ventricular activation: A proof-of-concept study.

Current non-invasive electrocardiographic imaging (ECGi) methods are often based on complex body surface potential mapping, limiting the clinical applicability. The aim of this pilot study was to evaluate the ability of a novel non-invasive ECGi method, based on the standard 12-lead ECG, to localize initial site of ventricular activation in right ventricular (RV) paced patients. Validation of the method was performed by comparing the ECGi reconstructed earliest site of activation against the true RV pacing site determined from cardiac computed tomography (CT). This was a retrospective study using data from 34 patients, previously implanted with a dual chamber pacemaker due to advanced atrioventricular block. True RV lead position was determined from analysis of a post-implant cardiac CT scan. The ECGi method was based on an inverse-ECG algorithm applying electrophysiological rules. The algorithm integrated information from an RV paced 12-lead ECG together with a CT-derived patient-specific heart-thorax geometric model to reconstruct a 3D electrical ventricular activation map. The mean geodesic localization error (LE) between the ECGi reconstructed initial site of activation and the RV lead insertion site determined from CT was 13.9 ± 5.6 mm. The mean RV endocardial surface area was 146.0 ± 30.0 cm2 and the mean circular LE area was 7.0 ± 5.2 cm2 resulting in a relative LE of 5.0 ± 4.0%. We demonstrated a novel non-invasive ECGi method, based on the 12-lead ECG, that accurately localized the RV pacing site in relation to the ventricular anatomy.

Constructing Bodily Emotion Maps Based on High-Density Body Surface Potentials for Psychophysiological Computing.

Emotion is a complex physiological and psychological activity, accompanied by subjective physiological sensations and objective physiological changes. The body sensation map describes the changes in body sensation associated with emotion in a topographic manner, but it relies on subjective evaluations from participants. Physiological signals are a more reliable measure of emotion, but most research focuses on the central nervous system, neglecting the importance of the peripheral nervous system. In this study, a body surface potential mapping (BSPM) system was constructed, and an experiment was designed to induce emotions and obtain high-density body surface potential information under negative and non-negative emotions. Then, by constructing and analyzing the functional connectivity network of BSPs, the high-density electrophysiological characteristics are obtained and visualized as bodily emotion maps. The results showed that the functional connectivity network of BSPs under negative emotions had denser connections, and emotion maps based on local clustering coefficient (LCC) are consistent with BSMs under negative emotions. in addition, our features can classify negative and non-negative emotions with the highest classification accuracy of 80.77%. In conclusion, this study constructs an emotion map based on high-density BSPs, which offers a novel approach to psychophysiological computing.

Classification of heart rhythm disturbances based on BSPM measurements

The multitude of measurement data obtained from BSPM (Body Surface Potential Mapping) requires automatic detection and classification methods to detect disturbances. The article describes the method of classification of heart rate disorders based on the characteristics of signals from sensors. For the research, a coefficient was created that allows the classification of cardiac arrhythmias in the BSPM measurements. In addition, BSPM signals were simulated using a system constructed for testing an innovative measuring vest with 102 measuring electrodes.

Body surface potential mapping time series recognition using convolutional and recurrent neural networks

This article shows recognition of biomedical time series from Body Surface Potential Mapping by means of different convolutional and recurrent neural networks models. The various kinds of neural networks models were examined and compared: model with 1D convolutional layer, model with Long - Short Term Memory layer and model with Gated Recurrent Unit layer.

A 3D-CNN with temporal-attention block to predict the recurrence of atrial fibrillation based on body-surface potential mapping signals.

Catheter ablation has become an important treatment for atrial fibrillation (AF), but its recurrence rate is still high. The aim of this study was to predict AF recurrence using a three-dimensional (3D) network model based on body-surface potential mapping signals (BSPMs). BSPMs were recorded with a 128-lead vest in 14 persistent AF patients before undergoing catheter ablation (Maze-IV). The torso geometry was acquired and meshed by point cloud technology, and the BSPM was interpolated into the torso geometry by the inverse distance weighted (IDW) method to generate the isopotential map. Experiments show that the isopotential map of BSPMs can reflect the propagation of the electrical wavefronts. The 3D isopotential sequence map was established by combining the spatial-temporal information of the isopotential map; a 3D convolutional neural network (3D-CNN) model with temporal attention was established to predict AF recurrence. Our study proposes a novel attention block that focuses the characteristics of atrial activations to improve sampling accuracy. In our experiment, accuracy (ACC) in the intra-patient evaluation for predicting the recurrence of AF was 99.38%. In the inter-patient evaluation, ACC of 3D-CNN was 81.48%, and the area under the curve (AUC) was 0.88. It can be concluded that the dynamic rendering of multiple isopotential maps can not only comprehensively display the conduction of cardiac electrical activity on the body surface but also successfully predict the recurrence of AF after CA by using 3D isopotential sequence maps.

Novel spatiotemporal processing tools for body-surface potential map signals for the prediction of catheter ablation outcome in persistent atrial fibrillation.

Background: Signal processing tools are required to efficiently analyze data collected in body-surface-potential map (BSPM) recordings. A limited number of such tools exist for studying persistent atrial fibrillation (persAF). We propose two novel, spatiotemporal indices for processing BSPM data and test their clinical applicability through a comparison with the recently proposed non-dipolar component index (NDI) for prediction of single-procedure catheter ablation (CA) success rate in persAF patients. Methods: BSPM recordings were obtained with a 252-lead vest in 13 persAF patients (8 men, 63 ± 8 years, 11 ± 13 months sustained AF duration) before undergoing CA. Each recording was divided into seven 1-min segments of high signal quality. Spatiotemporal ventricular activity (VA) cancellation was applied to each segment to isolate atrial activity (AA). The two novel indices, called error-ratio, normalized root-mean-square error (ERNRMSE) and error-ratio, mean-absolute error (ERABSE), were calculated. These indices quantify the capacity of a subset of BSPM vest electrodes to accurately represent the AA, and AA dominant frequency (DF), respectively, on all BSPM electrodes over time, compared to the optimal principal component analysis (PCA) representation. The NDI, quantifying the fraction of energy retained after removal of the three largest PCs, was also calculated. The two novel indices and the NDI were statistically compared between patient groups based on single-procedure clinical CA outcome. Finally, their predictive power for univariate CA outcome classification was assessed using receiver operating characteristic (ROC) analysis with cross-validation for a logistic regression classifier. Results: Patient clinical outcomes were recorded 6 months following procedures, and those who had an arrhythmia recurrence at least 2 months post-CA were defined as having a negative outcome. Clinical outcome information was available for 11 patients, 6 with arrhythmia recurrence. Therefore, a total of 77 1-min AA-BSPM segments were available for analysis. Significant differences were found in the values of the novel indices and NDI between patients with arrhythmia recurrence post-ablation and those without. ROC analysis showed the best CA outcome predictive performance for ERNRMSE (AUC = 0.77 ± 0.08, sensitivity = 76.2%, specificity = 84.8%). Conclusion: Significant association was found between the novel indices and CA success or failure. The novel index ERNRMSE additionally shows good predictive power for single-procedure CA outcome.

Body Surface Potential Mapping during Ventricular Depolarization in Rats after Acute Exhaustive Exercise.

Exhaustive physical exercise can cause substantial changes in the electrical properties of the myocardium. To evaluate, using body surface potential mapping, the electrical activity of the heart in rats during ventricular depolarization after acute exhaustive exercise. Twelve-week-old male rats were submitted to acute treadmill exercise at 36 m/min until exhaustion. Unipolar electrocardiograms (ECGs) from the torso surface were recorded in zoletil-anesthetized rats three to five days before (Pre-Ex), 5 and 10 minutes after exhaustive exercise (Post-Ex 5 and Post-Ex 10, respectively) simultaneously with ECGs in limb leads. The instantaneous body surface potential maps (BSPMs) were analyzed during ventricular depolarization. P values <0.05 were considered statistically significant. Compared with Pre-Ex, an early completion of the second inversion of potential distributions, an early completion of ventricular depolarization, as well as a decrease in the duration of the middle phase and the total duration of ventricular depolarization on BSPMs were revealed at Post-Ex 5. Also, compared with Pre-Ex, an increase in the amplitude of negative BSPM extremum at the R-wave peak on the ECG in lead II (RII-peak) and a decrease in the amplitude of negative BSPM extremum at 3 and 4 ms after RII-peak were showed at Post-Ex 5. At Post-Ex 10, parameters of BSPMs did not differ from those at Pre-Ex. In rats, acute exhaustive exercise causes reversible changes in the temporal and amplitude characteristics of BSPMs during ventricular depolarization, most likely related to alterations in the excitation of the main mass of the ventricular myocardium.

Identification of atrial fibrillation drivers by means of concentric ring electrodes

Background and objectiveThe prevalence of atrial fibrillation (AF) has tripled in the last 50 years due to population aging. High-frequency (DFdriver) activated atrial regions lead the activation of the rest of the atria, disrupting the propagation wavefront. Fourier based spectral analysis of body surface potential maps have been proposed for DFdriver identification, although these approaches present serious drawbacks due to their limited spectral resolution for short AF epochs and the blurring effect of the volume conductor. Laplacian signals (BC-ECG) from bipolar concentric ring electrodes (CRE) have been shown to outperform the spatial resolution achieved with conventional unipolar recordings. Our aimed was to determine the best DFdriver estimator in endocardial electrograms and to assess the BC-ECG capacity of CRE to quantify AF activity non-invasively. Methods31 AF episodes were simulated using realistic tridimensional models of the atria electrical activity and torso. Periodogram and autoregressive (AR) spectral estimators were computed and the percentile (P90th, P95th and P98th) to impose on the dominant frequencies (DFs) across whole atria to define the best DFdriver estimator evaluated. The identification of DFdriver on DFs from BC-ECG and unipolar surface signals with conventional disc electrodes was compared. ResultsThe best DFdriver estimator was P95th and AR order 100. BC-ECG signals allowed better detection of AF activity than unipolar signals, with a significantly greater percentage of electrode locations in which DFdriver was identified (p-value 0.0095). ConclusionsThe use of BC-ECG signals for body surface Laplacian potential mapping with CRE could be helpful for better AF diagnosis, prognosis and ablation procedures than those with conventional disk electrodes.