Electrical cardioversion presents one of the treatment options for atrial fibrillation (AF). However, the early recurrence rate is high, reaching ~40% three months after the procedure. Features based on vectorcardiographic signals were explored to find association with early recurrence of AF. Eighty-four patients with non-paroxysmal AF referred to electrical cardioversion were prospectively studied; early AF recurrence was present in 40 (47.6%). Patients underwent 24-h Holter ECG monitoring three months after the procedure to assess AF recurrence. Pre-procedural 12-lead ECGs (10 s, 1 kHz) were recorded and automatically analyzed. We explored associations of VCG-based features with early AF recurrence. Two features were strongly associated with AF recurrence: (1) a mean VCG (y-axis) signal slope in a window starting 145 ms before QRS center, lasting for 190 ms (AUC 0.778, p < 0.001), and (2) a mean VCG (z-axis) signal slope in a window starting 60 ms after QRS center, lasting for 465 ms (AUC 0.744, p < 0.001). These features showed higher association to the outcome than eighteen baseline clinical features. Our approach revealed features based on a slope of vectorcardiographic signals. This work also suggests that state of ventricles strongly affects the AF recurrence after electrical cardioversion.
- MeSH
- Electric Countershock * MeSH
- Electrocardiography, Ambulatory MeSH
- Atrial Fibrillation * therapy physiopathology MeSH
- Middle Aged MeSH
- Humans MeSH
- Prospective Studies MeSH
- Recurrence * MeSH
- Aged MeSH
- Vectorcardiography * methods MeSH
- Treatment Outcome MeSH
- Check Tag
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Introduction: This study proposes an algorithm for preprocessing VCG records to obtain a representative QRS loop. Methods: The proposed algorithm uses the following methods: Digital filtering to remove noise from the signal, wavelet-based detection of ECG fiducial points and isoelectric PQ intervals, spatial alignment of QRS loops, QRS time synchronization using root mean square error minimization and ectopic QRS elimination. The representative QRS loop is calculated as the average of all QRS loops in the VCG record. The algorithm is evaluated on 161 VCG records from a database of 58 healthy control subjects, 69 patients with myocardial infarction, and 34 patients with bundle branch block. The morphologic intra-individual beat-to-beat variability rate is calculated for each VCG record. Results and Discussion: The maximum relative deviation is 12.2% for healthy control subjects, 19.3% for patients with myocardial infarction, and 17.2% for patients with bundle branch block. The performance of the algorithm is assessed by measuring the morphologic variability before and after QRS time synchronization and ectopic QRS elimination. The variability is reduced by a factor of 0.36 for healthy control subjects, 0.38 for patients with myocardial infarction, and 0.41 for patients with bundle branch block. The proposed algorithm can be used to generate a representative QRS loop for each VCG record. This representative QRS loop can be used to visualize, compare, and further process VCG records for automatic VCG record classification.
- Publication type
- Journal Article MeSH
This article presents an overview of existing approaches to perform vectorcardiographic (VCG) diagnostics of ischemic heart disease (IHD). Individual methodologies are divided into categories to create a comprehensive and clear overview of electrical cardiac activity measurement, signal pre-processing, features extraction and classification procedures. An emphasis is placed on methods describing the electrical heart space (EHS) by several features extraction techniques based on spatiotemporal characteristics or signal modelling and signal transformations. Performance of individual methodologies are compared depending on classification of extent of ischemia, acute forms - myocardial infarction (MI) and myocardial scars localization. Based on a comparison of imaging methods, the advantages of VCG over the standard 12-leads ECG such as providing a 3D orthogonal leads imaging, better performance, and appropriate computer processing are highlighted. The issues of electrical cardiac activity measurements on body surface, the lack of VKG databases supported by a more accurate imaging method, possibility of comparison with the physiology of individual cases are outlined as potential reserves for future research.
- MeSH
- Electrocardiography methods MeSH
- Myocardial Infarction * MeSH
- Humans MeSH
- Myocardium MeSH
- Signal Processing, Computer-Assisted MeSH
- Heart physiology MeSH
- Vectorcardiography * methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
BACKGROUND: Left bundle branch area pacing (LBBAP) has recently been introduced as a novel physiological pacing strategy. Within LBBAP, distinction is made between left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP, no left bundle capture). OBJECTIVE: To investigate acute electrophysiological effects of LBBP and LVSP as compared to intrinsic ventricular conduction. METHODS: Fifty patients with normal cardiac function and pacemaker indication for bradycardia underwent LBBAP. Electrocardiography (ECG) characteristics were evaluated during pacing at various depths within the septum: starting at the right ventricular (RV) side of the septum: the last position with QS morphology, the first position with r' morphology, LVSP and-in patients where left bundle branch (LBB) capture was achieved-LBBP. From the ECG's QRS duration and QRS morphology in lead V1, the stimulus- left ventricular activation time left ventricular activation time (LVAT) interval were measured. After conversion of the ECG into vectorcardiogram (VCG) (Kors conversion matrix), QRS area and QRS vector in transverse plane (Azimuth) were determined. RESULTS: QRS area significantly decreased from 82 ± 29 µVs during RV septal pacing (RVSP) to 46 ± 12 µVs during LVSP. In the subgroup where LBB capture was achieved (n = 31), QRS area significantly decreased from 46 ± 17 µVs during LVSP to 38 ± 15 µVs during LBBP, while LVAT was not significantly different between LVSP and LBBP. In patients with normal ventricular activation and narrow QRS, QRS area during LBBP was not significantly different from that during intrinsic activation (37 ± 16 vs. 35 ± 19 µVs, respectively). The Azimuth significantly changed from RVSP (-46 ± 33°) to LVSP (19 ± 16°) and LBBP (-22 ± 14°). The Azimuth during both LVSP and LBBP were not significantly different from normal ventricular activation. QRS area and LVAT correlated moderately (Spearman's R = 0.58). CONCLUSIONS: ECG and VCG indices demonstrate that both LVSP and LBBP improve ventricular dyssynchrony considerably as compared to RVSP, to values close to normal ventricular activation. LBBP seems to result in a small, but significant, improvement in ventricular synchrony as compared to LVSP.
- Publication type
- Journal Article MeSH
BACKGROUND: Cardiac resynchronization therapy (CRT) is an established treatment in patients with heart failure and conduction abnormalities. However, a significant number of patients do not respond to CRT. Currently employed criteria for selection of patients for this therapy (QRS duration and morphology) have several shortcomings. QRS area was recently shown to provide superior association with CRT response. However, its assessment was not fully automated and required the presence of an expert. OBJECTIVE: Our objective was to develop a fully automated method for the assessment of vector-cardiographic (VCG) QRS area from electrocardiographic (ECG) signals. METHODS: Pre-implantation ECG recordings (N = 864, 695 left-bundle-branch block, 589 men) in PDF files were converted to allow signal processing. QRS complexes were found and clustered into morphological groups. Signals were converted from 12‑lead ECG to 3‑lead VCG and an average QRS complex was built. QRS area was computed from individual areas in the X, Y and Z leads. Practical usability was evaluated using Kaplan-Meier plots and 5-year follow-up data. RESULTS: The automatically calculated QRS area values were 123 ± 48 μV.s (mean values and SD), while the manually determined QRS area values were 116 ± 51 ms; the correlation coefficient between the two was r = 0.97. The automated and manual methods showed the same ability to stratify the population (hazard ratios 2.09 vs 2.03, respectively). CONCLUSION: The presented approach allows the fully automatic and objective assessment of QRS area values. SIGNIFICANCE: Until this study, assessing QRS area values required an expert, which means both additional costs and a risk of subjectivity. The presented approach eliminates these disadvantages and is publicly available as part of free signal-processing software.
- MeSH
- Bundle-Branch Block diagnosis therapy MeSH
- Electrocardiography MeSH
- Humans MeSH
- Cardiac Resynchronization Therapy * MeSH
- Heart Failure * diagnosis therapy MeSH
- Vectorcardiography MeSH
- Treatment Outcome MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
This paper deals with transformations from electrocardiographic (ECG) to vectorcardiographic (VCG) leads. VCG provides better sensitivity, for example for the detection of myocardial infarction, ischemia, and hypertrophy. However, in clinical practice, measurement of VCG is not usually used because it requires additional electrodes placed on the patient's body. Instead, mathematical transformations are used for deriving VCG from 12-leads ECG. In this work, Kors quasi-orthogonal transformation, inverse Dower transformation, Kors regression transformation, and linear regression-based transformations for deriving P wave (PLSV) and QRS complex (QLSV) are implemented and compared. These transformation methods were not yet compared before, so we have selected them for this paper. Transformation methods were compared for the data from the Physikalisch-Technische Bundesanstalt (PTB) database and their accuracy was evaluated using a mean squared error (MSE) and a correlation coefficient (R) between the derived and directly measured Frank's leads. Based on the statistical analysis, Kors regression transformation was significantly more accurate for the derivation of the X and Y leads than the others. For the Z lead, there were no statistically significant differences in the medians between Kors regression transformation and the PLSV and QLSV methods. This paper thoroughly compared multiple VCG transformation methods to conventional VCG Frank's orthogonal lead system, used in clinical practice.
- MeSH
- Databases, Factual MeSH
- Diagnosis, Computer-Assisted methods MeSH
- Electrocardiography methods MeSH
- Humans MeSH
- Linear Models MeSH
- Mathematical Computing MeSH
- Heart Diseases diagnosis MeSH
- Signal Processing, Computer-Assisted * MeSH
- Vectorcardiography methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Comparative Study MeSH
ECG body surface mapping (BSM) parameters in patients with diabetes mellitus Type 1 (DM1) are significantly different comparing to healthy non-diabetic subjects. Hypothesis that these changes are more pronounced in DM1 patients with autonomic neuropathy (AN) was tested. The parameters of BSM were registered by diagnostic system Cardiag 112.2 in 54 DM1 patients including 25 with AN and 30 control subjects. AN was diagnosed according to Ewing criteria when two or more Ewing tests were abnormal. In classic 12-lead ECG the heart rate was increased, QRS and QT shortened (p<0.01) and QTC prolonged in DM1 patients. The VCG measurement of QRS-STT angles and spatial QRS-STT angle showed non-significant differences. The absolute values of maximum and minimum in depolarization and repolarization isopotential, isointegral, isoarea maps were significantly different in DM1 patients in comparison with controls (p<0.01). The changes were more pronounced in DM1 patients with AN than in DM patients without AN (p<0.05). The QT duration measured in 82 leads of thorax was significantly shortened in 68 leads of both groups of DM 1 patients (p<0.01) when compared with controls. In 34 of them this shortening was more pronounced in DM1 patients with AN than in DM1 patients without AN (p<0.05). The results showed that the method of ECG BSM is capable to confirm the presence of autonomic neuropathy in diabetic patients.
- MeSH
- Diabetes Mellitus, Type 1 physiopathology MeSH
- Diabetic Neuropathies diagnosis physiopathology MeSH
- Adult MeSH
- Electrocardiography methods MeSH
- Financing, Organized MeSH
- Controlled Clinical Trials as Topic MeSH
- Humans MeSH
- Body Surface Potential Mapping methods MeSH
- Autonomic Nervous System Diseases diet therapy physiopathology MeSH
- Heart Rate physiology MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Comparative Study MeSH
Calbindin (CB) and S100 are calcium-binding proteins expressed in the inner ear in vertebrates. Information about their developmental roles is incomplete. This study investigated the expression patterns of CB and S100 in C3H mice using immunohistochemistry, from embryonic day 11 (E11) to postnatal day 10 (P10). CB was expressed in the otocyst and vestibulocochlear ganglion (VCG) from E11. In the cochlea at E17, CB immunoreactivity clearly labeled the VCG, the outer and inner hair cells, and the stria vascularis. CB staining was also present in the vestibular sensory cells, including their nerve fibers. Two days later, to this expression pattern was added the labeling of Kolliker's organ. Early postnatal CB expression encompassed VCG neurons, auditory hair cells, their afferent nerve fibers, and cells of the cochlear lateral wall. The first signs of S100 immunostaining of cochlear and vestibular epithelial cells appeared at E14. At E17 S100 immunoreactivity was found in a restricted expression pattern in the cochlea. Immunostaining was also present in the sacculus and utriculus and their afferent fibers. The Deiters', pillar and inner hair cells, and the VCG were S100-positive from E19. Postnatally, S100 staining also appeared in the inner hair cells and Deiters' cells, in some VCG neurons, and, in addition, in the spiral limbus, the spiral prominence, and the intermediate cells of the stria vascularis. This study demonstrates that the sites of CB and S100 expression in the mouse inner ear during embryonic and early postnatal development do not overlap and signal independent developmental patterns. (c) 2009 Wiley-Liss, Inc.
- MeSH
- Embryo, Mammalian MeSH
- Financing, Organized MeSH
- Immunohistochemistry MeSH
- Cochlea embryology metabolism growth & development MeSH
- Mice, Inbred C3H MeSH
- Mice MeSH
- Neurons metabolism MeSH
- Animals, Newborn MeSH
- S100 Proteins metabolism MeSH
- S100 Calcium Binding Protein G MeSH
- Stria Vascularis metabolism MeSH
- Pregnancy MeSH
- Tissue Distribution MeSH
- Hair Cells, Auditory metabolism MeSH
- Ear, Inner embryology metabolism growth & development MeSH
- Blotting, Western MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Pregnancy MeSH
- Female MeSH
- Animals MeSH
Východisko. V návaznosti na výsledky našich recentních studií, které zjistily zvýšení QT disperze (QTd) u skupiny těhotných, bylymatematickými postupy hledánymožné geometrické příčiny tohoto nálezu, zejména, zda pozorované změny mohou být důsledkem rotace případně posunu srdce. Metody a výsledky. Byl vytvořen model elektrického pole srdečního, které bylo studováno jako pole časově proměnného dipólu v homogenním prostorovém vodiči. Z experimentálně získaných vektorkardiografických záznamů, reprezentujících časový průběh srdečního dipólu, byly pomocí modelu vypočteny povrchové elektrokardiogramy. Ověření adekvátnosti modelu bylo provedeno srovnáním takto rekonstruovaných elekrokardiogramů s empirickými daty. Pro zjištění vlivu rotace byla originální empirická VKG data kontrolní skupiny transformována ve shodě s předpokládanými či zjištěnými změnami v důsledku těhotenství, proveden výpočet povrchových elektrokardiogramů a ty porovnány s empiricky získanými kardiogramy skupiny těhotných. Závěry. Na základě uvedených výsledků lze odvodit několik závěrů: 1) Na QT disperzi se nutně podílí složka způsobená čistě geometrickými vztahy mezi orientací srdečního vektoru terminální fáze repolarizace a směrem os konkrétního svodového systému. Takto vzniklá disperze má typický výskyt na povrchu hrudníku – minima trvání QT se nacházejí v rovině kolmé na osu svodu terminálního vektoru. 2) Při stanovení trvání repolarizace z klasických hrudních svodů existují v rámci fyziologické variability sklonu elektrické osy orientace terminálního vektoru, z nichž u některých zmíněné minimum trvání QT bude a u jiných nebude zachyceno. Hodnota zjištěné QT disperze mezi těmito dvěma extrémy pak bude významně různá. 3) U horizontálního sklonu srdce bude mít EKG signál ve velké většině svodů systému povrchového mapování vyšší voltáž oproti svodům s vertikálnějším sklonem srdeční osy v důsledku menšího úhlu mezi osami terminálního vektoru a většinou svodů. Tato skutečnost bude přispívat k přesnějšímu odečtu konce vlny T a stanovení trvání QT intervalu, obvykle s menší hodnotou QTd. 4) Změna srdečního pole odpovídající změněné poloze srdce (rotace) sama o sobě nevede ke změně QTd, pokud je tato hodnocena z EKG záznamů z celého hrudníku. Naopak, horizontalizace srdce spíše přispívá ke stanovení nižších hodnot QTd, jak je uvedeno výše. 5) QT disperze zjištěná u souboru těhotných ve vysokém stupni těhotenství je spíše než důsledkem geometrických změn zapříčiněná změnou morfologie T smyčky, která byla u souboru těhotných pozorována. Dalším možným vysvětlením pozorované disperze je nedipolární charakter změn elektrického pole během těhotenství. Naše výsledky svědčí pro hypotézu, že nález QT disperze je v podstatné míře důsledkem rozdílných geometrických poměrů (srdce, hrudníku a detekčního systému) a takto nutně subjektem možných chyb díky ne zcela standardizovanému způsobu měření. Vyvinuté prostředí umožňuje další, podrobnější studium problematiky elektrického pole srdečního.
Background. In concurrence of our recent findings of the elevation of QT dispersion (QTd) in the group of pregnant women, mathematical approaches were developed aimed to give possible geometrical explanation whether the observed changes result from the rotation or from the changed position of the heart. Methods and Results. Mathematical model of the cardiac electrical field approximated as a time variable dipole in a homogenous spatial conductor was developed. From the experimental vectocardiographic records, representing time course of the cardiac dipole, body surface potential maps were calculated on the basis of the model. To validate the adequacy of the model, the reconstructed electrocardiograms were compared with the empiric data. To determine the effects of rotation, original empiric VCG data of the control group were transformed accordingly the hypothetic pregnancy related changes. Calculated surface electrocardiograms were then compared with empiric cardiograms of the pregnant women. Conclusions. Based on the results, several conclusions can be drawn: 1) QT dispersion is associated also with the geometrical relations between the direction of cardiac vector during the terminal phase of repolarization and the direction of axes in the given system of leads. The dispersion then has its typical occurrence at the thoracic surface – minimums of the QT duration are found in the plane perpendicular to the axis of the terminal vector lead. 2) When the duration of repolarization is estimated from the classic thoracic leads within the phisiological variations of terminal–depolarization vector orientations, can exist that in some cases the minimum of QT interval is and in others it is not recorded by the lead system. Value of QT dispersion between these two extremes will be significantly different. 3) In case of the horizontal declination of the heart, the ECG signal in most of the leads of the body surface mapping has a higher voltage than in case of vertical declination due to a smaller angle between axes of the terminal vector and most of the leads. Such factwill contribute tomore accurate reading of the T wave end and to the estimation of QT interval, usually with smaller value of QTd. 4) The change of the cardiac electrical field corresponding to the changed position of the heart (rotation) does not result by itself in QTd changes, if it is evaluated from the records from the whole thorax. Obversely, horizontalization of the heart contributes more to the evaluation of lower QTd values, as it is given above. 5) More then the result of geometrical changes, QT dispersion found in the group women in high level of pregnancy is an effect of changes in the T loop morphology, which was observed in this group. Another possible explanation of the observed dispersion is the non-dipolar character of the electrical field changes during pregnancy.
