RU2268640C2 - Method for localizing additional conducting paths in wolff-parkinson-white syndrome cases using vector electrocardiograms - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: method involves recording cardiac biopotentials with vector electrocardiograph, processing and visualizing signal with graphical plane integral cardiac electric vector projections (vector electrocardiograms) being built and analyzed. Shape, QRS-loop value and vector orientation-recording process are determined. Analysis is based on planar vector electrocardiograms in horizontal, frontal and sagittal planes and in spatial 3-D-form. Vector loop direction is studied in X-,Y-,Z-axis projections, values, dynamics and localization are evaluated in resulting integral cardiac electric vector delta-vector space. To do it, QRS-loop is divided into four segments, one of which characterizes excitation in middle part of axial partition surface, the second one is related to excitation in lower ventricular septum one-third with cardiac apex being involved and the third and the fourth one is related to excitation in basal parts of the left and right heart ventricles. Delta-vector existence and its magnitude are determined from changes in loop segment localization when compared to reference values.

EFFECT: improved data quality usable in planning surgical treatment.

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Description

The method relates to medicine, in particular to cardiology (arrhythmology), and can be used for non-invasive topical diagnosis of additional pathways with Wolff-Parkinson-White syndrome (WPW).

Known methods for non-invasive diagnosis of WPW syndrome by electrocardiogram (ECG) and vector electrocardiogram (ECG).

The prototype adopted a method of registration, processing and graphical presentation of the biopotentials of the heart to obtain vector loops P, QRS, T in standard planes: horizontal, frontal and sagittal, i.e. vector electrocardiograms with their subsequent analysis [1].

The disadvantage of the method adopted for the prototype is the lack of necessary information and, as a result, the inability to localize additional pathways with WPW syndrome. This method only allows you to diagnose WPW syndrome and to differentiate the changes that occur with WPW syndrome from changes caused by myocardial infarction, ventricular hypertrophy and blockade of excitation.

The purpose of the invention is the ability to localize additional pathways for WPW syndrome according to VECG to increase the effectiveness of surgical treatment.

The essence of this invention is as follows.

Upon excitation of the myocardium, an alternating electric field arises, characterized by an integral electric vector of the heart (IVES), the end of which during the cardiocycle describes a complex curve in space - a vector loop, which is recorded using a vector cardiograph [2, 3]. The technique of vector electrocardiography, due to the possibility of spatial visualization of IVES, makes it possible to estimate its size and localization in space at various moments of the electrical systole of the ventricles.

The delta wave arising on the standard leads of ECG-12 with WPW syndrome, from the point of view of the dipole theory of cardiac electrogenesis and the Grant-Penelots-Tranchezi concept of the existence of three main electric vectors that make up the IVES (interventricular septum excitation vector) 1), the apex and free walls of the ventricles (2), the basal parts of the heart (3) [1], Fig. 1), is nothing more than a projection of an additional delta (Δ) -vector. The onset, direction, and localization of the Δ vector depend on the anatomical location of the pre-excision site, which in turn indicates the localization of the DPS. VECGs recorded with WPW syndrome are the result of addition of the Δ vector to IVES.

The trajectory of the loops on the VECG in all areas is accompanied by a numerical analysis.

The purpose of the invention is achieved by the following steps.

The biopotentials of the heart are recorded by a vector cardiograph using an orthogonal electrode lead system. After processing and visualization of the signal, the projections of the IEDs on the frontal, horizontal and sagittal planes and in space are obtained — planar EECGs and 3D-form, respectively. There are vector loops arising from the depolarization of the atria (P), ventricles (QRS) and repolarization of the ventricles (T). Next, the analysis of the vector loop QRS. The values, dynamics and localization in the space of the resulting IEVS and Δ-vector arising during the functioning of the additional atrioventricular connection (DPS) are analyzed. The analysis is carried out in accordance with the dipole theory of cardiac electrogenesis and the Grant-Penelots-Tranchezi concept. Typical changes in the QRS loop trajectory that occur with a functioning DPS are identified. The area of pre-excision is determined. The conclusion is formulated.

The QRS loop vector analysis is performed as follows.

Figure 2 shows the QRS loop in space and its projection in the standard frontal, horizontal and sagittal planes, which are observed when the excitation propagates through the ventricles in normal.

QRS loop recording progress clockwise in the sagittal plane and counterclockwise in the horizontal plane. In the frontal plane, the QRS loop is uninformative. The loop is tilted back, left and down.

We divide the QRS loop into four conditional sections with points A, B, C (C '), D. At each section, we can note the predominance of excitation in certain anatomical regions of the left and right ventricles. Figure 1 shows a diagram of the anatomical localization of the above vectors. For convenience and visibility of vector analysis, a diagram of the structure of the heart is presented in the horizontal plane and in the XZ plane, which makes an angle of 45 ° with the frontal plane.

Section AB on this VECG reflects the localization and direction in space of vector 1, which occurs in the middle part of the left septal surface and is directed to the base of the anterior papillary muscle of the right ventricle, oriented forward, up or down (depending on the position of the heart). In the presented diagram, vector 1 is directed somewhat downward and strictly forward along the Z axis, which is due to the anatomical location of the heart in the chest cavity. Then, vector 1 during its development begins to deviate downward, to the left and backward and gradually turns into vector 2. This process reflects the BC region on the VECG, which is caused by the spread of excitation along the lower third of the interventricular septum with capture of the apex of the heart.

In the future, the transition of excitation to the free walls of the ventricles: left and right with the formation of vectors 2 'and 2' ', respectively. Since the mass of the left ventricular myocardium is significantly greater than the mass of the right ventricular myocardium, the potentials of the left ventricle prevail when the excitation spreads to the walls of the ventricles. This fact explains the localization in space of vector 2, which, being the result of adding vectors 2 'and 2' 'according to the parallelogram rule, is oriented in space to the left, back and down (section CC').

The following sections C'D and DA characterize the localization in the space of vector 3. This vector, due to the excitation of the basal parts of the left (3 ') and right (3' ') ventricles, is the result of the addition of vectors 3' and 3 ''. It turns to the right, up and forward until the end of the excitation cycle.

Figure 3 presents a typical spatial VECG (3D-form) and its projection on a plane with the left upper lateral LVJ, which, located between the left atrium and the left ventricle, leads to premature excitation of the basal portion of the upper lateral wall of the left ventricle. QRS loop recording progress clockwise in the sagittal plane and counterclockwise in the horizontal plane. The loop is offset forward, left, and down compared to normal.

The QRS loop is divided into characteristic sections AB, BC, SS ', S'A. A diagram of the structure of the heart with vector analysis is presented in figure 4. In the diagram, the DPS is marked with a bold line in the -XZ plane and - with a dot in the horizontal plane. The analysis used similar schemes in other planes.

On the VECG in the sagittal plane, compared with the norm, there is a shift of the AB section somewhat downward. This change can be explained by the following features of the spread of excitation along the myocardium of the ventricles: due to preexcitation due to DPS of the basal portion of the upper lateral wall of the left ventricle, additional vectors arise. Let us designate them: 1Δ '- a vector due to the spread of excitation to the lower lateral region of the left ventricle, 1Δ' '- a vector arising from the spread of excitation to the paraseptal region of the left ventricle. When adding vectors, the resulting vector 1Δ is formed, which is oriented down, left and forward (Fig. 4).

Almost simultaneously with the process of forming the Δ-vector, the excitation propagates through the conducting system of the heart with the formation of vector 1. As a result of the addition of vector 1Δ and vector 1, the resulting vector 1'Δ is formed. Its localization in space is clearly reflected in the section of the QRS loop AV in the sagittal and horizontal planes. The change in the localization of the AB site compared to the norm is due to the interaction of excitation waves that arise in the heart, including the functioning DPS, at the beginning of the depolarization process.

The next segment of the sun reflects the prevailing potentials of vector 2. Despite its slight forward displacement in the sagittal and horizontal planes, it does not significantly differ from that in the norm. Its localization in space is also due to the interaction of excitation waves. Taking into account the different speeds of excitation propagation along and across the muscle fibers, it becomes clear that during the same time, when the excitation propagates through the cardiac conduction system and the myocardium, more anatomical structures of the heart are involved in the depolarization process, namely the lower third of the interventricular septum and the apex, in comparison with the site of excitation of the wall of the left ventricle due to the additional pathway. Therefore, the potentials of vector 2 in magnitude will prevail over the potentials of the Δ-vector. The analysis of the WECG shows that, despite the pronounced predominance of vector 2, the Δ-vector does not fade away and continues to influence the localization in the space of IVES. The excitation wave forming the Δ-vector continues to propagate along the wall of the left ventricle until its interaction with the oncoming excitation wave propagating through the conduction system of the heart and myocardium.

The localization of the portion of the QRS loop near point C reflects the continuation of the process of interaction of excitation waves in the wall of the left ventricle. On the VECG in the sagittal and horizontal planes, the area near point C, in comparison with the norm, is shifted forward and to the left. These changes are due to the following: as a result of the spread of excitation due to the functioning of the DPS, in the wall of the left ventricle, the vector 1Δ grows into the vector 2D, which is oriented downward and forward. At the same time, as a result of the transition of excitation from the top of the heart to the walls of the left and right ventricles, two more vectors are normally formed: 2 '- in the left ventricle and 2' '- in the right ventricle. However, the localization in the space of the vector 2 'is influenced by the vector 2Δ existing in the same ventricle. When 2 'and 2Δ are added together, we get the resulting vector 2'Δ, which, compared to the vector 2', first more sharply falls down, but as a whole it is weakened, especially in the development backward, due to mutual compensation of the excitation waves. With further addition of the vectors 2'Δ and 2 '' we get the resulting vector 2 (figure 4). Its formation and localization in space at different points in time reflect the sections of the BC and SS 'QRS loops in the sagittal and horizontal planes.

With the further spread of excitation along the myocardium of the ventricles, normally, in accordance with the accepted concept, vector 3 should be formed. However, by the time of excitation transfer from the free walls of the ventricles to their basal sections, part of the basal section of the more powerful left ventricle was already excited, therefore vector 3 'for this the localization of DPS is significantly weakened. Vector 3 '', due to excitation of the basal parts of the right ventricle, does not differ from that normal. When the vectors 3 'and 3' 'are added together, the resulting basal vector 3 is formed, which in this case changed its direction towards the right ventricle (Fig. 3). The S'A site on the VECG in the sagittal and horizontal planes is shifted forward and towards the right ventricle.

Conclusion: according to the revealed deviations from the norm, namely, the shift of the AB sections down and CA forward, DPS is localized in the upper lateral region of the left ventricle.

Using the proposed method of vector analysis, it is possible to determine the localization of DPS at the preoperative stage, to reduce the risk of complications during surgery by reducing the time of surgery, the duration of fluoroscopy and anesthesia, which increases the effectiveness of surgical treatment. In addition, the result of the WECG anatomically clearly reflects the processes of myocardial depolarization in WPW syndrome, which also leads to an increase in the accuracy of the topical diagnosis of additional pathways.

Information sources

1. Dolabchyan Z.L. Fundamentals of clinical electrophysiology and biophysics. M .: Medicine, 1968; 101-367.

2. Volobuev A.N., Bakutsky V.N., Kryukov N.N., Romanchuk P.I. Spatial vector electrocardiography. Cardiology 2003; 4: 52-54.

3. Gadzhaeva F.U., Grigoryants R.A., Masenko V.P., Khadartsev A.A. Electrocardiographic lead systems. Tula: Research Institute of NMP 1996; 116.

Claims (1)

A method for localizing an additional pathway for Wolf-Parkinson-White syndrome by recording the biopotentials of the heart using a vector cardiograph, processing and visualizing the signal, obtaining graphic planar projections of the integral electrical vector of the heart - vector electrocardiograms and analyzing them with determining the shape, recording progress of the magnitude and orientation of the vector QRS loops, characterized in that the analysis is carried out on planar vector electrocardiograms in the horizontal, frontal and sagittal planes and using the 3D spatial form, determine the direction of the vector loop along the X, Y, Z axes, estimate the magnitude, dynamics and localization in space of the resulting integral electric vector of the heart and the delta vector, for which the QRS vector loop is divided into four sections, one of which characterizes the excitation in the middle part of the axial septal surface, the second - the excitation along the lower third of the interventricular septum with the capture of the apex of the heart, the third and fourth - the excitation, respectively, of the basaltic sections of the left and the right ventricles of the heart, determine the presence of a delta vector and its value by changing the localization of the loop when compared with the norm.

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