Cube System Research Articles

The vectorcardiogram in cystic fibrosis. Diagnostic significance and correlation with pulmonary function tests.

One hundred and one children with cystic fibrosis had detailed studies of the vectorcardiograms and pulmonary function tests. The vectorcardiographic diagnoses were (1) right ventricular hypertrophy (14 patients), (2) right ventricular hypertrophy plus abnormally posterior vector (24 patients), (3) abnormally posterior vector (26 patients), (4) low voltage (nine patients), and (5) tracing within normal limits (35 patients). Right ventricular hypertrophy correlated well with a decreased vital capacity. Abnormally posterior vector correlated well with increased residual volume and functional residual capacity. The presence of the abnormally posterior vector was demonstrated to be the major factor in the difficulty in interpreting right ventricular hypertrophy from the electrocardiogram, for a large terminal rightward vector was often too far posterior to be registered as a terminal R in the right chest leads. The Frank system vectorcardiogram was demonstrated to be better able to detect right ventricular hypertrophy than was the cube system vectorcardiogram. This was particularly true in the presence of an abnormally posterior vector. An abnormally leftward 0.01-second vector, if it is anterior, is frequently seen in right ventricular hypertrophy.

A Quantitative Study on Normal P sE Loop of Vectorcardiogram and P Wave of Scalar Electrocardiogram by Frank Lead System

The vectorcardiogram has been generally used not only for clinical diagnosis of heart disease but also for understanding of electrical activity of the heart. The informations sup-plied from various parameters as to the spatial vectors were contained sufficiently in vector-cardiogram projected to three planes consisted of frontal, horizontal, and left sagittal planes, whereas the informations as to the time parameters may not be sufficiently contained in these planes. Therefore, in addition to the analysis of vector loop itself, quantitative analysis of X, Y and Z leads scalar electro-cardiogram is also desirable in order to provide the informations of time parameters. The main problem of quantitative study in vectorcardiogram has been focussed to analysis of QRS SE^^^ and T SE^^^ loops. However, vector-cardiographic study of P SE Ioop has been re-ported only a few. Moreover, those reports were almost limited to the study by the cube system. Provided the informations obtained from analysing various pararneters upon P SE loop are added to those from QRS SE and T SE Ioops diagnosis of heart disease by vector-cardiogram will be made more accurately. In this paper, P SE lopofvectorcardiogram and P wave of scalar electrocardiogram by Frank lead system were recorded from normal adults and were analysed. The material was divided into two groups consisting of the nor-mal young adults and the normal aged adults and the age trend was discussed. Materials and Methods Eighty-nine normal young male adults ranged from 17 to 36 years (mean 26.4 years) and 33 normal aged male adults ranged from 40 to 70 years (mean 52.9 years) were selected, totaling 122 cases. Young adults were arbitrarily selected from the office personnel of Nagoya University Hospital who had had roentogenographic and physical examinations and were presumed free from pulmonary and cardiovascular diseases. Aged adults were select-ed from the subjects who had had thorough examinations containing roentogenographic and physical examinations and were presumed free from not only pulmonary and cardiovascular diseases but central nervous system disorders, metabolic and deficiency diseases. Those who had displayed abnormalities of QRS complex, ST-T changes, supraventricular arrhythmia, bradycardia less than 60/min and tachycardia more than 90/min in standard 12 lead ECG were excluded from the both groups.

Intrinsic properties of uncorrected and highly corrected leads.

An improved experimental method was employed to determine the dipolar and nondipolar sensing characteristics of various lead connections in an electrically homogeneous human torso model. The intrinsic properties of the cube and tetrahedron leads were compared with those of an ideal vectorcardiographic system. The conventional precordial leads, V 1 through V 6 , were analyzed anatomically and electrically with respect to corresponding ideal unipolar leads, with similar treatment of the augmented unipolar extremity leads. Finally, methods of constructing highly corrected anteroposterior and transverse vectorcardiographic leads were developed. The study of the cube and tetrahedron systems confirms in strict quantitative terms that they are not suited for accurate vectorcardiographic registration. The defects of existing Z leads are greatly minimized by the use of a grid system in which the electrodes of the anteriorly applied array are individually weighted. An X lead of similar quality was achieved by a transverse grid in which the left-sided electrodes, including the arm connection, were also weighted individually. These two corrected leads, together with a previously described vertical connection, form a vectorcardiographic system whose inherent properties approach those of an ideal system. Analysis of the precordial unipolar leads demonstrates that they are in fact proximity electrodes and some of them are approximately unipolar in their behavior. Leads aV R and aV L are classed as semi-remote, and lead aV F as remote. Thoracic structures are not electrically homogeneous or isotropic. Nevertheless, lacking definitive information on the manner in which these factors influence the electrocardiographic transfer properties of the body, the study of electrolyte-filled models remains a valid experimental basis for lead analysis and synthesis.

The normal adult spatial vectorcardiogram the timed sequence of inscription of the QRSsÊ of the cube and frank systems

The mean instantaneous QRS vectors in 70 normal adults have been studied by using the cube system in all cases and by the Frank system in 20 of these cases. The mean values and the ranges for each 0.01 sec. of the QRS inscription are reported. In the horizontal planes of both systems the 0.01 sec. vector is normally to the right of +90 °. Also, the initial superior duration did not exceed 0.02 sec. and the 0.01 sec. vector did not exceed 30° above the E point. Up to the 0.04 sec. vector the mean of the angular sequence of inscription is the same for both systems for the horizontal plane. The clinical value of understanding the angular inscription sequence of depolarization of the horizontal QRS loop is described.

Studies on spatial vector analysis of electrocardiogram in chronic pulmonary disease

Many reports have been published on the morphology of the electrocardiographic patterns in chronic cor pulmonale, but no available report has been described for the spatial characteristics of the ventricular vectors in chronic cor pulmonale as determined by the orthogonal systems. This study was intended to investigate the spatial changes of the electromotive forces of the heart and to clarify the process how the typical patterns of the right ventricular overloading fully developed in chronic pulmonary diseases. 190 cases with chronic pulmonary diseases were classified in 3 groups as shown in table 3. Group I (84 cases) : normal in pulmonary functions as well as cardiovascular examinations. Group II (66 cases) : pulmonary functions were moderately impaired. Group III (40 cases): pulmonary functions were severely impaired. Vectorcardio-graphic scalar electrocardiograms of the orthogonal systems(FRANK and SVEC-III) and of the cube systems(GRISHMAN and KIMURA)as well as the standard 1 2 leads electrocardiograms were recorded in all cases. Ventricular electromotive forces were expressed as azimuth, elevation, magnitude of mean QRS and T vectors and QRS-T angle using SIMONSON'S Vector analyzer. The results obtained were as follows : I . Electrocardiographic criteria for the diagnosis of the right ventricular hypertrophy proposed by various authors were evaluated concerning their positivities as well as false positivities. SOKOLOW'S criteria showed high incidence of false positivity (32%) in Group I, and MILNOR'S criteria showed low incidence of positivity (2.5 %) in Group III. MORI's criteria appeared to be most useful clinically among these criteria, because it had low false positivity (3.5 %) and high positivity (20%). 2 Electrocardiographic pentalogy of pulmonary emphysema proposed by WASSERBURGER were corrected quantitatively near the normal limits as shown in table 5. These corrected pentalogy and other electrocardiographic findings, which were occasionally en-countered in pulmonary emphyserna, were also examined concerning their positivities as well as false positivities as shown in table 6. It was shown that MACRUZ'S index was not adequate for clinical use because it yielded high incidence of false positivity (16.7 %). 3. Vector analysis of these subjects indicated that the characteristic changes of the spatial ventricular vectors in the right ventricular overloading due to pulmonary ventilatory impairement were marked decrease in azimuth and elevation of QRS and T vectors and decrease in magnitude of T vector.

The QRS Vectorcardiogram in Congenital Heart Disease During the First Year of Life: A New Diagnostic Vectorcardiographic Technique

SUMMARY A new diagnostic vectorcardiographic technique was employed in the study of 21 patients with congenital heart disease under one year of age. The QRS vectorcardiograms were studied according to the position of the 0.02, 0.03, 0.04 and 0.05 second vectors and the rotation of the loop in the horizontal plane of the cube system of Grishman. Abnormalities in the location of these vectors and changes in the rotation of the loop including the appearance of figure of 8 loop during the first week of life were found useful in detecting ventricular hypertrophy in this age group. Criteria for the vectorcardiographic diagnosis of right ventricular hypertrophy and left ventricular hypertrophy were outlined for this method. Combined ventricular hypertrophy was diagnosed in two patients.

The vectorcardiogram in pulmonary stenosis: Correlation with the hemodynamic state in patients with and without ventricular septal defect

In 33 patients with pulmonary stenosis (PS) and intact ventricular septum and 45 patients having PS with ventricular septal defect (VSD) vectorcardiograms recorded by the cube system showed four types of variant loops, which were defined by their configuration, direction of rotation, and measurement of direction of selected instantaneous vectors in the mid-portion of the QRS complex. In PS with peak pressure ratios less than 1.0 and PS with VSD with arterial oxygen saturations at rest between 90 to 100 per cent, Type I variant loop was dominant; types III and IV did not occur. Counterclockwise-inscribed horizontal loops were seen in these groups only, but not with severer forms of these defects. The direction of the 0.03 sec. QRS vectors, as projected on the horizontal plane, separated this mild group from PS with peak pressure ratios greater than one and also mild forms of PS with VSD from those having arterial oxygen saturations less than 75 per cent. PS with peak pressure ratios of 1.0 and PS with VSD with arterial oxygen saturations between 75–89 per cent showed dominant right-ward and anterior forces reflected largely by Type n loops. The 0.03 and 0.035 sec. vectors as well as maximal QRS vectors in the horizontal plane overlapped the same QRS measurements in patients with milder and more severe forms of these disorders. Thus, no specific measurement identified this hemodynamic category. The PS group with peak pressure ratios greater than 1.0 and PS with VSD with severe arterial oxygen desaturation showed mainly Types III and IV loops. Type I loops never occurred. Maximal horizontal plane vectors of these groups were found in a small range and were all oriented more rightward and superiorly than anteriorly. The 0.03 and 0.035 sec. vectors in the horizontal plane were located to the right of 100 ° and were easily distinguished from the corresponding measurements in the milder forms of this disease. The vectorcardiogram derived by the cube reference system, when compared to hemodynamic parameters obtained at rest during cardiac catheterization, is capable of separating mild forms of PS and PS with VSD from the severe forms of these defects. It is not capable of characterizing the largest group of patients with these disorders in whom right ventricular pressure is equal to systemic pressure, or arterial desaturation ranges from 89 to 100 per cent.

The orthogonal vectorcardiogram in 100 normal children (Frank system). With some comparative data recorded by the cube system.

The orthogonal vectorcardiogram in 100 normal children (Frank system). With some comparative data recorded by the cube system.

Comparison of the Cube and Tetrahedral Lead Systems for Vectorcardiography

A comparative analysis of cube and tetrahedral vectorcardiograms from 50 individuals consisting of 13 normals and 37 pathological cases is presented. The comparison between vector loops has been performed with a Subjective method of evaluation and with measurement of the angular deviation of corresponding vectors. Further, the extent to which normal respiration affects the orientation of the QRS vector in successive beats has been investigated. It is considered that:1. There was unsatisfactory correspondence of vectorcardiograms recorded with the cube and tetrahedral lead systems.2. There was a tendency to anterior, rightward and inferior displacement of the tetrahedral loops when compared with the cube vectorcardiograms.3. The observed discrepancy calls for standardisation of lead systems for vectorcardiography and the adoption of modern electrically orthogonal lead systems.4. Changes of the QRS vectors in successive heats under normal respiration seem to have no importance for practical clinical purpose...

Comparison of the Cube and Tetrahedral Lead Systems for Vectorcardiography

Comparison of the Cube and Tetrahedral Lead Systems for Vectorcardiography

A clinical appraisal of the vectorcardiogram in myocardial infarction. I. The cube system.

A total of 161 vectorcardiograms was recorded with the Grishman cube system in patients with suspected myocardial infarction. In the group of 49 cases subsequently examined post mortem and of 73 non-autopsied cases, in whom the diagnosis of infarction appeared certain, a comparison was made between the standard electrocardiogram and the vectorcardiogram taken in succession. The vectorcardiogram demonstrated more infarcts than the electrocardiogram. Of a total of 122 cases in which the vectorcardiogram showed infarction, 19 had normal and 17 equivocal electrocardiograms. A number of simple and easily applicable criteria for the vectorcardiographic diagnosis of infarction are given. It appears that even the older, uncorrected cubelead system permits a more accurate diagnosis than currently available standard electrocardiographic procedure. It is suggested that this method of exploration may be useful in cases of suspected myocardial infarction in which the routine electrocardiographic examination leaves doubt.

The clinical value of vectorcardiography

1. 1. Vectorcardiograms of 1,000 adult patients were studied and correlated with clinical data. Autopsy findings were also available in 11 per cent of the group. 2. 2. The cube system was used in all cases, and the tetrahedron system of vectorcardiography was also employed in 477. The tetrahedron system usually revealed abnormalities better than the cube system in right ventricular hypertrophy, combined left and right ventricular hypertrophy, inferior myocardial infarction and posterior myocardial infarction. The cube system, on the other hand, was generally more helpful than the tetrahedron in cases of anterior myocardial infarction, left ventricular hypertrophy, left bundle branch block and right bundle branch block. 3. 3. The vectorcardiogram provided additional and more decisive information in about half of 525 patients with somewhat equivocal electrocardiographic findings; the electrocardiogram revealed abnormalities better than the vectorcardiogram in only 6 per cent of the same group of cases. However, the vectorcardiogram and the electrocardiogram were interpreted similarly in the majority of the 1,000 cases. The vectorcardiogram was extremely unlikely to be diagnostic of an abnormality when the electrocardiogram was well within normal limits. 4. 4. The vectorcardiogram offered additional help in the diagnosis of right ventricular hypertrophy, combined left and right ventricular hypertrophy, right bundle branch block and myocardial infarction in various locations with the exception of lateral or high anterior infarcts.

The normal qrs vectorcardiogram in infants and children from birth to fifteen years

One hundred sixty-six QRS vectorcardiograms from 154 patients with normal hearts have been analyzed according to morphology and rotation of the loop and position of the 0.02, 0.03, 0.04 and 0.05 second instantaneous vectors. The patients' age ranged from birth to fifteen years inclusive. The vectorcardiograms were taken with an apparatus similar to that of Shillingford and Brigden using the cube system of Grishman. Variations in the morphology and rotation of the QRS loop are not uncommon in the first month of life. The “transition” period has also considerable variation as to the time of onset and termination. As a rule, in the horizontal plane of the cube system, counterclockwise rotation should be seen at four months and the figure of eight pattern should be absent at ten years in a normal vectorcardiogram. At three months and over, the 0.03 second instantaneous vector normally should not be directed to the right. The horizontal plane of the cube system of Grishman gives the most information relative to the progressive changes in the QRS loop from birth to fifteen years.

The vectorcardiogram in dorsal or posterior myocardial infarction

The vectorcardiograms of twenty-five patients with dorsal infarction of the heart were studied. These infarctions were classified into four groups as follows, all of which showed an increase of the R wave in the B (anterior-posterior) component of Grishman's cube system: 1. 1. Strictly dorsal infarction, showing only an increase of the R wave in the B component. In this group were three cases, including one complicated by complete right bundle branch block. 2. 2. Inferodorsal infarction, showing pathologic Q waves in the C (superior-inferior) component. There were five cases in this class. 3. 3. Laterodorsal infarction, showing abnormal Q waves in the A (right-left) component. Eight cases were placed in this class. 4. 4. Inferolaterodorsal infarction, with abnormal Q waves in the A and C components. There were nine cases, including two complicated by complete right bundle branch block, in this group. The vectorcardiograms of these cases showed increased magnitude and forward orientation of the initial portions (0.02 second) of the ventricular activation loop. These initial portions frequently had a higher speed of inscription due to the absence of opposing forces. The necrotic areas in the dorsal wall which should undergo early depolarization were not activated at the same time; therefore, no electrical forces were produced in those areas. In dorsal infarction, the rotation of the QRSsÊ in the horizontal plane was predominantly counterclockwise. This, together with the direction of predominant forces forward (average 0.048 second) and the orientation of the TsÊ in the same direction, facilitates the diagnosis of dorsal infarction in those cases in which a tall R wave in the right precordial leads might suggest right ventricular hypertrophy. In eleven cases a certain delay of inscription and deformity in the morphology of the terminal portions of the QRS loop was observed.

Clinical Vectorcardiography and Electrocardiography

It is customary when reviewing a book on electrocardiography to use the opening gambit that "still another book has been added to an already overcrowded field." It is a pleasure to say that this book deserves to be added to an overcrowded field, and that it can be highly recommended. The authors succeed in fulfilling the obligations indicated by the title, and this excellent book correlates loop electrocardiography and classic linear electrocardiography. In terms of its context, there is little to criticize in this book. The vectorcardiograms are practically all recorded with use of the cube system, and it is possible that the authors will, in a second edition, find themselves changing to a corrected orthogonal system. The index of the book is not satisfactory in that such words and phrases as hypertrophy, atrial repolarization, unidirectional block, and block are not in the index. The book could be materially improved

A comparative study of four lead systems of vector-cardiography.

(1) Vectorcardiographic tracings were taken by 4 different lead systems, viz., Cube system by Grishman, Equilateral tetrahedron system by Wilson, Orthogonal lead systems by Frank and by Schmitt in 17 normal subjects, 36 cases with coronary sclerosis and 20 cases with valvular heart disease. The direction of the inscription of QRS-loop, the direction of the half area vector and the maximal amplitude of X, Y and Z components of the loop were examined.(2) Very similar tracings can be obtained by Frank and Schmitt lead systems in most cases. (3) In normal subjects, agreement of the 4 lead systems was satisfactory, but in patients with coronary sclerosis and valvular disease, these 4 lead systems could not be considered interchangeable. (4) Compared with orthogonal system by Frank or Schmitt, Z component in Grishman's system is smaller and Y component in Wilson's system is larger.

A vectorcardiographic analysis of left ventricular strain pattern comparatively studied with ST-T change of left bundle branch block and ventricular premature beat of right ventricular origin

A vectorcardiographic analysis is made of left ventricular strain pattern. The T loop of left bundle branch block and ventricular premature beat of right ventricular origin are also discussed. Grishman's cube system is used. 1. 1. The T loop of left ventricular strain pattern, with a few exceptions, changes in the following order: it starts left inferiorly and shifts rightward, passing in lower front of the origin (in some cases in upper front), and then reaches right and anteroinferiorly, twisting around its own long axis clockwise in the view from its tip, and finally, right and anterosuperiorly. 2. 2. The process described above is divided into the following five grades on three plane projections: Grade I: The T loop protrudes from the QRS loop, but it is still situated to the left and inferiorly; its direction of inscription in most cases is the same as that of the QRS loop. Grade II: The T loop is situated opposite to the QRS loop, but it shows the same direction of inscription as the QRS loop on three plane projections. Grade III: Additionally, the T loop is inscribed in an adverse direction (clockwise) to the QRS loop in the horizontal view. Grade IV: The T loop shows an adverse direction of inscription (clock-wise) to the QRS loop in the frontal view as well as in the horizontal view. Grade V: The T loop also shows an adverse direction of inscription (counterclockwise) in the right sagittal view as well as in the horizontal and frontal views, i.e., adverse to the QRS loop in all three plane projections. 3. 3. This serial change of the T loop seems to be parallel with other clinical findings. 4. 4. The T loop of left bundle branch block is situated opposite to the QRS loop, and, in general, it either shows the same direction of inscription as the QRS loop or is rod-shaped. 5. 5. The T loop cf ventricular premature beat of right ventricular origin is generally situated opposite to the QRS loop; it either is inscribed in the same direction as the QRS loop or is rod-shaped. 6. 6. Throughout left ventricular strain pattern, left bundle branch block, and ventricular premature beat of right ventricular origin the T loop which is situated opposite to the QRS loop and is inscribed in the same direction as the QRS loop corresponds to secondary T-wave change; an additional development of torsion of the QRS loop means a participation of primary T-wave change. But when the influences of secondary T-wave change are overwhelmingly more dominant than those of primary T-wave change, the former come to govern mainly the configuration of the T loop.

Diseases of the Cardiovascular System (Excluding Hypertension and Atherosclerosis)

Electrocardiography has continued to be an active field, with studies relating to intraventricular conduction and leads or lead systems suitable for vectorcardiography contributing heavily. The important and contro­ versial problem is still undecided regarding the nature of excitation of the free wall of the left ventricle, namely, whether the subendocardial muscle is activated in a rapid and chaotic fashion with only the epicardial layers con­ tributing substantially to the QRS complex as recorded in external (direct or semidirect) leads, or whether radial spread 9f excitation occurs through the entire wall of this chamber. The group bf workers ( 1) whose studies have favored the latter view have provided no further evidence to support it, but in investigations using the same techniques, have shown that in the dog with left branch block the septum is excited from right to left, with the left ventricle activated earliest on the anterior, epicardial aspect. The latter causes excitation to pass inward toward the cavity of the left ventricle for a short time. In experimental studies and limited observations on the human heart directed toward an analysis of the form of the QRS complex in epicar­ dial leads, Pipberger and his associates (2) have confirmed their earlier im­ pression that only the outer layers of the left ventricle contribute signifi­ cantly to the R wave seen in: epicardial leads. The implications of these observations, particularly in myocardial infarction, were pointed out and in this connection, the frequent occurrence of a QRS complex with a small initial r wave and large S wave (rS) in the epicardial lead over an infarct was mentioned. Sodi-Pallares and his colleagues (3), in ingenious experimental studies, attempted to relate pathways of ventricular activation to findings in vector­ cardiograms. This was done by determining the locations of maximal posi­ tivity and negativity on the epicardial surface of the ventricles at a number of instants of time during excitation. These they designated as the apparent maximal potential gradients and, when represented by vectors, made it possible to construct vectorcardiograms in the three usual planes. These vectorcardiograms were compared with vector figures recorded by the use of the cube system of electrode placement, and agreement was sufficiently close to justify the conclusion that vectorcardiograms give valuable in-

The electrocardiogram and vectorcardiogram in various degrees of left bundle branch block ∗

Electrocardiograms and vectorcardiograms were recorded simultaneously from a patient with varying degrees of left bundle branch block. It was found that a slight degree of left bundle branch block is unrecognizable as an abnormality either in the electrocardiogram or in the vectorcardiogram (tetrahedron, cube, Frank). A slightly greater degree of left bundle branch block is not recognizable as an abnormality in the electrocardiogram but produces a definitely abnormal horizontal vectorcardiogram when the cube system is used. The latter, however, is not distinguishable from vectorcardiograms seen in some anteroseptal infarcts. Varying slight degrees of left bundle branch block may produce a series of electrocardiograms that can be mistakenly interpreted as showing acute anteroseptal injury followed by ischemia.

Comparison of four orthogonal systems of vectorcardiography.

Four orthogonal systems of vectorcardiography that are considered to be more accurate than the tetrahedron and cube systems were compared. In a large majority of subjects the records made with each of the 4 systems were similar. However, in 5 of 60 subjects in whom the Z lead was studied, dissimilarities were found that were considered to be significant. The possible reasons for these dissimilarities are discussed. Comparative normalization data for the systems were obtained in the living human subject, based upon comparison of wave forms.