Book Reviews

DAS ELEKTRISCHE HERZBILD. By Wilhelm Ernsthausen. (In Zusammenarbeit mit Dr. Franz Kienle.) 231 pages, 227 figures, Mtinchen, 1953, Verlag fiir Biophysik Hermann Rinn.

The author presents in the book the theoretical basis of a new electrocardiographic procedure and its diagnostic application to various abnormal conditions, In five introductory chapters, the structural, chemical, and particularly the electrophysiologicai basis is discussed very competently (pp. 13 to 84). A great part of this treatment is highly mathematical (the author is an electrical engineer).

Of interest is quantitative information from experiments on dogs and sheep about the eHect of the distance between heart and chest wall on the precordial ECG. The decrease of the ampli- tude with increasing distance is not identical for QKS and for T and is also different for various anatomic locations. The resulting distortion is due to various factors; the geometrical arrangement of electrical sources, the electrical conductivity of interlying tissues, area of electrodes and dis- tance between electrodes, and different electrode resistance for the heart surface and chest wall.

The author concludes that spatial vector analysis from surface potentials is not justified with- out experimental proof that the distorting factors are relatively small (p. 84). It was not known

to the author that such experimental proof has been recently provided for normal individuals (Schmitt, O., Levine, R., and Simonson, E. : AM. HEART J. 45:416, 1953) as well as for patients (Simonson, E., Schmitt, O., and Levine, R.: AM. HEART J. 45:655, 1953).

Since \-ector analysis was believed not to be applicable, the author proposes the following method: Numerous precordial bipolar electrocardiograms, 1.5 cm. apart, are taken with a fixed- electrode distance of 3.0 cm. The fluoroscopic heart shadow is outlined on the chest and framed

in a rectangular coordinate system, exceeding the extreme right and left heart borders by 1 to 3 cm. Ten (horizontal hearts) to twelve (vertical hearts) horizontal lines are designated with letters and eight to fourteen vertical lines are numbered with 0 as the mid-line, positive to the left and negative to the right. The electrocardiograms are taken for all squares first with the bipolar electrode in horizontal position, and then with the electrode in vertical position. The resulting number of electrocardiograms varies between 190 and 240. The electrocardiograms are mounted on two sheets with the same coordinate system, one for the horizontal and the other one for the vertical “electrical heart picture.”

It is, perhaps, somewhat surprising that the amplitudes are quite sizable, and in general comparable in magnitude to the standard leads, although smaller than the conventional chest leads. This system of bipolar chest leads is held to be superior to the V leads, because of the elimination of the central terminal, and a better local resolution. For analysis, a line is drawn connecting the equiphasic QRS complexes. This “phase-line” IS comparable to the “null-line” in the analysis of spatial vectors in spite of the different interpretation.

Superimposing the horizontal and the vertical “electrical heart picture,” the “phase-lines” intercept in one point from which the activation seems to radiate in two main directions: one to the left border, and the other one to the right border. The author finds that this pattern distri- bution resembles that on the’heart surface of dogs, which is somewhat surprising in view of the distortion found in his own animal experiments. The center (intercept of the two phase-lines) is assumed to correspond to Schaefer and Trautwein’s “Quellpunkt.” Furthermore it is assumed

that the potentials above and to the right of the phase-line reflect the electrical activity of the right ventricle, while those below and to the left of the phase-line project the electrical activity of the left ventricle (p. 105). This is a revival of Lewis’ dextro- and levo -gram, and of Groedel’s right and left partial ECG. In a way, it is also a revival of so-called “rlnipolar electrocardiography” (but without V leads), so far as the basic principle of interpretation of surface electrocardiograms as local patterns is concerned. This interpretation is not tenable since about 90 per cent of the potentials on any point of the body surface can be cancelled at anatomically roughly opposite points (AM. HEART J. 45:500, 1953).

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642 AMERICAN HEART JOURNa4L

From the pattern distribution in one of the horizontal coordinates the attempt is made to construct Lead I, and from one of the vertical coordinates Lead III by algebraic integration. In nine out of twelve experiments, the similarity is indeed, quite good. According to the author, this makes it possible to “. . obtain information about the character of the elements of the limb ECG and to relate them to the function of single parts of the heart, such as right or left ventricle or anterior and posterior wall.” However, the results are quite compatible with the interpretation on the basis of spatial vector analysis.

The author holds that the distribution of electrical patterns can be satisfactorily explained by the assumption of two imaginary groups of parallel fibers, arranged in the two directions of the spread of activation. With a time reference ECG, this apparent spread was measured in the two directions: the right ventricular excitation wave spreads from the cross section of the hori- zontal and vertical phase-line with a speed of 4 M./set., and the left ventricular excitation wave spreads with a speed of 5.7 M./set. These speeds are considerably higher than muscular conduc- tion (1 M./set.) and are identical with the conduction speed of Purkinje fibers.

From Fourier analysis to the twelfth harmonic, it was concluded that the heart may be considered as a fixed electrical source, with its spatial characteristics independent of amplitudes and phases of the ECG, and that QRS and T is a continuous process. These conclusions are at variance with other available information. The author did not make Fourier analyses for ab- normal electrocardiograms.

The effect of the following fundamental types of pathology in the regional pattern distribution was investigated: local damage (including ischemia, infarct, bundle branch block), diffuse damage, ventricular hypertrophy, decompensation, and low voltage. In the last chapter, a graphic method of analysis is proposed as a “Functional Diagram of the Heart,” essentially representing geometri- cal coordinates for the right and left ventricular ECG.

Important objections can be made against interpretation of surface electrocardiograms as local patterns. However, practical considerations are perhaps even more important for the critical appraisal of a new diagnostic method. Even if the theoretical basis is not valid or at least debat- able, a new method might well, on an empirical basis, allow a better differentiation between normal and abnormal, or between the various abnormal conditions, than a conventional method. There is no doubt that the numerous precordial leads will give very detailed information about the pat- tern distribution on the anterior chest wall, and it is conceivable that this might be of diagnostic importance in certain conditions. However, no convincing proof of diagnostic superiority, sup- ported by autopsy evidence, is given. Even if such a proof for certain conditions should still be forthcoming, the number of leads (up to 240) necessary to obtain the complete “electrical heart picture” is entirely impractical. For the construction of the “functional diagram of the heart” the author limits the leads to a wide horizontal band and vertical band of 3 to 4.5 cm. with a total of 44 leads, which is still too large for routine clinical use.

The “normal standard material” obtained in only 100 normal persons, without consideration of body build, age, and sex, is not adequate.

The book is somewhat cumbersome to read because of the use of numerous symbols and abbreviations, given in a list of 3fd pages in an appendix. Some of these symbols are, indeed, confusing; for instance, for the major QRS deflection, the author uses the symbol Sr or Sl, even if it is an R and not an S wave.

Although, at the present state, acceptance of this method for clinical electrocardiography cannot be expected, it has intriguing possibilities and deserves further exploration.

E. s.

EINP~~HRUNG IN DIE VEKTORIELLE DEUTUNG DES EKG. By Helmut Gillmann, M.D., 106 pages, Darmstadt, 19.54, Dr. Dietrich Steinkopff Verlag, 83 figures.

In purpose and size this book is comparable to Spatial Vector Electrocardiography, by R. P. Grant and E. H. Estes, but it is more detailed in the discussion of the theoretical and experi- mental background. There is a brief but excellent historical introduction,

The view that the precordial leads are suitable for vector analysis is accepted and supported by experiments on the isolated animal hearts. In the analysis of vectors from precordial leads, a semiquantitative evaluation is made with an attempt to correct for proximity effects. This