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

BOOK REVIEWS 643

correction is made from the distance between the various electrode positions and a hypothetical center (null point) on a diagram of the cross section of the chest, based on the average values of twenty-five normal persons. The QRS amplitude of VZ is taken as 1.0, and the amplitudes of the other precordial leads are expressed in relative values of VP.

The author shows in one normal case (p. 52) and in one abnormal case (p. 96) a good agree- ment between the actual and predicted amplitudes of the precordial leads “as a demonstration of the excellent agreement between theory and practice.” Since the different precordial leads repre- sent projections of different parts of the spatial loop, such agreement must ap,pear fortuitous. This is an entirely empirical approach to arrive at a correction for the various electrode positions and has little to do with electrocardiographic theory, but it might be conceivably of practical merit. However, the only way to test an empirical correction is the evaluation of the error of prediction by statistical analysis with adequate material, and this was not done.

The author uses for analysis of spatial vectors not only the V leads, but also the CR, CL, and CF leads, because their axes are different. Any vector will coincide in the direction most closely with one or the other of these numerous leads, and this lead then will be the optimum for the projection of such vector. Therefore, this approach is called the “Optimalen schema” (scheme of optimals).

The use of such a large number of leads, however, in order to determine the direction of spatial vectors is far from optimum for two important reasons: (1) The direction of spatial vectors should be given in terms of azimuth and elevation rather than in terms of one of the conventional leads (including CR, CL, and CF), and (2) if one accepts the view (as the author does) that all leads are projections of a centrally located spatial vector, this vector can be cal- culated or constructed from the standard leads and the V leads without CR, CL, and CF leads.

In the apphcation to abnormal conditions (pp. 66 to 98), however, the author makes little use of his “Optimalen schema.” The essential information is obtained from Leads I to III and Vt to Ve, although occasionally additional leads are taken. The spatial vectors are shown as projections on the frontal and horizontal plane as stereodiagrams, and this presentation.is in certain respects superior to that of Grant and Estes.

One would not expect that an introduction is comprehensive, but since the greater part of the book is devoted to the fundamentals, it would have gained by consideration of the recent American literature. Two examples may serve as illustration. The author finds the variability of the augmentation ratio of the Goldberger leads too variable to be practical but ignores the more comprehensive study by Simonson and Keys (Circulation 1:954, 19.50). In regard to the mirror patterns of leads in anatomically opposite points the author refers to Swiss and French literature but does not refer to the larger and more precise quantitative information in the publi- cations of Schmitt and associates. (AM. HEART J. 45:416, 500, 655, 1954).

The book will serve its purpose as an introduction into spatial vector analysis, particularly for a reader who is interested in the theoretical basis as much as in the practical application.

E. S.