The Usefulness of Vectorcardiography in the Early Diagnosis of Acute

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The usefulness of vectorcardiography Vectorcardiography in the early diagnosis of acute myocardial infarction: Preliminary report

LEONARD MENNEN, D.O. Kansas City, Missouri

This paper is a preliminary report technical problem in receiving laboratory re- of experience with a panoramic sults promptly, and valuable time may elapse before the seriousness of the patients condi- vectorcardiograph in confirming the tion is known. presence or absence of acute myocardial When such procedures give only equivocal infarction when the initial results, one searches for a more comprehensive electrocardiogram was equivocal. and sophisticated method of studying the vec- The theoretical basis for tors produced by the heart. vectorcardiography is discussed. Three This paper will relate preliminary experience using a panoramic vectorcardiograph to cases are reported to illustrate the confirm the presence of acute myocardial in- usefulness of vectorcardiography. The farction when the initial electrocardiogram was depolarization changes that occur inconclusive. when myocardial activity is altered are pointed out. Vectorcardiography is Basis for vectorcardiography still in the embryonic stage and there Vectorcardiography is a theoretical advance- ment over the electrocardiogram for the follow- are technical difficulties and lack of ing reason : The electric field of the heart agreement on such factors as the exists in three-dimensional space and there- most efficacious lead system. In this fore must be expressed as such. One can predict study vectorcardiography has been a three-dimensional synthesis from the given found to be a useful tool in the electrocardiogram curves, but only within lim- evaluation of acute myocardial its, since precise vector synchronism cannot be attained. infarction. Its value in other instances A minimum of three physical leads will rep- of altered myocardial activity is under resent true X, Y, and Z electrical co-ordinates. continuing study. This is necessary for accurate measurements of the X, Y, and Z components of the dipole vector.2 To form the frontal plane vectorcardiogram, one lead representing the X co-ordinate is used

The importance of early diagnosis of acute myocardial infarction has been stressed re- peatedly. Electrocardiography and laboratory _1_ studies have aided clinical determination of 1 altered myocardial activity. However, the H ---I--0- z-H---t- --- T electrocardiogram does not always substan- r tiate the diagnosis, and the laboratory studies, Frontal Sagittal Horizontal namely serum enzymes, are often elevated in Fig. 1. non-cardiac diseases. Frequently there is a

494/70 centripetal

t R (vertex) i II (R loop) S i T .. ■ ---7 % .- . .. • Alba.-- .. , %..?I

4,- centrifugal I (Q loop)

Fig. 2. Components of the vectorcardiographic loop.

Fig. 4. Admission electrocardiogram of patient in Case 1. Fig. 3. Mobile panoramic vectorca/rdiograph used in study.

ueiuieu uy analyzing ine imam 5 posiLion.- as the horizontal axis input, and a second lead The sagittal plane is formed by using the representing the Y axis is used as the vertical lead representing the Z component and the axis input to an oscilloscope. When this is lead representing the Y component as the two accomplished, the X input and the Y input act perpendicular signal inputs to the same cath- simultaneously upon the beam and cause the ode ray tube beam.2 beam to be displaced in an XY graphic pat- The horizontal plane projection of the dipole tern. At any one instant during the cardiac vector is obtained by utilizing a lead which cycle the XY axis of the dipole vector can be represents the X and Z components of the

Journal AOA/vol. 66, January 1967 495/71 R R

Frontal plane — Horizontal plane-- I A

Horizontal plane Rt. sagittal plane A I

Fig. 5. The vectorcardiogram of patient in Case I shows a disappearance of the Q loop in. the horizontal plane indicating a loss of the normal first septal vector. In the same plane (upper right and, for greater magnification, lower left) the centrifugal limb of the R loop has lost its normal configuration and is rotated backward, suggesting necrosis to the anterior and lateral regions of the free left ventricular wall. The J-point is also displaced. The sagittal plane demonstrates significant posterior displacement of the initial vectorial forces. In the frontal plane abnormal rotation is also noted. These findings were interpreted as representing an acute myocardial infarction involving the middle and lower portions of the interventricular septum, and the anterior and lateral regions of the free left ventricular wall. dipole vector as perpendicular signal inputs to rectangular systems and the modifications by the same cathode ray tube beam. In a similar Grishman and Frank. manner, the frontal (XY), sagittal (ZY), and Orthogonal lead systems differ from those horizontal (XZ) plane projections of the di- based on the equilateral triangle by having pole vector may be obtained throughout the their lead electrodes formed perpendicular to cardiac cycle2 (Fig. 1). one another.3 Proper magnification of the loops is of the We have found the Frank and Grishman utmost importance so that every component systems to be the most convenient technically. may be adequately studied. Our vectorcardio- We are still experimenting with other lead graph gives magnification from 50 millivolts systems and are particularly interested in the per centimeter to 1 millivolt per centimeter, "balanced bipolar system" used by Lamb, and related to the oscilloscope input sensitivity. the McFee and Parungao system. Lambs sys- Many lead reference systems have been tem has a major advantage of obtaining large, devised to measure X, Y, and Z components. clear signals because of its high signal-to-noise Basically there are two types. One type of ratio. It also measures the vectors representing system is based on the Einthoven equilateral the atria more accurately than other available triangle and includes those devised by Milo- systems. The McFee and Parungao system vanovich, Jouve, Vastesaeger, and the "equi- supposedly has the advantage of eliminating lateral tetrahedron" system suggested by Wil- the inaccuracy or error in the location of an- son. The other consists of orthogonal lead terior and lateral thoracic electrodes. systems. These include Duchosal and Sulzers The components of the vectorcardiographic

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QRS loop a vertex is noted (Fig. 2, left). This la P. is due to the activation in the lateral free left T.41: ventricular wall at its thickest region.4 The S loop (Fig. 2) is actually a portion of the centripetal segment of the QRS loop. It represents the activation within the basal portions of the heart. This includes the high posterior portions of the left ventricular wall, high portions of the right septal mass, and the free right ventricular wal1.4 The P loop (Fig. 2, left) reflects the activation of the atria, and the T loop (Fig. 2, left) depicts the repolarization of the ventricles.4 In order to use the vectorcardiograph as a useful clinical instrument, one must under- stand the vectorcardiographic changes which

occur when myocardial activity is altered. In 0 sY: . 444,4 this preliminary report, discussion will be sontomarf limited to the depolarization changes noted in 41,101110NOR an acute myocardial infarction. The repolarization abnormalities reflected by the T loop are not specific for myocardial infarction and therefore will not be mentioned. Necrotic tissue does not produce an action Fig. 6. Serial electrocardiograms of patient in Case 1.

Journal AOA/vol. 66, January 1967 497/73 /RLL ,10.f“

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36 Horizontal plane A Fig. 7. Admission electrocardiogram of patient in Case 2. S current and therefore contributes little to the configuration of the vectorcardiograph loop.4 It is this absence of vectorial forces at the site P of necrosis that is responsible for the changes in the magnitude and configuration of normal loop morphology.

Materials and methods Rt. sa6ittal plane A fully mobile panoramic vectorcardiograph was used (Fig. 3). This instrument not only Fig. 8. The vectorcardiogram of patient in Case 2 records the standard frontal, horizontal, and demonstrates an abnormally oriented Q loop, most sagittal planes, but any azimuth and elevation noticeable in the right sagittal plane where it is pro- longed upward and anteriorly. This abnormal configu- reference on a 360 degree sphere. Frank, ration is due to the loss of the normal inferior forces Grishman, Duchosal, and SVEC lead systems and was interpreted as representing an acute myo- are available. cardial infarction at the inferior surface of the left ventricle. Approximately 100 vectorcardiograms have been taken during a 5-month period on patients whose history was suggestive of cardiac disease. The patients selected for this study presence or absence of an acute myocardial in- paper were from a group of twelve with car- farction. diac symptoms, but the presence or absence The following cases are from our study of acute myocardial damage could not be as- group and depict the vectorcardiographic rep- certained from the initial electrocardiograms. resentation of an acute myocardial infarction Vectorcardiograms were taken on all these when the initial electrocardiogram was equivo- patients upon admission to assess the clinical cal. usefulness of this instrument in confirming the Case 1 •The Frank system was used for all vectorcardiographic tracings in this paper ; the majority of the T and P loops have been elec- The patient, a white man, age 48, with known tronically blanked out for clarity in the illustrative slides. Each dash on the loops represents 2 milliseconds. coronary insufficiency, was admitted to the

498/74 4.1„impww4150

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Fig. 9. Serial electrocardiograms of patient in Case 2.

hospital with the chief complaint of indiges- tion. On admission the blood pressure was 144/100 ; pulse, 88 ; respirations, 20 ; temperature, 98.8 F. ; hemoglobin, 14.6 grams per 100 ml. ; hematocrit, 43 per cent; white blood cell count, 10,400 ; serum glutamic oxaloacetic transaminase (SGOT) , 80 units ; lactic dehy- drogenase (LDH), 480 units ; and creatine phosphokinase (CPK), 560 units. The electrocardiogram taken on admission is shown in Figure 4 ; the initial vectorcardiogram is shown in Figure 5. Follow-up serial electrocardiograms demonstrated the evolutionary changes of an acute myocardial infarction (Fig. 6). Subsequent enzyme studies on the second, third, and fifth hospital days showed the following changes in values : second hospital day, SGOT, 175 units ; LDH, 1,870 units ; and CPK, 1,190 units ; with the later values of SGOT, 75 units ; LDH, 1,810 units ; and CPK, 640 units.

Case 2 A white man, age 51, was admitted to the hospital with the chief complaint of retrosternal chest pain radiating down the ulnar surfaces of both arms. Hyperhidrosis was present. On Fig. 10. Admission electrocardiogram of patient in admission the blood pressure was 102/68 ; Case 3. pulse, 78; respirations, 18; temperature, 98.6

Journal AOA/vol. 66, January 1967 499/75 CPK, 640 units ; and third hospital day, SGOT, 38 units ; LDH, 480 units ; and CPK, 880 units.

Case 3 The patient, a white 52-year-old man, was admitted to the hospital with the chief complaint of epigastric discomfort. Numbness of the left arm and pressure discomfort of the chest were accompanying complaints. The on- set of the symptoms was a day before admission. No hyperhidrosis was evident. The admission blood pressure was 144/90 ; pulse, 80 ; respirations, 24 ; temperature, 98 F. ; hemoglobin, 17 grams per 100 ml. ; hematocrit, 52 per cent ; white blood cells, 12,600 ; sedimenta- tion rate, 21 mm. ; LDH, 320 units ; SGOT, 16 units ; CPK, 200 units. The admission electrocardiogram is seen in Figure 10, with the vectorcardiogram in Figure 11. Follow-up serial electrocardiograms demonstrated the evolutionary changes of an acute myocardial infarction (Fig. 12). Subsequent enzyme studies on the Fig. 11. The vectorcardiogram of patient in Case 3 demonstrates a loss of the normal outward convexity second and third hospital days were as follows: of the centrifugal limb of the R loop and an increase SGOT, 170 units ; LDH, 720 units ; CPK, 310 in the magnitude of the centripetal portion best seen units ; and SGOT, 320 units ; LDH, 1,750 units ; in the frontal and horizontal planes. These changes indicate a significant decrease of the normal left CPK, 120 units. ventricular activation shown by the summation vector 2 (Fig. 2, right), and were interpreted as repre- Summary senting a myocardial infarction involving the middle and lower portions of the anterior wall of the left This preliminary report has discussed the ventricle. basis of vectorcardiography. Over a 5-month period, approximately 100 VCGs have been taken on patients whose history was sugges- F. ; hemoglobin, 13.2 grams per 100 ml. ; hemat- tive of cardiac disease. Three cases from a ocrit, 40 per cent; white blood cell count, study group of twelve have been presented 6,800 ; SGOT, 32 units ; LDH, 210 units ; CPK, to illustrate the usefulness of the vectorcardio- 800 units. The admission electrocardiogram is graph in assessing the presence of an acute shown in Figure 7, with the vectorcardiogram myocardial infarction when the electrocardio- Figure 8. Follow-up serial electrocardiograms gram was equivocal. demonstrated the evolutionary changes of an Vectorcardiography is still in its embryonic acute myocardial infarction (Fig. 9) . Subse- stage. There is no complete agreement by quent enzyme studies were as follows : second present-day standards as to quantitation of the hospital day, SGOT, 65 units ; LDH, 450 units ; vectorcardiogram or the most efficacious lead

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system. At times, technical difficulties can also be a problem. The author has employed vectorcardiography as a useful clinical tool and be- lieves that it has a place in the evaluation of acute myocardial infarction. At present studies are continuing to assess the value of vectorcardiography in other instances of altered 41.14AP. myocardial activity. .411IPTINNANIzi;11A 4UNIONNONt# gniMME tt,

1. Laufberger, V.: Spatiocardiography. Textbook and atlas. R:41tUfatilitim 51, Charles C Thomas, Springfield, Ill., 1966 isaaffieVagif igiliglak 2. Lamb, L. E.: Electrocardiography and vectorcardiography: in- strumentation, fundamentals, and clinical applications. W. B. ItiONSiNIVRO Mt VI Saunders Co., Philadelphia, 1965 Vita,3111ww<4.4.4§.<11gst:44 3. Massie, E., and Walsh, T. J.: Clinical vectorcardiography and AllikiD4E 411kiiial electrocardiography. Year Book Medical Publishers, Inc., Chicago, ANNINANIEM CAPPANIK 1960 3.4T,IiRuCtu. 4. Sodi-Pallares, D., and Medrano, G. A.: Personal communica- litINIPPittilffirorgt1 gv, tions, 1965 ANNFAiAii4tOltgAlilaii ihNINIKENNRICIONVANN

lf This paper, written during Dr. Mennens residency in the Depart- otimsapokfiltio4.--aii,E ment of Internal Medicine, Lakeside Hospital, Kansas City, Mis- souri. of which Dr. Elias E. Zirul is chairman, won the 1966 residents award offered by the American College of Osteopathic Nif4tinkiifflEdiffig Internists. 1311104.11,11t Dr. Mennen, Lakeside Hospital, 8701 Troost Ave., Kansas City, Missouri 64131.

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