right bundle-branch block with left axis deviation* · brit. heart j., 1966, 28, 703. right...

Brit. Heart J., 1966, 28, 703.

Right Bundle-branch Block with Left Axis Deviation*PAUL SALTZMAN, HAROLD LINN, AND ALFRED PICK

From the Cardiovascular Institute and the Division of Cardiovascular Disease, Department of Medicine, MichaelReese Hospital and Medical Center, Chicago, Illinois, U.S.A.

The electrocardiographic pattern of right bundle-branch block in the precordial leads associated withleft axis deviation in the limb leads has been notedby others. Wilson, Johnston, and Barker (1934)were the first to describe a small wide R and S wavein lead I, with a wide and deep S wave in leads II andIII, and a typical RBBB pattern in the praecordialleads. Recently, Lepeschkin (1964) reviewed thevarious cardiographic and pathological alterationsassociated with this pattern. There now appearsto be general agreement that the basic lesion consistsofpredominant right bundle-branch block associatedwith defects in the distribution of the left bundle-branch. Left and right ventricular hypertrophy,as well as infarction and fibrosis of variable locationand extent, are frequently present (Lepeschkin,1964). The present study was undertaken to deter-mine whether additional and more specific informa-tion could be obtained under these circumstancesby a detailed study of the spatial vectorcardiograph.The results obtained are the basis for a proposedclassification of possible clinical utility.

SUBJECTS AND METHODSSpatial vectorcardiograms, along with a standard

cardiogram (including V4R), were taken in 23 patientson an Electronics for Medicine DR-8 recorder. Patientswere selected on the basis of routine analysis of the dailycardiograms performed in the Heart Station, the onlycriterion being the availability ofthe subject. The Franklead system was used, employing the frontal, horizontal,and right sagittal projections. Table I gives a briefresume of the significant clinical diagnoses in the totalgroup. Of the 23 patients, 21 were men and 2 werewomen. The age range was 49 to 88 years-the average69.

Received November 5, 1965.* Aided by a grant from the National Heart Institute

(HE-06375). A preliminary report was presented at theAmerican Heart Association meetings in October 1964.

703

RESULTS

Analysis of the 23 vectorcardiograms revealed thatthe majority fell into two basic patterns, with therest in a smaller intermediate category that showedmixed features or was otherwise unclassifiable. Thecharacteristic distinguishing features of the twomain types, type A and type B, were found in the

TABLE ISUMMARY OF CASES

Patient Age Sex Clinical data(yr.)

Type AH. S. 74 M Diabetes mellitus, bronchogenic car-

cinomaH. M. 74 M Diabetes mellitus, cerebrovascular ac-

cidentB. W. 72 M Diabetes mellitus, hypertensionJ. C. 49 M Hypertension, chronic endobronchial

diseaseR. 0. 51 M Mild hypertensionA. F. 76 M Chronic pulmonary disease, atypical

angina pectorisN. N. 66 M Atypical angina pectoris, paroxysmal

atrial fib!ilationJ. B. 67 F Hypertension, angina pectorisE. F. 62 M Complete A-V block with Stokes-Adams

seizuresS. G. 77 M Post-operative coronary insufficiencyS. S. 58 M Old myocardial infarct

Intermediate formD. G. 71 M Syphilitic aortic insufficiencyJ. H. 83 M Atypical angina pectoris, hypertensionC. S. 58 M Congestive heart failure, diabetes mellitusM. C. 72 M Old myocardial infarct, hypertensionA. T. 76 F Old myocardial infarct

Type BE. S. 76 M Old myocardial infarct by historyB. P. 74 M Angina pectorisJ. L. 74 M Angina pectorisJ. 0. 57 M Angina pectoris, ischmmic heart diseaseJ. K. 68 M Angina pectoris, congestive heart failure,

complete A-V blockJ. L.* 68 M Shock of undetermined mtiology, died

with ventricular fibrillationC. M.* 88 M Antero-septal and inferior myocardial

infarct (necropsy)

* Patient died.

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TYPE A

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H

'S

F

F

FIG. 1.-Comparisdn of characteristic vector loops of type A (Case A. F.) and B (Case B. P.) in the horizontal(H) and frontal (F) plane. Note differences in rotation of the horizontal and in the shape and position of thefrontal loops. Note in this, as well as in other figures, the direction of movement is toward the narrow part

of the interrupted instantaneous vectors.

TYPE A

Nr

4,

.I

F -

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FIG. 2.-Characteristic electrocardiogram and vectorcardiogram in type A (Case E. F.). Note prominentS wave in V4R and VI; counterclockwise rotation ofhorizontal and frontal loops, the latter flattened (enlarged

in lowest panel).

TYPE B

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horizontal and frontal planes and are shown in Fig. 1and characterized in Table II. Fig. 2 illustrates thetypical 3-plane vectorcardiogram, as well as theusual cardiographic pattern of the type A group.The horizontal QRS loop is oriented both anteriorlyand posteriorly, often to an equal extent, and rotatesin a counterclockwise direction. While the earlyand mid-portion is essentially normal with initialrightward and anterior forces, and mid-forcesdirected first leftward and then mainly posteriorly,the pre-terminal and terminal forces are orientedanteriorly and to the right with striking slowing ofthe inscription. Thus, in the horizontal plane, theloop resembles that seen in uncomplicated RBBB(Braunwald et a!., 1956; Scherlis and Lee, 1963).The frontal QRS loop also showed a characteristic

form in group A. The loop always presented earlyforces directed inferiorly with the main body lyingsuperiorly and rotating in a counterclockwisedirection. The over-all shape of this loop wasparticularly striking as it was flattened and almostrounded in appearance. As expected, the delay wasin the pre-terminal and terminal forces. The rightsagittal QRS loop, as well as the T loop (as in allvectorcardiograms studied), did not show anycharacteristic or additionally useful alterations.The cardiogram in type A usually had a prominentS wave in V4R and/or VI, a Q in lead I, an initial Rin leads 1, III, and AVF, and a QRS that was often

TYPE 8,..4 j z

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,., . .. TABLE II

VECTORCARDIOGRAPHIC CHARACTERISTICS OFTWO VCG TYPES

Type A Type B

Horizontal Antero-posterior, counter- Mainly anterior, clock-clockwise wise

Frontal Mainly superior, counter- Mainly superior, counter-clockwise, flat, and clockwise, elongatedrounded

less widened, the delay being confined to the latterpart of the complex.A total of 10 vectorcardiograms were included in

type A. Clinical data (Table I) revealed that 5patients had no evidence of clinical coronary diseaseand/or myocardial infarction, though generalizedvascular disease was apparent. Significant coronarydisease and/or myocardial infarction was possiblypresent in 3, and definitely found in 2 of the re-maining 5 patients.

Fig. 3 illustrates the typical 3 plane vectorcardio-graphic and cardiographic pattern of type B. Thehorizontal loop is almost or completely anterior, andapart from a tendency for the early forces to movecounterclockwise, shows almost complete clockwiserotation. On occasion, the initial forces weredirected posteriorly, the loop then turning anteriorlythroughout the remainder of its course. This latter

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H X ,

FIG. 3.-Characteristic electrocardiogram and vectorcardiogram in type B (Case J. L.). Note a broader QRScomplex with a slurred R wave in Vi; counterclockwise rotation of an elongated superiorly oriented frontal

loop and clockwise rotation of a predominantly anterior horizontal loop.

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INTERMEDIATE TYPES

H

F

N

F

FIG. 4.-Intermediate types of vectorcardiogram. Left (Case M. C.). In the horizontal plane there is a

figure of 8; the central loop is clockwise, left, and anterior, and the terminal portion counterclockwise, right,and posterior. Right (Case A. T.). In the horizontal plane there is a counterclockwise loop, predominantlyanterior, and left; the terminal portion is right and anterior. The frontal loop is flattened, counterclockwise,

and superior.

pattern was invariably present when prominent andslurred Q waves were present across the cardio-graphic prmcordial leads ("anterior wall infarction").The delay or slowing of the QRS loop was generallymore pronounced in all planes and often occurredin the mid, as well as later portions of depolarization.The frontal loop of type B generally also assumed

a typical form. Initial forces were directed eitherinferiorly or immediately superiorly while the mainbody was superior and the rotation was counter-clockwise. Again, the over-all shape of this loopwas its distinctive feature, being elongated andnarrow. The cardiogram in this group generallyshowed a Q wave in V4R and/or V1, and had a

broader QRS complex with more generalized slow-ing compared to type A.

Seven vectorcardiograms fell into the type Bcategory (Table I). Six patients had evidence ofclinical coronary disease and/or myocardial in-farction, and the two cardiovascular deaths in the23 patients occurred in this group. None of the7 patients were found to be free of significantcoronary disease, and the frequency of importantsymptoms referable to a diseased myocardium was

apparent.A third, or intermediate, group was also identified

(Fig. 4). This group, consisting of 6 patients, hadvariable pattems, often with mixed characteristics of

both type A and B. Others showed a more bizarreconfiguration and could not be readily classified.The clinical background in this group is seen inTable I. Coronary artery disease was generallypresent in this mixed group.

DISCUSSIONRight bundle-branch block with left axis devia-

tion, as pointed out by Lepeschkin (1964), is onlyone type of electrocardiographic manifestation ofbilateral bundle-branch block. In his extensivereview, Lepeschkin has classified this particularcardiographic finding into 3 types, Va, Vb, and Vi.This classification depends upon variable QRSalterations within the major pattern of a prominentand widened R or R' in lead V1 and deep S waves inleads II, III, and AVF. However, the pathologicalalterations appear to be similar in all three types.Based on detailed studies by Unger et al. (1958),Lenegre (1957), and others, there now appears to begeneral agreement that this pattern is associatedwith complete, or nearly complete, interruption ofthe right bundle-branch and marked involvement,up to nearly complete interruption, of the leftbundle-branch. These histological studies are sup-ported by clinical evidence of the frequency ofcomplete heart block in these patients. In addition,

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variable degrees of both left and right ventricularhypertrophy have been described, as well as myo-cardial infarction, though the latter has been provedin less than half of the reported cases (Lepeschkin,1964).In 1954, Richman and Wolff described electro-

cardiographic and vectorcardiographic studies in 4patients who were characterized as having "leftbundle branch block masquerading as right bundlebranch block". As pointed out above, this des-cription does not fit the generally accepted patho-logical alterations for this entity. More recentvecorcardiographic studies were carried out by aJapanese group (Mashima et al., 1963), but 2 of their4 patients were young men and, thus, are notcomparable to our findings.Our present classification into three major groups,

ofwhich two, usually, have clear and easily definablevectorcardiographic characteristics, appears to offera simpler and perhaps more useful approach tostudies of this abnormality. A summary of themajor features seen is presented in Table II.Type A shows a more normal-appearing vector-

cardiogram apart from the superior orientation of aflattened frontal loop (left axis deviation). Inaddition, the horizontal loop appears essentiallynormal except for the terminal delay oriented to theright and anteriorly, the pattern described for thetypical and uncomplicated RBBB (Braunwald et al.,1956; Scherlis and Lee, 1963). Indeed, the absenceof clinically apparent coronary artery disease in 5 ofthe 10 patients in this group, along with the fre-quently insignificant cardiac findings, i.e. normalheart size, suggest a better prognosis for the patientwhen type A is present.On the other hand, the type B loop shows con-

siderable deviation from the normal, as well as fromthat ordinarily encountered in patients with RBBB.There is usually greater delay which involves mostof depolarization rather than being limited to thepre-terminal and terminal forces. Even moreapparent is the narrow and elongated frontal loopwhich, on occasion, shows initial forces directedimmediately superiorly. Also, the horizontal loopis completely, or almost completely, anterior indirection and clockwise in rotation. The frequencyof overt and symptomatic coronary disease inpatients with type B, along with the frequentlyassociated cardiomegaly, congestive heart failure,and death is striking, and suggests a generallypoorer prognosis as compared to patients with thetype A form.The significance of the intermediate group is, so

far, not clear, though it is tempting to consider thisform to be in transition between type A and type B,and thus indicate progressing myocardial damage.2z

The precise pathological differences that couldaccount for these differing vectorcardiogram patternsare unknown but deserve further study. Althoughcharacteristically attributed to right ventricularhypertrophy, a clockwise and anteriorly directedhorizontal loop has been described in the presence ofRBBB alone (Scherlis and Lee, 1963; Milnor, 1957;Miquel et al., 1958). It is tempting to relate thelatter to more extensive alterations in the rightbundle-branch (fibrosis and/or infarction), butthis requires histological proof. Right ventricularhypertrophy alone may produce the horizontal looppattern described in type B (Milnor, 1957). Al-though hypertrophy of the right ventricle has beendescribed in pathological descriptions of the QRSabnormalities that we are concerned with (Lepes-chkin, 1964; Unger et al., 1958), such vectorcardio-graphic alterations are usually encountered withmore severe right-sided hemodynamic changes.Infarction of the true posterior wall of the leftventricle has also been described as giving rise tothe type B horizontal loop alteration (Walsh et al.,1962; Hugenholtz, Forkner, and Levine, 1961). Itis, thus, possible to indict additional fibrosis and/orinfarction in this region as the direct causative factorthat accounts for the differences in the horizontalplane between types A and B. Unfortunately,these interpretations are purely speculative andtheir substantiation must await more refined patho-logical studies. The meaning of frontal loop varia-tions is still undetermined.Although the vectorcardiogram appears to de-

lineate more clearly the described types, standardcardiographic analysis offers similar, if less precise,indications as to whether type A or type B will bepresent. Thus, absence of a Q wave with a pro-minent S wave in V4R and/or Vl indicates type A.This interpretation is supported by a slightlywidened QRS complex showing its delay in the latterpart of the complex. Alternately, a Q wave ispresent in V4R and/or VI in the type B pattern.In addition, a broad QRS showing more diffusedelay may be seen and a QS pattern may be presentin leads II, III, and AVF. However, these standardcardiographic findings were not always readilyapparent, particularly when V4R was not taken orwhen rapid paper speeds were not employed.

SUMMARY

Twenty-three patients with right bundle-branchblock and left axis deviation were analysed vector-cardiographically utilizing the Frank lead system.Two basic vectorcardiographic patterns, types A andB, were identified, as well as an intermediate group.

In type A, present in 10 patients, the characteristic

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findings were a rounded or flattened frontal loop anda horizontal loop showing the classical features ofright bundle-branch block, i.e. terminal anterior andrightward delay with counterclockwise rotation.Type B, present in 7 cases, showed an elongated,

narrow frontal loop. The horizontal loop wasoriented predominantly anteriorly and showedclockwise rotation. The delay associated withbundle-branch block was usually more diffuse andpronounced in this type.These vectorcardiographic findings were cor-

related with the electrocardiographic alterations aswell as the clinical data. The latter suggested moreextensive myocardial disease and a poorer prognosisin type B as compared with type A.

REFERENCESBraunwald, E., Donoso, E., Sapin, S. O., and Grishman, A.

(1956). Right bundle-branch block. Hemodynamic,vectorcardiographic and electrocardiographic observa-tions. Circulation, 13, 866.

Hugenholtz, P. G., Forkner, C. E., and Levine, H. D. (1961).A clinical appraisal of the vectorcardiogram in myo-cardial infarction. II. The Frank system. Circulation,24, 825.

Lenegre, J. (1957). Contribution a l'Ttude des Blocs deBranche Comportant Notamment les Confrontations k6lec-

triques et Histologiques. Bailliere, Paris. (Arch. Mal.C&eur, 50, Suppl. 1.)

Lepeschkin, E. (1964). The electrocardiographic diagnosis ofbilateral bundle branch block in relation to heart block.Progr. cardiovasc. Dis., 6, 445.

Mashima, S., Harumi, K., Sato, C., Yanai, Y., and Ueda, H.(1963). Atypical bundle branch block-report of fourcases with vectorcardiographic observation. Jrap.Heart J., 4, 303.

Milnor, W. R. (1957). Electrocardiogram and vectorcardio-gram in right ventricular hypertrophy and right bundle-branch block. Circulation, 16, 348.

Miquel, C., Sodi-Pallares, D., Cisneros, F., Pileggi, F.,Medrano, G. A., and Bisteni, A. (1958). Right bundlebranch block and right ventricular hypertrophy.Electrocardiographic and vectorcardiographic diagnosis.Amer. J7. Cardiol., 1, 57.

Richman, J. L., and Wolff, L. (1954). Left bundle branchblock masquerading as right bundle branch block.Amer Heart J., 47, 383.

Scherlis, L., and Lee, Y. (1963). Transient right bundlebranch block. Amer. J. Cardiol., 11, 173.

Unger, P. N., Lesser, M. E., Kugel, V. H., and Lev, M.(1958). The concept of "masquerading" bundlebranch block. Circulation, 17, 397.

Walsh, T. J., Tiongson, P. M., Stoddard, E. A., and Massie, E.(1962). The vectorcardiographic QRSsE-loop findingsin inferoposterior myocardial infarction. Amer. HeartJ., 63, 516.

Wilson, F. N., Johnston, F. D., and Barker, P. S. (1934).Electrocardiograms of an unusual type in right bundle-branch block. Amer. Heart J7., 9, 472.

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