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Right bundle branch block combined with left axis deviation: A vectorcardiographic study of 48 cases
J. ELECTROCARDIOLOGY, 5 (2) 127-134, 1972
Right Bundle Branch Block Combined With Left Axis Deviation: A Vectorcardiographic Study of 48 Cases* BY M. CERQUEIRA-GOMES, J. CORREIA-DOS-SANTOS, R. PAULA-PINTO, C. ABREU-LIMA, C. RAMALH,g,O AND F. ROCHA-GON(~ALVES SUMMARY The vectorcardiograms (VCGs) of 48 patients with complete right bundle branch block combined with marked left axis deviation were studied and compared with electrocardiographic and clinical data. In these patients the VCG enables two patterns to be separated, i.e., type A (28 cases) and B (11 cases), with a different position and rotation of the horizontal loop. Type A configuration is shnilar to uncomplicated RBBB. Type B shows an anteriorly displaced loop with clockwise rotation. The ECG fails to distinguish type A from B. Contrary to the hypothesis of others, data are presented indicating that an associated posterior infarction cannot be, at least in some cases, the explanation for type B pattern. Type B reveals a more serious prognosis than type A mainly as regards the tendency to develop complete A~ block (18% as against 75%). This fact can suggest a new potential clinical usefulness for the VCG. In the last few years there has been an increasing number of reports on the association of complete right bundle block (CRBBB) with marked left axis deviation 1,z,9,10,~2,14,15. Most o f the authors agree that this electrocardiographic pattern should be interpreted as an association of RBBB with another conduction defect located on the anterior division o f the left bundle branch. T h e l a t t e r is c a l l e d left a n t e r i o r h e m i - b l o c k ( L A H B ) by Rosenbaum ~~ It is also generally accepted that the prognosis o f RBBB combined
*From the Laboratorio de Vectocardiografia Ortogonal, Serviqo de Proped~utica Mrdica, Faculdade de Medicina, Porto, Portugal. This study was supported, in part, by a grant from the Instituto de Alta Cultura, Ministrdo da Eduea~o Nacional (PMCr/71) Reprint requests to: M. Cerqueira-Gomes, Faculdade de Medicina, Porto, Portugal,
with L A H B is significantly more severe than that of isolated RBBB, as manifested chiefly by a greater incidence of complicating A-V conduction defects 1,2,6,8,j~ The vectorcardiographic aspects of this pattern have received little attention. T h e purpose of this paper is to report our experience on the V C G analysis o f R B B B + L A H B and its relation to certain clinical data. METHODS W e s t u d i e d 48 c o n s e c u t i v e p a t i e n t s w i t h C R B B B combined with L A H B . The cases were selected according to the E C G criteria described by Rosenbaum ~~ V C G loops and X, Y and Z scalar leads were recorded by the Frank system, with a Hewlett-Packard 1520-A machine, using the fourth intercostal space. O u r findings were correlated with some clinical parameters, namely the presence of heart failure, marked cardiomegaly, arterial hypertension and the tendency to develop A-V conduction defects. The maximal period o f follow-up was 2 years. RESULTS The age of all patients (with exception o f a nine-year old child with an ostium primun type of atrial septal defect) exceeded 40 years (average - 68 years). A s would expected in C R B B B , all the V C G s exhibited increased Q R S duration with right and anterior terminal forces, showing in most cases conduction delay (Figs. 1 and 2). In each case the frontal loop presented a very suggestive aspect of L A H B , viz. initial forces directed downward and the remainder o f the loop located in the superior quadrants with counterclockwise rotation 11. A s regards the horizontal plane configuration five c a s e s w e r e e x c l u d e d f r o m the o v e r - a l l analysis, namely, the child with ostium primun who showed a very suggestive pattern of right ventricular hypertrophy and 4 other patients with
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Fig. 1. CRBBB combined with LAHB: four cases with type A V C G pattern. The horizontal loop exhibits the classical aspect of uncomplicated CRBBB. The frontal plane shows the features seen in LAHB. For detailed explanation see text.
Fig. 2. CRBBB associated with LAHB: four cases with type B VCG pattern. The horizontal loop exhibits wholly anterior situation, with clockwise rotation. The frontal loop morphology is similar to that of type A pattern. For detailed explanation see text.
an extensive anterior infarction which markedly d i s t o r t e d the loop. T h e r e m a i n d e r could be grouped, according to the position and rotation of the horizontal plane, into two well-defined types, previously described by Saltzman et al la
and more recently confirmed by Kulbertus et al r . T h e first one, type A, c o n s i s t i n g o f 28 patients, exhibited the typical horizontal loop seen in uncomplicated RBBB, viz. the body of the loop presenting counterclockwise rotation d. E L E C T R O C A R D I O L O G Y ,
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3. ECOs corresponding to the VCGs of Fig. I.
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Fig. 4. E C G s corresponding to the V C O s of Fig. 2. This E C G pattern is indistinguishable flxim the one shown in Fig. 3.
and the characteristic anterior and fight t e r m i n a l appendage (Fig. 1). T h e second group, t y p e B, J. E L E C T R O C A R D I O L O G Y ,
VOL
5, N O . 2, 1 9 7 2
consisted of 12 patients w h o r e v e a l e d a m o r e u n e x p e c t e d v e c t o r c a r d i o g r a p h i c configuration.
130
CERQUEIRA-GOMES ET AL
Fig. 5. CRBBB combined alternatively with LAHB and left posterior hemiblock (LPHB). The electrocardiographic description of this case has been presented elsewhere 4. On the left, CRBBB + LAHB: top, X, Y and Z scalar leads; underneath, VCG loops. The horizontal exhibits a characteristic type B pattern. On the fight, CRBBB+LPHB; top, scalar leads; beneath, horizontal loop. When this last pattern occurs, the loop is displaced to a very posterior position and its rotation becomes almost entirely counterclockwise. TABLE I Relationship Between Clinical Parameters and the V C G Pattern Total N u m b e r o f Cases: 40 Cardiac failure
Cardiomegaly + +
Adams-Stokes attacks*
Type A (28 cases)
7 (25%)
9 (32%)
5 (18%)
Type B (12 cases)
8 (66%)
6 (50%)
9 (75%
*The maximum ~eriod of follow-up was 2 The horizontal loop was wholly or almost wholly located anteriorly with clockwise rotation (Fig. 2). T h e r e w e r e 3 p a t i e n t s w i t h i n t e r m e d i a t e morphology between A and B. The E C G o f the two V C G types, A and B, were practically indistinguishable (Figs. 3 and 4), The two V C G types were correlated with the
'ears
aforementioned clinical data (Table I). T y p e B shows a higher incidence o f heart failure (66% as against 25%), cardiomegaly (55% as against 32%), and above all a greater tendency to develop complete A V block (75% as against 18%). In two patients the pattern o f R B B B + L A H B type B appeared intermittently. The electrocardiographic description o f the first one has been d. ELECTROCARDIOLOGY, VOl_ 5, NO. 2, 1972
RBBB COMBINED WITH LAD
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Fig. 6. ECGs of a 72 year-old-woman with acute myocardial infarction. The tracings reveal acute anteroseptal subepicardial ischemia and intermittent CRBBB, present in records B and D and absent in A, C and E. discussed in detail elsewhere 4. T h e tracing showed a pattern of CRBBB associated alternatively with either L A H B or left posterior hemiblock (LPHB). In the V C G (Fig. 5), when L A H B was presented the horizontal loop exhibited a type B pattern; when L P H B appeared the loop was displaced very posteriorly with counterclockwise rotation. Postmortem examination showed no myocardial infarction. The second patient was a female who was admitted with an acute antei'oseptal infarction. The E C G revealed L A H B complicated by intermittent C R B B B (Fig. 6). As regards the V C G , in the presence of RBBB a type B pattern was observed (Fig. 7). In the absence of RBBB the horizontal loop showed a fairly normal position and rotation. An attempt was made to correlate the patterns of the horizontal loop, i.e., types A and B, to the configuration in the frontal plane, viz. the presence of a superiorly elongated loop or of J. ELECTROGARDIOLOGY, VOL. 5, NO. 2, 1972
a flattened one 13. N o correlation was found (Table II). The only consistent finding was the association of a superiorly elongated frontal loop in both types A and B with the presence o f arterial hypertension (Table llI).
DISCUSSION Despite the limitations resulting from the small number o f cases studied in this report, some important points must be emphasized. (1) Our study confirms that in patients showing C R B B B a s s o c i a t e d with L A H B , the V C G enables us to separate two patterns, A and B, with different position and rotation of the horizontal loop (Figs. 1 and 2). While type A exhibits the classical m o r p h o l o g y o f C R B B B , type B reveals an anterior displaced horizontal loop with clockwise rotation. (2) The E C G fails to distinguish one pattern from the other (Figs. 3 and 4).
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CERQUEIRA-GOMES ET AL
TABLE II Relationship Between the Frontal Loop Morphology and the Horizontal Loop Pattern Total Number of Cases: 40
Horizontal plane
Type A
Flattened 18
Frontal Loop Morphology Intermediate ] 5 [
Enlongated 5
Type B
6
3
3
TAB LE 111 Relationship Between the Frontal Loop Morphology and the Presence of Arterial Hypertension Total Number o f Cases: 43* Frontal Loop Morphology Flattened [ Enlongated or Intermediate Horizontal plane
-
23
+
1
]
6 12
*Includes types A and B (40 cases), plus 3 intermediate horizontal loops. (3) Clinical correlations indicate that type B has a much more ominous prognosis, showing serious organic manifestations (Table I). The most striking clinical difference between types A and B is the far greater tendency of the latter to develop AV block (18% as against 75%). In order to explain the atypical VCG configuration of the type B pattern the association of posterior (dorsal) infarction has been suggested by Saltzman et a113, although anatomical confirmation has not been presented. At first we accepted this explanation for two main reasons: (a) The high posterior infarction predominantly affects the second half of QRS loop, displacing it forward 3. This fact could explain the change of rotation in the horizontal plane. (b) When posterior infarction occurs in a setting pre-existing CRBBB+LHAB, a high incidence of complete AV block is to be expected. In fact, we can accept that the association of posterior infarction can easily involve the posterior division of the left bundle branch and lead to intraventricular trifaacicular block. This fact would explain the far higher incidence of complete heart block in the type B group. However, the cases of the two aforementioned patients, who exhibited an intermittent CRBBB
+ L A H B with type B configuration (Figs. 5, 6 and 7) do not seem to support such a view. Indeed, the disappearance or the change in the conduction defects in both cases as well as the autopsy in the first one proved that no posterior infarction was present in these two patients. In addition, Cohen et aP were recently able to produce aberrant ventricular conduction in man by the introduction of atrial premature beats through a transvenous catheter electrode. In several individuals showing previously normal horizontal loops, the aberrant ventricular conduction revealed patterns of CRBBB associated with LAHB; some of them exhibited a type A loop, while others showed a type B configuration. All these f'mdings seem to indicate that, at least in some instances of combined CRBBB and LAHB, a change in the sequence of ventricular activation may produce a type B pattern without the association of posterior infarction. Why most patients with CRBBB + LAHB show a VCG pattern of classical CRBBB while others reveal a B type loop is unclear. Recently Rothfeld et aP ~ reported that the type B VCG pattern simply represents a posterior infarction and not RBBB. The aforementioned two examples of intermittent conduction J. ELECTROCARDIOLOGY, VOL. 5, NO. 2, 1972
RBBB COMBINED WITH LAD
133
Fig. 7. VCG loops of the same patient as in Fib. 6. VCGs no. 436/69 441/69correspond, respectively, to ECGs B and D, in which CRBBB is present. VCGs no. 439/69 and 445/69 correspond respectively to ECGs C and E, without CRBBB. When CRBBB occurs, and particularly in the VCG 436/69, the loop is found by a completely anterior position with clockwise rotation, i.e. a type B pattern of CRBBB+LAHB. When CRBBB disappears, the horizontal loop is almost entirely located in the left posterior quadrant, with counter-clockwise rotation. defects as well as the findings of Cohen ~ clearly show that this assumption is incorrect. The intermittent change from normal to abnormal rotation of Q R S loop with QRS prolongation supports our opinion. Concerning the frontal loop configuration, all cases of this report revealed the typical aspect of the V C G in L A H B 11, as mentioned above. Our results did not confirm previous references of Saltzman et al ~3that the type B pattern characteristically shows a superiorly elongated frontal loop while type A reveals a more flattened one. Each of these configurations were seen in the frontal loops of both types A and B (Table II). The only apparent correlation of a superiorly elongated frontal loop was found to be the presence of high blood pressure (Table I II). Because a superiorly elongated frontal loop will correspond in the E C G to deep S waves in II, III and a V F , the above correlation seems to be in agreement with Rosenbaum's previous findings a. ELECTROCARDIOLOGY, VOL. 5, NO. 2, 1972
on hemiblocks 1~ He observed that one group of left anterior hemiblocks, which he called type IV, was characterized by a marked increase in the amplitude of $2 and $3 and was present in patients with arterial hypertension or aortic valve disease corresponding to marked left ventricular hypertrophy associated to left anterior hemiblock. We suggest that the o c c u r r e n c e o f a superiorly elongated frontal loop in our group may also indicate the presence of marked left ventricular hypertrophy. In conclusion, the most relevant findings of our study are: (a) in patients with C R B B B + L A H B the V C G confguration enables two types, A and B, to be distinguished, while the E C G fails to do so; (b) type B characteristically reveals a much more serious prognosis, mainly as regards the tendency to develop A V block. However, the number of patients is too small to justify definite conclusions. Should a more significant number of cases con-
134
C E R Q U E I R A - G O M E S ET A L
firm these results a n o t h e r clinical application o f the V C G will b e c o m e apparent. In such a case, the finding o f a type B pattern in the V C G o f a patient with C R B B B + L A H B will m e a n a m o r e pressing n e e d for electrical pacing. REFERENCES 1. Blondeau, M. and Len~gre, J.: Bloc atypique de la branche droite. Masson, Paris, 1970. 2. Castellanos, A., Maytin, O., Arcebal, A. G. et al: Alternating and co-existing block in the divisions of the left bundle branch. Dis Chest. 56: 103, 1969. 3. Cerqueira-Gomes, M. : Myocardial infarction and orthogonal leads. Diagnostic value of the instantaneous vectors of the second halfofQRS. In Wenger R. (ed.), Aktuelle Probleme der Vektordardiographic. G. T. Verlag, Stuttgart, 1968. 4. Cerqueira-Gomes, M. and Teixeira, A.V. : Wenckebach phenomenon in the posterior division of the left branch, Am Heart J. 82: 377, 1971. 5. Cohen, S.I., Lau, S. H., Stein, E. et al: Variations of aberrant ventricular conduction in man: evidence of i s o l a t e d and c o m b i n e d b l o c k within the specialized conduction system. Circulation 38: 899, 1968. 6. Kulbertus, H. and Collignon, P.: Association of right bundle branch block with superior or inferior intraventricular block: its relation to complete heart block and Adams-Stokes syndrome. Brit. Heart J. 31: 435, 1969.
7. Kulbertus, P. H., Colignon, P. and Humblet, L.: Vectorcardiographic study of Q RS loop in patients with left superior axis deviation and right bundle branch block. Brit. Heart J. 32: 386, 1970. 8. Lasser, R. P., Haft, J. I. and Friedberg, C. K.: Relationship of right bundle-branch block and marked left axis deviation (with left parietal or periinfarction block) to complete heart block and syncope. Circulation 37: 429, 1968. 9. Lepeschkin, E.: Electrocardiographic diagnosis of bilateral bundle branch in relation to heart block. Progr. Cardiov. Dis. 6: 445, 1964. 10. Rosenbaum, M. B., Elizari, M. B. and Lazzari, J. O.: Los hemibloqueos. Paidos, Buenos Aires, 1967. 11. Rosenbaum, M. B., Elizari, M.V., Levi, R. J. et al: Five cases of intermittent left anterior hemiblock. Am. J. Cardiol. 24: l, 1969. 12. Rothfeld, E. L., Zucker, I. R. et al: The electrocardiographic syndrome of superior axis and right bundle Branch block. Dis. Chest. 55: 306, 1969. 13. Saltzman, P., Linn, H. and Pick, A. : Right bundle branch block with left axis deviation. Brit. Heart J. 23: 703, 1966. 14. Sugiura, M., Okada, R., Hiraoka, K. et al: Hystological studies on the conduction system of right bundle branch block associated with left axis deviation. Jap. Heart J. 10: 121, 1969. 15. Watt, T. W. and Pruitt, R. D.: Character, cause, and consequence of combined left axis deviation and fight bundle branch block in human electrocardiograms. Am. Heart J. 77: 460, 1969.
J. ELECTROCARDIOLOGY,VOL. 5, NO. 2, 1972
Right Bundle Branch Block Combined With Left Axis Deviation: A Vectorcardiographic Study of 48 Cases* BY M. CERQUEIRA-GOMES, J. CORREIA-DOS-SANTOS, R. PAULA-PINTO, C. ABREU-LIMA, C. RAMALH,g,O AND F. ROCHA-GON(~ALVES SUMMARY The vectorcardiograms (VCGs) of 48 patients with complete right bundle branch block combined with marked left axis deviation were studied and compared with electrocardiographic and clinical data. In these patients the VCG enables two patterns to be separated, i.e., type A (28 cases) and B (11 cases), with a different position and rotation of the horizontal loop. Type A configuration is shnilar to uncomplicated RBBB. Type B shows an anteriorly displaced loop with clockwise rotation. The ECG fails to distinguish type A from B. Contrary to the hypothesis of others, data are presented indicating that an associated posterior infarction cannot be, at least in some cases, the explanation for type B pattern. Type B reveals a more serious prognosis than type A mainly as regards the tendency to develop complete A~ block (18% as against 75%). This fact can suggest a new potential clinical usefulness for the VCG. In the last few years there has been an increasing number of reports on the association of complete right bundle block (CRBBB) with marked left axis deviation 1,z,9,10,~2,14,15. Most o f the authors agree that this electrocardiographic pattern should be interpreted as an association of RBBB with another conduction defect located on the anterior division o f the left bundle branch. T h e l a t t e r is c a l l e d left a n t e r i o r h e m i - b l o c k ( L A H B ) by Rosenbaum ~~ It is also generally accepted that the prognosis o f RBBB combined
*From the Laboratorio de Vectocardiografia Ortogonal, Serviqo de Proped~utica Mrdica, Faculdade de Medicina, Porto, Portugal. This study was supported, in part, by a grant from the Instituto de Alta Cultura, Ministrdo da Eduea~o Nacional (PMCr/71) Reprint requests to: M. Cerqueira-Gomes, Faculdade de Medicina, Porto, Portugal,
with L A H B is significantly more severe than that of isolated RBBB, as manifested chiefly by a greater incidence of complicating A-V conduction defects 1,2,6,8,j~ The vectorcardiographic aspects of this pattern have received little attention. T h e purpose of this paper is to report our experience on the V C G analysis o f R B B B + L A H B and its relation to certain clinical data. METHODS W e s t u d i e d 48 c o n s e c u t i v e p a t i e n t s w i t h C R B B B combined with L A H B . The cases were selected according to the E C G criteria described by Rosenbaum ~~ V C G loops and X, Y and Z scalar leads were recorded by the Frank system, with a Hewlett-Packard 1520-A machine, using the fourth intercostal space. O u r findings were correlated with some clinical parameters, namely the presence of heart failure, marked cardiomegaly, arterial hypertension and the tendency to develop A-V conduction defects. The maximal period o f follow-up was 2 years. RESULTS The age of all patients (with exception o f a nine-year old child with an ostium primun type of atrial septal defect) exceeded 40 years (average - 68 years). A s would expected in C R B B B , all the V C G s exhibited increased Q R S duration with right and anterior terminal forces, showing in most cases conduction delay (Figs. 1 and 2). In each case the frontal loop presented a very suggestive aspect of L A H B , viz. initial forces directed downward and the remainder o f the loop located in the superior quadrants with counterclockwise rotation 11. A s regards the horizontal plane configuration five c a s e s w e r e e x c l u d e d f r o m the o v e r - a l l analysis, namely, the child with ostium primun who showed a very suggestive pattern of right ventricular hypertrophy and 4 other patients with
127
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Fig. 1. CRBBB combined with LAHB: four cases with type A V C G pattern. The horizontal loop exhibits the classical aspect of uncomplicated CRBBB. The frontal plane shows the features seen in LAHB. For detailed explanation see text.
Fig. 2. CRBBB associated with LAHB: four cases with type B VCG pattern. The horizontal loop exhibits wholly anterior situation, with clockwise rotation. The frontal loop morphology is similar to that of type A pattern. For detailed explanation see text.
an extensive anterior infarction which markedly d i s t o r t e d the loop. T h e r e m a i n d e r could be grouped, according to the position and rotation of the horizontal plane, into two well-defined types, previously described by Saltzman et al la
and more recently confirmed by Kulbertus et al r . T h e first one, type A, c o n s i s t i n g o f 28 patients, exhibited the typical horizontal loop seen in uncomplicated RBBB, viz. the body of the loop presenting counterclockwise rotation d. E L E C T R O C A R D I O L O G Y ,
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3. ECOs corresponding to the VCGs of Fig. I.
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Fig. 4. E C G s corresponding to the V C O s of Fig. 2. This E C G pattern is indistinguishable flxim the one shown in Fig. 3.
and the characteristic anterior and fight t e r m i n a l appendage (Fig. 1). T h e second group, t y p e B, J. E L E C T R O C A R D I O L O G Y ,
VOL
5, N O . 2, 1 9 7 2
consisted of 12 patients w h o r e v e a l e d a m o r e u n e x p e c t e d v e c t o r c a r d i o g r a p h i c configuration.
130
CERQUEIRA-GOMES ET AL
Fig. 5. CRBBB combined alternatively with LAHB and left posterior hemiblock (LPHB). The electrocardiographic description of this case has been presented elsewhere 4. On the left, CRBBB + LAHB: top, X, Y and Z scalar leads; underneath, VCG loops. The horizontal exhibits a characteristic type B pattern. On the fight, CRBBB+LPHB; top, scalar leads; beneath, horizontal loop. When this last pattern occurs, the loop is displaced to a very posterior position and its rotation becomes almost entirely counterclockwise. TABLE I Relationship Between Clinical Parameters and the V C G Pattern Total N u m b e r o f Cases: 40 Cardiac failure
Cardiomegaly + +
Adams-Stokes attacks*
Type A (28 cases)
7 (25%)
9 (32%)
5 (18%)
Type B (12 cases)
8 (66%)
6 (50%)
9 (75%
*The maximum ~eriod of follow-up was 2 The horizontal loop was wholly or almost wholly located anteriorly with clockwise rotation (Fig. 2). T h e r e w e r e 3 p a t i e n t s w i t h i n t e r m e d i a t e morphology between A and B. The E C G o f the two V C G types, A and B, were practically indistinguishable (Figs. 3 and 4), The two V C G types were correlated with the
'ears
aforementioned clinical data (Table I). T y p e B shows a higher incidence o f heart failure (66% as against 25%), cardiomegaly (55% as against 32%), and above all a greater tendency to develop complete A V block (75% as against 18%). In two patients the pattern o f R B B B + L A H B type B appeared intermittently. The electrocardiographic description o f the first one has been d. ELECTROCARDIOLOGY, VOl_ 5, NO. 2, 1972
RBBB COMBINED WITH LAD
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72 ano~
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A
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i!~!:
ii!ii::!
:.ii
11.9.69 11,45 h.
'N N N N N N
16.9.6 9
Fig. 6. ECGs of a 72 year-old-woman with acute myocardial infarction. The tracings reveal acute anteroseptal subepicardial ischemia and intermittent CRBBB, present in records B and D and absent in A, C and E. discussed in detail elsewhere 4. T h e tracing showed a pattern of CRBBB associated alternatively with either L A H B or left posterior hemiblock (LPHB). In the V C G (Fig. 5), when L A H B was presented the horizontal loop exhibited a type B pattern; when L P H B appeared the loop was displaced very posteriorly with counterclockwise rotation. Postmortem examination showed no myocardial infarction. The second patient was a female who was admitted with an acute antei'oseptal infarction. The E C G revealed L A H B complicated by intermittent C R B B B (Fig. 6). As regards the V C G , in the presence of RBBB a type B pattern was observed (Fig. 7). In the absence of RBBB the horizontal loop showed a fairly normal position and rotation. An attempt was made to correlate the patterns of the horizontal loop, i.e., types A and B, to the configuration in the frontal plane, viz. the presence of a superiorly elongated loop or of J. ELECTROGARDIOLOGY, VOL. 5, NO. 2, 1972
a flattened one 13. N o correlation was found (Table II). The only consistent finding was the association of a superiorly elongated frontal loop in both types A and B with the presence o f arterial hypertension (Table llI).
DISCUSSION Despite the limitations resulting from the small number o f cases studied in this report, some important points must be emphasized. (1) Our study confirms that in patients showing C R B B B a s s o c i a t e d with L A H B , the V C G enables us to separate two patterns, A and B, with different position and rotation of the horizontal loop (Figs. 1 and 2). While type A exhibits the classical m o r p h o l o g y o f C R B B B , type B reveals an anterior displaced horizontal loop with clockwise rotation. (2) The E C G fails to distinguish one pattern from the other (Figs. 3 and 4).
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CERQUEIRA-GOMES ET AL
TABLE II Relationship Between the Frontal Loop Morphology and the Horizontal Loop Pattern Total Number of Cases: 40
Horizontal plane
Type A
Flattened 18
Frontal Loop Morphology Intermediate ] 5 [
Enlongated 5
Type B
6
3
3
TAB LE 111 Relationship Between the Frontal Loop Morphology and the Presence of Arterial Hypertension Total Number o f Cases: 43* Frontal Loop Morphology Flattened [ Enlongated or Intermediate Horizontal plane
-
23
+
1
]
6 12
*Includes types A and B (40 cases), plus 3 intermediate horizontal loops. (3) Clinical correlations indicate that type B has a much more ominous prognosis, showing serious organic manifestations (Table I). The most striking clinical difference between types A and B is the far greater tendency of the latter to develop AV block (18% as against 75%). In order to explain the atypical VCG configuration of the type B pattern the association of posterior (dorsal) infarction has been suggested by Saltzman et a113, although anatomical confirmation has not been presented. At first we accepted this explanation for two main reasons: (a) The high posterior infarction predominantly affects the second half of QRS loop, displacing it forward 3. This fact could explain the change of rotation in the horizontal plane. (b) When posterior infarction occurs in a setting pre-existing CRBBB+LHAB, a high incidence of complete AV block is to be expected. In fact, we can accept that the association of posterior infarction can easily involve the posterior division of the left bundle branch and lead to intraventricular trifaacicular block. This fact would explain the far higher incidence of complete heart block in the type B group. However, the cases of the two aforementioned patients, who exhibited an intermittent CRBBB
+ L A H B with type B configuration (Figs. 5, 6 and 7) do not seem to support such a view. Indeed, the disappearance or the change in the conduction defects in both cases as well as the autopsy in the first one proved that no posterior infarction was present in these two patients. In addition, Cohen et aP were recently able to produce aberrant ventricular conduction in man by the introduction of atrial premature beats through a transvenous catheter electrode. In several individuals showing previously normal horizontal loops, the aberrant ventricular conduction revealed patterns of CRBBB associated with LAHB; some of them exhibited a type A loop, while others showed a type B configuration. All these f'mdings seem to indicate that, at least in some instances of combined CRBBB and LAHB, a change in the sequence of ventricular activation may produce a type B pattern without the association of posterior infarction. Why most patients with CRBBB + LAHB show a VCG pattern of classical CRBBB while others reveal a B type loop is unclear. Recently Rothfeld et aP ~ reported that the type B VCG pattern simply represents a posterior infarction and not RBBB. The aforementioned two examples of intermittent conduction J. ELECTROCARDIOLOGY, VOL. 5, NO. 2, 1972
RBBB COMBINED WITH LAD
133
Fig. 7. VCG loops of the same patient as in Fib. 6. VCGs no. 436/69 441/69correspond, respectively, to ECGs B and D, in which CRBBB is present. VCGs no. 439/69 and 445/69 correspond respectively to ECGs C and E, without CRBBB. When CRBBB occurs, and particularly in the VCG 436/69, the loop is found by a completely anterior position with clockwise rotation, i.e. a type B pattern of CRBBB+LAHB. When CRBBB disappears, the horizontal loop is almost entirely located in the left posterior quadrant, with counter-clockwise rotation. defects as well as the findings of Cohen ~ clearly show that this assumption is incorrect. The intermittent change from normal to abnormal rotation of Q R S loop with QRS prolongation supports our opinion. Concerning the frontal loop configuration, all cases of this report revealed the typical aspect of the V C G in L A H B 11, as mentioned above. Our results did not confirm previous references of Saltzman et al ~3that the type B pattern characteristically shows a superiorly elongated frontal loop while type A reveals a more flattened one. Each of these configurations were seen in the frontal loops of both types A and B (Table II). The only apparent correlation of a superiorly elongated frontal loop was found to be the presence of high blood pressure (Table I II). Because a superiorly elongated frontal loop will correspond in the E C G to deep S waves in II, III and a V F , the above correlation seems to be in agreement with Rosenbaum's previous findings a. ELECTROCARDIOLOGY, VOL. 5, NO. 2, 1972
on hemiblocks 1~ He observed that one group of left anterior hemiblocks, which he called type IV, was characterized by a marked increase in the amplitude of $2 and $3 and was present in patients with arterial hypertension or aortic valve disease corresponding to marked left ventricular hypertrophy associated to left anterior hemiblock. We suggest that the o c c u r r e n c e o f a superiorly elongated frontal loop in our group may also indicate the presence of marked left ventricular hypertrophy. In conclusion, the most relevant findings of our study are: (a) in patients with C R B B B + L A H B the V C G confguration enables two types, A and B, to be distinguished, while the E C G fails to do so; (b) type B characteristically reveals a much more serious prognosis, mainly as regards the tendency to develop A V block. However, the number of patients is too small to justify definite conclusions. Should a more significant number of cases con-
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C E R Q U E I R A - G O M E S ET A L
firm these results a n o t h e r clinical application o f the V C G will b e c o m e apparent. In such a case, the finding o f a type B pattern in the V C G o f a patient with C R B B B + L A H B will m e a n a m o r e pressing n e e d for electrical pacing. REFERENCES 1. Blondeau, M. and Len~gre, J.: Bloc atypique de la branche droite. Masson, Paris, 1970. 2. Castellanos, A., Maytin, O., Arcebal, A. G. et al: Alternating and co-existing block in the divisions of the left bundle branch. Dis Chest. 56: 103, 1969. 3. Cerqueira-Gomes, M. : Myocardial infarction and orthogonal leads. Diagnostic value of the instantaneous vectors of the second halfofQRS. In Wenger R. (ed.), Aktuelle Probleme der Vektordardiographic. G. T. Verlag, Stuttgart, 1968. 4. Cerqueira-Gomes, M. and Teixeira, A.V. : Wenckebach phenomenon in the posterior division of the left branch, Am Heart J. 82: 377, 1971. 5. Cohen, S.I., Lau, S. H., Stein, E. et al: Variations of aberrant ventricular conduction in man: evidence of i s o l a t e d and c o m b i n e d b l o c k within the specialized conduction system. Circulation 38: 899, 1968. 6. Kulbertus, H. and Collignon, P.: Association of right bundle branch block with superior or inferior intraventricular block: its relation to complete heart block and Adams-Stokes syndrome. Brit. Heart J. 31: 435, 1969.
7. Kulbertus, P. H., Colignon, P. and Humblet, L.: Vectorcardiographic study of Q RS loop in patients with left superior axis deviation and right bundle branch block. Brit. Heart J. 32: 386, 1970. 8. Lasser, R. P., Haft, J. I. and Friedberg, C. K.: Relationship of right bundle-branch block and marked left axis deviation (with left parietal or periinfarction block) to complete heart block and syncope. Circulation 37: 429, 1968. 9. Lepeschkin, E.: Electrocardiographic diagnosis of bilateral bundle branch in relation to heart block. Progr. Cardiov. Dis. 6: 445, 1964. 10. Rosenbaum, M. B., Elizari, M. B. and Lazzari, J. O.: Los hemibloqueos. Paidos, Buenos Aires, 1967. 11. Rosenbaum, M. B., Elizari, M.V., Levi, R. J. et al: Five cases of intermittent left anterior hemiblock. Am. J. Cardiol. 24: l, 1969. 12. Rothfeld, E. L., Zucker, I. R. et al: The electrocardiographic syndrome of superior axis and right bundle Branch block. Dis. Chest. 55: 306, 1969. 13. Saltzman, P., Linn, H. and Pick, A. : Right bundle branch block with left axis deviation. Brit. Heart J. 23: 703, 1966. 14. Sugiura, M., Okada, R., Hiraoka, K. et al: Hystological studies on the conduction system of right bundle branch block associated with left axis deviation. Jap. Heart J. 10: 121, 1969. 15. Watt, T. W. and Pruitt, R. D.: Character, cause, and consequence of combined left axis deviation and fight bundle branch block in human electrocardiograms. Am. Heart J. 77: 460, 1969.
J. ELECTROCARDIOLOGY,VOL. 5, NO. 2, 1972