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Left bundle branch block and abnormal left axis deviation without left anterior hemiblock
Left Bundle Branch Block and Abnormal Left Axis Deviation Without Left Anterior Hemiblock
NICHOLAS P. DePASQUALE, MD M I C H A E L S. BRUNO, MD
New York, New York
Electrocardiograms of 3 patients with complete left bundle branch block and left axis deviation of AQRS greater than - 3 0 ° in the frontal plane, who had either intermittent normal intraventricular conduction or restoration of normal intraventricular conduction within 12 hours of complete left bundle branch block, are presented. None of the 3 patients had abnormal left axis deviation during normal intraventricular conduction. These findings suggest that left axis deviation of AQRS greater than - 3 0 ° in patients with left bundle branch block is not reliable evidence for block within the anterior fascicles of the left bundle in addition to block of the left main bundle.
It has been suggested t h a t c o m p l e t e left b u n d l e b r a n c h block with true left axis deviation of the Q R S c o m p l e x (defined as deviation of the m e a n Q R S axis to the left of - 3 0 ° in the frontal plane) reflects block within the anterior fascicles of the left b u n d l e (left anterior hemiblock) in addition to more p r o x i m a l block of the m a i n left b u n dle. 1 T h i s report presents evidence t h a t this hypothesis m a y be invalid. Description of E l e c t r o c a r d i o g r a m s
Figure 1 shows a standard lead electrocardiogram obtained from a 62 year old woman admitted to the coronary care unit because of suspected myocardial infarction. The electrocardiogram displays intermittent complete left bundle branch block. During complete left bundle branch block, the •~QRS axis is located at -35°; during normal intraventricular conduction it is located at - 7 ° (Fig. 1). Figure 2A shows a standard lead electrocardiogram obtained from a 52 year old man admitted to the coronary care unit because of retrosternal pain associated with previously unrecognized complete left bundle branch block. Within about 7 hours of admission normal intraventricular conduction was restored (Fig. 2B). During complete left bundle branch block, the ,~QRS axis is located at -34°; during normal intraventricular conduction it is located at - 2 5 °. Figure 3 shows a standard lead electrocardiogram obtained from a 36 year old man with coxsackievirus group B4 myocarditis. The electrocardiograms were registered within about 12 hours of each other. During complete left bundle branch block the ,~QRS axis is located at - 3 7 ° (Fig. 3A); during normal intraventricular conduction it is located at - 2 0 ° (Fig. 3B). Comments
From the Cardiovascular Service, Lenox Hill Hospital, New York, N. Y. Manuscript accepted November 29, 1972. Address for reprints: Nicholas P. E)ePasquale, MD, Cardiovascular Service, Lenox Hill Hospital, 100 E. 77th St., New York, N. Y. 10021.
98
It is well e s t a b l i s h e d t h a t left anterior h e m i b l o c k results in a shift of the m a j o r Q R S axis superiorly a n d to the left in the frontal plane. 2,3 On the other hand, left bundle b r a n c h block is generally considered to result only in a leftward shift of the early QRS vectors without significant deviation of the m a j o r QRS axis to the left. 1,4,~ T h u s , it would s e e m reasonable to p o s t u l a t e t h a t true left axis deviation of /~QRS in the presence of c o m p l e t e left bundle b r a n c h block reflects block within the anterior fascicles of the left bundle in addition to m a i n left bundle b r a n c h block. 1 T h e purpose of this report is not to
July 1973 The American Journalof CARDIOLOGY Volume32
LEFT B U N D L E B R A N C H B L O C K - - D E P A S Q U A L E
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F I G U R E 2. Standard leads registered during left bundle branch block (A) and after restoration of n o r m a l intraventricular conduction 7 hours later (B). The r e s p e c t i v e /~,QRS axes are shown.
So ~ s . F I G U R E 1. S t a n d a r d lead e l e c t r o c a r d i o g r a m f r o m a patient with intermittent left bundle b r a n c h block. The a r r o w s indicate normal i n t r a v e n t r i c u l a r c o n d u c t i o n . The ~,QRS axis during left bundle b r a n c h block (LBBB) and normal intraventricular c o n d u c t i o n ( N I V C ) is shown.
deny that main left bundle branch block and left anterior hemiblock may coexist but rather to indicate that the electrocardiographic diagnosis of this species of combined intraventricular block is unreliable. Indeed, in some patients with left bundle branch block and true left axis deviation left anterior hemiblock was evident after restoration of normal intraventricular conduction. However, the diagnosis of left anterior hemiblock was possible only in retrospect, that is, after restoration of normal intraventricular conduction. In contrast to previous reports, 4,5 a report by Rosenbaum et al. 6 has shown that left bundle branch block may be associated with a marked shift of the AQRS axis to the left. Although the leftward shift of the AQRS axis during left bundle branch block in our 3 patients averaged only 18°, in each case the axis was located beyond - 3 0 ° and therefore satisfied this usual criterion for the diagnosis of left anterior hemiblock. It should be pointed out that the degree of left axis deviation of AQRS necessary to render a reliable diagnosis of left anterior hemiblock has not been established. In most recent reports of the electrocardiogram or vectorcardiogram, or both, in left anterior hemiblock, left axis deviation of ~,QRS greater than - 3 0 ° has been accepted as evidence of left anterior hemiblock. 1,7-1° Rosenbaum et al., 6 while recognizing that discrimination between ordinary left axis deviation and the left axis deviation of left anterior hemiblock is arbitrary, proposed -45 ° as the inferior limit of the AQRS axis in left anterior hemiblock. Nevertheless, in their recent report lz of 5 patients with intermittent left anterior hemiblock these same authors and their colleagues described 2 patients considered to have left anterior hemiblock
whose AQRS axis located at - 3 0 ° and -35 °, respectively. More marked leftward deviation of the AQRS axis during left bundle branch block than occurred in our patients might represent more convincing evidence of coexisting left anterior hemiblock. The fact that Rosenbaum et al. observed a shift of the" AQRS axis as great as 160° during intermittent left bundle branch block makes it doubtful that even marked leftward deviation of this axis can be considered reliable evidence of combined left bundle branch block and left anterior hemiblock.
A
B
m
...-30 °
5.0 la,,cs. F I G U R E 3. Standard leads registered during left bundle branch block (A) and after restoration Of normal intraventricular conduction 12 hours later (B). The respective ~,QRS axes are shown.
July 1973
The American Journal of C A R D I O L O G Y
V o l u m e 32
99
LEFT BUNDLE BRANCH BLOCK--DEPASQUALE AND BRUNO
References 1. Pryor R, Blount GG: The clinical significance of true left axis deviation. Amer Heart J 72:391-413, 1966 2. Rosenbaum MB: Types of left bundle branch block. J Electrocardiol 2:197-208, 1969 3. Watt TB, Pruitt RD: Character, cause and consequence of combined left axis deviation and right bundle branch block in human electrocardiograms. Amer Heart J 77:460-465, 1969 4. Jones AM, Fell H: On axis deviation in human bundle branch block. Amer Heart J 36:98-105, 1948 5. Boyadjian N, Van Dooren C: Etude de deux cas de "bloc de branche" bilateral. Acta Cardiol 5:532--535, 1950. 6. Rosenbaum MB, Elizari MV, Lazzari JO: The Hemiblocks. Oldsmar, Fla., Tampa Tracings, 1970, p 157 7. Lasser RP, Haft JL, Friedberg CK: Relationship of right bundle branch block and marked left axis deviation (with left
100
July 1973
The American Journal of CARDIOLOGY
8.
9.
10.
11.
Volume 32
parietal or peri-infarction block) to complete heart block and syncope. Circulation 37:429-437, 1968 Kulbertus H, Collignon P: Association of right bundle branch block with left superior or inferior intraventricular block. Its relation to complete heart block and Adams-Stokes syndrome. Brit Heart J 31:435-439, 1969 Roos JC, Dunning AJ: Right bundle branch block and left axis deviation in acute myocardial infarction. Brit Heart J 32:847-851,1970 Narula OS, Samet P: Right bundle branch block with normal, left or right axis deviation. Amer J Med 51:432-455, 1971 Rosenbaum MB, Elizari MV, Levi RJ, et al: Five cases of intermittent left anterior hemiblock. Amer J Cardiol 24:1-7, 1969
NICHOLAS P. DePASQUALE, MD M I C H A E L S. BRUNO, MD
New York, New York
Electrocardiograms of 3 patients with complete left bundle branch block and left axis deviation of AQRS greater than - 3 0 ° in the frontal plane, who had either intermittent normal intraventricular conduction or restoration of normal intraventricular conduction within 12 hours of complete left bundle branch block, are presented. None of the 3 patients had abnormal left axis deviation during normal intraventricular conduction. These findings suggest that left axis deviation of AQRS greater than - 3 0 ° in patients with left bundle branch block is not reliable evidence for block within the anterior fascicles of the left bundle in addition to block of the left main bundle.
It has been suggested t h a t c o m p l e t e left b u n d l e b r a n c h block with true left axis deviation of the Q R S c o m p l e x (defined as deviation of the m e a n Q R S axis to the left of - 3 0 ° in the frontal plane) reflects block within the anterior fascicles of the left b u n d l e (left anterior hemiblock) in addition to more p r o x i m a l block of the m a i n left b u n dle. 1 T h i s report presents evidence t h a t this hypothesis m a y be invalid. Description of E l e c t r o c a r d i o g r a m s
Figure 1 shows a standard lead electrocardiogram obtained from a 62 year old woman admitted to the coronary care unit because of suspected myocardial infarction. The electrocardiogram displays intermittent complete left bundle branch block. During complete left bundle branch block, the •~QRS axis is located at -35°; during normal intraventricular conduction it is located at - 7 ° (Fig. 1). Figure 2A shows a standard lead electrocardiogram obtained from a 52 year old man admitted to the coronary care unit because of retrosternal pain associated with previously unrecognized complete left bundle branch block. Within about 7 hours of admission normal intraventricular conduction was restored (Fig. 2B). During complete left bundle branch block, the ,~QRS axis is located at -34°; during normal intraventricular conduction it is located at - 2 5 °. Figure 3 shows a standard lead electrocardiogram obtained from a 36 year old man with coxsackievirus group B4 myocarditis. The electrocardiograms were registered within about 12 hours of each other. During complete left bundle branch block the ,~QRS axis is located at - 3 7 ° (Fig. 3A); during normal intraventricular conduction it is located at - 2 0 ° (Fig. 3B). Comments
From the Cardiovascular Service, Lenox Hill Hospital, New York, N. Y. Manuscript accepted November 29, 1972. Address for reprints: Nicholas P. E)ePasquale, MD, Cardiovascular Service, Lenox Hill Hospital, 100 E. 77th St., New York, N. Y. 10021.
98
It is well e s t a b l i s h e d t h a t left anterior h e m i b l o c k results in a shift of the m a j o r Q R S axis superiorly a n d to the left in the frontal plane. 2,3 On the other hand, left bundle b r a n c h block is generally considered to result only in a leftward shift of the early QRS vectors without significant deviation of the m a j o r QRS axis to the left. 1,4,~ T h u s , it would s e e m reasonable to p o s t u l a t e t h a t true left axis deviation of /~QRS in the presence of c o m p l e t e left bundle b r a n c h block reflects block within the anterior fascicles of the left bundle in addition to m a i n left bundle b r a n c h block. 1 T h e purpose of this report is not to
July 1973 The American Journalof CARDIOLOGY Volume32
LEFT B U N D L E B R A N C H B L O C K - - D E P A S Q U A L E
A ....
Tt
~
i" !
.....
AND BRUNO
B
: [ : l . T ] - I - I"T ~ F I " T ' T ' ~ : ~
I
liiiil.il! I I I:1 t .I l ~ - [ L - L ~
Ill/~J:l"~,,~l~l~ZlVl Ii!iiliiiili~:l:i~!i!l!;.:il;: il !l::t:!il'::l
l"r
._
II r
_
- f I I t I ~ J ~ r J ~
I I I I
;' ~"~ fl "PM'~It"l"'l"~ If I'~,11"7
III ZI, i l I I , I I I
I lill
I 1;1'
~ 111' AQRS/
\
QRS
LBBB
30
......
LBBB
~
s.o--'~,.s.
F I G U R E 2. Standard leads registered during left bundle branch block (A) and after restoration of n o r m a l intraventricular conduction 7 hours later (B). The r e s p e c t i v e /~,QRS axes are shown.
So ~ s . F I G U R E 1. S t a n d a r d lead e l e c t r o c a r d i o g r a m f r o m a patient with intermittent left bundle b r a n c h block. The a r r o w s indicate normal i n t r a v e n t r i c u l a r c o n d u c t i o n . The ~,QRS axis during left bundle b r a n c h block (LBBB) and normal intraventricular c o n d u c t i o n ( N I V C ) is shown.
deny that main left bundle branch block and left anterior hemiblock may coexist but rather to indicate that the electrocardiographic diagnosis of this species of combined intraventricular block is unreliable. Indeed, in some patients with left bundle branch block and true left axis deviation left anterior hemiblock was evident after restoration of normal intraventricular conduction. However, the diagnosis of left anterior hemiblock was possible only in retrospect, that is, after restoration of normal intraventricular conduction. In contrast to previous reports, 4,5 a report by Rosenbaum et al. 6 has shown that left bundle branch block may be associated with a marked shift of the AQRS axis to the left. Although the leftward shift of the AQRS axis during left bundle branch block in our 3 patients averaged only 18°, in each case the axis was located beyond - 3 0 ° and therefore satisfied this usual criterion for the diagnosis of left anterior hemiblock. It should be pointed out that the degree of left axis deviation of AQRS necessary to render a reliable diagnosis of left anterior hemiblock has not been established. In most recent reports of the electrocardiogram or vectorcardiogram, or both, in left anterior hemiblock, left axis deviation of ~,QRS greater than - 3 0 ° has been accepted as evidence of left anterior hemiblock. 1,7-1° Rosenbaum et al., 6 while recognizing that discrimination between ordinary left axis deviation and the left axis deviation of left anterior hemiblock is arbitrary, proposed -45 ° as the inferior limit of the AQRS axis in left anterior hemiblock. Nevertheless, in their recent report lz of 5 patients with intermittent left anterior hemiblock these same authors and their colleagues described 2 patients considered to have left anterior hemiblock
whose AQRS axis located at - 3 0 ° and -35 °, respectively. More marked leftward deviation of the AQRS axis during left bundle branch block than occurred in our patients might represent more convincing evidence of coexisting left anterior hemiblock. The fact that Rosenbaum et al. observed a shift of the" AQRS axis as great as 160° during intermittent left bundle branch block makes it doubtful that even marked leftward deviation of this axis can be considered reliable evidence of combined left bundle branch block and left anterior hemiblock.
A
B
m
...-30 °
5.0 la,,cs. F I G U R E 3. Standard leads registered during left bundle branch block (A) and after restoration Of normal intraventricular conduction 12 hours later (B). The respective ~,QRS axes are shown.
July 1973
The American Journal of C A R D I O L O G Y
V o l u m e 32
99
LEFT BUNDLE BRANCH BLOCK--DEPASQUALE AND BRUNO
References 1. Pryor R, Blount GG: The clinical significance of true left axis deviation. Amer Heart J 72:391-413, 1966 2. Rosenbaum MB: Types of left bundle branch block. J Electrocardiol 2:197-208, 1969 3. Watt TB, Pruitt RD: Character, cause and consequence of combined left axis deviation and right bundle branch block in human electrocardiograms. Amer Heart J 77:460-465, 1969 4. Jones AM, Fell H: On axis deviation in human bundle branch block. Amer Heart J 36:98-105, 1948 5. Boyadjian N, Van Dooren C: Etude de deux cas de "bloc de branche" bilateral. Acta Cardiol 5:532--535, 1950. 6. Rosenbaum MB, Elizari MV, Lazzari JO: The Hemiblocks. Oldsmar, Fla., Tampa Tracings, 1970, p 157 7. Lasser RP, Haft JL, Friedberg CK: Relationship of right bundle branch block and marked left axis deviation (with left
100
July 1973
The American Journal of CARDIOLOGY
8.
9.
10.
11.
Volume 32
parietal or peri-infarction block) to complete heart block and syncope. Circulation 37:429-437, 1968 Kulbertus H, Collignon P: Association of right bundle branch block with left superior or inferior intraventricular block. Its relation to complete heart block and Adams-Stokes syndrome. Brit Heart J 31:435-439, 1969 Roos JC, Dunning AJ: Right bundle branch block and left axis deviation in acute myocardial infarction. Brit Heart J 32:847-851,1970 Narula OS, Samet P: Right bundle branch block with normal, left or right axis deviation. Amer J Med 51:432-455, 1971 Rosenbaum MB, Elizari MV, Levi RJ, et al: Five cases of intermittent left anterior hemiblock. Amer J Cardiol 24:1-7, 1969