- Email: [email protected]
Reply to Drs. Cheng and Castellanos
LETTERS
TO
THE
EDITOR
2.
3. 4.
5.
6.
Cheng TO: Transvenous ventricular pacing in the treatment of paroxysmal atrial tachyarrhythmias alternating with sinus bradycardia and standstill. Amer J Cardiol 22:874, 1968 Siddons SH, Sowton E: Cardiac Pacemakers. Springfield, III.. Charles C Thomas, 1967 p 33, 60 Barold SS, Narula OS, Javiar RP, et al: Significance of right bundle branch block patterns during pervenous~ventricuiar pacing. Brit Heart J 31:285. 1969 Castellanos A Jr, tiaytln 0, Lemberg L, et al: Unusual QR -cmplexes produced by pacemaker stimuli with special reference to myocardial tunneling and coronary sinus stimulation. Amer Heart J 77:732. 1969 Mower MM, Aranaga CE, Tabatznik B: Unusual patterns of conduction produced by pacemaker stimuli. Amer Heart J 74:24, 1967
Coronary Sinus Pacing Masquerading As Interventricular Septal Perforation by Transvenous Catheter-II
Figure 3. Cinefluorographic frames demonstrating the position of the catheter in the apical position of the left ventricular silhouette. A, 15” right anterior oblique projection; B, 70” left anterior oblique projection.
coronary vein, both the pacemaker electrocardiogram and the roentgenogram may suggest a left ventricular location of the electrode catheter which was introduced initially into the right ventricle, and thus septal perforation may be erroneously diagnosed. Whereas perforation of the free wall of the right ventricle has been observed after insertion of a transvenous catheter pacemaker, perforation of the interventricular septum has never been reported.“!4 On the other hand, when a right bundle branch block pattern occurs in a patient with a right ventricular endocardiac pacemaker, the usual causes are stimulation through the coronary sinus or its tributary, stimulation of specific areas of the right ventricular septum that function as the left ventricle, retrograde conduction within the right bundle branch to the atrioventricular junction with subsequent antegrade conduction down the left bundle branch, and right ventricular activation delay due to disease of the conduction system of that ventricle rather than septal perforation.3-5 TSUNG 0. CHENG, MD George Washington University Medical Division DC General Hospital Washington, D.C. References 1.
Stlllman MT, Richards AM: Perforation of the interventricular septum by transven,ous pacemaker catheter. Diagnosis by change in pattern of depolarization on the electrocardiogram. Amer J Cardiol 24:269, 1969
548
The article by Stillman and Richards, “Perforation of the interventricular septum by transvenous pacemaker catheter. Diagnosis by change in pattern of depolarization on the electrocardiogram,” which appeared in the American Journal of Cardiology 24:269-273, 1969 is interesting. However, there are 2 points worth commenting on. First, their Figure 1 supposedly presents the QRS changes induced by a catheter located i,n the right ventricular apex. This is not so, since the AQRS is close to +30°, and it is known that in these cases, (right ventricular apical catheter) almost invariably the AQRS is shifted abnormally to the left. Rather, as s_tated in their Figure 3 (which shows a similar AQRS), the catheter was most probably located in the right ventricular outflow tract. Second, the most important point in this paper is that a change from a left to a right bundle branch block pattern is very suggestive of septal perforation. This complication (as stated by the authors) is extremely rare-if not exceptional. A more likely interpretation is that the catheter penetrated the coronary sinus and was advanced into one of the veins draining into the latter. From this location the tip could have been stimulating the posterolateral part of the left ventricular epicardium. Hence, a right bundle branch block pattern would result. The location of the catheter tip by X-ray is consistent with its assumption. A similar case, with necropsy findings, was recently reported.1 AGUSTIN CASTELUINOS, CESAR CASTILLO, MD University of Miami Section of Cardiology Department of Medicine School of Medicine Miami, Florida
Jr., MD
Reference 1. Castellanos A Jr, Maytin QRS complexes produced 77~732. 1969
0,
Castillo C and Lemberg by pacemaker stimuli.”
L: Amer
“Unusual Heart J
Reply to Drs. Cheng and Castellanos It is gratifying that the case study has provoked interest. As Doctor Castellanos points out, the initial electrocardiographic pattern is not typical of apical place-
The American
Journal
of CARDIOLOGY
LETTERS TO THE EDITOR
ment of the pacing catheter since the patient had a pre-existing conduction defect resulting from an old inferior wall myocardial infarction. The pacemaker catheter tip was in the apex of the right ventricle, not the outflow tract, at the time of the original placement when the electrocardiogram was recorded. It is unfortunate that we do not have vectorcardiograms since the frontal plane QRS vector suggested by the scalar electrocardiogram does not permit elaborate conclusions. The possibility that the pacemaker catheter was lodged in the great cardiac vein was fully considered in our patient, but discarded for the following reasons: (1) The catheter tip was free within the right ventricular cavity after being withdrawn past the interventricular septum as determined by fluorography. (2) Close examination of the anteroposterior and lateral chest X-ray films shows the course of the pacing catheter not to correspond with the anatomic position of the coronary sinus and great cardiac vein although some anatomic variance is possible. (3) The pacing threshold was 3 MA at this position, far less than the stimulus ordinarily required to pace from an epicardial or venous position. Doctor Cheng does not include sufficient data to be of real help in studying this event. We would be most interested to have a further description of the findings at operation, the pacing thresholds and the opportunity to examine a better reproduction of the films taken at cinetluoroscopy. Since the appearance of the paper, we have learned of another case in which, unfortunately, the tip of the pacing catheter was found in the left ventricular cavity at autopsy. This patient had likewise suffered an acute infarction, and the catheter had traversed the necrotic wall. Admittedly, argument could be made that the catheter had incidentally traversed a septal defect occurring acutely in the presence of myocardial infarction, but this certainly does not diminish the importance of recognition of the event. In short, for the reasons enumerated we believe that our case represents a perforation of the interventricular septum by a pacing catheter, and our conviction that perforation of the septum must be ranked among the complications of the transvenous pacemaking has been strengthened by the second case alluded to in which this misadventure was documented by autopsy. A. M. RICHARDS, MD Hennepin County General Fifth and Portland South Minneapolis, Minn. 55415
In my opinion both interpretations are unsatisfactory and the correct diagnosis is second degree (partial) A-V block and A-V junctional (nodal) tachycardia producing A-V dissociation. Dr. Beregovich is right when he admits the presence of A-V block but not when he calls it third degree (complete) A-V block, because it is only a second degree (partial) A-V block. He ought to be perplexed by the normal (68/min) ventricular rate and the normal (supraventricular) morphology of the QRS complexes, which are incompatible with third degree (complete) A-V block. The interference, consequence of a nodal tachycardia superimposed on second degree (partial) block a-6 is overlooked Dr: Hunsaker is right when he speaks of A-V dissociation, instead of third degree (complete) A-V block, but he fails to mention the underlying second degree (partial) block, which is the single possible explanation for an A-V dissociation when the atria1 rate is higher than the ventricular rate and for the blocking of atria1 impulses arriving after the refractory period of the A-V tissue. Both these points are rightly emphasized by Dr. Beregovich in his reply. The most important aspect of the problem, in my opinion, is a practical one: there was no indication for artificial cardiac pacing (which may even be hazardous in an acutely ill patient) because it was not a third degree (complete) A-V block but only a transient A-V A
I
II
III
aVR
Hospital
A-V Heart Block in Myocardial Infarction The June 1969 issue of the Journal1 carried a critique by Dr. Hunsaker of a paper published by Dr. Beregovich and the latter’s reply. The debate is about a set of electrocardiograms (Fig. 1) from a patient with acute diaphragmatic myocardial infarction complicated by atrioventricular dissociation. Strip 1C of this figure is diagnosed as third degree (complete) atrioventricular (A-V) block by Dr. Beregovich and as complete A-V dissociation produced by nonparoxysmal A-V junctional tachycardia by Dr. Hunsaker.
VOLUME
26,
NOVEMBER
1970
Section of Figure I as it appeared (Am. J. Cardiol., 23:54, 1969).
in the January
issue
549
TO
THE
EDITOR
2.
3. 4.
5.
6.
Cheng TO: Transvenous ventricular pacing in the treatment of paroxysmal atrial tachyarrhythmias alternating with sinus bradycardia and standstill. Amer J Cardiol 22:874, 1968 Siddons SH, Sowton E: Cardiac Pacemakers. Springfield, III.. Charles C Thomas, 1967 p 33, 60 Barold SS, Narula OS, Javiar RP, et al: Significance of right bundle branch block patterns during pervenous~ventricuiar pacing. Brit Heart J 31:285. 1969 Castellanos A Jr, tiaytln 0, Lemberg L, et al: Unusual QR -cmplexes produced by pacemaker stimuli with special reference to myocardial tunneling and coronary sinus stimulation. Amer Heart J 77:732. 1969 Mower MM, Aranaga CE, Tabatznik B: Unusual patterns of conduction produced by pacemaker stimuli. Amer Heart J 74:24, 1967
Coronary Sinus Pacing Masquerading As Interventricular Septal Perforation by Transvenous Catheter-II
Figure 3. Cinefluorographic frames demonstrating the position of the catheter in the apical position of the left ventricular silhouette. A, 15” right anterior oblique projection; B, 70” left anterior oblique projection.
coronary vein, both the pacemaker electrocardiogram and the roentgenogram may suggest a left ventricular location of the electrode catheter which was introduced initially into the right ventricle, and thus septal perforation may be erroneously diagnosed. Whereas perforation of the free wall of the right ventricle has been observed after insertion of a transvenous catheter pacemaker, perforation of the interventricular septum has never been reported.“!4 On the other hand, when a right bundle branch block pattern occurs in a patient with a right ventricular endocardiac pacemaker, the usual causes are stimulation through the coronary sinus or its tributary, stimulation of specific areas of the right ventricular septum that function as the left ventricle, retrograde conduction within the right bundle branch to the atrioventricular junction with subsequent antegrade conduction down the left bundle branch, and right ventricular activation delay due to disease of the conduction system of that ventricle rather than septal perforation.3-5 TSUNG 0. CHENG, MD George Washington University Medical Division DC General Hospital Washington, D.C. References 1.
Stlllman MT, Richards AM: Perforation of the interventricular septum by transven,ous pacemaker catheter. Diagnosis by change in pattern of depolarization on the electrocardiogram. Amer J Cardiol 24:269, 1969
548
The article by Stillman and Richards, “Perforation of the interventricular septum by transvenous pacemaker catheter. Diagnosis by change in pattern of depolarization on the electrocardiogram,” which appeared in the American Journal of Cardiology 24:269-273, 1969 is interesting. However, there are 2 points worth commenting on. First, their Figure 1 supposedly presents the QRS changes induced by a catheter located i,n the right ventricular apex. This is not so, since the AQRS is close to +30°, and it is known that in these cases, (right ventricular apical catheter) almost invariably the AQRS is shifted abnormally to the left. Rather, as s_tated in their Figure 3 (which shows a similar AQRS), the catheter was most probably located in the right ventricular outflow tract. Second, the most important point in this paper is that a change from a left to a right bundle branch block pattern is very suggestive of septal perforation. This complication (as stated by the authors) is extremely rare-if not exceptional. A more likely interpretation is that the catheter penetrated the coronary sinus and was advanced into one of the veins draining into the latter. From this location the tip could have been stimulating the posterolateral part of the left ventricular epicardium. Hence, a right bundle branch block pattern would result. The location of the catheter tip by X-ray is consistent with its assumption. A similar case, with necropsy findings, was recently reported.1 AGUSTIN CASTELUINOS, CESAR CASTILLO, MD University of Miami Section of Cardiology Department of Medicine School of Medicine Miami, Florida
Jr., MD
Reference 1. Castellanos A Jr, Maytin QRS complexes produced 77~732. 1969
0,
Castillo C and Lemberg by pacemaker stimuli.”
L: Amer
“Unusual Heart J
Reply to Drs. Cheng and Castellanos It is gratifying that the case study has provoked interest. As Doctor Castellanos points out, the initial electrocardiographic pattern is not typical of apical place-
The American
Journal
of CARDIOLOGY
LETTERS TO THE EDITOR
ment of the pacing catheter since the patient had a pre-existing conduction defect resulting from an old inferior wall myocardial infarction. The pacemaker catheter tip was in the apex of the right ventricle, not the outflow tract, at the time of the original placement when the electrocardiogram was recorded. It is unfortunate that we do not have vectorcardiograms since the frontal plane QRS vector suggested by the scalar electrocardiogram does not permit elaborate conclusions. The possibility that the pacemaker catheter was lodged in the great cardiac vein was fully considered in our patient, but discarded for the following reasons: (1) The catheter tip was free within the right ventricular cavity after being withdrawn past the interventricular septum as determined by fluorography. (2) Close examination of the anteroposterior and lateral chest X-ray films shows the course of the pacing catheter not to correspond with the anatomic position of the coronary sinus and great cardiac vein although some anatomic variance is possible. (3) The pacing threshold was 3 MA at this position, far less than the stimulus ordinarily required to pace from an epicardial or venous position. Doctor Cheng does not include sufficient data to be of real help in studying this event. We would be most interested to have a further description of the findings at operation, the pacing thresholds and the opportunity to examine a better reproduction of the films taken at cinetluoroscopy. Since the appearance of the paper, we have learned of another case in which, unfortunately, the tip of the pacing catheter was found in the left ventricular cavity at autopsy. This patient had likewise suffered an acute infarction, and the catheter had traversed the necrotic wall. Admittedly, argument could be made that the catheter had incidentally traversed a septal defect occurring acutely in the presence of myocardial infarction, but this certainly does not diminish the importance of recognition of the event. In short, for the reasons enumerated we believe that our case represents a perforation of the interventricular septum by a pacing catheter, and our conviction that perforation of the septum must be ranked among the complications of the transvenous pacemaking has been strengthened by the second case alluded to in which this misadventure was documented by autopsy. A. M. RICHARDS, MD Hennepin County General Fifth and Portland South Minneapolis, Minn. 55415
In my opinion both interpretations are unsatisfactory and the correct diagnosis is second degree (partial) A-V block and A-V junctional (nodal) tachycardia producing A-V dissociation. Dr. Beregovich is right when he admits the presence of A-V block but not when he calls it third degree (complete) A-V block, because it is only a second degree (partial) A-V block. He ought to be perplexed by the normal (68/min) ventricular rate and the normal (supraventricular) morphology of the QRS complexes, which are incompatible with third degree (complete) A-V block. The interference, consequence of a nodal tachycardia superimposed on second degree (partial) block a-6 is overlooked Dr: Hunsaker is right when he speaks of A-V dissociation, instead of third degree (complete) A-V block, but he fails to mention the underlying second degree (partial) block, which is the single possible explanation for an A-V dissociation when the atria1 rate is higher than the ventricular rate and for the blocking of atria1 impulses arriving after the refractory period of the A-V tissue. Both these points are rightly emphasized by Dr. Beregovich in his reply. The most important aspect of the problem, in my opinion, is a practical one: there was no indication for artificial cardiac pacing (which may even be hazardous in an acutely ill patient) because it was not a third degree (complete) A-V block but only a transient A-V A
I
II
III
aVR
Hospital
A-V Heart Block in Myocardial Infarction The June 1969 issue of the Journal1 carried a critique by Dr. Hunsaker of a paper published by Dr. Beregovich and the latter’s reply. The debate is about a set of electrocardiograms (Fig. 1) from a patient with acute diaphragmatic myocardial infarction complicated by atrioventricular dissociation. Strip 1C of this figure is diagnosed as third degree (complete) atrioventricular (A-V) block by Dr. Beregovich and as complete A-V dissociation produced by nonparoxysmal A-V junctional tachycardia by Dr. Hunsaker.
VOLUME
26,
NOVEMBER
1970
Section of Figure I as it appeared (Am. J. Cardiol., 23:54, 1969).
in the January
issue
549