CONCEALED JUNCTIONAL ECTOPIC IMPULSES/Fisch, Zipes, McHenry regurgitation and of mitral stenosis. Boston Med Surg J 195: 1146, 1926 3. Segal JP, Harvey WP, Corrado MA: The Austin Flint murmur: its differentiation from the murmur of rheumatic mitral stenosis. Circulation 18: 1025, 1958 4. Lochaya S, Igarashi M, Shaffer AB: Late diastolic mitral regurgitation; its relationship to the Austin Flint murmur. Am Heart J 74: 161, 1967 5. Oliver GC Jr, Gazetopoulos N, Deuchar DC: Reversed mitral diastolic gradient in aortic incompetence. Br Heart J 29: 239, 1967 6. O'Brien KP, Cohen LS: Hemodynamic and phonocardiographic correlates of the Austin Flint murmur. Am Heart J 77: 603, 1969 7. Jonsson B, Szamosi A, Tornell G: Presystolic mitral regurgitation in severe aortic incompetence observed by cineangiography. Cardiology 58: 347, 1973 8. Fortuin NJ, Craige E: On the mechanism of the Austin Flint murmur. Circulation 45: 558, 1972 9. Fortuin NJ, Craige E: Echocardiographic studies of genesis of mitral diastolic murmurs. Br Heart J 35: 75, 1973 10. Cohn LH, Mason DT, Ross J Jr, Morrow AG, Braunwald E: Preoperative assessment of aortic regurgitation in patients with mitral valve disease. Am J Cardiol 19: 177, 1967 11. Madeira HC, Ziady G, Oakley CM, Pridie RB: Echocardiographic assessment of left ventricular volume load. Br Heart J 36: 1175, 1974
217
12. Herrmann GR: The Austin Flint phenomenon; an experimental and clinical study. Am Heart J 1: 671, 1926 13. Gouley BA: The aortic valvular lesion associated with the Austin Flint murmur. Am Heart J 22: 208, 1941 14. Ueda H, Sakamoto T, Kawai N, Watanabe H, Uozumi Z, Okada R, Kobayashi T, Tetsura Y, Inoue K, Kaito G: The Austin Flint murmur. Phonocardiographic and patho-anatomical study. Jap Heart J 6: 294, 1965 15. Rees JR, Epstein EJ, Criley JM, Ross RS: Haemodynamic effects of severe aortic regurgitation. Br Heart J 26: 412, 1964 16. Weigle ED, Labrosse CJ: Sudden, severe aortic insufficiency. Circulation 32: 708, 1965 17. Pridie RB, Benham R, Oakley CM: Echocardiography of the mitral valve in aortic valve disease. Br Heart J 33: 296, 1971 18. Spencer MP, Greiss FC: Dynamics of left ventricular ejection. Circ Res 10: 274, 1962 19. Rushmer RF: Cardiovascular Sounds. In Cardiovascular Dynamics, edited by Rushmer RF. Philadelphia, W.B. Saunders Company, 1970, p 293 20. Schaefer RA, McAnulty JH, Starr A, Rahimtoola SH: Diastolic murmurs in the presence of Starr-Edwards mitral prosthesis: with emphasis on the genesis of the Austin Flint murmur. Circulation 51: 402, 1975
Electrocardiographic Manifestations of Concealed Junctional Ectopic Impulses CHARLES FISCH,
M.D.,
DOUGLAS P. ZIPES, M.D.,
AND PAUL
L. MCHENRY, M.D.
SUMMARY Thirteen episodes of concealed junctional ectopic impulses (JEI) in ten patients are described. In nine patients the JEI manifested as isolated automatic impulses and in one as a parasystolic junctional tachycardia. In addition to the previously described unexpected prolongation of the P-R, Type I and Type II A-V block, the following phenomena were recorded: 1) marked, greater
than 400 msec, and persistent prolongation of the P-R interval, 2) striking changes in the duration of the P-R with an occasional sequence of R-P and P-R intervals simulating "supernormal" A-V conduction, 3) unexpected variation of the junctional escape interval explained by junctional parasystole with entrance block, 4) postponed conpensatory pause, 5) concealed junctional discharge with reciprocation.
ATRIOVENTRICULAR (A-V) BLOCK due to concealed junctional ectopic impulses (JEI) was first described in 1947.' Not until 1962 was the next case of A-V block due to JEI reported.' To the best of our knowledge a total of 11 instances of spontaneous JEI concealed within the junctional tissue because of an antegrade and retrograde block have been reported.3 "' In each instance the presence of JEI was suspected by its effect on the behavior of the subsequent impulse. The assumption that the unexpected and "unphysiological" behavior of A-V conduction was due to concealed JEI proposed by Langendorf and Mehlman' was confirmed in man by direct recording from the His bundle by Rosen, Rahimtoola and Gunnar,5 in the dog by Damato, Lau and Bobb" and in the isolated rabbit A-V conduction system by Moore, Knoebel and Spear.12 The purpose of this communication is to present 13 episodes of concealed JEI recorded in ten patients. Manifestations, phenomena, not previously described include: 1) initiation of a marked, greater than 400 msec,
prolongation of the P-R interval; 2) persistence of this prolongation; 3) wide variation of P-R duration in the same record with occasional R-P, P-R relationship suggesting " supernormality" of A-V conduction; 4) variation of junctional escape interval; 5) postponed compensatory pause; and 6) reciprocation due to concealed junctional discharge, as opposed to the well recognized phenomenon of concealed reciprocation. It is also the purpose of this communication to illustrate and emphasize that much information can be learned from a careful deductive analysis of the surface electrocardiogram and that, indeed, so many of our current electrophysiological concepts were arrived at by just such a process.'3 This approach is especially important in clinical electrocardiography where the observations are truly "experiments" of nature, frequently not reproducible, and where invasive procedures for their documentation or analysis are not always justifiable, nor, as illustrated in this paper, necessary.'4 In this regard, His bundle electrocardiography using standard techniques" was performed in cases 4 and 8. In case 4, the invasive study confirmed that early premature JEI conducted aberrantly (fig. 4A). During His bundle electrocardiography in case 8, only intermittent JEI which conducted normally or blocked totally (concealed) were recorded. Thus, the diagnosis of a concealed junctional parasystolic tachycardia still had to be
From the Krannert Institute of Cardiology, the Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana. Supported in part by the Herman C. Krannert Fund, by Grants HL-06308, HL-05363, and HL-05749 from the National Heart and Lung Institute, by the American Heart Association, and by the Indiana Heart Association. Address for reprints: Charles Fisch, M.D., Indiana University School of Medicine, 1 100 West Michigan Street, Indianapolis, Indiana 46202. Received April 7, 1975; revision accepted for publication August 22, 1975.
218
VOL. 53, No. 2, FEBRUARY 1976
CIRCULATION ....
....
Z
i .l ....kl
............
L .......a3
g.l:i i:.f. f :
it}U E d X~~ ~~~~titit-fll ~ ~lt ~ ..~ ~~. . . 1_:~.~ ~ ~ .~ ~.~.
FIGURE I Sections taken from patient 7 and shown for the purpose of defining the varying ECG manifestations of the JEI. (I) - Conducted, interpolated junctional impulse with mild to moderate prolongation of the P-R (Vff, L2). (2) Conducted, interpolated junctional impulse with marked (greater than 400 msec) prolongation of the P-R interval (KV left upper strip). (3) - Conducted junctional impulse with complete block of P wave (LU). (Cl) - Concealed, interpolated junctional impulse with mild to moderate prolongation of the P-R (V5 - right lower strip). (C2) - Concealed, interpolated junctional impulse with marked (greater than 400 msec) prolongation of the P-R (1V'). (C3) - Concealed junctional impulse with complete block of P wave ( V5- right lower strip). In V5 the left upper strip illustrates an interpolated, conducted JEI with marked and persistent prolongation of the P-R interval with postponement of the compensatory pause. V6 demonstrates marked prolongation of the P-R but this time is due to concealed JEI. Lead 2 demonstrates two consecutive conducted JEI, the first interpolated and the second blocking the P wave. V5 (right lower strip) illustrates the same sequence of events as recorded in L2 but due to concealed JEI resulting in Type I A - V block.
made using deductive analysis of the surface electrocardiogram (figs. 6-8). Description of the Electrocardiogram In order to facilitate description of the ECG, the JEI recognized by their effect on subsequent A-V conduction
were arbitrarily divided into three groups. These include: 1) interpolated JEI with slight or moderate prolongation of the P-R intervals defined as a P-R of 400 msec or less, 2) interpolated JEI, but with a marked prolongation of the P-R interval, greater than 400 msec, and 3) JEI completely blocking transmission of the P wave. They were identified as (l),
L2
4E L-
..f*E.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~........
~ ~ ~ ~ ~ s~ ~ ~ ~
S.*.
pi k
f.
.t
B*
1C4
a
uk
Jp# ALI
AVR
V
C7
FIGURE 2 (Case 1). Interpolated concealed JE!. This is probably the simplest manifestation of concealed 1Ff discharge. The rhythm is normal sinus with a P-R of .26 -.28 sec with an interpolated JIF in L2 (J) followed by a P-R of.40 sec. Prolongation of P-R tO .40 and .48 sec is also recorded in aVR and aVL, this time without a manifest QRS: thus the prolongation is unexpected and due to a concealed JIF (Cl). The presence of conducted 1Ff (Il) and of R-R intervals of approximately the same duraltion, irrespective of whether encompassing the conducted (1) or concealed (Cl) 1Ff, make concealed 1Ff an acceptable explanation for the sudden unexpected prolongation of the P-R interval in a VR and aVL.
La
FIGURE 3 (Case 3). Sinus rhythm with a P-R of.20 sec, JEI and premature ventricular complexes. The Lewis diagram suggests that the concealed impulses originate in the ventricles. However, it appears more likely that, with exception of the second ectopic impulse in L3, these are junctional in origin, with intraventricular aberrancy. Some of the conducted ectopic impulses are interpolated as (1) in LU and Vs while others block P wave conduction as (3) in V5, V4R, a VL and LU. Concealed ectopic discharges (Cl) are responsible for sudden and unexpected prolongation of the P-R in aVL and for complete block of P wave with Type II A- V block (C3) in V4R and L3.
219
CONCEALED JUNCTIONAL ECTOPIC IMPULSES/Fisch, Zipes, McHenry
H,Hj, 'J
ii RE
HE1-
-
.-
JiH-H415
i
t
-
-
H-A 530*
,235k
275
-
3
_
~
-HA 485
-
I-
I ________'- -'_
T
FIGURE 4 Figure 4 was recorded in case 4. The basic rhythm in figure 4 is sinus with a P-R of.20 sec. Top) Conducted interpolated JEI (I) with prolongation of P-R to .24 sec are present in L2 and L3. In addition, two conducted interpolated JEI (2) followed by P-R of .68 sec are seen in L3. Following the second of the two, the P-R again measures .64 sec. Unexpected prolorngation of the P-R to .60 sec but without a conducted interpolated JEI is seen in L,. Failure of P wave conduction following a JEI (3) is recorded in L. Similarly, failure of P wave conduction is seen in L, (C3), but without a preceding conducted JEI. The unexpected prolongation of P-R in L1 (C2) and block of P wave in L2 (C3), suggesting Type II A-V block, are due to concealed JEI. Bottom left) This record demonstrates unexpected prolongation of P-R from 225 to 285 msec a nd the A -H from 130 to 190 msec due to concealed discharge from the bundle of His (H'). HE bundle of His electrogram, A atrial depolarization, H His bundle depolarization, H' - concealed His bundle depolarization. Time lines, I second intervals Bottom right) In the top panel, concealed His discharge (H') results in a sudden failure of A-V conductio n with the block above the His bundle. On the surface ECG the concealed His discharge simulates Type II A- V block. In the lower panel, Ihe P-R lengthens from 225 to 275 msec with failure of the third P wave to condu ct. The pattern is that of a Type I A - V block. A nalysis of the His electrogram reveals that the A - V block is due to concealed junctional discharge. The first concealed His impulse (H') is followed by an H'-A interval of 530 msec and prolongation of the A-H interval from 130 to 180 msec. The H- V remains constant. The next H'-A is shorter (485 msec) and the atrial impulse is blocked above the bundle of His. =
=
.--t
220
ClIRCULATION
TABlLE 1. Eleotrocardiographic 2fanifestations of Concealed Junctional Impulse Case
1 2 3 4
5 6 7 8
9 10 1
Figure
2 3 4
5) 6, 7, 8
9 10 11
Manifestations
Proloingation of P-It PIolon}gaf ioni of P-t, Type II A-V block2 Prolonigationi of P-It, Type If A-V block Prolonlgatioll Of P-It, Type I, Type II A-V block Type II A-V block Type II A-V block Prolongation of P-li, Type II A-V block Prolongation of P-IR, Type I, Type II A-V block, atternpted Type I A-V block, postpon ed compensatory pause, ''supernormality" of A-V conduction Variable jnnctional escape initerval
Iteciprocation Iteciprocation
(2), (3) respectively when conducted to the ventricle, and (C1), (C2), (C3) when concealed (fig. 1). The figures are presented in a sequence calculated to simplify as much as possible the description of the electrocardiograms. The manifestations of JEI were those of Wenckebach A-V block (Type I), attempted Type I block, defined as a gradual prolongation of the P-R interval but without an ultimate block of the P wave, Mobitz II A-V block (Type II), paradoxical R-P, P-R relationship suggesting "supernormality" of A-V conduction and interpolation with a postponed compensatory pause.'6 In addition, there were two cases of reciprocation due to concealed junctional discharge and one instance with an unexpected variation of the junctional escape interval. The ECG manifestations of concealed JEI observed in each of the tracings are summarized in table 1.
t Cn~~~~~A A,.
1112 1 ---
7-1...........
---
-1
) 121 1 el 1cl FIGURE 6 (Case 8). Figures 6, 7, 8 were obtainedfrom patient 8 on three separate admissions. Analysis offigures 6 and 7 clearly indicates that what appears to be a grossly chaotic A- V conduction in figure 8 is, in reality, an orderly behavior of A-V conduction in response to a concealed junctional parasystolic tachycardia. Figure 6 identified conducted interpolated JEI (1), (2), interpolated concealed JEI (Cl), (C2) and concealed JE1 blocking the P wave (C3). Type I A-V block is registered in L3 due to two consecutive concealed JEI (Cl ), (C3). Type *I A-V block due to concealed JEI (C3) is recorded in aVR. A postponed compensatory pause follows the second conducted interpolated JEI (2) in L3. Persistence of the long P-R for the one cycle following a conducted (2) and again after a concealed JEI (C2) are illustrated in a VR. The sudden failure of P to conduct is not a function of a shorter R-P (e.g., block of P wave after /C3] in L3), but is due to concealedJEI. This is proven by the numerous P waves which follow a much shorter R-P but still conduct to the ventricles.
Discussion The presence of concealed JEI is recognized by its effect on the conduction of the subsequent impulse. The JEI may present as isolated ectopic discharges, junctional parasystole7' ' or parasystolic tachycardia. An assumption that an unexpectedly altered rhythm is due to concealed JEI can be made only if a similar sequence of events is recorded when the junctional impulses conduct to
ow-K 1 T'1 FIGURE 5 (Case 7). Sinus rhythm and JEI, with or without intraventricular aberrancy. Interpolated JEI are followed either by mild (I) or marked (2) prolongation of the P-R. Complete block of P waves due to JEI (3) are also recorded. Postponed compensatory pause is seen following the two conducted interpolated JEI in the top strip. Concealed JEI with unexpected prolongation of the P-R (C]) or unexpected block of P wave (CS) are also recorded. The QRS following JEI (2) in ihe top and bottom strip are assumed to be conducted from the atrium with a long P-R.
~
VOL. 53, No. 2, FEBRUARY 1976
1
_l.
'I -1
.A
_t
C2 *
FIGURE 7 (Case 8). This figure is in many respects similar to figure 6 and demonstrates attempted Type I, Type I and Type Il A-V block due to a variety of combinations of conducted and concealed JEI. Persistence of prolonged A-V conduction following interpolated conducted JEI (2) is also recorded in the bottom strip. It was important to document this latter phenomenon because similar unexpected and persistent P-R prolongation is seen following a concealed JEI in figure 8.
CONCEALED JUNCTIONAL ECTOPIC IMPULSES/Fisch, Zipes, McHenry
Cla
* 0SigEiR
C,
l000ttS:*
C00EdDE ''S000d te.
221
C1
FIGURE 8 (Case 8). The record is continuous with the last P-QRS complex in each strip reproduced as the first P-QRS complex of the subsequent strip. The basic rhythm is sinus with a P-R of .18 sec. Only one, the next to the last, P wave in the top row is blocked. The remainder of the record represents a wide range of P-R intervals. The length of the P-R is influenced by JEI which may be conducted or concealed. The Lewis diagram and identification of the interpolated JEI as either conducted (1), (2) or concealed (Cl), (C2) aid in analysis of A-V conduction. Thefact that the variation of the P-R duration is due to concealed JEI, is in each instance confirmed by the presence of similar P-R changes but in association
with conducted JEI. The evidence suggests that the junctional rhythm is an intermittent parasystolic tachycardia with an interectopic interval of about 680 msec. A n "unphysiological" R-P, P-R relationship exists where shorter R-P are followed by shorter P-R and longer R-P by longer P-R, this relationship suggesting "supernormal'" A-V conduction. In aoctuality, howe ver, this " unphysiological" relationship is due to concealed JEI. This relationship is illustrated in the bottom row where the sixth P wave with an R-P ofabout 80 msec is followed by a P-R of about 260 msec, while the next P wave, with an R-P of 380 msec is followed by a P-R of520 msec. The unexpected prolongation ofthe P-R following the seventh P wave is due to concealed JEI while the preceding unexpectedly short P-R reflects normal A-V conduction. The prolongation of the latter from a normal P-R of .18 to .24 sec can be accounted for by the foreshortened R-P interval.
the ventricles. This criterion was satisfied in all our cases. Although the concealed ectopic impulse may originate in the junctional or, rarely, in the ventricular conduction system,9' ' it may at times be impossible from the surface ECG to differentiate between the two sites because the junctional impulse may be followed by aberrant intraventricular conduction5 (figs. 3, 6). Thus, the Lewis diagrams in figure 3 may well have been constructed to show a junctional origin of the ectopic impulses. The concealment of JEI is more common after a longer preceding cycle with the latter cycle frequently caused by the compensatory pause following a conducted JEI. Since refractoriness is directionally related to the preceding cycle length, one might postulate that physiological lengthening of refractoriness following a long cycle, rather than concealed JEI, results in a sudden prolongation or block of A-V conduction. For example, such a relationship exists in figure 3, which illustrates blocked P waves following a long preceding cycle (V4R, L3). However, careful analysis of this example
indicates that the unexpected delay or block of A-V conduction cannot be due only to lengthened A-V refractoriness following long cycle because the fifth P in V5 and sixth and thirteenth P waves in V4R follow equally long or longer R-R intervals and yet their respective P-R intervals are normal. The most likely explanation for this observation is that prolongation of refractoriness following a longer R-R interval increases the likelihood of both antegrade and retrograde block of conduction of JEI, causing concealed JET discharge after a long pause. The determinants of whether JEI remains concealed or is conducted include coupling interval between JET and the preceding QRS and the duration of the preceding R-R interval; or, as determined in the His electrogram, coupling interval between the H' of the premature JEI and the preceding H, and the duration of the last regular H-H interval which preceded the H'.5 The assumption is made that the markedly prolonged P-R, as seen for example in figure 4A, terminates with a conducted QRS rather than a junctional escape. This
222
VOL. 53, No. 2, FEBRUARY 1976
CI RCU LATION
7.4.
A
Y
I!
I
...
C~-
i8
960 1840
1840
A' A FI GURE 9 (Case 9). The basic rhythm is sinus with an R-R of 580 msec interrupted by an accelerated ju nctional rhythm exhibiting an interectopic interval of 880 msec. Some of the JEI are conducted to the ventricles while others conceal resulting in a changing SA to junctional QRS interval (escape intervals). The rhythm is analyzed with the aid of a Lewis diagram in lead V,. There are two sequences of three JEI each, with an interectopic interval of 880 msec. The junctional focus is not discharged by the sinus impulses because ofparasystolic nature of the pacemaker with an entrance block. The first JEI of the first series (A') is concealed, fails to reach the ventricles, but blocks the sinus P wave and results in a long, 960 msec, manifest junctional escape interval. The next two JEI conduct to the ventricles. The first JEl of the second series (A) reaches the ventricles after a delay and results in a short, 440 msec, manifest escape interval. The diagnosis of concealment of thefirst JEI is supported by the fact that intervals from the sinus QRS to the last junctional QRS in both A and A' sequences are eq ual (1840 msec), this despite the marked difference in length of the two escape intervals.
assumption is supported by the fact that the R-R cycles in question are not constant and the fact that much longer R-R intervals without escape complexes are recorded (L2). One may postulate, however, that the latter results from concealed discharge and displacement of the escape focus by the blocked P wave, allowing an SA impulse to terminate the longest R-R intervals. Thus, simply the presence of longer cycles is not a convincing argument that conduction is SA in origin with a long P-R interval rather than an accelerated junctional escape. There is, however, compelling evidence that the JEI is probably automatic rather than re-entrant,5 that it originates in the bundle of His, and that the sinus P wave is blocked in the A-V node proper and thus incapable of displacing a His focus even if such existed. Thus, the evidence put forth suggests that the cycles in question are terminated by an SA impulse conducting with a long P-R interval. Furthermore, the patients did not have any of the disorders known to give rise to accelerated junctional dis-
In
summary,
the observations reported in this
paper sup-
port the conclusion that the manifestations of concealed JEI
extend far beyond simple first degree and Type I and Type II second degree A-V block. The manifestations include, or will probably be shown in the future to include, virtually all L2
.e.
T
charge.'7
The purist may argue that the reciprocating rhythm illustrated in figures 10 and 11 does not represent concealment in the true sense of the word but that it is an example of the limitation of the surface ECG when applied to recognition of site of origin of abnormal P waves. In both cases the junctional impulses conduct to the atrium, thus are not truly concealed. However, such retrograde P waves have been considered as examples of concealed junctional discharge by Langendorf and Mehlman' and their junctional origin confirmed by recording directly from the His bundle'8 and by stimulating the bundle of His in the experimental animal."
FIGURE 10 (Case 10). Reciprocation due to concealed JEI. The ectopic impulse in the bottom row cannot be differentiated from an ordinary junctional, low atrial or coronary sinus impulse nor would there be any reason to suspect a JEI with antegrade block, retrograde conduction and reciprocation. Such a diagnosis is possible only after an analysis of the ectopic impulses in the upper and middle rows. The two ectopic impulses in L, are junctional with both antegrade and retrograde conduction. Reciprocation is clearly recognized in the middle strip. The phenomenon in the bottom row is identical to that seen in the middle row except for an antegrade block of the JEI.
:r~ ~ .:_
CONCEALED JUNCTIONAL ECTOPIC IMPULSES/Fisch, Zipes, McHenry
tz
223
of the electrocardiographic phenomena which have been documented to occur following manifest JEI. References
1. Langendorf R, Mehlman JS: Blocked (nonconducted) A-V nodal premature systoles imitating first and second degree A-V block. Am Heart J 34: 500, 1947 2. Need RL, Fisch C: Heart block resulting from concealed discharge of V5j ' atrioventricular node. Am J Cardiol 10: 138, 1962 3. Langendorf R: Alternation of A-V conduction time. Am Heart J 55: 181, 1958 4. Langendorf R, Pick A: Concealed conduction in the A-V junction. In Mechanisms and Therapy of Cardiac Arrhythmias, edited by Dreifus LS, Likoff W, Moyer JH. New York, Grune and Stratton, 1966, p 395 5. Rosen KM, Rahimtoola SH, Gunnar RM: Pseudo A-V block secondary to premature nonpropagated His bundle depolarizations. Documentation by His bundle electrocardiography. Circulation 42: 367, 1970 WT&o&aty+.Vo r * *I ttr!^>Ere-~.t.>Z,
217
12. Herrmann GR: The Austin Flint phenomenon; an experimental and clinical study. Am Heart J 1: 671, 1926 13. Gouley BA: The aortic valvular lesion associated with the Austin Flint murmur. Am Heart J 22: 208, 1941 14. Ueda H, Sakamoto T, Kawai N, Watanabe H, Uozumi Z, Okada R, Kobayashi T, Tetsura Y, Inoue K, Kaito G: The Austin Flint murmur. Phonocardiographic and patho-anatomical study. Jap Heart J 6: 294, 1965 15. Rees JR, Epstein EJ, Criley JM, Ross RS: Haemodynamic effects of severe aortic regurgitation. Br Heart J 26: 412, 1964 16. Weigle ED, Labrosse CJ: Sudden, severe aortic insufficiency. Circulation 32: 708, 1965 17. Pridie RB, Benham R, Oakley CM: Echocardiography of the mitral valve in aortic valve disease. Br Heart J 33: 296, 1971 18. Spencer MP, Greiss FC: Dynamics of left ventricular ejection. Circ Res 10: 274, 1962 19. Rushmer RF: Cardiovascular Sounds. In Cardiovascular Dynamics, edited by Rushmer RF. Philadelphia, W.B. Saunders Company, 1970, p 293 20. Schaefer RA, McAnulty JH, Starr A, Rahimtoola SH: Diastolic murmurs in the presence of Starr-Edwards mitral prosthesis: with emphasis on the genesis of the Austin Flint murmur. Circulation 51: 402, 1975
Electrocardiographic Manifestations of Concealed Junctional Ectopic Impulses CHARLES FISCH,
M.D.,
DOUGLAS P. ZIPES, M.D.,
AND PAUL
L. MCHENRY, M.D.
SUMMARY Thirteen episodes of concealed junctional ectopic impulses (JEI) in ten patients are described. In nine patients the JEI manifested as isolated automatic impulses and in one as a parasystolic junctional tachycardia. In addition to the previously described unexpected prolongation of the P-R, Type I and Type II A-V block, the following phenomena were recorded: 1) marked, greater
than 400 msec, and persistent prolongation of the P-R interval, 2) striking changes in the duration of the P-R with an occasional sequence of R-P and P-R intervals simulating "supernormal" A-V conduction, 3) unexpected variation of the junctional escape interval explained by junctional parasystole with entrance block, 4) postponed conpensatory pause, 5) concealed junctional discharge with reciprocation.
ATRIOVENTRICULAR (A-V) BLOCK due to concealed junctional ectopic impulses (JEI) was first described in 1947.' Not until 1962 was the next case of A-V block due to JEI reported.' To the best of our knowledge a total of 11 instances of spontaneous JEI concealed within the junctional tissue because of an antegrade and retrograde block have been reported.3 "' In each instance the presence of JEI was suspected by its effect on the behavior of the subsequent impulse. The assumption that the unexpected and "unphysiological" behavior of A-V conduction was due to concealed JEI proposed by Langendorf and Mehlman' was confirmed in man by direct recording from the His bundle by Rosen, Rahimtoola and Gunnar,5 in the dog by Damato, Lau and Bobb" and in the isolated rabbit A-V conduction system by Moore, Knoebel and Spear.12 The purpose of this communication is to present 13 episodes of concealed JEI recorded in ten patients. Manifestations, phenomena, not previously described include: 1) initiation of a marked, greater than 400 msec,
prolongation of the P-R interval; 2) persistence of this prolongation; 3) wide variation of P-R duration in the same record with occasional R-P, P-R relationship suggesting " supernormality" of A-V conduction; 4) variation of junctional escape interval; 5) postponed compensatory pause; and 6) reciprocation due to concealed junctional discharge, as opposed to the well recognized phenomenon of concealed reciprocation. It is also the purpose of this communication to illustrate and emphasize that much information can be learned from a careful deductive analysis of the surface electrocardiogram and that, indeed, so many of our current electrophysiological concepts were arrived at by just such a process.'3 This approach is especially important in clinical electrocardiography where the observations are truly "experiments" of nature, frequently not reproducible, and where invasive procedures for their documentation or analysis are not always justifiable, nor, as illustrated in this paper, necessary.'4 In this regard, His bundle electrocardiography using standard techniques" was performed in cases 4 and 8. In case 4, the invasive study confirmed that early premature JEI conducted aberrantly (fig. 4A). During His bundle electrocardiography in case 8, only intermittent JEI which conducted normally or blocked totally (concealed) were recorded. Thus, the diagnosis of a concealed junctional parasystolic tachycardia still had to be
From the Krannert Institute of Cardiology, the Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana. Supported in part by the Herman C. Krannert Fund, by Grants HL-06308, HL-05363, and HL-05749 from the National Heart and Lung Institute, by the American Heart Association, and by the Indiana Heart Association. Address for reprints: Charles Fisch, M.D., Indiana University School of Medicine, 1 100 West Michigan Street, Indianapolis, Indiana 46202. Received April 7, 1975; revision accepted for publication August 22, 1975.
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CIRCULATION ....
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i .l ....kl
............
L .......a3
g.l:i i:.f. f :
it}U E d X~~ ~~~~titit-fll ~ ~lt ~ ..~ ~~. . . 1_:~.~ ~ ~ .~ ~.~.
FIGURE I Sections taken from patient 7 and shown for the purpose of defining the varying ECG manifestations of the JEI. (I) - Conducted, interpolated junctional impulse with mild to moderate prolongation of the P-R (Vff, L2). (2) Conducted, interpolated junctional impulse with marked (greater than 400 msec) prolongation of the P-R interval (KV left upper strip). (3) - Conducted junctional impulse with complete block of P wave (LU). (Cl) - Concealed, interpolated junctional impulse with mild to moderate prolongation of the P-R (V5 - right lower strip). (C2) - Concealed, interpolated junctional impulse with marked (greater than 400 msec) prolongation of the P-R (1V'). (C3) - Concealed junctional impulse with complete block of P wave ( V5- right lower strip). In V5 the left upper strip illustrates an interpolated, conducted JEI with marked and persistent prolongation of the P-R interval with postponement of the compensatory pause. V6 demonstrates marked prolongation of the P-R but this time is due to concealed JEI. Lead 2 demonstrates two consecutive conducted JEI, the first interpolated and the second blocking the P wave. V5 (right lower strip) illustrates the same sequence of events as recorded in L2 but due to concealed JEI resulting in Type I A - V block.
made using deductive analysis of the surface electrocardiogram (figs. 6-8). Description of the Electrocardiogram In order to facilitate description of the ECG, the JEI recognized by their effect on subsequent A-V conduction
were arbitrarily divided into three groups. These include: 1) interpolated JEI with slight or moderate prolongation of the P-R intervals defined as a P-R of 400 msec or less, 2) interpolated JEI, but with a marked prolongation of the P-R interval, greater than 400 msec, and 3) JEI completely blocking transmission of the P wave. They were identified as (l),
L2
4E L-
..f*E.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~........
~ ~ ~ ~ ~ s~ ~ ~ ~
S.*.
pi k
f.
.t
B*
1C4
a
uk
Jp# ALI
AVR
V
C7
FIGURE 2 (Case 1). Interpolated concealed JE!. This is probably the simplest manifestation of concealed 1Ff discharge. The rhythm is normal sinus with a P-R of .26 -.28 sec with an interpolated JIF in L2 (J) followed by a P-R of.40 sec. Prolongation of P-R tO .40 and .48 sec is also recorded in aVR and aVL, this time without a manifest QRS: thus the prolongation is unexpected and due to a concealed JIF (Cl). The presence of conducted 1Ff (Il) and of R-R intervals of approximately the same duraltion, irrespective of whether encompassing the conducted (1) or concealed (Cl) 1Ff, make concealed 1Ff an acceptable explanation for the sudden unexpected prolongation of the P-R interval in a VR and aVL.
La
FIGURE 3 (Case 3). Sinus rhythm with a P-R of.20 sec, JEI and premature ventricular complexes. The Lewis diagram suggests that the concealed impulses originate in the ventricles. However, it appears more likely that, with exception of the second ectopic impulse in L3, these are junctional in origin, with intraventricular aberrancy. Some of the conducted ectopic impulses are interpolated as (1) in LU and Vs while others block P wave conduction as (3) in V5, V4R, a VL and LU. Concealed ectopic discharges (Cl) are responsible for sudden and unexpected prolongation of the P-R in aVL and for complete block of P wave with Type II A- V block (C3) in V4R and L3.
219
CONCEALED JUNCTIONAL ECTOPIC IMPULSES/Fisch, Zipes, McHenry
H,Hj, 'J
ii RE
HE1-
-
.-
JiH-H415
i
t
-
-
H-A 530*
,235k
275
-
3
_
~
-HA 485
-
I-
I ________'- -'_
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FIGURE 4 Figure 4 was recorded in case 4. The basic rhythm in figure 4 is sinus with a P-R of.20 sec. Top) Conducted interpolated JEI (I) with prolongation of P-R to .24 sec are present in L2 and L3. In addition, two conducted interpolated JEI (2) followed by P-R of .68 sec are seen in L3. Following the second of the two, the P-R again measures .64 sec. Unexpected prolorngation of the P-R to .60 sec but without a conducted interpolated JEI is seen in L,. Failure of P wave conduction following a JEI (3) is recorded in L. Similarly, failure of P wave conduction is seen in L, (C3), but without a preceding conducted JEI. The unexpected prolongation of P-R in L1 (C2) and block of P wave in L2 (C3), suggesting Type II A-V block, are due to concealed JEI. Bottom left) This record demonstrates unexpected prolongation of P-R from 225 to 285 msec a nd the A -H from 130 to 190 msec due to concealed discharge from the bundle of His (H'). HE bundle of His electrogram, A atrial depolarization, H His bundle depolarization, H' - concealed His bundle depolarization. Time lines, I second intervals Bottom right) In the top panel, concealed His discharge (H') results in a sudden failure of A-V conductio n with the block above the His bundle. On the surface ECG the concealed His discharge simulates Type II A- V block. In the lower panel, Ihe P-R lengthens from 225 to 275 msec with failure of the third P wave to condu ct. The pattern is that of a Type I A - V block. A nalysis of the His electrogram reveals that the A - V block is due to concealed junctional discharge. The first concealed His impulse (H') is followed by an H'-A interval of 530 msec and prolongation of the A-H interval from 130 to 180 msec. The H- V remains constant. The next H'-A is shorter (485 msec) and the atrial impulse is blocked above the bundle of His. =
=
.--t
220
ClIRCULATION
TABlLE 1. Eleotrocardiographic 2fanifestations of Concealed Junctional Impulse Case
1 2 3 4
5 6 7 8
9 10 1
Figure
2 3 4
5) 6, 7, 8
9 10 11
Manifestations
Proloingation of P-It PIolon}gaf ioni of P-t, Type II A-V block2 Prolonigationi of P-It, Type If A-V block Prolonlgatioll Of P-It, Type I, Type II A-V block Type II A-V block Type II A-V block Prolongation of P-li, Type II A-V block Prolongation of P-IR, Type I, Type II A-V block, atternpted Type I A-V block, postpon ed compensatory pause, ''supernormality" of A-V conduction Variable jnnctional escape initerval
Iteciprocation Iteciprocation
(2), (3) respectively when conducted to the ventricle, and (C1), (C2), (C3) when concealed (fig. 1). The figures are presented in a sequence calculated to simplify as much as possible the description of the electrocardiograms. The manifestations of JEI were those of Wenckebach A-V block (Type I), attempted Type I block, defined as a gradual prolongation of the P-R interval but without an ultimate block of the P wave, Mobitz II A-V block (Type II), paradoxical R-P, P-R relationship suggesting "supernormality" of A-V conduction and interpolation with a postponed compensatory pause.'6 In addition, there were two cases of reciprocation due to concealed junctional discharge and one instance with an unexpected variation of the junctional escape interval. The ECG manifestations of concealed JEI observed in each of the tracings are summarized in table 1.
t Cn~~~~~A A,.
1112 1 ---
7-1...........
---
-1
) 121 1 el 1cl FIGURE 6 (Case 8). Figures 6, 7, 8 were obtainedfrom patient 8 on three separate admissions. Analysis offigures 6 and 7 clearly indicates that what appears to be a grossly chaotic A- V conduction in figure 8 is, in reality, an orderly behavior of A-V conduction in response to a concealed junctional parasystolic tachycardia. Figure 6 identified conducted interpolated JEI (1), (2), interpolated concealed JEI (Cl), (C2) and concealed JE1 blocking the P wave (C3). Type I A-V block is registered in L3 due to two consecutive concealed JEI (Cl ), (C3). Type *I A-V block due to concealed JEI (C3) is recorded in aVR. A postponed compensatory pause follows the second conducted interpolated JEI (2) in L3. Persistence of the long P-R for the one cycle following a conducted (2) and again after a concealed JEI (C2) are illustrated in a VR. The sudden failure of P to conduct is not a function of a shorter R-P (e.g., block of P wave after /C3] in L3), but is due to concealedJEI. This is proven by the numerous P waves which follow a much shorter R-P but still conduct to the ventricles.
Discussion The presence of concealed JEI is recognized by its effect on the conduction of the subsequent impulse. The JEI may present as isolated ectopic discharges, junctional parasystole7' ' or parasystolic tachycardia. An assumption that an unexpectedly altered rhythm is due to concealed JEI can be made only if a similar sequence of events is recorded when the junctional impulses conduct to
ow-K 1 T'1 FIGURE 5 (Case 7). Sinus rhythm and JEI, with or without intraventricular aberrancy. Interpolated JEI are followed either by mild (I) or marked (2) prolongation of the P-R. Complete block of P waves due to JEI (3) are also recorded. Postponed compensatory pause is seen following the two conducted interpolated JEI in the top strip. Concealed JEI with unexpected prolongation of the P-R (C]) or unexpected block of P wave (CS) are also recorded. The QRS following JEI (2) in ihe top and bottom strip are assumed to be conducted from the atrium with a long P-R.
~
VOL. 53, No. 2, FEBRUARY 1976
1
_l.
'I -1
.A
_t
C2 *
FIGURE 7 (Case 8). This figure is in many respects similar to figure 6 and demonstrates attempted Type I, Type I and Type Il A-V block due to a variety of combinations of conducted and concealed JEI. Persistence of prolonged A-V conduction following interpolated conducted JEI (2) is also recorded in the bottom strip. It was important to document this latter phenomenon because similar unexpected and persistent P-R prolongation is seen following a concealed JEI in figure 8.
CONCEALED JUNCTIONAL ECTOPIC IMPULSES/Fisch, Zipes, McHenry
Cla
* 0SigEiR
C,
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221
C1
FIGURE 8 (Case 8). The record is continuous with the last P-QRS complex in each strip reproduced as the first P-QRS complex of the subsequent strip. The basic rhythm is sinus with a P-R of .18 sec. Only one, the next to the last, P wave in the top row is blocked. The remainder of the record represents a wide range of P-R intervals. The length of the P-R is influenced by JEI which may be conducted or concealed. The Lewis diagram and identification of the interpolated JEI as either conducted (1), (2) or concealed (Cl), (C2) aid in analysis of A-V conduction. Thefact that the variation of the P-R duration is due to concealed JEI, is in each instance confirmed by the presence of similar P-R changes but in association
with conducted JEI. The evidence suggests that the junctional rhythm is an intermittent parasystolic tachycardia with an interectopic interval of about 680 msec. A n "unphysiological" R-P, P-R relationship exists where shorter R-P are followed by shorter P-R and longer R-P by longer P-R, this relationship suggesting "supernormal'" A-V conduction. In aoctuality, howe ver, this " unphysiological" relationship is due to concealed JEI. This relationship is illustrated in the bottom row where the sixth P wave with an R-P ofabout 80 msec is followed by a P-R of about 260 msec, while the next P wave, with an R-P of 380 msec is followed by a P-R of520 msec. The unexpected prolongation ofthe P-R following the seventh P wave is due to concealed JEI while the preceding unexpectedly short P-R reflects normal A-V conduction. The prolongation of the latter from a normal P-R of .18 to .24 sec can be accounted for by the foreshortened R-P interval.
the ventricles. This criterion was satisfied in all our cases. Although the concealed ectopic impulse may originate in the junctional or, rarely, in the ventricular conduction system,9' ' it may at times be impossible from the surface ECG to differentiate between the two sites because the junctional impulse may be followed by aberrant intraventricular conduction5 (figs. 3, 6). Thus, the Lewis diagrams in figure 3 may well have been constructed to show a junctional origin of the ectopic impulses. The concealment of JEI is more common after a longer preceding cycle with the latter cycle frequently caused by the compensatory pause following a conducted JEI. Since refractoriness is directionally related to the preceding cycle length, one might postulate that physiological lengthening of refractoriness following a long cycle, rather than concealed JEI, results in a sudden prolongation or block of A-V conduction. For example, such a relationship exists in figure 3, which illustrates blocked P waves following a long preceding cycle (V4R, L3). However, careful analysis of this example
indicates that the unexpected delay or block of A-V conduction cannot be due only to lengthened A-V refractoriness following long cycle because the fifth P in V5 and sixth and thirteenth P waves in V4R follow equally long or longer R-R intervals and yet their respective P-R intervals are normal. The most likely explanation for this observation is that prolongation of refractoriness following a longer R-R interval increases the likelihood of both antegrade and retrograde block of conduction of JEI, causing concealed JET discharge after a long pause. The determinants of whether JEI remains concealed or is conducted include coupling interval between JET and the preceding QRS and the duration of the preceding R-R interval; or, as determined in the His electrogram, coupling interval between the H' of the premature JEI and the preceding H, and the duration of the last regular H-H interval which preceded the H'.5 The assumption is made that the markedly prolonged P-R, as seen for example in figure 4A, terminates with a conducted QRS rather than a junctional escape. This
222
VOL. 53, No. 2, FEBRUARY 1976
CI RCU LATION
7.4.
A
Y
I!
I
...
C~-
i8
960 1840
1840
A' A FI GURE 9 (Case 9). The basic rhythm is sinus with an R-R of 580 msec interrupted by an accelerated ju nctional rhythm exhibiting an interectopic interval of 880 msec. Some of the JEI are conducted to the ventricles while others conceal resulting in a changing SA to junctional QRS interval (escape intervals). The rhythm is analyzed with the aid of a Lewis diagram in lead V,. There are two sequences of three JEI each, with an interectopic interval of 880 msec. The junctional focus is not discharged by the sinus impulses because ofparasystolic nature of the pacemaker with an entrance block. The first JEI of the first series (A') is concealed, fails to reach the ventricles, but blocks the sinus P wave and results in a long, 960 msec, manifest junctional escape interval. The next two JEI conduct to the ventricles. The first JEl of the second series (A) reaches the ventricles after a delay and results in a short, 440 msec, manifest escape interval. The diagnosis of concealment of thefirst JEI is supported by the fact that intervals from the sinus QRS to the last junctional QRS in both A and A' sequences are eq ual (1840 msec), this despite the marked difference in length of the two escape intervals.
assumption is supported by the fact that the R-R cycles in question are not constant and the fact that much longer R-R intervals without escape complexes are recorded (L2). One may postulate, however, that the latter results from concealed discharge and displacement of the escape focus by the blocked P wave, allowing an SA impulse to terminate the longest R-R intervals. Thus, simply the presence of longer cycles is not a convincing argument that conduction is SA in origin with a long P-R interval rather than an accelerated junctional escape. There is, however, compelling evidence that the JEI is probably automatic rather than re-entrant,5 that it originates in the bundle of His, and that the sinus P wave is blocked in the A-V node proper and thus incapable of displacing a His focus even if such existed. Thus, the evidence put forth suggests that the cycles in question are terminated by an SA impulse conducting with a long P-R interval. Furthermore, the patients did not have any of the disorders known to give rise to accelerated junctional dis-
In
summary,
the observations reported in this
paper sup-
port the conclusion that the manifestations of concealed JEI
extend far beyond simple first degree and Type I and Type II second degree A-V block. The manifestations include, or will probably be shown in the future to include, virtually all L2
.e.
T
charge.'7
The purist may argue that the reciprocating rhythm illustrated in figures 10 and 11 does not represent concealment in the true sense of the word but that it is an example of the limitation of the surface ECG when applied to recognition of site of origin of abnormal P waves. In both cases the junctional impulses conduct to the atrium, thus are not truly concealed. However, such retrograde P waves have been considered as examples of concealed junctional discharge by Langendorf and Mehlman' and their junctional origin confirmed by recording directly from the His bundle'8 and by stimulating the bundle of His in the experimental animal."
FIGURE 10 (Case 10). Reciprocation due to concealed JEI. The ectopic impulse in the bottom row cannot be differentiated from an ordinary junctional, low atrial or coronary sinus impulse nor would there be any reason to suspect a JEI with antegrade block, retrograde conduction and reciprocation. Such a diagnosis is possible only after an analysis of the ectopic impulses in the upper and middle rows. The two ectopic impulses in L, are junctional with both antegrade and retrograde conduction. Reciprocation is clearly recognized in the middle strip. The phenomenon in the bottom row is identical to that seen in the middle row except for an antegrade block of the JEI.
:r~ ~ .:_
CONCEALED JUNCTIONAL ECTOPIC IMPULSES/Fisch, Zipes, McHenry
tz
223
of the electrocardiographic phenomena which have been documented to occur following manifest JEI. References
1. Langendorf R, Mehlman JS: Blocked (nonconducted) A-V nodal premature systoles imitating first and second degree A-V block. Am Heart J 34: 500, 1947 2. Need RL, Fisch C: Heart block resulting from concealed discharge of V5j ' atrioventricular node. Am J Cardiol 10: 138, 1962 3. Langendorf R: Alternation of A-V conduction time. Am Heart J 55: 181, 1958 4. Langendorf R, Pick A: Concealed conduction in the A-V junction. In Mechanisms and Therapy of Cardiac Arrhythmias, edited by Dreifus LS, Likoff W, Moyer JH. New York, Grune and Stratton, 1966, p 395 5. Rosen KM, Rahimtoola SH, Gunnar RM: Pseudo A-V block secondary to premature nonpropagated His bundle depolarizations. Documentation by His bundle electrocardiography. Circulation 42: 367, 1970 WT&o&aty+.Vo r * *I ttr!^>Ere-~.t.>Z,
