electrocardiogram of the month
Complete Atrioventricular Block with Intact Retrograde Conduction due to a Concealed Extranodal Anomalous Pathway* Delon Wu, M.D.;t ]ames Cummings, M.D.;t Pablo Denes, M.D.;t and Kenneth M. Rosen, M.D., F.C.C.P.§
patients with advanced or complete heart block occasionally manifest intact retrograde conduction.1"" It has usually been postulated that such patients have lesions of the conduction system that produce unidirectional block. There has been some electrophysiologic evidence supporting that hypothesis.w In this report, we describe a patient with complete heart block and intact retrograde conduction. Electrophysiologic studies in our patient demonstrated that retrograde conduction was via a concealed extranodal anomalous pathway. CASE REPoRT
The patient was an 81-year-old woman admitted to the University of Illinois Hospital because of dyspnea and recurrent syncope. Physical examination revealed a blood pressure of 220/70 mm Hg a:nd bradycardia (pulse rate of 40 beats per minute). There was mild distention of the neclc veins, °From the Section of Cardiology Department of Medicine, Abraham Lincoln School of Medicine, University of Illinois College of Medicine, Chicago. Supported in part by Public Health Service training grant HL 05879-06 and Natonal Institutes of Health grant 08794-01. tFellow, Cardiology Section. tAssociate Professor of Medicine. §Professor of Medicine and Chief, Cardiology Section. Reprint requests: Dr. Wu, University of IUirwis Hospital, 840 South Wood Street, Chicago 60612
bilateral basilar rales, and an audible third heart sound. A chest x-ray fihn showed cardiomegaly with mild congestion. Electrocardiograms revealed complete atrioventricular block with a wide QRS escape rhythm. With prior informed consent, electrophysiologic studies were performed at the time of insertion of a permanent pacemaker. A tripolar electrode catheter was percutaneously introduced into the right femoral vein and positioned across the tricuspid valve for recording of His bundle and low septal right atrial electrograms.6 A second hexapolar electrode catheter (pairs of electrodes at the tip and 10 em and 13.5 em proximal to the tip) was introduced into the left antecubital vein and positioned in the distal coronary sinus. The distal two electrodes were used for recording of left atrial electrograms from the distal coronary sinus, the middle two electrodes for right atrial stimulation, and the proximal two electrodes for recording of the high right atrial electrograms. A third bipolar electrode catheter was positioned in the right ventricular apex for ventricular pacing. Multiple electrocardiographic leads and atrial and His bundle electrograms were simultaneously recorded on a multichannel oscilloscopic recorder (Electronics for Medicine DR-16) at paper speeds of 100 and 200 mm/sec. Stimuli were approximately twice the diastolic threshold and 2 msec in duration and were delivered via a programmable digital stimulator (M. Bloom). The functional properties of the atrioventricular conducting system were evaluated with incremental pacing and extrastimulus techniques.7,8 Conduction intervals and refractory periods were defined and measured as previously described.7,8 Control recordings revealed complete atrioventricular block distal to the His bundle recording site (complete
1 :I ll
v,
A
HBE
H
A .' \ ~
H8E
,•
I'
,,
'.
AH
A
~' 'l
FIGURE 1. Simultaneous recordings of multiple electrocardiographic leads and His bundle electrogram ( HBE), showing complete atrioventricular block distal to the His bundle recording site. A and H are low septal right atrial and His bundle electrograms recorded from His bundle catheter. Paper speed is 100 mm/sec, and time lines are at one-second intervals. A-H interval was 70 msec, atrial rate was 66 beats per minute, and ventricular rate was 35 beats per minute.
782 WU ET AL
CHEST, 71: 6, JUNE, 1977
A
Paced
~R•70/min.
FIGURE 2. Recordings showing intact retrograde ventriculoatrial conduction with fixed ventriculoatrial conduction times and abnormal retrograde sequences of atrial activation during incremental ventricular pacing. HR, Heart rate; A, low septal right atrial electrogram recorded from His bundle catheter; DSC, left atrial electrogram recorded from distal coronary sinus. Beats marked with asterisk in panel C indicate ventricular paced beats with type-2 ventriculoatrial block. Paper speed is 100 mm/ sec, and time lines are at one-second intervals. bilateral bundle-branch block), with an atrial rate of 66 beats per minute, an atrio-His interval of 70 msec, and an idioventricular escape rhythm with a rate of 35 beats per minute (Fig 1). Intact atrio-His bundle conduction was noted up to a paced rate of 190 beats per minute. The effective and functional refractory periods of the atrioventricular node at a driven cycle length of 600 msec were, respectively, less than 310 msec and 380 msec. Intact ventriculoatrial conduction was noted up to a ventricular paced rate of 140 beats per minute (Fig 2A and 2B). Ventriculoatrial conduction times ventriculo-distal coronary sinus interval [V-DCS] of 150 msec and ventriculo-atrium interval [V-A] of 190 msec) were constant at ventricular paced rates of 70 to 140 beats per minute (Fig 2A and 2B) . Type-2 ventriculoatrial block occurred at a ventricular paced rate of 150 beats per minute ( Fig 2C). Retrograde refractory periods were measured with ventricular extrastimulus technique at a driven cycle length of 600 msec ( Fig 3). Ventriculoatrial conduction times ( V2- DCS2 and V2-A2 intervals) increased only 20 msec as coupling intervals were shortened from 580 to 390 rnsec. The effective refractory period of the ventriculoatrial conducting system was 380 rnsec. Analysis of atrial activation sequences during incremental ventricular pacing and during ventricular extrastimulus testing revealed early activation of the lateral left atrium (distal coronary sinus recording site), with a V-DCS interval of 150 msec and a ventriculo-low septal right atrium
CHEST, 71: 6, JUNE, 1977
interval of 190 msec (Fig 2 and 3) . This was an abnormal retrograde sequence of atrial activation, the nonnal being early activation of the low septal right atrium.9,10 DISCUSSION
Concealed extranodal anomalous pathways have been described in patients with paroxysmal reentrant tachycardia. 11"15 These patients do not demonstrate antegrade preexcitation but are able to sustain circus movements utilizing antegrade conduction via the normal pathway and retrograde conduction via the anomalous pathway. Studies of ventricular stimulation have also suggested that patients without paroxysmal tachycardia may on occasion have concealed extranodal anomalous pathways. 18 In our patient, complete atrioventricular block occurred distal to the His bundle recording site, suggesting bilateral bundle-branch disease. Intact retrograde conduction was noted with rapid ventricular pacing. Ventriculoatrial conduction times were fixed, 18 and sequences of atrial activation were abnormal (distal coronary sinus) being activated earlier than the low septal right atrium ) uo during
COMPLETE ATRIOVENTRICULAR BLOCK 763
CL•600
A
][
3. Recordings showing retrograde effective refractory period and abnormal sequence of atrial activation during ventricular extrastimulus testing at driven cycle length ( CL) of 600 msec. St, Vt, DCS1, and At are, respectively, stimulus artifact and ventricular, left atrial (recorded from distal coronary sinus) , and low septal right atrial (recorded from His bundle catheter) responses to driven beats. S2, V2, DCS2, and A2 are, respectively, stimulus artifact and ventricular, left atrial, and low septal right atrial responses to test stimulus. Effective refractory period of ventriculo-atrial conducting system was 380 msec, and sequenees of atrial activation were abnormal. FiGURE
incremental and coupled ventricular pacing. These findings strongly suggested the presence of a leftsided, concealed, retrogradely conducting, extranodal anomalous pathway, which accounted for the presence of retrograde conduction. 10•15 The present patient therefore illustrates a new manifestation of concealed extranodal anomalous pathways. Such pathways may allow retrograde conduction in a patient with antegrade atrioventricular block. REFERENCES
1 Castillo C, Samet P : Retrograde conduction in complete heart block. Br Heart J 29:553-558, 1967 2 Goldreyer BN, Bigger TJ: Ventriculo-atrial conduction in man. Circulation 41:935-946, 1970 3 Gupta PK, Haft Jl: Retrograde ventriculo-atrial conduction in complete heart block: Studies with His bundle electrography. Am J Cardiol30:408-411, 1972 4 Schuilenburg RM: Patterns of V-A conduction in the human heart in the presence of normal and abnormal A-V conduction. In Wellens HJJ, Lie Kl, Janse MJ (eds): The Conduction System of the Heart. Leiden, the Netherlands, HE Stenfert Kroese BV, 1976 5 Cohen Sl, Smith LK, Aroesty JM, et al: Concealed retrograde conduction in complete atrioventricular block. Circulation 50:496-498, 1974 6 Scherlag BJ, Lau SH, Helfant RH, et al: Catheter technique for recording His bundle activity in man. Circulation 39:13-18, 1969 7 Denes P, Wu D, Dhingra R, et al : The effects of cycle length on cardiac refractory periods in man. Circulation 49:32-41, 1974
764 WU ET AL
8 Akhtar M, Damato AN, Batsford WP, et al: A comparative analysis of antegrade and retrograde conduction pattern in man. Circulation 52:766-778, 1975 9 Amat-y-Leon F, Dhingra R, Wu D, et al: Catheter mapping of retrograde atrial activation: Observations during ventricular pacing and A-V nodal reentrant paroxysmal tachycardia. Br Heart J 38:355-362, 1976 10 Svenson RH, Gallagher JJ, Sealy WC, et al: An electrophysiologic approach to the surgical treatment of the Wolff-Parkinson-White syndr001e : Report of two cases utilizing catheter recording and epicardial mapping techniques. Circulation 49:799-804, 1974 11 Zipes DP, DeJoseph RL, Rothbaum PS: Unusual properties of accessory pathways. Circulation 49:1200-1211, 1974 12 Spurrell RA, Krikler DM, Sowton E: Retrograde invasion of the bundle branch producing aberrations of the QRS complex during supraventricular tachycardia studied by programmed electrical stimulation. Circulation 50:487 495, 1974 13 Coumel P., Attuel P: Reciprocating tachycardia in overt and latent preexcitation: Influence of functional bundle branch block on the rate of the tachycardia. Eur J Cardiol 1:423-436, 1974 14 Neuss H, Schlepper M, Thormann J: Analysis of reentry mechanism in three patients with concealed Wolff-Parkinson-White syndrome. Circulation 51:75-81, 1975 15 Denes P, Wyndham C, Rosen KM : Intractable paroxysmal tachycardia due to a concealed retrogradely conducting Kent bundle: Demonstration by epicardial mapping and cure of tachycardia by surgical interruption of the His bundle. Br Heart J 38:758-763, 1976 16 Narula OS: Retrograde preexcitation: Comparison of retrograde and antegrade conduction intervals in man. Circulation 50:1129-1143, 1974
CHEST, 71: 6, JUNE, 1977
Complete Atrioventricular Block with Intact Retrograde Conduction due to a Concealed Extranodal Anomalous Pathway* Delon Wu, M.D.;t ]ames Cummings, M.D.;t Pablo Denes, M.D.;t and Kenneth M. Rosen, M.D., F.C.C.P.§
patients with advanced or complete heart block occasionally manifest intact retrograde conduction.1"" It has usually been postulated that such patients have lesions of the conduction system that produce unidirectional block. There has been some electrophysiologic evidence supporting that hypothesis.w In this report, we describe a patient with complete heart block and intact retrograde conduction. Electrophysiologic studies in our patient demonstrated that retrograde conduction was via a concealed extranodal anomalous pathway. CASE REPoRT
The patient was an 81-year-old woman admitted to the University of Illinois Hospital because of dyspnea and recurrent syncope. Physical examination revealed a blood pressure of 220/70 mm Hg a:nd bradycardia (pulse rate of 40 beats per minute). There was mild distention of the neclc veins, °From the Section of Cardiology Department of Medicine, Abraham Lincoln School of Medicine, University of Illinois College of Medicine, Chicago. Supported in part by Public Health Service training grant HL 05879-06 and Natonal Institutes of Health grant 08794-01. tFellow, Cardiology Section. tAssociate Professor of Medicine. §Professor of Medicine and Chief, Cardiology Section. Reprint requests: Dr. Wu, University of IUirwis Hospital, 840 South Wood Street, Chicago 60612
bilateral basilar rales, and an audible third heart sound. A chest x-ray fihn showed cardiomegaly with mild congestion. Electrocardiograms revealed complete atrioventricular block with a wide QRS escape rhythm. With prior informed consent, electrophysiologic studies were performed at the time of insertion of a permanent pacemaker. A tripolar electrode catheter was percutaneously introduced into the right femoral vein and positioned across the tricuspid valve for recording of His bundle and low septal right atrial electrograms.6 A second hexapolar electrode catheter (pairs of electrodes at the tip and 10 em and 13.5 em proximal to the tip) was introduced into the left antecubital vein and positioned in the distal coronary sinus. The distal two electrodes were used for recording of left atrial electrograms from the distal coronary sinus, the middle two electrodes for right atrial stimulation, and the proximal two electrodes for recording of the high right atrial electrograms. A third bipolar electrode catheter was positioned in the right ventricular apex for ventricular pacing. Multiple electrocardiographic leads and atrial and His bundle electrograms were simultaneously recorded on a multichannel oscilloscopic recorder (Electronics for Medicine DR-16) at paper speeds of 100 and 200 mm/sec. Stimuli were approximately twice the diastolic threshold and 2 msec in duration and were delivered via a programmable digital stimulator (M. Bloom). The functional properties of the atrioventricular conducting system were evaluated with incremental pacing and extrastimulus techniques.7,8 Conduction intervals and refractory periods were defined and measured as previously described.7,8 Control recordings revealed complete atrioventricular block distal to the His bundle recording site (complete
1 :I ll
v,
A
HBE
H
A .' \ ~
H8E
,•
I'
,,
'.
AH
A
~' 'l
FIGURE 1. Simultaneous recordings of multiple electrocardiographic leads and His bundle electrogram ( HBE), showing complete atrioventricular block distal to the His bundle recording site. A and H are low septal right atrial and His bundle electrograms recorded from His bundle catheter. Paper speed is 100 mm/sec, and time lines are at one-second intervals. A-H interval was 70 msec, atrial rate was 66 beats per minute, and ventricular rate was 35 beats per minute.
782 WU ET AL
CHEST, 71: 6, JUNE, 1977
A
Paced
~R•70/min.
FIGURE 2. Recordings showing intact retrograde ventriculoatrial conduction with fixed ventriculoatrial conduction times and abnormal retrograde sequences of atrial activation during incremental ventricular pacing. HR, Heart rate; A, low septal right atrial electrogram recorded from His bundle catheter; DSC, left atrial electrogram recorded from distal coronary sinus. Beats marked with asterisk in panel C indicate ventricular paced beats with type-2 ventriculoatrial block. Paper speed is 100 mm/ sec, and time lines are at one-second intervals. bilateral bundle-branch block), with an atrial rate of 66 beats per minute, an atrio-His interval of 70 msec, and an idioventricular escape rhythm with a rate of 35 beats per minute (Fig 1). Intact atrio-His bundle conduction was noted up to a paced rate of 190 beats per minute. The effective and functional refractory periods of the atrioventricular node at a driven cycle length of 600 msec were, respectively, less than 310 msec and 380 msec. Intact ventriculoatrial conduction was noted up to a ventricular paced rate of 140 beats per minute (Fig 2A and 2B). Ventriculoatrial conduction times ventriculo-distal coronary sinus interval [V-DCS] of 150 msec and ventriculo-atrium interval [V-A] of 190 msec) were constant at ventricular paced rates of 70 to 140 beats per minute (Fig 2A and 2B) . Type-2 ventriculoatrial block occurred at a ventricular paced rate of 150 beats per minute ( Fig 2C). Retrograde refractory periods were measured with ventricular extrastimulus technique at a driven cycle length of 600 msec ( Fig 3). Ventriculoatrial conduction times ( V2- DCS2 and V2-A2 intervals) increased only 20 msec as coupling intervals were shortened from 580 to 390 rnsec. The effective refractory period of the ventriculoatrial conducting system was 380 rnsec. Analysis of atrial activation sequences during incremental ventricular pacing and during ventricular extrastimulus testing revealed early activation of the lateral left atrium (distal coronary sinus recording site), with a V-DCS interval of 150 msec and a ventriculo-low septal right atrium
CHEST, 71: 6, JUNE, 1977
interval of 190 msec (Fig 2 and 3) . This was an abnormal retrograde sequence of atrial activation, the nonnal being early activation of the low septal right atrium.9,10 DISCUSSION
Concealed extranodal anomalous pathways have been described in patients with paroxysmal reentrant tachycardia. 11"15 These patients do not demonstrate antegrade preexcitation but are able to sustain circus movements utilizing antegrade conduction via the normal pathway and retrograde conduction via the anomalous pathway. Studies of ventricular stimulation have also suggested that patients without paroxysmal tachycardia may on occasion have concealed extranodal anomalous pathways. 18 In our patient, complete atrioventricular block occurred distal to the His bundle recording site, suggesting bilateral bundle-branch disease. Intact retrograde conduction was noted with rapid ventricular pacing. Ventriculoatrial conduction times were fixed, 18 and sequences of atrial activation were abnormal (distal coronary sinus) being activated earlier than the low septal right atrium ) uo during
COMPLETE ATRIOVENTRICULAR BLOCK 763
CL•600
A
][
3. Recordings showing retrograde effective refractory period and abnormal sequence of atrial activation during ventricular extrastimulus testing at driven cycle length ( CL) of 600 msec. St, Vt, DCS1, and At are, respectively, stimulus artifact and ventricular, left atrial (recorded from distal coronary sinus) , and low septal right atrial (recorded from His bundle catheter) responses to driven beats. S2, V2, DCS2, and A2 are, respectively, stimulus artifact and ventricular, left atrial, and low septal right atrial responses to test stimulus. Effective refractory period of ventriculo-atrial conducting system was 380 msec, and sequenees of atrial activation were abnormal. FiGURE
incremental and coupled ventricular pacing. These findings strongly suggested the presence of a leftsided, concealed, retrogradely conducting, extranodal anomalous pathway, which accounted for the presence of retrograde conduction. 10•15 The present patient therefore illustrates a new manifestation of concealed extranodal anomalous pathways. Such pathways may allow retrograde conduction in a patient with antegrade atrioventricular block. REFERENCES
1 Castillo C, Samet P : Retrograde conduction in complete heart block. Br Heart J 29:553-558, 1967 2 Goldreyer BN, Bigger TJ: Ventriculo-atrial conduction in man. Circulation 41:935-946, 1970 3 Gupta PK, Haft Jl: Retrograde ventriculo-atrial conduction in complete heart block: Studies with His bundle electrography. Am J Cardiol30:408-411, 1972 4 Schuilenburg RM: Patterns of V-A conduction in the human heart in the presence of normal and abnormal A-V conduction. In Wellens HJJ, Lie Kl, Janse MJ (eds): The Conduction System of the Heart. Leiden, the Netherlands, HE Stenfert Kroese BV, 1976 5 Cohen Sl, Smith LK, Aroesty JM, et al: Concealed retrograde conduction in complete atrioventricular block. Circulation 50:496-498, 1974 6 Scherlag BJ, Lau SH, Helfant RH, et al: Catheter technique for recording His bundle activity in man. Circulation 39:13-18, 1969 7 Denes P, Wu D, Dhingra R, et al : The effects of cycle length on cardiac refractory periods in man. Circulation 49:32-41, 1974
764 WU ET AL
8 Akhtar M, Damato AN, Batsford WP, et al: A comparative analysis of antegrade and retrograde conduction pattern in man. Circulation 52:766-778, 1975 9 Amat-y-Leon F, Dhingra R, Wu D, et al: Catheter mapping of retrograde atrial activation: Observations during ventricular pacing and A-V nodal reentrant paroxysmal tachycardia. Br Heart J 38:355-362, 1976 10 Svenson RH, Gallagher JJ, Sealy WC, et al: An electrophysiologic approach to the surgical treatment of the Wolff-Parkinson-White syndr001e : Report of two cases utilizing catheter recording and epicardial mapping techniques. Circulation 49:799-804, 1974 11 Zipes DP, DeJoseph RL, Rothbaum PS: Unusual properties of accessory pathways. Circulation 49:1200-1211, 1974 12 Spurrell RA, Krikler DM, Sowton E: Retrograde invasion of the bundle branch producing aberrations of the QRS complex during supraventricular tachycardia studied by programmed electrical stimulation. Circulation 50:487 495, 1974 13 Coumel P., Attuel P: Reciprocating tachycardia in overt and latent preexcitation: Influence of functional bundle branch block on the rate of the tachycardia. Eur J Cardiol 1:423-436, 1974 14 Neuss H, Schlepper M, Thormann J: Analysis of reentry mechanism in three patients with concealed Wolff-Parkinson-White syndrome. Circulation 51:75-81, 1975 15 Denes P, Wyndham C, Rosen KM : Intractable paroxysmal tachycardia due to a concealed retrogradely conducting Kent bundle: Demonstration by epicardial mapping and cure of tachycardia by surgical interruption of the His bundle. Br Heart J 38:758-763, 1976 16 Narula OS: Retrograde preexcitation: Comparison of retrograde and antegrade conduction intervals in man. Circulation 50:1129-1143, 1974
CHEST, 71: 6, JUNE, 1977
