- Email: [email protected]
Atrioventricular block and preexcitation in hypertrophic cardiomyopathy
March 15. 1984
terograde conduction lover the accessory pathway by the subsequent atrial-paced complex. When ventricular activation does not occur, concealed conduction is absent and the subsequent paced atrial complex conducts over the accessory pa.thway. The frequency for which retrograde concealed conduction into the accessory pathway accounts for spontaneous loss of anterograde preexcitation is unknown.
AtrioventricularIBlockand Preexcitation in HypertroplhicCardiomyopathy PAUL TOUBOUL, MD GILBERT KIRKORIAN, MD GEORGE3 ATALLAH, MD POL. CAHEN, MD CLAUDIO DE ZULOAGA, MD PIERRE MOLEUR, MD
Various electrocardiographic abnormalities are known to be present in patients with hypertrophic cardiomyopathy (HC). Patterns of ventricular preexcitation, including the classic Wolff-Parkinson-White (WPW) syndrome, have been noted.1 The following report describes 2 patients with atrioventricular (AV) block in association with p:reexcitation, and this combination, to our knowledge, has not previously been observed in HC. The patients were studied in the postabsorptive, nonsedated state. FOUF electrode catheters were introduced percutaneously through the femoral veins for pacing and recording of intracardiac (atrium and His bundle) electrograms, An 8-channel direct ink-jet recorder (Elema, Mingograph 81) was used. Standard techniques of programmed cardiac stimulation (Janssen) were used. Data were stored on magnetic tape (Hewlett-Packard). Case 1: A 65-year-old man was admitted in March 1977 for recurrent syncope. HC had been diagnosed 7 years earlier and the patient had been taking pindolol(7.5 mglday) since then. The ECG on admission showed sinus rhythm. The PR interval was short (0.08 second) and the QRS pattern suggested a type B WPW syndrome (Fig. 1). Brief episodes of complete AV block were recorded (Fig. 1). The AH interval was 50 ms and the HV interval 30 ms (Fig. 2). Rapid atria1 by 1:I AV pacing up to 200 beatslmin was accompanied conduction. The AH interval showed a minimal lengthening (20 ms) and the HV remained constant. Premature atria1 stimulation at a paced cycle length of 500 ms provoked only a slight variation of the AH interval, At a coupling interval of 240 ms, the AH interval abruptly increased to 310 ms and an atria1 echo beat occurred. The HV interval and the QRS complex were unaltered (Fig. 2). Increasingly rapid stimulation of the right ventricle (maximum, 200 beatslmin) was followed by retrograde conduction to the atria. The ventriculoatrial (VA) conduct,ion time was xonstant. The carotid sinus massage resulted in a sinus pause longer than 4 secFrom the Laboratory of Clinical Electrophysiology, H6pital Cardiovasculaire et Pneumologique Louis Pradel, BP Lyon Mont&at, 69394 Cedex 3, France. Manuscript received August 24, 1983; revised manuscript received October 27, 1983, accepted October 31, 1983.
THE Al&RICAN
JOURNAL OF CARDIOLOGY
Volume 53
961
References 1. Langendorl R. Concealed AV conduction. The effect of blocked impulses on the formation and conduction of subsequent impulses. Am Heart J 1948;35:542-552. 2. Durrer D, Wellens HJJ. The Wolff-Parkinson-White syndrome anno 1973. Eur J Cardiol 1974;1:347-367. 3. Zipes DP, DeJoseph RL, Rothbaum DA. Unusual properties of accessory pathways. Circulation 1974;49:1200-1211. 4. Gallagher JJ, Prftchett ELC, Bendill DB, Tonkin AM, Campbell RWF, Dugan FA, Bashore TM, Wallace AG. New catheter techniques for analysis of the sequence of retrograde atrial activation in man. Eur J Cardiol 1977;6:114.
onds. A ventricular escape beat then ensued, followed by a premature contraction and several atria1 depolarizations blocked distal to H (Fig. 3). The investigation was concluded with iv. administration of 50 mg of ajmaline base (Servier, France) over 2.5 minutes. The HV interval then increased to 70 ms and after a short episode of type 2 second-degree AV block, a complete infra-Hisian AV block appeared (Fig. 3). Since the insertion of a demand cardiac pacemaker, the patient has presented no further syncopes. The pacemaker inhibition test subsequently unmasked a complete AV block. Case 2: A 45-year-old man had known HC for 8 years. Pindolol(15 mg/day) had been prescribed. The patient was referred to our hospital in May 1979 because of frequent syncopal attacks. The ECG showed a PR interval of 0.11 second and wide QRS complexes with a type B WPWpattern (Fig. 4). Some beats with a PR interval of 0.14 second and a left bundle branch block (LBBB) were occasionally seen. During preercitation, the AH interval was 50 ms and the HVinterval25 ms (Fig. 5). Rapid atria1 pacing increased the AH interval by 40 ms at the maximum, without altering the HV interval and the QRS configuration. At 150 beatsfmin, the HVinterval lengthened to 60 ms and a left bundle branch block appeared. The extrastimulus method at an atria1 cycle
I
VI
VL VF
W
V3
W
V5 V6
FIGURE 1. Case 1. The ECG shows type B Wolff-Parkinson-Whiie syl~ drome. The lower tracing (bipolar chest lead) reveals a 2: 1 atrioventricular block followed by a pause and a ventricular escape beat.
962
BRIEF REPORTS
500 msec
,
FIGURE 2. Case 1. Panel 3, electrophysiologic data in sinus rhythm. Panels 1 and 2, the effects of premature atrial stimulation. At a coupling interval of 250 ms the premature atrial response was followed by a slight lengthening of the AH interval without any associated change in HV, or in the preexcitation pattern. When the coupling interval was reduced to 240 ms, a marked increase in the AH interval was produced, accompanied by an atrial echo beat (E). The HV interval and QRS complex were not modified. A = right atrial bipolar electrogram; HIS = His bundle lead.
length of 700 ms provoked premature responses similar to the basic beats. At most, the AH interval was prolonged insignificantly. When the coupling interval was shortened to 380 ms, a LBBB became manifest and the HV conduction time increased to 60 ms. The relevant HlHz interval was 400 ms. Reduction of the coupling interval to 310 ms was accompanied by a sudden lengthening of the AH interval to 210 ms (HIHZ 460 ms). Simultaneously, the WPW pattern recurred and the HV interval was again 25 ms. Rapid and premature ventricular stimulation resulted in retrograde conduction to the atria with a fixed VA time. His bundle pacing resulted in WPW beats similar to the sinus beats. Finally, the iv. injection of ajmaline (50 mg in 2.5 minutes) at first suppressed the preexcitation pattern. Only LBBB beats persisted. A complete infra-Hisian AV block appeared (Fig. 6). After this study, a cardiac demand pacemaker was inserted. There was no recurrence of syncope. The ECGs have shown a permanent paced rhythm for the past 2 years.
Our 2 cases revealed striking similarities. A type B WPW syndrome was noted in both patients with HC, and the preexcitation in each had the same basis. Enhanced AV nodal conduction was present. The AH interval was short, and the rate-related changes were minimal. Furthermore, at a critical coupling interval, premature atria1 stimulation produced a marked lengthening of the AV nodal conduction time, suggesting block within a fast pathway. These data suggest bypass of the area of physiologic conduction delay.2 The combination of Mahaim fibers connecting the His bundle to the ventricle must be invoked in our patients. This accounts for the short HV interval and the delta wave.3 Such abnormalities did not vary despite the changes in the AH interval. Moreover, in case 2, His bundle pacing resulted in preexcitation beats.3 In the same patient, early atria1 depolarizations suppressed the His-ventricular preexcitation, revealing an underlying LBBB. Surprisingly, at shorter coupling intervals, the abrupt increase in the AH interval was accompanied
lssc FIGURE 3. Case 1. Top, the effect of carotid massage. The sinus pause was followed by complete infra-Hisian atrioventricular block. The i.v. injection of 50 mg of ajmaline (bottom) resulted in second-degree (Mobitz type 2) infra-Hisian atrioventricular block, which then became complete. Abbreviations in Figure 2.
by the recurrence of preexcitation. One must assume that slow conduction in the AV node enabled the accessory fibers to recover (gap phenomenon). However, we cannot exclude that the LBBB pattern may have represented complete infra-Hisian block with persisting conduction through the Mahaim fibers. In our cases, an infra-Hisian AV block was also present. Severe lesions of the His-Purkinje system were unmasked by i.v. administration of ajmaline, which resulted in complete AV block distal to H.4 Moreover, in 1 patient carotid sinus massage was followed by phase 4 paroxysmal AV block. Previous studies in HC have shown HV intervals superior to 60 ms in 58% of patients5 However, the cases of HC with high-degree AV block are rare. The infranodal site of block has occasionally been documented by His bundle recordings.6
I
Vi
II
Ill
V2
V3
VR
V4
VL
V5
VF -_
V6
FfGURE 4. Case 2. The standard ECG shows type B Wolff-ParkinsonWhite syndrome.
March 15, 1984
THE AMERICAN JOURNAL OF CARDIOLOGY Volume 53
963
r500msec, FIGURE 5. Case 2. Right, electrophysiologic data in sinus rhythm. Panels 1 to 3 visualize the effects of premature atrial stimulation. At a coupling interval of 400 ms the premature atrial response was followed by a slight increase in the AH interval, whereas the HV interval and the OR.5 complex did not change. At a coupling interval of 380 ms the Wolff-Parkinson-White pattern was replaced by a complete left bundle branch block and the HV interval increased from 25 to 80 ms. An even more premature atrial response (AlA 310 ms) induced a marked increase in the AH interval associated with the reappearance of preexcitation.
FKXJRE 6. Case 2. The i.v. injaction of 50 mg ajmaline caused 2:l block in the anomalous conduction and then suppressed all preexcitation. Only beats with left bundle branch block persisted temporarily. Complete infra-Hisian atrioventricular block then followed.
Previous reports have dealt with the combination of AV block and preexcitation.738 In our patients the infranodal preexcitation usually masked AV block, allowing the cardiac impulse to bypass the damaged area of the His-Purkinje system. However, the His bundle lesions likely involved the takeoff site of the Mahaim fibers. In Case 1 there w,asno evidence of persisting AV conduction through the normal pathways. Permanent complete block remained possible, associated with the preexcitation syndrome. The second patient did not show any blocked P wave in the standard ECGs. The diagnosis of AV block could not be made during routine examination. After insertion of a cardiac pacemaker, our patients were asymptomatic. This tends to confirm the participation of the conduction disease in the genesis of syncope.
References
5. 6. 7. 6.
Frank S, Brsunwald E. Idiopathic hypertrophic subaortic stenosis. Clinical analysis of 126 patients with emphasis on the natural history. Circulation 1968:37:759-788. Caracta AR, Damato AN, Gallagher JJ, Josephson ME, Vargher PJ, Lau SW,Westura EE. Electrophysiologic studies in the syndrome of short P-R interval, normal QRS complex. Am J Cardiol 1973;31:245-253. Gallagher JJ, Smith WY, Kasell JH, Benson DW Jr, Stsrba R, Grant AO. Role of Mahaim fibers in cardiac arrhythmias in man, Circulation 1981;64: 176-189. Guerot C, Caste A, Valere PE, Tricot R. L’Bpreuve & I’ajmaline dans le dla nostic du bloc auriculo-ventriculaire paroxystique. Arch Mal Coeur 18 73;66:1241-1253. lngham RE, Mason JW, Roseen RM, Goodmen DJ, Hanlwn DC. Electrophysiologic findings in patients with idiopathic hyperbophic subaortic stenosis. Am J Cardiol 1978;41:811-816. Chmlelewekl CA, Riley RS, Mahendran A, Most AS. Complete heart block as a cause of syncope in asymmetric septal hypertrophy. Am Heart J 1977;93:91-93. Soherf D, Blumenfeld S, Mueiler P. A-V conduction disturbance in the presence of the pre-excitation syndrome. Am Heart J 1952;43:829-839. Lev M, Leffler WB, Langendorf R, Pick A. Anatomic findings In a case of ventricular pre-excitation (WPW) terminating In complete atrioventricular block. Circulation 1966;34:718-733.
terograde conduction lover the accessory pathway by the subsequent atrial-paced complex. When ventricular activation does not occur, concealed conduction is absent and the subsequent paced atrial complex conducts over the accessory pa.thway. The frequency for which retrograde concealed conduction into the accessory pathway accounts for spontaneous loss of anterograde preexcitation is unknown.
AtrioventricularIBlockand Preexcitation in HypertroplhicCardiomyopathy PAUL TOUBOUL, MD GILBERT KIRKORIAN, MD GEORGE3 ATALLAH, MD POL. CAHEN, MD CLAUDIO DE ZULOAGA, MD PIERRE MOLEUR, MD
Various electrocardiographic abnormalities are known to be present in patients with hypertrophic cardiomyopathy (HC). Patterns of ventricular preexcitation, including the classic Wolff-Parkinson-White (WPW) syndrome, have been noted.1 The following report describes 2 patients with atrioventricular (AV) block in association with p:reexcitation, and this combination, to our knowledge, has not previously been observed in HC. The patients were studied in the postabsorptive, nonsedated state. FOUF electrode catheters were introduced percutaneously through the femoral veins for pacing and recording of intracardiac (atrium and His bundle) electrograms, An 8-channel direct ink-jet recorder (Elema, Mingograph 81) was used. Standard techniques of programmed cardiac stimulation (Janssen) were used. Data were stored on magnetic tape (Hewlett-Packard). Case 1: A 65-year-old man was admitted in March 1977 for recurrent syncope. HC had been diagnosed 7 years earlier and the patient had been taking pindolol(7.5 mglday) since then. The ECG on admission showed sinus rhythm. The PR interval was short (0.08 second) and the QRS pattern suggested a type B WPW syndrome (Fig. 1). Brief episodes of complete AV block were recorded (Fig. 1). The AH interval was 50 ms and the HV interval 30 ms (Fig. 2). Rapid atria1 by 1:I AV pacing up to 200 beatslmin was accompanied conduction. The AH interval showed a minimal lengthening (20 ms) and the HV remained constant. Premature atria1 stimulation at a paced cycle length of 500 ms provoked only a slight variation of the AH interval, At a coupling interval of 240 ms, the AH interval abruptly increased to 310 ms and an atria1 echo beat occurred. The HV interval and the QRS complex were unaltered (Fig. 2). Increasingly rapid stimulation of the right ventricle (maximum, 200 beatslmin) was followed by retrograde conduction to the atria. The ventriculoatrial (VA) conduct,ion time was xonstant. The carotid sinus massage resulted in a sinus pause longer than 4 secFrom the Laboratory of Clinical Electrophysiology, H6pital Cardiovasculaire et Pneumologique Louis Pradel, BP Lyon Mont&at, 69394 Cedex 3, France. Manuscript received August 24, 1983; revised manuscript received October 27, 1983, accepted October 31, 1983.
THE Al&RICAN
JOURNAL OF CARDIOLOGY
Volume 53
961
References 1. Langendorl R. Concealed AV conduction. The effect of blocked impulses on the formation and conduction of subsequent impulses. Am Heart J 1948;35:542-552. 2. Durrer D, Wellens HJJ. The Wolff-Parkinson-White syndrome anno 1973. Eur J Cardiol 1974;1:347-367. 3. Zipes DP, DeJoseph RL, Rothbaum DA. Unusual properties of accessory pathways. Circulation 1974;49:1200-1211. 4. Gallagher JJ, Prftchett ELC, Bendill DB, Tonkin AM, Campbell RWF, Dugan FA, Bashore TM, Wallace AG. New catheter techniques for analysis of the sequence of retrograde atrial activation in man. Eur J Cardiol 1977;6:114.
onds. A ventricular escape beat then ensued, followed by a premature contraction and several atria1 depolarizations blocked distal to H (Fig. 3). The investigation was concluded with iv. administration of 50 mg of ajmaline base (Servier, France) over 2.5 minutes. The HV interval then increased to 70 ms and after a short episode of type 2 second-degree AV block, a complete infra-Hisian AV block appeared (Fig. 3). Since the insertion of a demand cardiac pacemaker, the patient has presented no further syncopes. The pacemaker inhibition test subsequently unmasked a complete AV block. Case 2: A 45-year-old man had known HC for 8 years. Pindolol(15 mg/day) had been prescribed. The patient was referred to our hospital in May 1979 because of frequent syncopal attacks. The ECG showed a PR interval of 0.11 second and wide QRS complexes with a type B WPWpattern (Fig. 4). Some beats with a PR interval of 0.14 second and a left bundle branch block (LBBB) were occasionally seen. During preercitation, the AH interval was 50 ms and the HVinterval25 ms (Fig. 5). Rapid atria1 pacing increased the AH interval by 40 ms at the maximum, without altering the HV interval and the QRS configuration. At 150 beatsfmin, the HVinterval lengthened to 60 ms and a left bundle branch block appeared. The extrastimulus method at an atria1 cycle
I
VI
VL VF
W
V3
W
V5 V6
FIGURE 1. Case 1. The ECG shows type B Wolff-Parkinson-Whiie syl~ drome. The lower tracing (bipolar chest lead) reveals a 2: 1 atrioventricular block followed by a pause and a ventricular escape beat.
962
BRIEF REPORTS
500 msec
,
FIGURE 2. Case 1. Panel 3, electrophysiologic data in sinus rhythm. Panels 1 and 2, the effects of premature atrial stimulation. At a coupling interval of 250 ms the premature atrial response was followed by a slight lengthening of the AH interval without any associated change in HV, or in the preexcitation pattern. When the coupling interval was reduced to 240 ms, a marked increase in the AH interval was produced, accompanied by an atrial echo beat (E). The HV interval and QRS complex were not modified. A = right atrial bipolar electrogram; HIS = His bundle lead.
length of 700 ms provoked premature responses similar to the basic beats. At most, the AH interval was prolonged insignificantly. When the coupling interval was shortened to 380 ms, a LBBB became manifest and the HV conduction time increased to 60 ms. The relevant HlHz interval was 400 ms. Reduction of the coupling interval to 310 ms was accompanied by a sudden lengthening of the AH interval to 210 ms (HIHZ 460 ms). Simultaneously, the WPW pattern recurred and the HV interval was again 25 ms. Rapid and premature ventricular stimulation resulted in retrograde conduction to the atria with a fixed VA time. His bundle pacing resulted in WPW beats similar to the sinus beats. Finally, the iv. injection of ajmaline (50 mg in 2.5 minutes) at first suppressed the preexcitation pattern. Only LBBB beats persisted. A complete infra-Hisian AV block appeared (Fig. 6). After this study, a cardiac demand pacemaker was inserted. There was no recurrence of syncope. The ECGs have shown a permanent paced rhythm for the past 2 years.
Our 2 cases revealed striking similarities. A type B WPW syndrome was noted in both patients with HC, and the preexcitation in each had the same basis. Enhanced AV nodal conduction was present. The AH interval was short, and the rate-related changes were minimal. Furthermore, at a critical coupling interval, premature atria1 stimulation produced a marked lengthening of the AV nodal conduction time, suggesting block within a fast pathway. These data suggest bypass of the area of physiologic conduction delay.2 The combination of Mahaim fibers connecting the His bundle to the ventricle must be invoked in our patients. This accounts for the short HV interval and the delta wave.3 Such abnormalities did not vary despite the changes in the AH interval. Moreover, in case 2, His bundle pacing resulted in preexcitation beats.3 In the same patient, early atria1 depolarizations suppressed the His-ventricular preexcitation, revealing an underlying LBBB. Surprisingly, at shorter coupling intervals, the abrupt increase in the AH interval was accompanied
lssc FIGURE 3. Case 1. Top, the effect of carotid massage. The sinus pause was followed by complete infra-Hisian atrioventricular block. The i.v. injection of 50 mg of ajmaline (bottom) resulted in second-degree (Mobitz type 2) infra-Hisian atrioventricular block, which then became complete. Abbreviations in Figure 2.
by the recurrence of preexcitation. One must assume that slow conduction in the AV node enabled the accessory fibers to recover (gap phenomenon). However, we cannot exclude that the LBBB pattern may have represented complete infra-Hisian block with persisting conduction through the Mahaim fibers. In our cases, an infra-Hisian AV block was also present. Severe lesions of the His-Purkinje system were unmasked by i.v. administration of ajmaline, which resulted in complete AV block distal to H.4 Moreover, in 1 patient carotid sinus massage was followed by phase 4 paroxysmal AV block. Previous studies in HC have shown HV intervals superior to 60 ms in 58% of patients5 However, the cases of HC with high-degree AV block are rare. The infranodal site of block has occasionally been documented by His bundle recordings.6
I
Vi
II
Ill
V2
V3
VR
V4
VL
V5
VF -_
V6
FfGURE 4. Case 2. The standard ECG shows type B Wolff-ParkinsonWhite syndrome.
March 15, 1984
THE AMERICAN JOURNAL OF CARDIOLOGY Volume 53
963
r500msec, FIGURE 5. Case 2. Right, electrophysiologic data in sinus rhythm. Panels 1 to 3 visualize the effects of premature atrial stimulation. At a coupling interval of 400 ms the premature atrial response was followed by a slight increase in the AH interval, whereas the HV interval and the OR.5 complex did not change. At a coupling interval of 380 ms the Wolff-Parkinson-White pattern was replaced by a complete left bundle branch block and the HV interval increased from 25 to 80 ms. An even more premature atrial response (AlA 310 ms) induced a marked increase in the AH interval associated with the reappearance of preexcitation.
FKXJRE 6. Case 2. The i.v. injaction of 50 mg ajmaline caused 2:l block in the anomalous conduction and then suppressed all preexcitation. Only beats with left bundle branch block persisted temporarily. Complete infra-Hisian atrioventricular block then followed.
Previous reports have dealt with the combination of AV block and preexcitation.738 In our patients the infranodal preexcitation usually masked AV block, allowing the cardiac impulse to bypass the damaged area of the His-Purkinje system. However, the His bundle lesions likely involved the takeoff site of the Mahaim fibers. In Case 1 there w,asno evidence of persisting AV conduction through the normal pathways. Permanent complete block remained possible, associated with the preexcitation syndrome. The second patient did not show any blocked P wave in the standard ECGs. The diagnosis of AV block could not be made during routine examination. After insertion of a cardiac pacemaker, our patients were asymptomatic. This tends to confirm the participation of the conduction disease in the genesis of syncope.
References
5. 6. 7. 6.
Frank S, Brsunwald E. Idiopathic hypertrophic subaortic stenosis. Clinical analysis of 126 patients with emphasis on the natural history. Circulation 1968:37:759-788. Caracta AR, Damato AN, Gallagher JJ, Josephson ME, Vargher PJ, Lau SW,Westura EE. Electrophysiologic studies in the syndrome of short P-R interval, normal QRS complex. Am J Cardiol 1973;31:245-253. Gallagher JJ, Smith WY, Kasell JH, Benson DW Jr, Stsrba R, Grant AO. Role of Mahaim fibers in cardiac arrhythmias in man, Circulation 1981;64: 176-189. Guerot C, Caste A, Valere PE, Tricot R. L’Bpreuve & I’ajmaline dans le dla nostic du bloc auriculo-ventriculaire paroxystique. Arch Mal Coeur 18 73;66:1241-1253. lngham RE, Mason JW, Roseen RM, Goodmen DJ, Hanlwn DC. Electrophysiologic findings in patients with idiopathic hyperbophic subaortic stenosis. Am J Cardiol 1978;41:811-816. Chmlelewekl CA, Riley RS, Mahendran A, Most AS. Complete heart block as a cause of syncope in asymmetric septal hypertrophy. Am Heart J 1977;93:91-93. Soherf D, Blumenfeld S, Mueiler P. A-V conduction disturbance in the presence of the pre-excitation syndrome. Am Heart J 1952;43:829-839. Lev M, Leffler WB, Langendorf R, Pick A. Anatomic findings In a case of ventricular pre-excitation (WPW) terminating In complete atrioventricular block. Circulation 1966;34:718-733.