Br Heart J: first published as 10.1136/hrt.40.11.1317 on 1 November 1978. Downloaded from
British Heart journal, 1978, 40, 1317-1320
Wolff-Parkinson-White syndrome (type A) complicated by heart block in both normal and accessory pathways
A. F. MACKINTOSH, D. A. CHAMBERLAIN, AND P. V. L. CURRY1" From the Departments of Cardiology, Royal Sussex County Hospital, Brighton, King's College Hospital, London, and Hammersmith Hospital, London
SUMMARY A 67-year-old man with Wolff-Parkinson-White syndrome type A presented with second degree atrioventricular block in the anomalous pathway and complete infra-Hisian block in the His- Purkinje pathway. He had increasingly frequent attacks ofdizziness not related to exercise. A permanent ventricular demand pacemaker was successfully implanted following intracardiac electrophysiological studies.
Disorders of conduction occurring simultaneously the sinus rate. His bundle recordings (Scherlag in both normal and abnormal atrioventricular path- et al., 1969) showed intermittent 2:1 conduction ways of patients with the Wolff-Parkinson-White of sinus beats across the accessory pathway when syndrome have only rarely been observed (Lev et al., the atrial rate fell below 80 per minute. Conducted 1966). Intracardiac studies to reveal the underlying sinus beats were preceded by a His potential with electrophysiological mechanisms have been under- an HV interval (His spike to earliest ventricular taken in a few such cases with iatrogenic or con- activity) of 25 ms. Sinus beats not conducted in the genital (nodal) atrioventricular block in the nodal- accessory pathway were completely blocked after His-Purkinje pathway (Coumel et al., 1973; the His potential (infra-Hisian block, Fig. 2A).
Seipel et al., 1976). Right atrial pacing at a cycle length of 485 ms (124 http://heart.bmj.com/ We report a case of Wolff-Parkinson-White beats/min) induced a normal atrioventricular syndrome type A presenting with episodes of dizzi- response, the AH interval increasing from 120 ms ness caused by combined conduction abnormalities (upper limit of normal range) during spontaneous in both the normal and theaccessoryatrioventricular rhythm to 155 ms. The apparent HV interval of pathways. An unusual feature was that the normal conducted beats shortened from 25 ms to 0 ms pathway was blocked below the His bundle. during incremental atrial pacing, without further widening of the QRS complex. Ventricular activa-
Case report tion never occurred by the normal pathway. One- on October 2, 2021 by guest. Protected copyright. to-one anterograde accessory pathway conduction A 67-year-old man was referred with transient occurred at atrial pacing rates up to 150 beats per episodes of dizziness over a period of 6 years. minute, during which the A-delta conduction Attacks occurred at rest and were not induced by interval increased from 145 to 155 ms (Fig. 2B). exercise. No episodes of complete syncope had Ventricular pacing showed no retrograde conduc- occurred and there was no history of paroxysmal tion in either the normal or accessory pathway. tachycardia in childhood or adult life. A permanent ventricular demand pacemaker was An electrocardiogram showed Wolff-Parkinson- implanted, initially with an endocardial electrode White syndrome type A with maximal ventricular but this was unstable and was later replaced by an pre-excitation, intermittent second degree atrio- epicardial one. The patient has had no more attacks ventricular block and a PR (P-delta) interval of 0 14 s of dizziness (follow-up 9 months). for conducted sinus beats (Fig. 1). Second degree atrioventricular block usually followed slowing of Discussion 'Present address: Department of Cardiology, Guy's Hospital, London. In patients with the Wolff-Parkinson-White syn- 'In receipt of a British Heart Foundation grant. drome and sinus rhythm the ventricle is activated 1317 Br Heart J: first published as 10.1136/hrt.40.11.1317 on 1 November 1978. Downloaded from
1318 A. F. Mackintosh, D. A. Chamberlain, and P. V. L. Curry G.B.
III III aVR aVL aVF Fig. 1 Electrocardiogram in spontaneous rhythn showing second degree block and pattern ofpre-excitation. P I- 1
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720 685 715 715 725 740 740 715 700 725
- HBE http://heart.bmj.com/
Fig. 2 His bundle electrogram (HBE) and three surface leads. (A) spontaneous rhythm; (B) atrial pacing at 124 beats per minute. Conduction is now 1:1.
HV interval is now zero but the QRS morphology is on October 2, 2021 by guest. Protected copyright. 0 A^18 9040 40 unchanged indicating that conduction must be down the AV I -%'- aberrant pathway in sponataneous rhythm and with atrial pacing. Br Heart J: first published as 10.1136/hrt.40.11.1317 on 1 November 1978. Downloaded from
Heart block in Wolff-Parkinson-White syndrome 1319 typically via two atrioventricular pathways; one is disturbance. In the case reported by Dreifus et al. the normal His-Purkinje pathway and the other is (1968) symptomatic complete heart block requiring the abnormal accessory pathway. The QRS con- ventricular pacing occurred after ligation of the His figuration ofthe fusion beats recorded on the surface bundle for recurrent re-entry tachycardias. Their electrocardiogram indicates the relative times explanation was that the accessory pathway had also required for sinus impulses to be conducted to the been ligated. ventricle 'in parallel' -down both the normal and A patient similar to ours with complete block in accessory atrioventricular pathways. Usually both the normal pathway and second degree block in the incremental atrial pacing and premature atrial accessory pathway has been described (Seipel et al., beats prolong conduction selectively in the 1976); the site of this block in the normal pathway normal atrioventricular nodal pathway causing was the atrioventricular node, but in contrast the more ventricular excitation via the accessory block in our patient was below the His bundle. A pathway. This results in further widening of the common feature was the absence of episodes of loss QRS complex. In our case a pattern of total ven- of consciousness (Adams-Stokes attacks) in spite of tricular pre-excitation was apparent on the electro- frequent episodes of dizziness. This probably cardiogram. The stability of QRS configuration depended upon improvement in accessory pathway during incremental atrial pacing confirmed that the conduction following reflex increases in the sinus accessory pathway was exciting most or all of the rate. Without the assurance that this protective ventricle. This in association with revealed infra- mechanism would always occur, and because of Hisian block in the normal pathway during non- increasingly frequent attacks of dizziness in our conducted sinus beats indicated complete heart otherwise healthy patient, permanent demand block rather than second degree block in the nodal- ventricular pacing was undertaken. Electrocardio- His-Purkinje pathway. Both the aetiology and the grams have subsequently shown continuous ven- duration of the infra-Hisian block were unknown. tricular pacing without retrograde atrial activation. The second degree block in the accessory pathway The occurrence of rapid ventricular rates caused appeared to be bradycardia dependent, occurring by 1:1 conduction across the accessory pathway usually at sinus rates of less than 80 beats per during atrial tachycardia is a well recognised com- minute. Electrocardiograms were not obtained plication in some patientswith theWolff-Parkinson- during attacks of dizziness and higher degrees of White syndrome. This case illustrates a contrasting block in the accessory pathway were never seen. problem: that of conduction block occurring simul- Combined conduction disturbances in both the taneously in both the normal and the accessory accessory and the normal atrioventricular pathways atrioventricular pathways. The electrophysiological http://heart.bmj.com/ have only rarely been seen in patients with the properties of an accessory pathway may vary con- Wolff-Parkinson-White syndrome (Seipel et al., siderably from moment to moment. When this 1976). The block in each pathway may be only for untrustworthy pathway is the only route of con- anterograde conduction or only for retrograde duction to the ventricle, continuous acceptable conduction. Several previous reports have empha- function cannot be assumed. sised the superiority of retrograde accessory path- way conduction to anterograde accessory pathway References et et conduction (Coumel al., 1973; Dreifus al., on October 2, 2021 by guest. Protected copyright. 1968; Massumi, 1970). Supranormal conduction Coumel, P., Gourgon, R., Slama, R., and Bouvrain, Y. (1973). Conduction auriculo-ventriculaire par des fibres de down an accessory pathway in association with pre-excitation, associee a un bloc complet de la voie nodo- normal conduction occurring in the nodal-His hissienne: Etude electrocardiographique de quatre cas. pathway has also been described (Coumel et al., Archives des Maladies du Coeur, 66, 285-304. 1973; McHenry et al., 1966). In our case retrograde Dreifus, L. S., Nichols, H., Morse, D., Watanabe, Y., and Truex, R. (1968). Control of recurrent tachycardia of conduction of ventricular impulses failed to occur Wolff-Parkinson-White syndrome by surgical ligature of across either the normal or the accessory pathways, the A-V bundle. Circulation, 38, 1030-1036. nor was supranormal conduction in either pathway Lev, M., Leffler, W. B., Langendorf, R., and Pick, A. (1966). seen following premature atrial beats. Anatomic findings in a case of ventricular pre-excitation (WPW) terminating in complete atrioventricular block. Patients with the Wolff-Parkinson-White syn- Circulation, 34, 718-733. drome and combined conduction disturbances McHenry, P. L., Knoebel, S. B., and Fisch, C. (1966). The rarely complain of symptoms of bradycardia. One Wolff-Parkinson-White (WPW) syndrome with super- of four patients previously reported by Coumel normal conduction through the anomalous bypass. Circula- tion, 34, 734-739. et al. (1973) presented with an episode of altered Massumi, R. A. (1970). His bundle recordings in bilateral consciousness, but this was attributed to sinus node bundle-branch block combined with Wolff-Parkinson- disease rather than an atrioventricular conduction White syndrome; antegrade type II (Mobitz) block and 1/1 Br Heart J: first published as 10.1136/hrt.40.11.1317 on 1 November 1978. Downloaded from
1320 A. F. Mackintosh, D. A. Chamberlain, and P. V. L. Curry retrograde conduction through the anomalous bundle. block combined with pre-excitation syndrome. American Circulation, 42, 287-295. Heart Journal, 92, 623-629. Scherlag, B. J., Lau, S. H., Helfant, R. H., Berkowitz, W. D., Stein, B., and Damato, A. N. (1969). Catheter technique for recording His bundle activity in man. Circulation, 39, Requests for reprints to Dr A. F. Mackintosh, 13-18. Seipel, L., Both, A., Breithardt, G., and Loogen, F. (1976). CricDprmn,Kn'Cardiac Department, King's Collegeolg Hospital,optl His bundle recordings in a case of complete atrioventricular Denmark Hill, London SE5. http://heart.bmj.com/ on October 2, 2021 by guest. Protected copyright.