Atrioventricular Dissociation with Prolonged QT Interval and Syncopal Attacks in a Io-Year-Old Boy

Br Heart J: first published as 10.1136/hrt.36.5.516 on 1 May 1974. Downloaded from

Atrioventricular dissociation with prolonged QT interval and syncopal attacks in a io-year-old boy

R. J. Kernohan and P. Froggatt From the Waveney Hospital, Ballymena, and The Department of Social and Preventive Medicine, The Queen's University, Belfast

A case is reported of a io-year-old boy with prolonged QT interval, syncopal attacks, and A V dissociation: a combination not previously described. Diagnosis and therapy are discussed.

Two heritable syndromes possibly genotypically On admission the patient appeared healthy, intelli- related and manifesting prolonged QT (or QU) gent, and of normal physique. Birthweight was 2-8 kg interval and TU wave changes, sinus bradycardia, after an uneventful pregnancy and confinement. Pre- syncopal attacks, ventricular arrhythmias, and fre- vious history and findings on systemic examination were sudden are respectively unremarkable. Pulse rate was 5S a minute; blood quently death, recognized pressure go/60 mmHg; and there was a minimal early with (Jervell and Lange-Nielsen, 1957) and with- apical systolic murmur. On x-ray the cardiac silhouette out (Romano, Gemme, and Pongiglione, I963; was normal and cardiothoracic index 0o45. Laboratory Ward, I964) profound childhood perceptive deaf- investigations including full blood examinations, ESR, ness. We report here a case seemingly of the latter serum electrolytes, serum magnesium, calcium and syndrome but with atrioventricular dissociation as phosphorus, and blood glucose, were all normal as was the dominant rhythm. Persistent supraventricular an electroencephalogram and audiogram. arrhythmias are only rarely documented in these The electrocardiogram was abnormal showing atrio- syndromes (James, I967), and moreover the present ventricular dissociation with intermittent ventricular http://heart.bmj.com/ case has other features that further warrant its capture and a characteristically variable prolongation of report. the QT interval (Fig. iA and B). Long runs showed ventricular and atrial rates as, respectively, 52 and 5i a minute. P waves were generally upright in all limb leads but were occasionally inverted in lead III following a Case report QRS complex, possibly indicating intermittent AV nodal dominance with retrograde atrial activation. The QT A 9-year-old boy was admitted to the Waveney Hospital, interval was in the range 048 to 0-54 sec (RR on 26 October a (QT.) Ballymena, 197I, after spell of uncon- interval = i-i5 sec); the 'normal' QT interval (QTc) for on September 26, 2021 by guest. Protected copyright. sciousness while playing in his garden the previous this ventricular rate is o038 sec, as calculated from re- afternoon. His mother (a nurse) found him pale, per- gression equation based on data from a random sample of spiring, and unconscious but with neither convulsive hearing schoolboys in Belfast (Fraser, Froggatt, and movements nor incontinence. His pulse was not pal- Murphy, i964b).' Subtraction gives (QTO- QTC)=o-Io pated. Recovery within 5 minutes was accompanied by to o i6 which is to 8 times the standard facial flushing but without pronounced residual symp- sec, 5 error of toms. There had been brief premonitory dizziness but QTC (=0-02 sec), a highly significant QT prolongation neither pain nor palpitations. Three months previously (P syncope due by a life-guard. He was unconscious for about 5 min- to ventricular tachyarrhythmia or asystole which have utes and subsequently disorientated for an equal period. been increasingly documented in these syndromes He also had, since December I970, minor episodes with (Jervell, 197I) even when the rate-related QT prolonga- pallor, epigastric discomfort, nausea, headache but no tion is less pronounced than here (Froggatt and James, loss of consciousness, pronounced face flushing during I973). recovery, and residual listlessness. The aetiology was unclear, but these episodes resembled in some ways the 1 QT0 =0.099+0.486 (RR) -0.231 (RR)' +0.0023 (age in ' minor' attacks previously described in these syndromes years). When RR > i.o sec, QT0 may be underestimated but (e.g. Fraser, Froggatt, and James, I964a; Jervell, 1971). to an unimportant extent. Br Heart J: first published as 10.1136/hrt.36.5.516 on 1 May 1974. Downloaded from

A V dissociation and prolonged QT interval 517

A AHII L A

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-- - C __ _-__ -r I;-_ 11 11 H III I'l III 11 I . I L II I I -I D e .--Mnm LI- 14 -Al- A I1,--I Ii .-

FIG. I (Paper speed is I sec=25 mm). A) Patient. Characteristic tracing (lead III) shows dominant A V dissociation. Long strip averaging gives: ventricular rate 52 a minute, atrial rate 5I a minute, QTo = o-48 sec, QT, = o038 sec, QTo- QTc = o-io sec (P < o-ooi - see text). P waves are upright in all limb leads (except aVR). B) Patient. Further strip (lead II) shows: QTo=0=54 sec; QTc=o038 sec; QTo- QT0=o-i6 sec (P

Sinus rhythm at 5i beats a minute (lead II). QTo = 0-47 sec; QT0 (Ljung's (z949) formula) = http://heart.bmj.com/ 0-41 sec; QTo- QT0 = oo6 sec (P < o-oI). D) Sister (aged i3). Sinus rhythm at 74 beats a minute andpronounced sinus arrhythmia (lead Vi). QTo = o045 sec; QT" = 0-36 sec; QTo- QT, = 0o09 sec (P < Ooo0I).

Family history a minute, with permanent capture of sinus rhythm on The patient is the third of 4 children (3F; iM) born to one record at a rate of I20 beats a minute (Fig. 2A). The healthy unrelated parents. Information covering kin- QT prolongation, however, increased (Fig. 2B), repli- on September 26, 2021 by guest. Protected copyright. ships up to the third degree gave no history of syncope, cating the (atypical) experience of, for example, Jervell fits, unexplained or untimely sudden death, or deafness. and Lange-Nielsen (1957) with adrenaline. Electrocardiograms of the first-degree relatives were No further syncopal attacks occurred and the patient normal for the father and one sister, but QT prolonga- was readmitted on 5 February I973 for reassessment. Saventrine was discontinued. After days' monitoring tion was pronounced in the mother (Fig. iC) and the 5 eldest sister (Fig. ID) and moderate in the youngest to establish basic patterns and exclude significant arrhythmias, a single bolus of o-6 mg atropine was given sister (QTO - QT =o0o5 sec: P = o-oi), the mother also having sinus bradycardia. intravenously. After 7 minutes, sinus rhythm was re- captured at 80 to go beats a minute and retained for go minutes before runs of AV dissociation recurred as the Therapy sinus rate slowed. QT prolongation also seemingly de- Long-acting oral isoprenaline hydrochloride (Saven- creased: pre-atropine control tracing gave QTo- QTC = trine) was started the day after admission since it in- 0- I2 sec (P < o-ooi) while the average for 7 to 30 minutes creases automaticity of the sinoatrial node, can raise the post-atropine tracings was o-o6 sec (P

5I8 Kernohan and Froggatt

- viewed in Froggatt and James, I973). Moreover, I 11 I 11 II one parent and two (of three) sibs show QT length- . A . I ening (though without syncope) consistent with A F I "111'r w I Mendelian 'dominant' inheritance as now clearly demonstrated for the Romano-Ward variant (Gale et al., 1970; van der Straaten and Bruins, I973). The AV dissociation is unlikely to be a chance concomitant. Sinus bradycardia (and sinus arrhyth- B mia) are common findings in the QT prolonga- F-T tion syndromes and the results here indicate that the AV dissociation, of the 'interference' or 're- fractory' type, is their electrophysiological sequel. On this hypothesis occasional supraventricular ectopic pacemaking would occur in these syndromes C ol and this has been documented as transient (James, Owllkkmm..4.,-o I967; Froggatt and Adgey, 1974) or, rarely, dominant patterns (James, I967) but with persistent FIG. 2 (Paper speed is I sec= 25 mm). A) Patient. retrograde atrial activation, as in the 'diving reflex' Sinus rhythm at 120 beats a minute 4 weeks after in normal subjects (Whayne and Killip, I967). The rhythm here described may be a rarer variant start of 'saventrine' (lead II). QTo = 0-38 sec; QTc= simply 0o30 sec, QTo-QTc=o-o8 sec (Pquinidine prolongs the QT interval; and practolol may block beneficial as well as unwanted adrenergic responses and in- tensify the bradycardia, thus predisposing to ven- reduced (QTo QTc = o0og sec for pre-drug control and tricular dysrhythmias (Han et al., i966a, b; Webb, o-o8 sec for post-drug tracing at 20 minutes). Adgey, and Pantridge, 1972). Furthermore, the The patient was discharged on oral atropine I-2 mg response to these drugs and to stellate ganglion block

6-hourly after further monitoring confirmed its effect. in QT prolongation syndromes has been inconsistent on September 26, 2021 by guest. Protected copyright. The electrocardiogram pattern persists (Fig. 2C) and (Jervell, I97I). Atropine fulfilled the therapeutic the patient remains well, follows full school regimen aims more than did without organized games, and has had no further attacks completely diphenylhydantoin of unconsciousness though the 'minor' unexplained and 'saventrine', has had no inconvenient side episodes continue. effects, and in this patient seems the drug of choice. The mechanism of the QT prolongation is un- Discussion known: imbalance of adrenergic influences on the myocardium is the current favoured theory (James, The patient seemingly manifests the heritable syn- I969). The frequent coexistent sinus bradycardia drome of QT prolongation without deafness (the may indicate a common neurogenic aetiology, Romano-Ward variant) with coexisting AV dissocia- especially if atropine has the rate-related QT inter- tion as the dominant rhythm, a combination not val shortening effect as the data here suggest. James previously described. The classical stigmata of the (I967) has theorized, on the basis of histopatho- syndrome are present: other known causes of QT logical findings in the sinus node and artery, a dis- prolongation are not (James, I969). The QT inter- turbance in sinus pacemaking with regular or irreg- val though not grossly prolonged is nevertheless ular escape mechanism and atrial premature beats significantly longer than in (a) 'normal' subjects and or arrhythnias which may trigger ventricular (b) many unequivocal cases of both of the QT pro- arrhythmias. The sinus node in this case is fully longation syndromes including some subjects with functioning and responsive which may explain the ventricular arrhythmias and/or sudden death (re- paucity of major syncopal episodes. Br Heart J: first published as 10.1136/hrt.36.5.516 on 1 May 1974. Downloaded from

AV dissociation and prolonged QT interval 59

Advice from Dr. Thomas N. James (University of Jervell, A., and Lange-Nielsen, F. (I957). Congenital deaf- Alabama) is gratefully acknowledged. mutism, functional heart disease with prolongation of the QT interval, and sudden death. American Heart Journal, 54, 59. References Linenthal, A. J., and Zoll, P. M. (I963). Prevention of ventricular tachycardia and fibrillation by intravenous isopro- Fraser, G. R., Froggatt, P., and James, T. N. (I964a). Con- terenol and epinephrine. Circulation, 27, 5. genital deafness associated with electrocardiographic Ljung, 0. (I949). A simple formula for clinical interpretation abnormalities, fainting attacks and sudden death. A re- of the QT interval. Acta Medica Scandinavica, 134, 79. cessive syndrome. Quarterly Journal of Medicine, 33, 36I. Ratshin, R. A., Hunt, D., Russell, R. O., and Rackley, C. E. Fraser, G. R., Froggatt, P., and Murphy, T. (I964b). Gen- (I97I). QT-interval prolongation, paroxysmal ventricular etical aspects of the cardlio-auditory syndrome of Jervell arrhythmias, and convulsive syncope. Annals of Internal and Lange-Nielsen (congenital deafness and electrocardio- Medicine, 75, 919. graphic abnormalities). Annals of Human Genetics, 28, I33. Romano, C., Gemme, G., and Pongiglione, R. (I963). Aritmie Froggatt, P., and Adgey, A. A. J. (I974). Clinical and thera- cardiache rare dell' eta pediatrica. II: Accessi sincopali per peutic observations on a two-year-old child with the fibrillazione ventricolare parosisstica. (Presentazione del cardio-auditory syndrome (QT interval prolongation and primo casa della letteratura pediatrica italiana.) Clinica congenital deafness) ascertained at birth. In preparation. Pediatrica (Bologna), 45, 656. Froggatt, P., and James, T. N. (I973). Sudden unexpected van der Straaten, P. J. C., and Bruins, C. L. D. (I973). A death in infants: evidence on a lethal cardiac arrhythmia. family with heritable electrocardiographic QT-prolonga- Ulster MedicalJournal, 42, I36. tion.Journal ofMedical Genetics, 30, I58. Gale, G. E., Bosman, C. K., Tucker, R. B. K., and Barlow, Ward, 0. C. (I964). A new familial cardiac syndrome in J. B. (I970). Hereditary prolongation of QT interval: children. J'ournal of the Irish Medical Association, 54, I03. study of two families. British Heart Journal, 32, 505. Webb, S. W., Adgey, A. A. J., and Pantridge, J. F. (1972). Autonomic disturbance at onset of acute myocardial in- Garza, L. A., Vick, R. L., Nora, J. J., and McNamara, D. G. farction. British MedicalJournal, 3, 89. (I970). Heritable Q-T prolongation without deafness. Whayne, T. F., and Killip, T. (I967). Simulated diving in Circulation, 41, 39. man: comparison of facial stimuli and response in Han, J., DeTraglia, J., Millet, D., and Moe, G. K. (I966a). arrhythmia. Journal of Applied Physiology, 22, 8oo. Incidence of ectopic beats as a function of basic rate in the ventricle. American HeartJournal, 72, 632. Addendum Han, J., Millet, D., Chizzonitti, B., and Moe, G. K. (I966b). Temporal dispersion of recovery of excitability in atrium Since preparation ofthis report, the patient (now on oral and ventricle as a function of heart rate. American Heart atropine) has had a third severe syncope, being discovered Journal, 71, 48I. unconscious, pale, and pulseless by his mother (a nurse). James, T. N. (I967). Congenital deafness and cardiac arrhy- Recovery followed the typical course. http://heart.bmj.com/ thmias. American Journal of Cardiology, 39, 627. James, T. N. (I969). QT prolongation and sudden death. Requests for reprints to Professor Peter Froggatt, Social Modern Concepts of Cardiovascular Disease, 38, 35. and Preventive Medicine Department, Institute of Clin- Jervell, A. (1971). Surdocardiac and related syndromes in ical Science, The Queen's University of Belfast, Gros- children. Advances in Internal Medicine, 17, 425. venor Road, Belfast BTI2 6BJ, Northern Ireland. on September 26, 2021 by guest. Protected copyright.