Heart 1998;80:627–628 627

CASE REPORT Heart: first published as 10.1136/hrt.80.6.627 on 1 December 1998. Downloaded from

Junctional ectopic evolving into complete

Department of H Henneveld, P Hutter, M Bink-Boelkens, N Sreeram Cardiology, Wilhelmina Children’s Hospital, Utrecht, Netherlands H Henneveld Abstract extend to sudden complete atrioventricu- P Hutter Transition from congenital junctional lar block. N Sreeram ectopic tachycardia to complete AV block (Heart 1998;80:627–628) was observed in an 8 month old girl, over Department of Keywords: junctional ectopic tachycardia; heart block; Cardiology, Academic a 36 hour period, during initial hospital congenital heart disease; paediatrics Hospital Groningen, admission. Two years later she had Netherlands evidence of a rapidly increasing left M Bink-Boelkens ventricular end diastolic diameter, Junctional ectopic tachycardia (JET) is one of Correspondence to: associated with lowest heart rates during the rarest forms of supraventricular tachycardia Dr N Sreeram, Department sleep of < 30 beats/min. A transvenous of Cardiology, Wilhelmina in infancy. The mechanisms of termination of Children’s Hospital, ABC permanent pacemaker was therefore the congenital form of JET are unclear from Straat, 3501 CA Utrecht, implanted. This finding supports the idea most clinical series.12Histological studies have Netherlands. that a pathological process in the area of shown His bundle degeneration and Purkinje 3 Accepted for publication the AV junction, initially presenting as cell tumours as well as fibroelastosis. Progres- 16 March 1998 junctional ectopic tachycardia may later sion to complete has been proposed,3 but has not been described in the clinical setting. We present a girl who pre- sented with JET at the age of 8 months who went into complete AV block during hospital admission 36 hours later. http://heart.bmj.com/

Case report An 8 month old girl presented to her local hos- pital after a period of crying, apnoea, and cyanosis at home. After stimulation she had

recovered fully but at the hospital tachycardia on September 26, 2021 by guest. Protected copyright. was noted at a frequency of 230 beats/min. The ECG at admission showed a regular, narrow QRS complex tachycardia with AV dissociation consistent with the diagnosis JET (fig 1). Echo- Figure 1 12 lead ECG demonstrating a regular, narrow QRS tachycardia with AV cardiography showed an anatomically normal dissociation. heart with decreased contractility (shortening fraction 15%) and left ventricular dilatation, suggesting longstanding tachycardia. Intrave- nous adenosine was ineVective, and digoxin was started (10 µg/kg at 8 hourly intervals). Thirty six hours later she exhibited complete AV dissociation with QRS rate of 100 beats/min (fig 2), and was discharged from hospital. At follow up ventricular function had normalised within three months (shortening fraction 38%). Two years later digoxin was discontinued. Routine Holter recordings at follow up showed no episodes of tachyarrhythmia and she was asymptomatic. At the age of 2 years and 8 months, she had evidence of a rapidly increas- ing left ventricular end diastolic diameter, asso- ciated with lowest heart rates during sleep of Figure 2 12 lead ECG 36 hours later, demonstrating resolution of tachyarrhythmia with < 30 beats/min. A transvenous permanent persistence of AV dissociation and narrow QRS complexes. pacemaker was therefore implanted. 628 Henneveld, Hutter, Bink-Boelkens, et al

Discussion patients in whom the tachycardia was satis- 1 Congenital JET is a rare form of supraventricu- factorily controlled with medications. In most Heart: first published as 10.1136/hrt.80.6.627 on 1 December 1998. Downloaded from lar tachycardia with an obscure aetiology. An patients in whom medical treatment was association with late onset AV block has been successful, normal AV conduction was re- postulated, and degeneration of the His bundle established, with intermittent episodes of JET with fibroelastosis, as well as His-Purkinje cell occurring when the sinus rate decreased. The tumours have been demonstrated by histology 3 clinical course in our patient supports an in patients with JET who died suddenly. The ongoing pathological process in the region of outcome is generally poor. Villain et al showed the His bundle presenting as JET and finally that congenital JET is associated with a high resulting in permanent loss of AV conduction. incidence of congestive and high mortality, (sometimes despite adequate medi- 1 cal control). The results of conventional drug 1 Villain E, Vetter VL, Garcia JM, et al. Evolving concepts in treatment have been unsatisfactory, with JET the management of congenital junctional ectopic tachycar- dia. Circulation 1990;81:1544–9. continuing at slower rates in most patients 2 Ludomirsky A, Garson A. Supraventricular tachycardia. In: receiving antiarrhythmic medication. In refrac- Garson A, Bricker JT, McNamara DG, eds. The science and tory cases, His bundle ablation and permanent practice of pediatric cardiology. Philadelphia: Lea & Febiger, 1990:1809–48. pacemaker implantation have been proposed, 3 Rossi L, PiVer R, Turolla E, et al. Multifocal Purkinje-like but these procedures have also been associated tumor of the heart. Occurrence with other anatomic 1 abnormalities in the atrioventricular junction of an infant with deaths. Late AV block has been postu- with junctional tachycardia, Lown-Ganong-Levine syn- lated as a cause of sudden death in some drome, and sudden death. Chest 1985;87:340–5. http://heart.bmj.com/ on September 26, 2021 by guest. Protected copyright.