Pediatr Cardiol 11:216-218, 1990

Pediatric Cardiology 9 Springer-Verlag New York Inc. 1990

Junctional Ectopic Tachycardia with a Benign Course in a Premature Infant Marc Bolens and Beat Friedli Unit6 de Cardiologie P6diatrique, Clinique de P6diatrie, H6pital Cantonal Universitaire, Gen~ve, Switzerland

S U M M A R Y . The case of a premature baby with junctional ectopic tachycardia is described. The arrhythmia had an unusually benign course, contrary to what has been reported in the literature. Sinus rhythm was restored after 3 days of treatment with quinidine, and there has been no recurrence. K E Y WORDS: Junctional tachycardia - - Newborn - - Ectopic tachycardia

Junctional ectopic tachycardia is a rare arrhythmia. Its existence was first postulated by Coumel in 1975, before it had been clearly d o c u m e n t e d [1]. In 1987, K a c h a n e r [3] published a series of six cases followed in 1988 by an American multicenter study collecting 27 cases [4]. Both studies demonstrated that this is essentially a rhythm disorder of the newborn and infant, and both stressed the difficulty of treating it with conventional antiarrhythmic drugs. We present herein a case of junctional ectopic tachycardia in a premature infant who had an unusually benign course.

row, there was a left axis deviation of - 9 0 ~ suggesting left anterior hemiblock. T h e infant was treated with quinidine, at 15 mg/kg/day. Both the atrial and the ventricular rates slowed. At the ventricular rate at 166/min, the QRS was narrow and the tracing was now typical of junctional ectopic tachycardia with atrioventricular (AV) dissociation and captures (Fig. 2). OccasionaLly, there was retrograde c o n d u c t i o n to the atria. Forty-eight hours later, the child was extubated. At that time, the ECG showed a junctional r h y t h m with retrograde conduction (Fig. 3). Quinidine dosage was d e c r e a s e d to 10 m g / k g / d a y . On the third day of treatment,

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Case Report The baby was the result of a first p r e g n a n c y in a healthy m o t h e r with no gestational problems. At 28 w e e k s of pregnancy, however, it appeared that fetal growth had stopped and, at 32 weeks, fetal distress with tachycardia led to e m e r g e n c y cesarian section. At birth, the baby p r e s e n t e d with a p n e a and bradycardia and was intubated. At 18 h of life, he was transferred to our institution b e c a u s e of t a c h y c a r d i a at a rate of 200/min. O n admission, the child weighed 1430 g. T h e heart rate varied b e t w e e n 200 and 220 b e a t s / m i n ; there was no m u r m u r or signs of heart failure. T h e blood p r e s s u r e was 50/37. T h e first E C G s h o w e d a variable t a c h y c a r d i a at 170 to 230 b e a t s / m i n . The atrial rate was dissociated at 160/min. B e c a u s e of a wide QRS, ventricular tachycardia was at first s u s p e c t e d . The tacbycardia alternated with short periods o f sinus r h y t h m ; following t h e s e periods, the beginning of tachycardia was characterized by decreasing cycle length, a w a r m - u p p h e n o m e n o n characteristic of an ectopic focus (Fig. 1). During this w a r m up, the QRS widened into a left bundle branch configuration. W h e n the QRS was nar-

Address offprint requests to." P r o f e s s o r B. Friedli, Hopital Cantonal Universitaire, Clinique de P6diatrie, 30, boulevard de la Cluse, 1205 G e n e v e , Switzerland.

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Fig. 1. First electrocardiogram showing intermittent tachycardia with a ventricular rate of 230/min and atrioventricular dissociation with an atrial rate of 160. The onset of tachycardia, marked by vertical bars, s h o w s progressive shortening of the R-R interval (i.e., a w a r m - u p p h e n o m e n o n ) . As the rate b e c o m e s faster, the QRS widens into a left bundle branch block pattern.

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