Junctional ectopic tachycardia evolving into complete heart block

Abstract

Transition from congenital junctional ectopic tachycardia to complete AV block was observed in an 8 month old girl, over a 36 hour period, during initial hospital admission. Two years later she had evidence of a rapidly increasing left ventricular end diastolic diameter, associated with lowest heart rates during sleep of < 30 beats/min. A transvenous permanent pacemaker was therefore implanted. This finding supports the idea that a pathological process in the area of the AV junction, initially presenting as junctional ectopic tachycardia may later extend to sudden complete atrioventricular block.

Figure 1

12 lead ECG demonstrating a regular, narrow QRS tachycardia with AV dissociation.

Figure 2

12 lead ECG 36 hours later, demonstrating resolution of tachyarrhythmia with persistence of AV dissociation and narrow QRS complexes.