Clinical and electrophysiologic characterization of automatic junctional tachycardia in adults.

Abstract

Junctional ectopic tachycardia has been described in infants but not in adults. Five adults with rapid symptomatic paroxysmal junctional tachycardia, distinct from the more common slower nonparoxysmal junctional tachycardia, were recently evaluated. The tachycardia was irregular (rate 120 to 250) and accompanied by periods of atrioventricular dissociation and narrow QRS complexes. A junctional origin was documented during electrophysiologic study in four of the five patients. Analysis of Holter recordings; the response to exercise, isoproterenol, and propranolol; and the effects of atrial and ventricular stimulation appeared to implicate abnormal automaticity of a high junctional focus that was catecholamine sensitive or dependent as the tachycardia mechanism. All patients responded somewhat to /3-blockers, although a combination of procainamide and propranolol proved to be the most effective therapy in one patient and another chose electrode catheter ablation of the atrioventricular junction rather than continued drug therapy. Thus, junctional ectopic tachycardia may occur in adults and its mechanism appears to be related to abnormal automaticity that is catecholamine sensitive or dependent. Initial therapy should include fl-blockers but selected patients may require more aggressive management.Circulation 73, No. 5, 930-937, 1986.

Incessant Automatic Ventricular Tachycardia Complicating Acute Coxsackie B Myocarditis

“…Our observations on this rare case of ven tricular tachycardia accord with those de scribed for automatic tachycardias originat ing from elsewhere in the heart, namely ec topic atrial tachycardia [13] and automatic junctional tachycardia [14,15]. This report adds to the rare clinical literature on auto matic ventricular arrhythmias.…”

Evidence for the presence of electrotonic depression of pacemakers in the rabbit atrioventricular node. The effects of uncoupling from the surrounding myocardium

“…In the case of impaired electrical cell coupling, a rapid junctional rhythm may develop and control ventricular rate. These arrhythmias have been reported by several investigators (7,34,36). Another situation in which uncoupling of the nodal fibers occurs is during digitalis intoxication, often resulting in junctional tachycardias in which both atria and ventricle are controlled by the junctional pacemaker, eventually complicated by conduction block (7).…”

“…However, non-reentrant AV nodal tachycardias (presumably not caused by sympathetic stimulation) having a higher frequency than sinus rhythm are reported from several recent in vivo (9,15,(34)(35)(36) and in vitro studies (44). This indicates that junctional pacemaker fibers are, under certain conditions, capable of impulse formation at higher rates than sinus rhythm.…”

Evolving concepts in the management of congenital junctional ectopic tachycardia. A multicenter study.

“…JET was defined electrocardiographically as an incessant tachycardia with normal QRS morphology and atrioventricular (AV) dissociation. The ventricular rate ranged from 140 to 370 beats/min (mean, 230 beats/min); 16 …”