Junctional Tachycardia
نویسنده
چکیده
IN THE ABSENCE of functioning anomalous connection between atria and ventricles, the A-V junction serves as the only link between these structures, allowing the atrial impulse to be transmitted to the ventricles. The A-V junction may be defined as consisting of the atrial approaches to the A-V node, the A-V node itself, and the penetrating portion of the His bundle. Total transection of the A-V junction at any point should produce A-V block, and stimulation in the presence of a normal His-Purkinje system should produce a narrow QRS. The electrophysiologic function of the A-V junction is primarily that of conduction. However, in addition, the A-V junction possesses intrinsic automaticity, allowing it to serve as a subsidiary pacemaker in the event of failure of proximal impulse formation or propagation. Under pathologic conditions, the A-V junction can serve as an ectopic pacemaker, or as a site of reentry.
منابع مشابه
Clinical and electrophysiologic characterization of automatic junctional tachycardia in adults.
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 ...
متن کاملPatients with two types of atrioventricular junctional (AV nodal) reentrant tachycardia. Evidence that a common pathway of nodal tissue is not present above the reentrant circuit.
BACKGROUND The site of the reentrant circuit in atrioventricular (AV) junctional reentrant tachycardia has not been defined; in particular, the existence of a common pathway of AV nodal tissue above the reentrant circuit is controversial. METHODS AND RESULTS Two types of AV junctional reentrant tachycardia were induced in each of three patients at electrophysiological study. In one type of ta...
متن کاملSlow pathway modification for atrioventricular node re-entrant tachycardia: fast junctional tachycardia predicts adverse prognosis.
OBJECTIVE To examine the cycle length of the junctional tachycardia often seen during successful slow pathway ablation for atrioventricular (AV) node re-entrant tachycardia, to determine whether shorter cycle lengths predict imminent atrioventricular block. DESIGN Retrospective analysis of consecutive patients undergoing slow pathway modification. Intracardiac recordings were analysed after d...
متن کاملProphylactic amiodarone reduces junctional ectopic tachycardia after tetralogy of Fallot repair.
OBJECTIVE Junctional ectopic tachycardia is common after pediatric heart surgery. After tetralogy of Fallot repair, the incidence of junctional ectopic tachycardia may be as high as 15% to 20%. We introduced prophylactic amiodarone for tetralogy repair. This study was conducted to evaluate the effectiveness of the prophylactic amiodarone. METHODS A continuous infusion of amiodarone was starte...
متن کاملABC of clinical electrocardiography. Junctional tachycardias.
Any tachyarrhythmia arising from the atria or the atrioventricular junction is a supraventricular tachycardia. In clinical practice, however, the term supraventricular tachycardia is reserved for atrial tachycardias and arrhythmias arising from the region of the atrioventricular junction as a result of a re-entry mechanism (junctional tachycardias). The most common junctional tachycardias are a...
متن کاملAbsence of junctional rhythm during successful slow-pathway ablation in patients with atrioventricular nodal reentrant tachycardia.
BACKGROUND The presence of junctional rhythm has been considered to be a sensitive marker of successful slow-pathway ablation. However, in rare cases, junctional rhythm was absent despite multiple radiofrequency applications delivered over a large area in the Koch's triangle, and successful ablation was achieved in the absence of a junctional rhythm. METHODS AND RESULTS This study included 35...
متن کامل