Characterization of Junctional Rhythm After Atrioventricular Node Ablation

Abstract

Radiofrequency ablation of the AV node is associated with development of a JER that is stable in the long-term setting. The lack of change in HV interval after ablation locates the junctional pacemaker proximal to the central fibrous body. The pattern of drug responses suggests an origin within the proximal His bundle at its junction with the AV node rather than the AV node itself. The overall similarity between short- and long-term characteristics of junctional pacemaker activity mitigates against any reversible thermal effects of RFC on this pacemaker focus.

Anatomic Localization and Autonomic Modulation of Atrioventricular Junctional Rhythm in Failing Human Hearts

“…Our observations in this study support the clinical observation of the existence of multiple pacemakers in the AVJ and their sensitivities to adrenergic and cholinergic agents. 5, 8, 18 Clinically, conduction in the AVJ is often thought of in terms of fast and slow pathway conduction. Conduction velocity is a function of both the ionic currents that create the action potential as well as the connexin proteins which compose the electrical synapses (gap junctions) between myocytes.…”

“…5–8 Microelectrode recordings from the rabbit AVJ have revealed several different cell types (transitional atrial-nodal [AN], compact nodal [N], and lower nodal-His [NH] regions) based on action potential morphology, which are functionally different from those recorded in typical atrial and His bundle cells. 9, 10 Moreover, cells of the AN, NH, and His regions of the AVJ exhibit independent pacemaker activity.…”

Pharmacological and Electrophysiological Characterization of Junctional Rhythm During Radiofrequency Catheter Ablation of the Atrioventricular Node. Possible Involvement of Neurotransmitters From Autonomic Nervous System.

“…[1][2][3][4][5][6][7][8][9] The following hypotheses have been proposed for the mechanism of accelerated junctional automaticity.…”

Arrhythmias in Children and Young Adults

“…The junctional pacemaker can exist in the region of the distal AV node or the proximal portion of the His-bundle near the AV-node (Alison et al 1995). Nodal escape rhythm is associated with apnea (Valimaki and Tarlo 1971).…”

“…Nodal escape rhythm is associated with apnea (Valimaki and Tarlo 1971). The rate of AV junctional escape rhythm varies with underlying conditions, such as sick sinus syndrome, complete heart block, ablation of AV node, congenital heart surgery, hypertrophic cardiomyopathy, and ischemia (Kleinfeld and Boal 1978;Alison et al 1995;Shepard et al 1998). Inflammation, hypoxia, metabolic, drugs, or electrolyte disturbances are implicated in the etiology of junctional rhythms (Fisch and Knoebel 1970).…”