Premature junctional complexes (PJCs)
Premature junctional complexes (PJCs) are premature depolarizations from the AV node or the proximal portion of the His-Purkinje system (more common). PJCs most often occur in the absence of structural heart disease but may occur also in clinical settings similar to those surrounding PACs.
Depolarization usually arises from the His-Purkinje system and can be triggered by alcohol ingestion, tobacco, or adrenergic stimulants. AV junctional complexes are less common than either atrial or ventricular premature complexes and are more often associated with cardiac disease or digitalis intoxication.
They usually do not lead to symptoms. In some they can lead to palpitations and on rare occasions, cannon a waves (synchronous contraction of both atria and ventricles). Cannon a waves can lead to distressing pulsations in the neck.
PJCs typically result in a premature, normally conducted QRS. It can be recognized by absence of the P wave preceding the QRS complex. With intact retrograde AV nodal conduction, an inverted P wave will occur during or just after the inscription of the QRS. The next, normally timed sinus P wave may experience delay or block in the AV node, owing to retrograde conduction of the PJC.
If symptomatic, therapy should be directed toward correction of underlying abnormalities. Beta-adrenergic antagonists or calcium channel antagonists may be useful.
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