The term premature junctional contraction refers to any ventricle contraction that occurs as the result of any junctional pacemaker site. Premature Junctional Contractions (PJCs) are a common cause of Sinus Arrythmia. Occasional PJCs are common occurences in otherwise healthy patients, however, if they occur too frequently, they can lead to Junctional Tachycardia or identify another underlying pathology.
Premature Junctional Contractions may occure as a single event or a set of PJCs. A set of two PJCs is refered to as Junctional Bigeminy, where as PJCs of three and four are refered to as Junctional Trigeminy and Quadrigeminy.
Premature Junctional Contractions ECG
Heart Rate: normal (usually between 60-100 per minutes), but may be accelerated.
Rhythm: irregular when PJCs are present.
Pacemaker Site: fundamentally SA node, but AV junction when PJCs occur.
P-waves: usually normal.
QRS complex: Normal.
PR Interval: Normal – 0.12-0.20 seconds in duration, but may vary between depending on when the PJCs depolarize, may appear shorter in duration.
Premature Junctional Contractions Signs and Symptoms
People who have premature atrial contractions usually are asymptomatic. If the condition is particularly exacerbated (by excess caffeine intake or stimulants) the patient may feel minor palpitations.