- Junctional rhythm
Junctional rhythm is an abnormal heart rhythm, where the AV node initiates electrical activity in the heart [ eMedicine: "Junctional Rhythms" http://www.emedicine.com/MED/topic1212.htm ] . This pathway does allow the atria to contract before the ventricles, however, this occurs via retrograde conduction [ medical dictionary http://medical-dictionary.thefreedictionary.com/retrograde+conduction] . An EKG exhibiting Junctional rhythm commonly presents with an inverted "P" wave (see
EKG ) due AV nodal origin of electrical signal [ Abnormalities in the ECG measurement http://library.med.utah.edu/kw/ecg/ecg_outline/Lesson4/index.html#PRinterval ]In contrast, in normal conditions,
sinus rhythm initiates in theSinus node and activates the atria then progresses into theHIS bundle , down to thePurkinje fibers and up the ventricle. This results in the atria contracting before the ventricles.
References
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