Junctional rhythm is an abnormal heart rhythm, where the AV node initiates electrical activity in the heart [1]. This pathway does allow the atria to contract before the ventricles, however, this occurs via retrograde conduction [2]. An EKG exhibiting Junctional rhythm commonly presents with an inverted "P" wave (see EKG) due AV nodal origin of electrical signal [3]
In contrast, in normal conditions, sinus rhythm initiates in the Sinus node and activates the atria then progresses into the HIS bundle, down to the Purkinje fibers and up the ventricle. Sinus rhythm is a term used in medicine to describe the normal beating of the heart as measured by an Electrocardiogram ( ECG) The Sinoatrial node (abbreviated SA node or SAN, also called the sinus node) is the impulse generating (pacemaker tissue located in the Right atrium The bundle of His, also known as the AV bundle or atrioventricular bundle is a collection of heart muscle cells specialized for electrical conduction that transmits the electrical For the nervous cells see Purkinje cell Purkinje fibers (or Purkyne tissue are located in the inner ventricular walls of the Heart, just This results in the atria contracting before the ventricles.
References
- ^ eMedicine: "Junctional Rhythms" http://www.emedicine.com/MED/topic1212.htm
- ^ medical dictionary http://medical-dictionary.thefreedictionary.com/retrograde+conduction
- ^ Abnormalities in the ECG measurement http://library.med.utah.edu/kw/ecg/ecg_outline/Lesson4/index.html#PRinterval
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