I'm new on medical science and I learned from my teachers that there are 4 specialized myocardium conducts on the right atrium that make the internodal conduction. I did an fast review on literature and realized that maybe this explanation was wrong and it is a old fashion way to explain the conduction.
So, I turn my question to more specialized scientists on the field, what do you think? There is these 4 conduction pathways or they are only differentiated due to the myocardium tissue which is naturally separated by the veins and anatomic structures of the right atrium?
Thanks all...
(PS. My college textbook is Latarjet & Liard and they didn't define these 4 pathways. I think Moore neither)
Hi Davison, among the primitive ventricles, is a ring of specialized myocardium that serves as the starting point for the ventricular conduction system. In the course of circling and annotation, the main ring joins forces and bundles to its branches, the retroaortic root branch, and the right atrioventricular ring bundle to create the AV conduction system, the latter two of which are lost during normal development.
That being said, operations affecting the interatrial septum can damage these pathways, resulting in a loss of interatrial rhythm in the heart. You need to also remember that surgical excision of left atrial myxomas at an unusual position, like near the sinus node, can cause injury to the sinus node and the Bachmann's bundle in certain cases. This lead in aberrant impulses originating from nonsinus node sites in the right and left atrium, can also result in arrhythmias such as atrial tachycardia and atrial flutter/fibrillation. You'll need to pay close attention to the location and architecture of cardiac tumors when conducting any surgical procedure in order to prevent damaging these electrical conduction channels while performing any surgical procedure. I would recommend to conduct an ECG to identify conduction delays and monitor for arrhythmias, so you can diagnose necessary measures to follow during and after the recovery period.
Dr. D Mourise
M.D.
Hello Dinah Mourise, thanks for you reply! It is very clarifier indeed. I'm just a young guy on the heart science to figure out how the nodular development takes place! I'll study it further more .
I can imagine how careful incisions on interatrial septum should be. But my point is, is there a way to physically distinguish the electrical connection between sinoatrial and atriovascular nodule?
There are none. The internodal tracts, posterior, middle, and superior were described at a time when we had very little understanding of the conduction system of the heart. They even had names like Thorel's and Wenckebach's bundles.
The reason tracts were thought to exist in the first place was based on the history of the discovery of the conduction system. Purkinje fibers were first described in the mid-1800s and, by tracking their course back toward to atria, led to the discovery of the AV node. Keith and Flack are credited with the discovery of the sinus node, finally in 1906.
Thus the conduction system's description unfolded in the reverse order. Because the Purkinje fibers represented the connection(s) between the AV node and the ventricles, people surmised there must be similar connection(s) between the sinus node and the AV node. This has been studied extensively throughout the 20th century but no one has found any histologic evidence of internodal tracts. That said, it is astonishing that the internodal tracts somehow continue to appear in modern literature. The best explanation for how the sinus impulse propagates through the right atrium is to recognize it simply dodges a few large holes: the SVC, the IVC, the coronary sinus, and the fossa ovalis. What's between the holes represents the 3 avenues of internodal access.
The internodal tracts are dead and should be buried. Their last breath was when the topic of "sinoventricular conduction" appeared in the literature. Ignore that too.
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