Conduction system in the swine heart: essential landmarks for gross dissection
Mingsakul, ThawornSurachon, PreeyapornSomana, Reon
Background: The components of the cardiac conduction system (CCS) were discovered almost two centuries and presentedin the diagrammatic forms. This should be due to the diffi culty in distinguishing the CCS from the surrounding cardiactissues and the lack of information concerning the precise landmarks for gross dissection. Furthermore the CCS in pig,the animal regarded as a suitable model for the assessment of catheter based intervention, has not been reported. The aimsof the present study were to demonstrate the gross anatomic architecture of CCS in the swine heart, and to provide thevaluable landmarks for the gross anatomic dissection of the CCS.Materials, Methods & Results: Twenty hearts of adult Large White pigs (Sus Scrofa domesticus) were used. Fifteen heartswere elucidated by gross anatomic dissection. The tissue blocks of the sinoatrial node (SAN) and atrioventricular conduction tissue of the fi ve hearts were prepared for histological investigation by staining with Massons trichrome. It was foundhistologically that the cardiac conduction tissues were clearly distinguishable from the surrounding cardiac myocardiumand connective tissue. Moreover, the histological information also navigated the location and anatomical architecture ofthe CCS which provided essential guideline for gross dissection. The SAN was somewhat spindle in shape which embedded in epicardial connective tissue of the terminal sulcus. In some cases, it was quite diffi cult to identifythe SAN, so thesinoatrial node artery was used as a clue. The AVN was an elliptical shaped which situated in subendocardial tissue atapex of the triangle of Koch on the atrial surface of the central fi brous body. The distal extremity of the AVN extended intothe central fi brous body to form the penetrating bundle of His. At the boundary between the membranous and muscularparts of the interventricular septum, the AV bundle of His divided into the right...(AU)
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