|Variation Of The Coronary Arteries|
Failure to distinguish between normal and anomalous structures may lead to misinterpretations and disastrous complications during heart surgery.
Normal coronary anatomy means structures that are habitually observed.
Anomaly is used for variation that occurs in less than 1 % in the general population.
Variation is the term used with a frequency over 1 %.
I ] Variation in the origin of the coronary orifices
A) Angle of origin
B) Situation of the coronary orifice
2) Frontal plane, the position of the orifice is described
in relation to the Sino tubular junction.
High origin of left coronary orifice is associated with long left coronary artery and at greater risk of injury either due to low clamping of aorta or due to incision of the aortic wall during valvular replacement.
Most frequent position of orifice is at the Sino tubular junction or below the junction ( 56% ), followed by high left orifice and a low right orifice or at junction ( 30 %).
C) Number of coronary orifices
1) Multiple orifices with right coronary sinus
2) Multiple orifices in the left aortic sinus
3) Multiple orifices in both aortic sinuses.
II] Variations in length and distribution of coronary
a) Common Trunk of Left Coronary Artery
Some authors reported existence of short common trunk and the risk factor for the development of coronary atherosclerosis or as a cause of blockage in the left branch of Bundle of His.
b) Trifurcation into LAD, Ramus and Circumflex artery of the left main is known between 25 to 40 %
2) Ramus (Median) artery is one in which
Bifurcation of the LAD: - Give rise to 2 arteries which are defined as long and short depending on the length. Bifurcation of the LAD should be distinguished from cases of voluminous diagonal arteries, which course parallel to the LAD. Look for septals and whether it comes to A-V groove distally to differentiate between bifurcating LAD and large diagonal.
4) Circumflex artery
5) Right Coronary Artery
The point of termination of the circumflex and the right
coronary artery in relation to the crux has been used to establish coronary
III] Variation in the route of coronary arteries
Myocardial Bridge was first described by Reyman (1737)
and called as coronary mural or the submerged artery.
Occasionally coronary arteries are intracavitatory.
IV] Variation in the origin of Sino-Atrial nodal
V] Variation in Atrio- ventricular node artery.