A dual left anterior descending coronary arteries are a group of rare variants of the left anterior descending artery. Almost all dual variants have short and long LAD branches.
Subtypes
Several (up to 11) subtypes have been described including the 4 initial types originally described by Spindola-Franco and colleagues 1.
These include
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type I:
considered commonest
both left-main and LAD proper present
short LAD originates from the LAD proper and terminates in the proximal anterior interventricular sulcus
long LAD originates from the LAD proper, courses on the LV side of the proximal anterior interventricular sulcus and reenters the distal anterior interventricular sulcus
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type II:
both left-main and LAD proper present
short LAD originates from the LAD proper and terminates in the proximal anterior interventricular sulcus
long LAD originates from the LAD proper, courses on the RV side of the proximal anterior interventricular sulcus and reenters the distal anterior interventricular sulcus
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type III:
both left-main and LAD proper present
short LAD originates from the LAD proper and terminates in the proximal anterior interventricular sulcus
long LAD originates from the LAD proper, follows an intramyocardial course in the septum proximally, emerges epicardially in the distal anterior interventricular sulcus (or does not emerge in the anterior interventricular sulcus and terminated, intramyocardially)
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type IV:
left-main present but LAD proper absent
short LAD originates from the LAD proper and terminates in the proximal anterior interventricular sulcus
long LAD originates from the proximal right coronary artery (RCA), follows an anomalous pre-pulmonic course anterior to the RVOT, and enters the distal anterior interventricular sulcus
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type V:
both left-main and LAD proper absent
short LAD originates from the left coronary sulcus, terminates in the proximal anterior interventricular sulcus
long LAD originates from the proximal right coronary sulcus, follows an anomalous intramyocardial course within the septal crest, emerges epicardially, and enters the distal anterior interventricular sulcus
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type VI:
left-main present but LAD proper absent
short LAD originates from the left main and terminates in the proximal anterior interventricular sulcus
long LAD originates from proximal RCA, follows an anomalous course between the RVOT and the aortic root, and enters the distal anterior interventricular sulcus
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type VII:
both left-main and LAD proper present
left-main originates from the right coronary sulcus and shows an inter-arterial malignant course
short LAD originates from the LAD proper, terminates in the proximal anterior interventricular sulcus
long LAD originates from the LAD proper, courses on the LV side of the proximal anterior interventricular sulcus, and reenters the distal anterior interventricular sulcus
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type VIII:
left-main present but LAD proper absent
left-main originates from the right coronary sulcus and shows a retro-aortic course
short LAD originates from the left main and terminates in the proximal anterior interventricular sulcus
long LAD originates from the mid-RCA, courses inferior wall surface of the RV, then turns around the apex, and reaches the distal anterior interventricular sulcus
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type IX: (triple LAD)
both left-main and LAD proper present
short LAD originates from the LAD proper, terminates in the mid-anterior interventricular sulcus
long LAD originates from the LAD proper, courses on the LV side of the mid anterior interventricular sulcus, reenters the distal anterior interventricular sulcus and terminates before reaching the apex
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type X: 6
long LAD and right coronary artery (RCA) originating from the right coronary sinus with different ostia
short LAD originates from the left main coronary artery (LMCA) and terminates in the proximal anterior interventricular sulcus.
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type XI: 7
short and long LAD arteries share a common ostium with the right coronary artery from the right coronary sinus 6