Left anterior descending artery

The left anterior descending (LAD) artery, also known as the anterior interventricular branch, is one of the two branches of the left coronary artery (the other branch being the circumflex (Cx) artery).

It descends along the interventricular groove.

It can be divided into proximal, mid and distal segments and this helps to differentiate the names of its various small branches 1:

  • origin: left coronary artery
  • branches 4
    • septal perforators: course to the right towards the septum on axial CTCA
    • diagonal branches: course to the left on the anterolateral wall of the left ventricle on axial CTCA
  • segments
    • proximal: from the origin to the first diagonal branch (D1) (although some authors use the first septal perforator (S1) as the landmark)
    • mid: from the origin of D1 to half the distance from the D1 origin to the apex
    • distal: distal to half the distance from the D1 origin to the apex

The LAD should arise from the left coronary cusp which lies between 3 and 6 o'clock on an axial view.

The length of the LAD can be highly variable. On angiography, it may be reported as types I-III:

  • type I: short vessel (can terminate before apex)
  • type II: intermediate vessel
  • type III: long wrap-around vessel (around the apex)

The LAD lies in the epicardial fat within the anterior interventricular septum 1

The LAD supplies the anterolateral myocardium and apex with one of its branches supplying the anterior two-thirds of the interventricular septum. 

  • dual left anterior descending coronary artery2:  two left anterior descending coronary arteries (one usually shorter in length) that are both situated in the anterior interventricular groove
    • it is important to know of this variation when planning surgical vascularization 3
  • the mid 1/3rd of the LAD is known on occasion to course through the myocardium, known as myocardial bridging; does not have any clinical significance
  • occlusion of LAD leading to myocardial infarction or sudden cardiac death
    • the LAD is the most commonly occluded of the coronary arteries
    • it provides the major blood supply to the interventricular septum, and bundle branches of the conducting system
    • blockage of this artery can lead to impairment or death (infarction) of the conducting system
  • Wellens syndrome
    • represents subacute occlusion of the LAD
  • de Winter's T wave pattern
    • indicates acute occlusion of the proximal LAD
Anatomy: Thoracic

Anatomy: Thoracic

Article information

rID: 35317
System: Cardiac, Vascular
Section: Anatomy
Synonyms or Alternate Spellings:
  • LAD
  • LAD artery
  • Left anterior descending artery (LAD)

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Cases and figures

  • Figure 1: coronary arteries (creative commons illustration)
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  • Case 1: normal coronary angiogram (DSA)
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  • Figure 2: LV myocardial segmentation and coronary artery territories
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  • Case 2: normal CTCA
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  • Figure 3: LV myocardial segments (diagram)
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