Left anterior descending artery
Ramus interventricularis anterior arteriae coronariae sinistrae
Also known as: LAD, anterior interventricular artery, widow-maker
The left anterior descending (LAD) artery is the anterior interventricular branch of the left coronary artery. It runs down the anterior interventricular groove to the apex and often around it, supplying the anterior left ventricular wall, the apex and the anterior two-thirds of the septum. It is the coronary artery most often occluded.
Overview
The LAD descends in the anterior interventricular sulcus beside the great cardiac vein. In most hearts it wraps around the apex and supplies the apical part of the inferior wall as well.
Diagonal branches (D1, D2 and so on) run over the anterolateral left ventricular wall and help supply the anterolateral papillary muscle. Septal perforators dive into the anterior two-thirds of the interventricular septum and supply the bundle of His, the right bundle branch and the left anterior fascicle.
The LAD territory is the largest single region of left ventricular myocardium. Proximal LAD occlusion is therefore nicknamed the "widow-maker".
Anatomy
- Course
It runs from the bifurcation of the left main stem down the anterior interventricular sulcus to the apex, and usually turns around the apex into the posterior interventricular sulcus.
- Branches
Diagonal branches (to the anterolateral LV wall), septal perforators (to the anterior two-thirds of the septum and the conduction tissue), small right ventricular branches, the left conus artery and apical branches.
Function
- Supplies the anterior LV wall, the anterior two-thirds of the septum and the apex.
- Supplies the bundle of His, the right bundle branch and the left anterior fascicle.
- Shares the supply of the anterolateral papillary muscle with the circumflex.
Clinical significance
Anterior STEMI
LAD occlusion causes ST elevation in V1–V4 (septal leads V1–V2). Because so much muscle is lost, it carries the worst prognosis of the coronary territories. Complications include heart failure and cardiogenic shock, new bundle branch block or Mobitz II and complete heart block (infranodal), LV aneurysm and apical thrombus.
LIMA-to-LAD bypass
In bypass surgery, the left internal thoracic (mammary) artery is anastomosed to the LAD. This graft remains open in more than 90% of patients at 10 years and improves survival.
Wellens syndrome
Deep or biphasic T waves in V2–V3 in a patient whose chest pain has settled indicate a critical proximal LAD stenosis. The patient needs urgent angiography, and stress testing must be avoided.
Compiled from standard anatomy and physiology references — see the Cardiovascular System sources. For education only; not medical advice.