Which regions of the heart are supplied by the left anterior descending (LAD) artery?

LAD Artery Cardiac Muscle Distribution

The left anterior descending (LAD) artery supplies the anterolateral wall of the left ventricle and the interventricular septum through its diagonal and septal perforator branches, respectively. 1

Primary Territories Supplied

Anterolateral Wall of Left Ventricle

• The diagonal branches (first, second, and third) originating from the LAD supply the anterolateral wall of the left ventricle. 1
• These are the three longest branches arising from the LAD artery 1

Interventricular Septum

• The anterior descending septal perforator vessels originating from the LAD supply the interventricular septum. 1
• These septal branches are critical for septal perfusion 1

Anterior Wall Territories

• Proximal LAD occlusion (above first septal and diagonal branches) results in involvement of the basal portion of the left ventricle, anterior and lateral walls, and interventricular septum. 2, 3
• Mid-LAD occlusion (between first septal and first diagonal) spares the basal interventricular septum. 2, 3
• Distal LAD occlusion (below both first septal and diagonal branches) spares the basal left ventricle. 2, 3

Right Ventricular Contribution

• The LAD supplies the paraseptal part of the right ventricular anterior wall in addition to left ventricular territories. 4
• During LAD occlusion, the right ventricular anterior wall shows less functional impairment (hypokinesia) compared to the left ventricular anterior wall (dyskinesia) 4

Anatomical Variations Affecting Distribution

Apical Blood Supply Variations

• In 77.7% of patients, the LAD totally supplies the left ventricular apex. 5
• In 12.1% of cases, the apex receives dual blood supply from both LAD and posterior descending artery 5
• In 10.2% of cases, the LAD terminates before the apex, which is supplied entirely by the posterior descending artery 5

LAD Length and Coronary Dominance

• In left coronary dominance, the LAD wraps around the apex in 87% of cases, compared to only 47% in right coronary dominance. 6
• Long LADs (type C, wrapping around apex and supplying inferoapical segment) are more common in women regardless of coronary dominance 6
• Wrap-around LAD is a strong predictor of prognosis in anterior wall myocardial infarction, with significantly higher mortality compared to shorter LAD. 7

Clinical Implications

ECG Correlation

• Anterior wall ischemia/infarction is invariably due to LAD occlusion and results in ST elevation in leads V1 through V6. 2, 3
• Proximal LAD occlusion produces ST elevation in V1-V4, I, aVL, and often aVR, with reciprocal ST depression in II, III, aVF 2, 3

Imaging Considerations

• The LAD is the preferred target vessel for coronary vasomotor testing, reflecting its subtended myocardial mass and coronary dominance. 8
• Typical sites of coronary aneurysms in Kawasaki disease include the proximal LAD as the most frequent location 9