Coronary Artery Territories in the 17-Segment Echocardiography Model
The 17-segment left ventricular (LV) model, standardized by the American Heart Association, is the cornerstone for regional wall motion analysis on echocardiography. Mapping each segment to its usual coronary artery supply helps localize ischemia and infarction accurately.
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The 17-Segment LV Model: Overview
The LV is divided into 3 levels + apex:
Basal level (6 segments)
Mid-cavity level (6 segments)
Apical level (4 segments)
True apex (1 segment)
Segments are named by level + wall (e.g., basal inferior, mid anteroseptal).
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Coronary Artery Territories
1. Left Anterior Descending (LAD) Artery
Supplies the anterior wall, septum, and apex.
Segments typically supplied by LAD
Basal anterior
Basal anteroseptal
Mid anterior
Mid anteroseptal
Apical anterior
Apical septal
Apical cap (segment 17)
Clinical correlation
LAD ischemia → anterior/septal wall motion abnormality
Proximal LAD occlusion → extensive dysfunction including the apex
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2. Left Circumflex (LCX) Artery
Supplies the lateral (posterolateral) wall.
Segments typically supplied by LCX
Basal anterolateral
Basal inferolateral
Mid anterolateral
Mid inferolateral
Apical lateral
Clinical correlation
LCX ischemia → lateral wall hypokinesia
Often subtle on ECG; echo is especially valuable
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3. Right Coronary Artery (RCA)
Supplies the inferior wall and often the inferoseptum (right-dominant circulation).
Segments typically supplied by RCA
Basal inferior
Basal inferoseptal
Mid inferior
Mid inferoseptal
Clinical correlation
RCA ischemia → inferior wall motion abnormality
Associated RV involvement may coexist
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Segment-Wise Coronary Distribution (Summary Table)
LV Segment Typical Coronary Supply
Basal anterior LAD
Basal anteroseptal LAD
Basal inferoseptal RCA
Basal inferior RCA
Basal inferolateral LCX
Basal anterolateral LCX
Mid anterior LAD
Mid anteroseptal LAD
Mid inferoseptal RCA
Mid inferior RCA
Mid inferolateral LCX
Mid anterolateral LCX
Apical anterior LAD
Apical septal LAD
Apical inferior RCA / LAD (variable)
Apical lateral LCX
Apical cap (17) LAD
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Important Practical Points
Coronary dominance matters
In left-dominant systems, LCX may supply inferior segments.
Overlap exists
Apical inferior and inferolateral segments can have mixed supply.
Wall motion abnormalities ≠ single-vessel disease always
Multivessel ischemia, prior infarction, or cardiomyopathy can mimic patterns.
Stress echo interpretation relies heavily on this mapping
New or worsening regional dysfunction localizes culprit vessels.
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Clinical Utility in Echocardiography
Localizes ischemia and infarction
Guides coronary angiography planning
Assesses viability and scar distribution
Standardizes reporting across imaging modalities
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Key Takeaway
The 17-segment echo model, when combined with coronary territory mapping, transforms regional wall motion assessment into a powerful diagnostic and prognostic tool. Understanding LAD, LCX, and RCA distributions is essential for accurate echo interpretation in ischemic heart disease.
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