Coronary Artery Territories in the 17-Segment Echocardiography Model

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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