Introduction to RWMA

Preamble

Let's be aware that to conclude on an ARC, we need excellent ETT images. We should not attempt to interpret suboptimal clips in order to remain as specific as possible in our conclusions in the emergency room . We do not need to have the sensitivity of the comprehensive ETTs of cardiology.

That being said, you are proof that we can indeed draw conclusions and evaluate them in an emergency! Thank you again for your studies.

Before we begin, I refer you to two resources:

· QUIZ format ''where's the lesion'' (be careful, each clip can take a long time to load): https://echo.anesthesia.med.utah.edu/wheres-the-lesion/

· 4-minute presentation covering the main concepts of ARCs in the emergency room: https://www.coreultrasound.com/5ms_rwma/

Below you will find:

The nomenclature of the walls in the 3 main views (PSL, PSC, apical 4)
The most common coronary vascularization (there is great anatomical variability)
Introduction to ARCs
A little quiz

Nomenclature of walls

Coronary anatomy
(the most frequent)

Introduction to RWMA

What is a WMA (Wall Motion Abnormality)?

A regional wall motion abnormality (RWMA) is an abnormality of contractility that occurs due to coronary artery involvement.
In other words, any condition that causes coronary hypoperfusion will lead to a WMA.
Each coronary artery supplies a specific region of myocardium (see image above).
Therefore, hypoperfusion of that artery will cause dysfunction of the ischemic myocardium in its territory — and this happens very early!
This myocardial dysfunction is mainly reflected by a reduction in wall thickening.
⚠️ Important: The myocardial thickening is the key element!
- Don’t fall into the trap of evaluating only wall movement — sometimes, apparent movement is simply caused by the surrounding normal myocardium compensating for the affected region.

Wall thickening is:

Normal if > 30%
Hypokinetic if 10–30%
Absent (akinetic) if < 10%

Therefore, each wall must be evaluated, ideally in more than one view, to confirm your findings.

Parasternal Short-Axis (PSAX) View:

Allows visualization of all the walls, but only over a small segment.
The PSAX view helps quickly identify major RWMAs (those involving several walls).
It’s a good screening view, but beware of being falsely reassured — if only one wall is affected, it can be very difficult to detect on PSAX.

For example:

A lateral wall abnormality will be obvious in the apical 4-chamber (A4) view but easily missed on PSAX.
Similarly, an anteroseptal wall abnormality will be easily seen in the parasternal long-axis (PLAX) view but can be missed if isolated in PSAX.

👉 In short: Always examine each wall in at least two views whenever possible!

Limitations:

It’s impossible to distinguish acute from chronic abnormalities — review a prior echocardiogram (TTE) if available.
Our primary goal is to detect acute ischemic changes with significant cardiac dysfunction — mainly areas with absent thickening in one or more walls.
We must accept that we may miss very focal abnormalities or those with only partial reduction in thickening.

In the emergency setting, the “regional” aspect is key.

Without advanced expertise, it’s difficult to differentiate between multiple regional abnormalities and diffuse disease.

➡️ So, whenever findings are diffuse, atypical, minor, or uncertain, it’s best to refrain from calling it a WMA — this helps preserve our specificity.

We don’t have 45 minutes, we rarely can position patients in the left lateral decubitus (LLD), and we often lack high-end machines…

Therefore, once again, it’s essential to have the humility to recognize when our images are inconclusive for WMA —
which does not prevent us from being conclusive for other parameters such as LVEF, RV function, pericardial effusion, or valve assessment.

Example of thickening

1) Focus on the anterior wall --> Normal thickening

2) Focus on the inferior and inferolateral walls --> Absence of thickening

Example of thickening

1) Focus on the basal wall of the septal --> Normal thickening

2) Focus on the apical wall --> No thickening

Quiz

The answers pinpointing the exact locations of the RWMAs are in the following section

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Case #1

40-year-old man, presenting with poorly defined malaise and diaphoresis that persisted throughout the night, 48 hours ago.

ECG: T-wave inversion in the anterolateral leads.

Clip 1: RWMA at the septal and apical levels, suggesting a lesion of the LAD (Left Anterior Descending artery).
Clip 2: Short-axis view showing an RWMA of the anterior wall, also suggesting involvement of the LAD.
The lesion was later confirmed by coronary angiography and treated with a stent.

Case #2

49-year-old man presenting as an outpatient with pain similar to his gallstone episodes.
Abdominal ultrasound and hepato-pancreatic workup were normal.

ECG repeated every 30 minutes ×2 showed suspicious ST elevation in the septal/anterior leads, along with the presence of Q waves. No recent comparison available.

Point-of-care ultrasound (POCUS) demonstrated an RWMA in the LAD territory (PLAX and A4 views).
The patient was immediately transferred to the cath lab, where the causal LAD lesion was confirmed.
Troponins later returned at 6500.

Case #3

64-year-old man. Return of spontaneous circulation (ROSC) after cardiac arrest (VF/VT).

Transesophageal echocardiogram (TEE) performed by the emergency physician showed an inferior wall RWMA.
The cardiologist decided to bring the patient directly to coronary angiography.
Unfortunately, the patient did not survive and never made it to the cath lab.

Case #4

68-year-old man. Intermittent fever for one year and shortness of breath.
History of chest pain while shoveling snow two months ago.
Troponin: 600. BNP: markedly elevated.
Chest X-ray: findings consistent with volume overload.
ECG: no acute ischemic changes.

POCUS: identified akinesia of the septal and anterior walls and hypokinesia of the inferior and inferolateral walls, suggesting three-vessel coronary disease.
Formal echocardiogram performed 48 hours later confirmed the findings.
The patient was hospitalized pending further investigations.