BloodSweatxED
PRN Education · No. 003 · POCUS Series

Echo for
Pulmonary Embolism.

Echo almost never shows you the clot. It shows you what the clot is doing to the right ventricle — and in the hypotensive patient, that indirect evidence is exactly what changes management.

Every finding on this page is a sign of RV strain, not of PE itself. Hold that thought the whole way down.

Source

Curated from POCUS 101's Right Ventricular Ultrasound: Qualitative and Quantitative Assessments and The D Sign. Their clips of McConnell's and the D-sign are worth ten paragraphs — watch them.

When to scan

And when not to trust it

Echo earns its keep

  • Undifferentiated shock or hypotension — is the RV the problem?
  • Suspected massive/submassive PE too unstable for CT
  • Peri-arrest or arrest: supporting the thrombolysis decision
  • Risk-stratifying a confirmed PE (strain = sicker)
  • Paired with a DVT scan: strain + DVT in a suspected PE is effectively diagnostic

Echo cannot do this

  • Rule out PE. Small and even submassive PEs routinely have a stone-normal echo. Sensitivity is poor by design — the test detects strain, not clot.
  • Replace CTPA in the stable patient. It doesn't.
  • Distinguish acute from chronic strain by itself — see the free wall thickness pearl below.

Setup

Same views as a standard TTE

Probe

Phased array

Cardiac preset, indicator on the right of the screen. New to the views? Start with TTE Basics (No. 006).

Key views

PSAX + A4C

Parasternal short axis at the papillary muscles for the D-sign; apical 4-chamber for RV:LV, McConnell's, and TAPSE. Add subcostal and IVC.

Position

LLD helps

Left lateral decubitus brings the apex to the probe for the apical views — the ones this exam lives on.

The signs, in order

From eyeball to caliper
PSAX · PAPILLARY LEVEL LV RV NORMAL · LV IS A CIRCLE LV RV PRESSURE OVERLOAD · FLAT SEPTUM, LV IS A "D" flattened septum
Fig. 1 — The D-sign. The dilated, pressurized RV flattens the septum and deforms the LV cross-section.

RV : LV ratio

Apical 4-chamber · compare end-diastolic chamber widths

Normal RV is about 60% of the LV (ratio ~0.6:1). When the RV appears equal to or larger than the LV, that's significant enlargement — in the right clinical picture, presumed pressure overload.

Eyeball rule: if the RV is winning the A4C real-estate contest, it's abnormal. You don't need calipers to call an RV bigger than the LV.

The D-sign

Parasternal short axis · papillary muscle level

The LV should be a circle with the septum bowing into the RV. Under RV pressure overload the septum flattens and pushes leftward, turning the LV into a "D."

  • Septal flattening in systole (or throughout) → pressure overload — the PE pattern
  • Flattening only in diastole → volume overload

McConnell's sign

Apical 4-chamber · watch the RV free wall vs. the apex

RV free wall akinesis or hypokinesis with preserved or hyperdynamic apical contraction — the apex keeps beating because it's tethered to the LV. Reported at roughly 77% sensitivity and 94% specificity for acute PE in the strained-RV population.

What it buys you: of all the strain signs, McConnell's points most specifically toward acute PE rather than chronic pulmonary hypertension.

TAPSE

Apical 4-chamber · M-mode through the lateral tricuspid annulus

Tricuspid Annular Plane Systolic Excursion quantifies how far the RV base descends in systole — a one-number proxy for RV systolic function. Normal ≥17 mm; below that is RV systolic dysfunction, and lower is worse.

The supporting cast

IVC · subcostal · the lucky shot

  • Plethoric IVC (>2.1 cm, <50% collapse): the RV is backing up into the tank
  • Clot in transit: mobile serpentine echodensity in the RA/RV — rare, essentially pathognomonic, and an emergency
  • 60/60 sign: pulmonary acceleration time <60 ms with TR gradient <60 mmHg favors acute over chronic — advanced, not required

Calling it

Numbers that matter
FindingThreshold / lookMeans
RV:LV ratio≥ 1:1RV enlargement — strain in the right context
D-sign (systolic)flat septum, PSAXRV pressure overload
McConnell'sfree wall out, apex workingMost specific bedside pattern for acute PE (~77% sens / ~94% spec)
TAPSE< 17 mmRV systolic dysfunction; prognostic in PE
RV free wall> 5 mm thickHypertrophy — the strain is probably chronic, not this morning's PE
Clot in transitseenTreat as confirmed PE with the cavalry on the phone

In the hypotensive patient with clinical suspicion, RV strain moves you toward action. In the well-appearing patient, a normal echo moves you nowhere — order the CTPA you were always going to order.

Pearls & pitfalls

Where this scan goes wrong
Pitfall

"Normal echo, PE ruled out"

The most dangerous sentence in this exam. Echo detects RV consequences, not clot. A normal RV is entirely consistent with a PE that still needs anticoagulation.

Pitfall

Foreshortened A4C

An off-axis apical view slices the RV obliquely and manufactures a big RV. Get the true apex — maximal LV length, no rocking — before you believe any ratio.

Pearl

Check the free wall thickness

An acutely strained RV is a thin-walled RV. A free wall over ~5 mm has been lifting weights for months — think chronic pulmonary hypertension and interpret "strain" accordingly.

Pearl

Add the legs

In a suspected PE, a positive compression DVT exam plus RV strain is effectively diagnostic — and the DVT scan takes five minutes. The combination is stronger than either alone.

Pitfall

Strain has a differential

RV infarct, ARDS, high PEEP, and chronic pulmonary hypertension all strain the RV. The echo finding is real; the attribution to PE is a clinical call.

Pearl

In arrest, look fast

A massively dilated RV during a pulse check in the right story supports empiric thrombolysis. Keep the look under ten seconds — the compressions matter more than the image.

Sample Epic documentation

Copy · edit · attest

A starting template for the POCUS note. Text in brackets [ ] and pick-lists in { } are fields to complete. Save it as a SmartPhrase, then edit every field to match the actual study.

.pocusRVecho
POINT-OF-CARE ULTRASOUND: FOCUSED ECHO - RV / PE

Indication: {suspected PE : shock : dyspnea} [***]
Exam type: Focused / limited, bedside
Operator: @ME@   Interpretation: independent, real-time
Probe: phased array

FINDINGS
- RV:LV size: {normal <1 : RV >= LV}
- Septal flattening (D-sign): {absent : present}
- McConnell's sign: {absent : present}
- TAPSE: {>= 17 mm : *** mm (reduced)}
- IVC: {normal collapse : plethoric}
- Pericardial effusion: {none : present}

IMAGE QUALITY: adequate / limited by [***]
Images saved and archived to [PACS / Qpath / ***].

IMPRESSION: {no echo signs of RV strain : echo findings of RV strain
consistent with acute cor pulmonale}. A normal focused echo does not
exclude PE. [***]

I personally performed and interpreted this study.
Electronically signed: @ME@  @TD@ @NOW@

Sample template only — not a validated institutional SmartPhrase. Verify wording, image-archival, and attestation requirements against your department's POCUS credentialing, coding, and compliance policies before clinical use. Documentation supports, but does not replace, the medical record and QA workflow.

PRN Education · POCUS Series

Keep scanning