Named Echocardiographic Signs in Pulmonary Embolism

When assessing a hemodynamically unstable patient for suspected acute pulmonary embolism (PE) — particularly when CTPA is precluded — identifying acute right heart strain is critical. The right ventricle (RV) adapts poorly to acute increases in afterload, yielding several classic, named echocardiographic signs that help differentiate acute cor pulmonale from chronic right-sided pathologies. Here are the primary named signs to look for:

McConnell’s Sign

Perhaps the most famous echo finding in PE, McConnell’s sign refers to a distinct regional wall motion abnormality: akinesia or severe hypokinesia of the RV mid-free wall with preserved (or hyperdynamic) contraction of the RV apex.

The pathophysiology is likely multifactorial. The RV apex is anatomically tethered to the left ventricle (LV), which is often hyperkinetic due to tachycardia, pulling the RV apex along for a proxy contraction. Additionally, the sudden pressure load increases wall stress on the mid-RV, causing relative ischemia, while the apex remains adequately perfused by the left anterior descending artery.

While highly specific for acute PE, its sensitivity is low (~20%), and it can occasionally be seen in right ventricular infarction.

The 60/60 Sign

The 60/60 sign is highly specific (up to 94%) for acute PE and is excellent for differentiating acute RV strain from chronic pulmonary hypertension (PH).

It requires the presence of both of the following parameters:

1. Tricuspid Regurgitation (TR) pressure gradient ≤ 60 mmHg. (Note: This is the gradient, not the estimated RVSP).
2. Pulmonary Artery Acceleration Time (PAAT) ≤ 60 ms.

Because the non-hypertrophied RV cannot generate extreme pressures acutely, a TR gradient > 60 mmHg typically points toward chronic PH. A shortened PAAT indicates rapid peaking of flow due to the acutely elevated pulmonary vascular resistance.

The “D” Sign (Septal Flattening)

The “D” sign is visualized in the parasternal short-axis view at the mid-papillary level. It refers to the flattening of the interventricular septum, which pushes into the LV cavity, giving the left ventricle a “D” shape rather than its normal circular appearance.

Timing in the cardiac cycle matters:

• Systolic flattening: Suggests RV pressure overload.
• Diastolic flattening: Suggests RV volume overload.
• Both systole and diastole: If severe tricuspid regurgitation is there along with pulmonary hypertension, there will be pressure and volume overload of right ventricle, resulting in septal flattening in both systole and diastole.

Early Systolic Notching (ESN)

Obtained by placing the pulse wave (PW) Doppler gate just proximal to the pulmonary valve in the RV outflow tract, ESN presents as a distinct “W-shaped” or asymmetrical notch in the spectral Doppler envelope.

This notch represents a brief mid-systolic deceleration of flow. When the RV ejects blood into an acutely occluded, high-resistance pulmonary arterial bed, a strong reflected pressure wave travels backward, prematurely decelerating forward flow before it recovers. ESN is highly specific for severe, proximally located PE.

Clinical Summary

Sign	Key Finding	Primary Clinical Utility
McConnell’s	Mid-free wall akinesia + apical sparing	High specificity for acute PE vs. global RV failure
60/60	TR gradient ≤ 60 mmHg + PAAT ≤ 60 ms	Differentiates acute cor pulmonale from chronic PH
“D” Sign	Septal flattening (systole/diastole)	Confirms severe RV pressure/volume overload
ESN	W-notch in RVOT PW Doppler	Suggests high-risk, proximal clot burden