4. Cardiac Ultrasound (Echo) Pathology

Pulmonary Embolism

A Pulmonary Embolism is a blood clot that has dislodged from a distal site which has lodged into one of the pulmonary arteries. Predominantly the clot originates from a deep vein thrombosis (DVT) in the lower extremities where it will travel in the venous circulation, enters the right side of the heart, and eventually into the pulmonary arteries. Learn how to perform DVT Ultrasound here.

Considering the rapid onset/timing of a Pulmonary embolism, patients typically show symptoms or complain of chest pain, shortness of breath, cough, hemoptysis, or even syncope. Risk factors include cancer, oral contraceptive (OCP) or hormone replacement therapy (HRT), immobility, and recent travel.

Here are the different types of pulmonary embolism you may encounter:

  • Submassive Embolism– Submassive (or intermediate-risk) PE refers to those patients with acute PE without systemic hypotension but with evidence of either right ventricle (RV) dysfunction or myocardial necrosis. RV dysfunction is characterized by RV dilation, hypokinesis, or elevation of brain natriuretic peptide (BNP); myocardial necrosis is suggested by elevated troponin. There is evidence that these patients may possibly benefit from “half dose” thrombolytic therapy.
  • Massive Pulmonary Embolism-Massive (or high-risk) PE is a term used to designate patients with right ventricular dysfunction and sustained hypotension (systolic blood pressure <90 mmHg for at least 15 minutes or requiring inotropic support, not due to a cause other than PE). These patients may benefit from thrombolytic therapy.
  • Saddle Embolism-A Saddle is a large pulmonary embolism that straddles the bifurcation of the pulmonary trunk, extending into both the left and right pulmonary arteries. Although it only occurs in about 2-5% of all pulmonary embolism, Saddle Embolisms can completely obstruct both left and right pulmonary arteries resulting in right heart failure and, unless treatment is prompt, death.

Bedside echo is extremely valuable in risk stratifying patients with pulmonary embolism to see if they may benefit from anticoagulation or thrombolytic therapy.

Ultrasound findings of Pulmonary Embolism:

The most definitive way to diagnose a pulmonary embolism is to directly visualize the clot either in the pulmonary artery itself or as a clot in transit.

Massive Submassive Pulmonary Embolism with Mobile Clot and McConnell's Sign cardiac ultrasound echocardiography echo
Direct Visualization of Mobile Clot in the Right Atrium – Apical 4 Chamber view

Unfortunately directly visualizing a clot in the heart or pulmonary artery is a rare finding. Most of the echocardiography findings for pulmonary embolism are “indirect signs” that evaluate for the dysfunction of the right ventricle from a significant clot burden. Usually, this is seen as an enlarged right ventricle.

The two most common and easy to recognize signs to look for right ventricular dysfunction on echo are the “D Sign” and McConnell’s sign.

The “D Sign” on Echocardiography

  • The “D Sign” is an ultrasound/echo finding that shows the left ventricle as a D-shaped structure. It is a result of right ventricular strain causing a shift of the septum towards the left side of the heart.
RV Pressure Overload D Sign
Right Ventricular Strain – D Sign

McConnell’s Sign” on Echocardiography

  • McConnell’s sign is where there is akinesia of the right ventricular lateral wall with hyperdynamic appearance of the right ventricular apical wall.
McConnell's Sign - Book
RV Strain with McConnell’s Sign

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