EchoBridgeMD Pearl #4: Understanding the Pathophysiology of McConnell's Sign

Originally described in 1996, McConnell's sign is an additional adjunct finding that can further raise suspicion for acute pulmonary embolism in the appropriate clinical setting.

It is characterized by diffuse hypokinesis of the right ventricular (RV) free wall with preserved contraction of the RV apex.

Several mechanisms have been proposed to explain this finding:

1) Mechanical tethering of the RV apex to the hyperdynamic left ventricle

2) Acute changes in RV geometry that preferentially affect the mid-RV free wall

3) Localized ischemia of the right coronary artery perfusing the acutely pressure-overloaded RV free wall (vs. the RV apex, which is also perfused by the left anterior descending artery).

Understanding the physiology behind McConnell's sign helps explain why it is more commonly associated with acute RV pressure overload than with chronic pulmonary hypertension.

References:

📖 McConnell MV, et al. Regional right ventricular dysfunction detected by echocardiography in acute pulmonary embolism. Am J Cardiol. 1996. https://pubmed.ncbi.nlm.nih.gov/8752195/

📖 Alerhand S, Sundaram T, Gottlieb M. What are the echocardiographic findings of acute right ventricular strain that suggest pulmonary embolism? Anaesth Crit Care Pain Med. 2021.

https://pubmed.ncbi.nlm.nih.gov/33781986/

📖 Alerhand S, Adrian RJ. What echocardiographic findings differentiate acute pulmonary embolism and chronic pulmonary hypertension? Am J Emerg Med. 2023. https://pubmed.ncbi.nlm.nih.gov/37499553/

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