McConnell sign in Pulmonary Embolism: Mechanism

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McConnell sign in Pulmonary Embolism: Mechanism

McConnell sign is hypokinesia of right ventricular free wall noted on echocardiography with sparing of the apex, seen in acute pulmonary embolism.1

Three mechanisms proposed for the McConnell sign are [2]:

  1. Tethering of the right ventricular apex to the left ventricle which is hyperdynamic
  2. Abrupt increase in afterload causing the right ventricle to assume a more spherical shape to equalize regional wall stress
  3. Localized ischemia of right ventricular free wall due to elevated wall stress

Echocardiography has low sensitivity for the diagnosis of pulmonary embolism. But accuracy is higher for the diagnosis of massive pulmonary embolism, especially when decision regarding early thrombolysis has to be taken at the bedside. Of course, the gold standard now for the diagnosis of pulmonary embolism is computed tomographic pulmonary angiography. But since it is not available at the bedside, it may be difficult to obtain in person who is very sick and hypotensive due to massive pulmonary embolism. In such situations, if McConnell sign is present, it may add more value for the presumptive diagnosis of pulmonary embolism prior to thrombolytic therapy which has potential bleeding risks.

Reference

  1. McConnell MV, Solomon SD, Rayan ME, Come PC, Goldhaber SZ, Lee RT. Regional right ventricular dysfunction detected by echocardiography in acute pulmonary embolism. Am J Cardiol. 1996; 78: 469-473.
  2. Sosland RP, Gupta K. Images in cardiovascular medicine: McConnell’s Sign. Circulation. 2008 Oct 7;118(15):e517-8.