超音波診斷肺栓塞：McConnell sign

McConnell's sign is a distinct echocardiographic finding described in patients with acute PE. There is a distinct regional pattern of right ventricular dysfunction, with akinesia of the mid free wall but normal motion at the apex.

Three mechanisms have been proposed that may explain these findings.

• First, in acute PE, the tethering of the right ventricular apex to a contracting and often hyperdynamic left ventricle may account for the preserved wall motion at the apex.
• Second, the right ventricle may be assuming a more spherical shape to equalize regional wall stress when subjected to an abrupt increase in afterload.Third, there may be localized ischemia of the right ventricular free wall as a result of increased wall stress.
  

Another case of submassive PE:


Overall, echocardiography has a low sensitivity for diagnosing PE; however, the accuracy is much higher in the diagnosis of massive PE.

Echocardiography may be useful in cases of massive PE in which a rapid presumptive diagnosis is required to justify the use of thrombolytic therapy. Regional wall motion abnormalities sparing the right ventricular apex (McConnell’s sign) are particularly suggestive of PE.

來源：
http://circ.ahajournals.org/cgi/content/full/118/15/e517