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.