Right Ventricular Apical Contractility in Acute Pulmonary Embolism: The McConnell Sign Revisited

Background: The McConnell sign has been regarded as a highly specific echo finding in acute pulmonary embolism (aPE). However, a completely satisfying explanation to account for this observation in aPE remains elusive. We used longitudinal velocity vector imaging (VVI) using a dedicated software program (Research Arena, Siemens, California) to assess regional right ventricular global and apical (RVa) mechanics between aPE and chronic pulmonary hypertension (cPH) patients. Methods: Standard echo parameters of RV performance as well as base to apex RV strain and dyssynchrony were quantified using VVI in a total of 30 patients. The population studied was divided into three groups: Group I included 10 healthy volunteers (50 +/- 16 years), Group II consisted of 10 patients (47 +/- 13 years) with known cPH, and Group III comprised 10 patients (58 +/- 18 years; P = 0.323) with documented aPE. Results: Progressively lower indices of RV performance as well as RV basal and apical strain were recorded in Groups II and III, respectively. Most importantly, no difference in RVa segmental strain values was seen between Groups II and III. Conclusions: Based on this pilot data, aPE patients demonstrate a significant reduction in overall RV strain with a similar reduction in RV apical deformation. Therefore, regional RVa function is not truly spared in aPE and the probable visual illusion of preserved contractility might simply reflect tethering of the RVa to a hyperdynamic left ventricle in the presence of an acutely dilated RV. (Echocardiography 2010;27:614-620).