Saturday, April 21, 2012

McConnell's Sign and acute PE

This week’s image is brought to us by Dr.Deepa Patel, who was able to make the bedside diagnosis of pulmonary embolus using ultrasound. The first image is a parasternal long axis view with evidence of enlarged RV. This is not the best view to assess chamber size, but even here we can begin to see that there is something abnormal. 
On the apical-four-chamber view we can compare the RV and the LV side by side. We consider an RV:LV ratio of >1:1 to be abnormal.  Here we can see that the RV is larger than the LV.  
 Large PEs that cause right heart strain will enlarge the RV, but so can several other chronic processes like pulmonary HTN. This patient had an additional finding called a “McConnell’s sign” that can be used to distinguish acute right heart strain from a PE from other chonic causes of right heart enlargement. Patients with PE can have distinct regional wall motion abnormalities of the RV.  In acute PE  there is no movement of the Mid RV, but preserved motion of the apex.  This finding, called McConnell’s sign is 77% sensitive and 94% specific for PE.  On the video below, pay close attention to the apex- you can seen that is moving while the rest of the RV does not.