Emergency physicians in Cambridge and Ipswich in the UK prospectively documented their echo use in cardiac arrest. Images were easily acquired, were quickly obtained, and influenced management. In keeping with previous studies, absence of ventricular wall motion predicted lack of return of spontaneous circulation, with a negative predictive value of 97%. An evaluation of echo in life support (ELS): is it feasible? What does it add? Emerg Med J. 2010 Oct 4. [Epub ahead of print]
In acute pulmonary embolism, a well-recognised pattern of right ventricular wall motion reported by McConnell is characterised by normal RV apex (RVa) contractility with akinesia of the RV free wall. A study using an echo techique called longitudinal velocity vector imaging (VVI) was conducted to describe RVa mechanics in relation to the rest of the RV in patients with a proven acute PE (aPE) and to compare these results to healthy volunteers and to patients with known chronic pulmonary hypertension (cPH). There were no significant differences in segmental strain patterns between the aPE and cPH groups. The authors suggest that McConnell’s sign is probably a visual illusion; preserved RVa contractility might be due to tethering of the RVa to a hyperdynamic left ventricle in the presence of an acutely dilated RV and this is the most likely explanation of the regional pattern of RV dysfunction seen in aPE patients.
Video describing McConnell’s sign from YouTube:
Academic Emergency Medicine has a free article on sonographic detection of submassive pumonary embolism, with three video clips.
One of the videos shows a nice demonstration of the McConnell sign (RV mid-segment dilation with apical sparing), which has been reported to be specific for (sub)massive PE. According to this article however, it has been reported that the McConnell sign is present in two thirds of patients with RV infarction and is only 33% specific for PE. Continuous wave Doppler helps differentiate RV infarction from submassive PE by demonstrating an increased tricuspid regurgitation RA-RV pressure gradient in submassive PE and a normal or low gradient in RV infarction.
The full article is available here
Three diagnostic tests for acute left ventricular heart failure in dyspnoeic patients were compared, with the gold standard being the diagnosis by three independent reviewers (two cardiologists and one respiratory physician) who were blinded to the results of the tests being examined. The tests in question were NT-proBNP, the Boston criteria, and limited echo performed by emergency physicians.
The primary goal of the echo study was the detection of the following echocardiographic variables, expressed as present or absent: reduced LV ejection fraction (LV ejection fraction <50% on subjective visual estimation of the change in LV size between diastole and systole) and the ‘‘restrictive’’ pattern on pulsed Doppler analysis of mitral inflow (using the apical view).
According to the authors, pulsed Doppler analysis of mitral inflow can be described by three patterns: 1) an ‘‘impaired relaxation’’ pattern, suggesting no increase in LV filling pressures; 2) a ‘‘normal’’ or ‘‘normalized’’ pattern; and 3) a restrictive pattern, suggesting an increase in LV filling pressures.
Trained emergency physicians were able to perform EDecho in a median of 4 minutes, obtaining Doppler data in an average of 80% of patients presenting for acute dyspnea. Considering the 125 patients with both EDecho variables available, reduced LV ejection fraction was less accurate than the restrictive mitral pattern for the diagnosis of aLVHF. The restrictive pattern was more sensitive (82%) and specific (90%) than reduced LV ejection fraction and more specific than the Boston criteria and NT-proBNP for the diagnosis of aLVHF. The accuracy of the restrictive pattern in the overall population was 75%, compared with accuracy of 49% for both NT-proBNP and Boston criteria. Diagnostic accuracy of emergency Doppler echocardiography for identification of acute left ventricular heart failure in patients with acute dyspnea: comparison with Boston criteria and N-terminal prohormone brain natriuretic peptide. Acad Emerg Med. 2010 Jan;17(1):18-26