McConnell’s sign unveiled

Summary McConnell’s sign is well described in echocardiography as a harbinger of severe RV failure and more extensive arterial thrombus burden but its mechanical basis has never been satifactorily defined despite multiple current theories. CMR RF tissue-tagging now unveils the mechanism. Background Evidence of echocardiographic RV ‘strain’ in the setting of a large, clinically important, often devasting pulmonary embolism (PE) is defined by the presence of paradoxical, often hyperdynamic RV apical contraction in the setting of severely dysfunctional RV function; so denoted ‘McConnell’ ss ign’. Despite its original observation by its namesake in 1996, it has neither been observed via CMR nor more importantly, while many theories exist, mechanistically explained. Hypothesis We hypothesize that McConnell’s sign (MS) is observable utilizing CMR and can be explained via CMR deformational analysis. Methods Modestly stable patients who had CT confirmed large (>one pulmonary branch obstruction and/or saddle PE) were evaluated via echocardiography and CMR. CMR radio-frequency tissue tagging was performed to determine midwall intramyocardial deformation patterns with superimposition of quiver plot technique to define direction and amplitude of myocardial displacements assuming homogenous tissue strain (%S). Results