Merlon sign and square root sign in endomyocardial fibrosis

Merlon sign and square root sign in endomyocardial fibrosis

Merlon sign in endomyocardial fibrosis is characterized by a hypercontractile basal ventricle opposing an obliterated apex which is hypokinetic or akinetic. There is a diastolic bulge of the interventricular septum into the left ventricle [1].

Square root sign is seen on M-mode echocardiography in the septum and posterior wall [2]. The finding is noted on M-mode slices through the mid ventricle in diastole.

Reference

1. C S Berensztein, D Piñeiro, M Marcotegui, R Brunoldi, M V Blanco, J Lerman. Usefulness of echocardiography and doppler echocardiography in endomyocardial fibrosis. J Am Soc Echocardiogr. 2000 May;13(5):385-92.
2. Brener MI, Ravalli S. Left Ventricular Cavity Obliteration From Eosinophilic Myocarditis in a Patient With Classic Hodgkin Lymphoma. JACC Case Rep. 2020 Sep; 2(2): 210-215.