MRI Versus 3D Echocardiography in Postinterventional Patients With Hypertrophic Obstructive Cardiomyopathy

To the Editor:The article by Schulz-Menger et al 1 describes the value of MRI for evaluation of the left ventricular outflow tract (LVOT) after septal artery embolization in patients with hypertrophic obstructive cardiomyopathy (HOCM). The concept of using imaging techniques for follow-up after therapeutic intervention in HOCM patients is not new and has been investigated previously using 2D2 as well as 3D echocardiography.3,4 Because MRI for analysis of LVOT area changes differs substantially from echocardiography, we would like to add some further comments.The method applied by Schulz-Menger et al is an indirect visualization of the residual LVOT area, measuring the smallest cross-sectional area of the turbulent flow (“vena contracta”) at only 1 preselected timepoint of the cardiac cycle. The vena contracta is known to underestimate the true anatomic orifice area …